Twenty-year temporal trends, risk profiles, and prognostic value of clinicopathological features in gallbladder cancer following cholecystectomy

Abstract

BACKGROUND

Gallbladder cancer (GBC) is a rare but highly aggressive malignancy often diagnosed at an advanced stage. Owing to its relatively low incidence, the clinicopathologic features of GBC and its precursor lesions remain poorly understood and insufficiently explored.

AIM

To examine temporal trends and clinicopathological features in post-cholecystectomy GBC to identify risks profiles and prognostic value.

METHODS

In this retrospective study, 15785 patients who underwent cholecystectomy over a 20-year period at a single center were reviewed, among whom 285 were diagnosed with GBC. Clinicopathological features were compared among patients with benign conditions, precursor lesions, and GBC. Long-term temporal trends (2004-2023) were analyzed alongside clinicopathological characteristics and survival outcomes.

RESULTS

GBC cases increased over time (P = 0.002). Compared to benign or precancerous conditions, GBC patients were older (P = 0.000) and had higher hypertension and cholangitis rates (both P = 0.000). Total cholesterol, triglycerides, and albumin were lowest in GBC (P = 0.000, P = 0.010, P = 0.000), with higher levels linked to better survival (P = 0.003, P = 0.026, P = 0.016), and tumor budding, size, and poorly cohesive or undifferentiated components correlated with advanced stage and poorer prognosis (P = 0.015, P = 0.002, P = 0.002) on univariate analysis. Age, metabolic parameters, and inflammatory conditions influenced both GBC risk and prognosis.

CONCLUSION

The clinicopathologic characteristics of GBC highlight the value of recognizing high-risk profiles and underscore the prognostic significance of detailed histopathological evaluation.

Key Words: Gallbladder cancer; Cholecystectomy; Risk factors; Time factors; Prognosis

Core Tip: This study examined temporal trends, clinicopathological features, and survival outcomes in post-cholecystectomy gallbladder cancer to identify risk factors for early detection and management. In this single-institutional study, our findings may be limited but still provide insights. Age, hypertension, cholangitis, and serological markers including total cholesterol, triglyceride, albumin were risk factors for cancer and related to survival outcomes. Pathological features, such as tumor budding, tumor size, and poorly cohesive or undifferentiated components were correlated with worse prognosis. These findings emphasize the value of early identification of high-risk profiles and the prognostic markers of gallbladder cancer.

INTRODUCTION

Gallbladder cancer (GBC) is the most common malignancy of the biliary tract and the fifth most prevalent cancer of the gastrointestinal system[1]. The disease accounts for approximately 1.3% of all cancer cases and 1.7% of cancer-related deaths worldwide[2]. Due to its non-specific clinical presentation and lack of early symptoms, GBC is frequently diagnosed at an advanced stage and associated with poor prognosis. Many patients present with unresectable tumors at the time of diagnosis and have limited therapeutic options, particularly in terms of effective chemotherapy.

Globally, the incidence and mortality rates of GBC increased by 76% and 65%, respectively, between 1990 and 2017[3]. Notably, Asian countries, such as China, Japan, and South Korea, have reported relatively high incidence rates (≥ 2.3 cases per 100000 population)[4]. In particular, South Korea recorded the highest age-standardized mortality rate for GBC among both sexes, at 4.1 per 100000[5]. The highest incidence rates have been reported in Chile (27 cases per 100000) and northern India (21.5 cases per 100000), indicating a growing burden in both developing and developed regions. Conversely, the incidence of GBC has shown a declining trend in the United States[5].

The pathogenesis and etiology of GBC remain poorly understood and insufficiently explored, primarily due to the rarity of the disease. Moreover, GBC is frequently grouped with other biliary tract cancers, which complicates the identification of its distinct biological and clinical features[6]. GBC development is considered multifactorial, arising from a complex interplay of genetic, environmental, dietary, and pathological influences. Established clinical risk factors include sex, age, ethnic background, and chronic gallbladder inflammation[7]. In particular, chronic inflammation and degenerative changes associated with gallstones are known to contribute to carcinogenic processes within the gallbladder mucosa[8].

Similar to other epithelial malignancies, GBC is preceded by a well-defined series of precancerous changes. Pathologically, its progression typically follows metaplasia-dysplasia-carcinoma in situ-invasive carcinoma sequence over a period of 5 years to 15 years[9]. Once invasive cancer develops, the progression of GBC is often rapid and asymptomatic, contributing to its poor prognosis. Early detection of GBC remains challenging due to its asymptomatic nature in the early stages and the current lack of reliable diagnostic tools[10]. Despite its clinical significance, knowledge of GBC and its precursor lesions remains limited and their clinicopathological features are insufficiently described in the existing literature. The identification of key clinicopathological risk factors is therefore essential for improving detection and prevention strategies and identifying high-risk patients.

The aim of this study was to investigate long-term temporal trends in the incidence, clinicopathological features, and survival outcomes of patients who underwent cholecystectomy and were diagnosed with GBC postoperatively. To evaluate the impact of clinicopathological factors, we conducted a 20-year, single-center retrospective analysis of GBC cases with available survival data. Data from four distinct periods (2004-2008, 2009-2013, 2014-2018, and 2019-2023) were compared, with the aim of assessing whether temporal changes have influenced the clinicopathological characteristics of the disease and survival outcomes. In addition, we compared the clinicopathological profiles of patients diagnosed with benign gallbladder conditions, precursor lesions, and GBC to identify the key factors associated with malignant transformation and prognosis.

MATERIALS AND METHODS

Study design

This retrospective study included 15785 patients who underwent cholecystectomy at Chungnam National University Hospital in Daejeon, South Korea, between January 2004 and December 2023. Clinicopathological characteristics and survival data were obtained from medical records and pathology archives. The follow-up period ranged from 1 year to 21 years with survival assessed in December 2024. Collected data included sex, age, body mass index (BMI), hypertension (HTN), diabetes mellitus (DM), and history of gallstones and cholangitis. Serologic and laboratory parameters were additionally collected, including aspartate aminotransferase (AST, IU/L), alanine transaminase (ALT, U/L), alkaline phosphatase (ALP, U/L), gamma-glutamyl transferase (γ-GT, IU/L), total cholesterol (mg/dL), triglycerides (mg/dL), blood urea nitrogen (BUN, mg/dL), creatinine (mg/dL), total protein (g/dL), and amylase (U/L).

Pathological features were independently reviewed by two pathologists (Kim KH and Yeo MK), including the assessment of accompanying premalignant neoplasms, histologic differentiation, non-neoplastic changes, anaplastic differentiation (such as poorly cohesive carcinoma, signet ring cell carcinoma, squamous carcinoma, sarcomatous components, and undifferentiated components), depth of invasion, tumor size, and staging[11-13]. Cancer classification and stages were defined according to the classification system of World Health Organization, 5^th Edition and American Joint Committee on Cancer, 8^th edition[11,14]. Treatments were administered in accordance with the 2023 NCCN Guidelines for Biliary Tract Cancers[15]. Tumor budding was evaluated on hematoxylin and eosin-stained slides based on the criteria established by the International Tumor Budding Consensus Conference[16]. All tissue specimens were provided by the National Biobank of Korea at Chungnam National University Hospital, a member of the Korea Biobank Network. A flow chart of the experimental steps of our study is presented (Supplementary Figure 1).

Statistical analysis

Statistical analyses were performed using SPSS version 30.0 and Microsoft Excel 2021. A significance level of P < 0.05 was used. Categorical variables were analyzed using the χ² test and continuous variables compared using one-way analysis of variance (ANOVA). Kaplan-Meier survival analysis was employed to identify the pathological factors influencing survival. Additionally, logistic regression analysis was performed to compare the risk of clinical factors across the benign, precancerous, and GBC groups.

RESULTS

Temporal distribution of pathologic diagnoses in cholecystectomy cases over a 20-year period

Among cholecystectomy patients, 285 patients (1.81%) were diagnosed with GBC, 248 (1.57%) with precancerous lesions, and 15252 (96.62%) with benign conditions. For the benign group, a representative sample of 601 patients was randomly selected using the Excel ‘RAND()’ function, because there were an excessive number of benign patients compared to GBC and precancerous patients. Benign conditions included acute and chronic cholecystitis, cholelithiasis, cholesterolosis, and other non-neoplastic gallbladder diseases. Precancerous lesions comprised adenoma, biliary intraepithelial neoplasia (BilIN), intracholecystic papillary neoplasm (ICPN), and (adeno)carcinoma in situ. GBC cases were classified according to the World Health Organization classification system for gallbladder tumors, with adenocarcinoma identified as the prevalent histologic subtype.

Over the past two decades, the number of cholecystectomies has steadily increased (Figure 1 and Supplementary Table 1). The number of patients who underwent surgery in 2019-2023 was more than double that in 2004-2008. While the absolute number of benign cases increased in parallel with the overall surgical volume, their proportion remained relatively stable throughout the study duration. In contrast, the incidence of precancerous lesions peaked in 2009-2013, nearly doubling compared to 2004-2008, but declined in subsequent years, resulting in an overall decrease in proportion over time (P = 0.002). The number of GBC cases recorded during 2019-2023 was 2.8 times higher than that in 2004-2008. Although the proportion of GBC cases declined across the first three time-periods, a notable increase was observed in the most recent interval.

Figure 1  Five-year interval trends in pathologic diagnoses following cholecystectomy.

Comparison of clinical factors among benign, precancerous, and GBC groups

The clinical characteristics of patients with benign conditions, premalignant lesions, and GBC are summarized in Table 1. Patients with GBC were significantly older than those in the other groups (mean age: 69.1 years vs 56.0 years and 57.3 years, P < 0.001) and had a higher male-to-female ratio (P = 0.337). The prevalence of HTN and cholangitis was highest in the GBC group (50.18% and 24.91%, respectively; both P < 0.001), whereas gallstones were predominantly observed in the benign group (72.05%, P < 0.001). No significant differences in the prevalence of DM were observed among the groups (P = 0.224). Among the serologic markers, ALT, ALP, and total protein levels were significantly higher in the benign group (P = 0.007, P = 0.035, and P = 0.002, respectively). In contrast, total cholesterol, triglyceride, albumin, and amylase levels were lowest in the GBC group (P < 0.001, P = 0.010, P < 0.001, and P = 0.026, respectively). BUN levels were markedly elevated in GBC patients compared to the other groups (P = 0.008). No significant differences were observed in BMI, AST, or creatinine levels across the groups.

Table 1 Comparison of clinical factors among benign, precancerous, and gallbladder, cancer groups (n = 1134), n (%).

Clinical factors	Group			P value
	Benign (n = 601)	Precancer (n = 248)	GBC (n = 285)
Sex ratio (male/female)	0.89	0.85	1.08	0.337
Age (years)	56.03	57.26	69.10	0.000
BMI (kg/m2)	24.86	24.76	24.72	0.960
AST (IU/L)	36.24	33.16	33.18	0.544
ALT (U/L)	45.85	34.76	33.72	0.007
ALP (U/L)	96.60	84.68	96.52	0.035
γ-GT (IU/L)	119.10	77.12	111.29	0.050
Total cholesterol (mg/dL)	176.39	177.38	164.79	0.000
Triglyceride (mg/dL)	147.67	147.98	124.08	0.010
BUN (mg/dL)	13.67	13.97	15.01	0.008
Creatinine (mg/dL)	0.82	0.82	0.85	0.673
Total protein (g/dL)	6.98	6.95	6.82	0.002
Albumin (g/dL)	4.05	4.16	3.90	0.000
Amylase (U/L)	61.93	77.99	53.35	0.026
HTN	207 (34.44)	82 (33.06)	143 (50.18)	0.000
DM	116 (19.30)	41 (16.53)	64 (22.46)	0.224
Gallstone	433 (72.05)	74 (29.84)	83 (29.12)	0.000
Cholangitis	105 (17.47)	31 (12.50)	71 (24.91)	0.000

BMI: Body mass index; AST: Aspartate aminotransferase; ALT: Alanine transaminase; ALP: Alkaline phosphatase; γ-GT: Gamma-glutamyl transferase; BUN: Blood urea nitrogen; HTN: Hypertension; DM: Diabetes mellitus.

Clinicopathologic characteristics of patients with GBC

A total of 285 patients were diagnosed with GBC following cholecystectomy between 2004 and 2023. The clinical characteristics of GBC patients are summarized in Supplementary Table 2. In 48.4% of cases, surgery was performed for a suspected gallbladder mass, while the remaining cases (51.6%) underwent surgical resection for polypoid lesions (13.7%) or abdominal pain related to cholecystitis (30.9%) and were diagnosed as GBCs by pathologists during postoperative examination of gallbladder specimens. The patient ages ranged from 31 years to 91 years, with a mean age of 69 years, and the male-to-female ratio was 1.08. Adenocarcinoma was the predominant histological type, accounting for 96.5% of GBC cases. The average tumor size was 2.58 cm, with stage II representing the most frequently observed tumor-node-metastasis stage (present in 36.5% of patients). Among the GBC cases, 29.12% were associated with gallstones and 24.91% had a history of cholangitis.

Changes in clinical characteristics of GBC patients by time period

The clinical characteristics of GBC patients were evaluated across four consecutive 5-year intervals (Table 2). While no statistically significant differences were observed in serologic markers between periods, several temporal trends emerged. The male-to-female ratio varied from 0.90 to 1.14, with a peak occurring in 2009-2013 (P = 0.820). Both age and BMI exhibited a gradual increase over time (P = 0.397 and P = 0.511, respectively). While liver function markers, such as AST, ALT, ALP, and γ-GT, showed minor fluctuations, no significant changes were evident. Additionally, levels of total cholesterol, triglycerides, and amylase displayed a declining trend over the study period (P = 0.675, P = 0.310, and P = 0.556, respectively).

Table 2 Changes in clinical characteristics of gallbladder cancer patients based on time period (n = 285), n (%).

Clinical factors	Years				P value
	2004-2008 (n = 38)	2009-2013 (n = 63)	2014-2018 (n = 75)	2019-2023 (n = 109)
Sex ratio (male/female)	0.90	1.25	0.97	1.14	0.820
Age (years)	67.05	69.11	68.68	70.10	0.397
BMI (kg/m2)	24.47	23.61	24.36	25.75	0.511
AST (IU/L)	34.13	31.38	34.92	32.70	0.909
ALT (U/L)	31.47	28.90	37.44	34.72	0.710
ALP (U/L)	91.26	102.53	98.48	94.90	0.786
γ-GT (IU/L)	83.07	94.05	135.03	112.30	0.719
Total cholesterol (mg/dL)	170.03	163.90	167.95	161.29	0.675
Triglyceride (mg/dL)	131.97	134.25	130.65	110.94	0.310
BUN (mg/dL)	13.47	15.65	14.39	15.61	0.246
Creatinine (mg/dL)	0.94	0.80	0.79	0.90	0.480
Total protein (g/dL)	6.80	6.88	6.76	6.66	0.794
Albumin (g/dL)	3.96	3.98	3.79	3.92	0.132
Amylase (U/L)	67.21	54.51	53.85	47.51	0.556
HTN	22 (57.90)	26 (41.30)	34 (45.30)	61 (56.00)	0.167
DM	5 (13.20)	11 (17.50)	18 (24.00)	30 (27.50)	0.212
Gallstone	13 (34.20)	21 (25.30)	19 (25.30)	30 (27.50)	0.643
Cholangitis	4 (10.50)	16 (25.40)	19 (25.30)	32 (29.40)	0.147
Stage I & II	26 (68.4)	34 (54.0)	51 (68.0)	76 (69.7)	0.177
Stage III & IV	12 (31.6)	29 (46.0)	24 (32.0)	33 (30.3)
5-year survival rate (%)	52.6	51.6	52.0	Not applicable	0.876

BMI: Body mass index; AST: Aspartate aminotransferase; ALT: Alanine transaminase; ALP: Alkaline phosphatase; γ-GT: Gamma-glutamyl transferase; BUN: Blood urea nitrogen; HTN: Hypertension; DM: Diabetes mellitus.

Renal function indicators, including BUN and creatinine, and nutritional markers, such as total protein and albumin, also remained relatively stable across the study periods. The proportion of patients with DM increased from 13.2% to 27.5% (P = 0.212) and the prevalence of cholangitis rose from 10.5% to 29.4% (P = 0.147). Although these increases did not reach statistical significance, they represent a notable shift over time. In contrast, the prevalence of HTN and gallstones remained relatively unchanged (P = 0.167 and P = 0.643, respectively). No significant differences were observed over time in tumor-node-metastasis stage distribution (P = 0.177). The 5-year survival rates were 52.6% (2004-2008, 31.6% stage III/IV), 51.6% (2009-2013, 46% stage III/IV), and 52.0% (2014-2018, 32.0% stage III/IV) that over the 15-year period, the 5-year survival rate did not change significantly (P = 0.876).

Changes in histopathologic features of GBC patients by time period

Pathological features were reviewed and quantitatively assessed, including the presence of accompanying premalignant neoplasms such as ICPN (Figure 2A) and BilIN (Figure 2B), histologic differentiation, non-neoplastic changes, undifferentiated components (Figure 2C), and poorly cohesive carcinoma components (Figure 2D). Additional parameters evaluated included depth of invasion, tumor size, and tumor staging.

Figure 2 Pathological features of the gallbladder. A-D: Premalignant neoplasms such as intracholecystic papillary neoplasm (A), biliary intraepithelial neoplasia (B), undifferentiated components (C), and poorly cohesive carcinoma components (D).

The distribution of clinicopathologic features of GBC was evaluated at 5-year intervals (Table 3). Notably, the proportion of tumors exhibiting intestinal differentiation was significantly increased in the most recent period (2019-2023) compared to 2004-2008 (18.4% vs 24.8%, P = 0.038). In contrast, no significant temporal changes were identified in other histopathological features, including the presence of preinvasive neoplasms (P = 0.472), non-neoplastic changes such as hyperplasia or metaplasia (P = 0.062), liver involvement (P = 0.445), poorly cohesive components including signet ring cells (P = 0.316), or undifferentiated components including squamous or sarcomatous elements (P = 0.173). Additionally, no significant differences were observed in tumor depth (P = 0.673), tumor size (P = 0.532) or tumor budding (P = 0.128) over time.

Table 3 Temporal changes in histopathologic features of gallbladder cancer patients (n = 285), n (%).

Pathological features	Years				P value
	2004-2008 (n = 38)	2009-2013 (n = 63)	2014-2018 (n = 75)	2019-2023 (n = 109)
Preinvasive neoplasm					0.472
ICPN	11 (28.95)	20 (32.26)	26 (35.14)	27 (24.77)
BilIN or adenoma	27 (71.05)	42 (67.74)	48 (64.86)	82 (75.23)
Histologic cell differentiation					0.038
Pancreaticobiliary	31 (81.58)	57 (91.94)	55 (74.32)	82 (75.23)
Intestinal	7 (18.42)	5 (8.06)	19 (25.68)	27 (24.77)
Non-neoplastic change (hyperplasia or metaplasia)	26 (68.42)	51 (82.26)	66 (89.19)	89 (81.65)	0.062
Liver involvement	4 (10.53)	9 (14.29)	5 (6.76)	15 (13.76)	0.445
Poorly cohesive component (including signet ring cells)	9 (23.68)	17 (27.42)	27 (36.49)	27 (24.77)	0.316
Undifferentiated component (including squamous or sarcomatous)	10 (26.32)	7 (11.29)	18 (24.32)	20 (18.35)	0.173
Depth of invasion (cm)	0.47	0.61	0.49	0.55	0.673
Tumor size (cm)	1.11	1.41	1.14	1.16	0.532
Tumor budding (buds/0.785 mm2)	4.92	3.66	5.41	3.33	0.128

ICPN: Intracholecystic papillary neoplasm; BilIN: Biliary intraepithelial neoplasia.

Clinical and prognostic factors in GBC patients according to stage and survival

Clinical features of GBC patients were compared between early-stage (stage I-II) and advanced-stage (stage III-IV) tumors (Supplementary Table 3). Among the variables analyzed, ALP, γ-GT, total cholesterol, and triglyceride levels were significantly different between the two groups (P = 0.027, P = 0.023, P = 0.040, and P = 0.024, respectively), with higher ALP and γ-GT levels and lower triglyceride levels observed in the advanced-stage disease group. HTN was linked to advanced stage significantly (P = 0.022).

Survival analyses were conducted to evaluate the prognostic impact of a range of clinical factors in patients with GBC (Figure 3). The results indicated that older age, elevated ALP, γ-GT, and amylase levels were associated with poorer survival outcomes (P = 0.049, P = 0.015, P = 0.002, and P = 0.001, respectively). Additionally, the presence of cholangitis was linked to significantly poorer prognosis compared to patients without this condition (P = 0.006). Conversely, higher BMI, total cholesterol, triglyceride, and albumin levels were associated with better survival (P = 0.018, P = 0.003, P = 0.026, and P = 0.016, respectively). Cox regression of overall survival with metabolic factors including total cholesterol, triglyceride, and albumin were evaluated with age and stage, but did not attain prognostic significance (P = 0.104, P = 0.290, and P = 0.068, respectively) (Supplementary Table 4).

Figure 3 Overall survival of gallbladder cancer patients according to clinical features. A-I: Kaplan-Meier survival analyses illustrating differences in overall survival based on: Age (A), body mass index (B), alkaline phosphatase (C), gamma-glutamyl transferase (D), total cholesterol (E), triglyceride (F), albumin (G), amylase (H), and cholangitis (I). BMI: Body mass index; ALP: Alkaline phosphatase; γ-GT: Gamma-glutamyl transferase.

Histopathologic features of GBC according to stage and survival

Pathologic features of GBC were compared between early-stage (stage I-II) and advanced-stage (stage III-IV) tumors (Table 4). Patients with advanced-stage disease were significantly more likely to present with preinvasive lesions of BilIN or adenoma than ICPN (P < 0.001). While pancreaticobiliary differentiation was identified as the predominant subtype in both groups, the distribution between pancreaticobiliary and intestinal types did not significantly differ (P = 0.722). Advanced-stage tumors were markedly associated with more aggressive features, including liver involvement (P < 0.001), poorly cohesive components such as signet ring cells (P < 0.001), and undifferentiated components, including squamous or sarcomatous elements (P = 0.025).

Table 4 Comparison of histopathologic features of gallbladder cancer according to tumor stage (n = 285), n (%).

Pathological features	Stage		P value
	I & II (n = 187)	III & IV (n = 98)
Preinvasive neoplasm			0.000
ICPN	70 (37.4)	15 (15.3)
BilIN or adenoma	117 (62.6)	83 (84.7)
Histologic cell differentiation			0.722
Pancreaticobiliary	147 (78.6)	79 (80.6)
Intestinal	40 (21.4)	19 (19.4)
Non-neoplastic change (hyperplasia or metaplasia)	152 (81.3)	80 (81.6)	0.943
Liver involvement	11 (5.9)	22 (22.4)	0.000
Poorly cohesive component (including signet ring cells)	38 (20.3)	42 (43.8)	0.000
Undifferentiated component (including squamous or sarcomatous)	29 (15.5)	26 (26.5)	0.025
Depth of invasion (cm)	0.38	0.88	0.000
Tumor size (cm)	0.83	1.93	0.000
Tumor budding (buds/0.785 mm2)	2.97	6.47	0.000

ICPN: Intracholecystic papillary neoplasm; BilIN: Biliary intraepithelial neoplasia.

Quantitative measures of tumor aggressiveness, such as depth of invasion (0.38 cm vs 0.88 cm), tumor size (0.83 cm vs 1.93 cm), and tumor budding (2.97 buds/0.785 mm² vs 6.47 buds/0.785 mm²), were significantly higher in advanced-stage cases (P < 0.001 for all). In contrast, the presence of non-neoplastic changes such as hyperplasia or metaplasia did not differ significantly between groups (P = 0.943).

Kaplan-Meier survival analysis was conducted to evaluate overall survival based on various pathological features (Figure 4). Significantly improved survival outcomes were observed in patients with preinvasive lesions such as ICPN (P < 0.001), intestinal-type histologic differentiation (P = 0.002), absence of poorly cohesive components (P = 0.002), shallow depth of invasion (≤ 0.4 cm; P = 0.002), limited tumor size (≤ 0.7 cm; P < 0.001), and lower tumor budding scores (P = 0.015). Cox regression of overall survival with metabolic factors including tumor budding, poorly cohesive and undifferentiated components were evaluated with age and stage, but did not attain prognostic significance (P = 0.317, P = 0.916, and P = 0.490, respectively) (Supplementary Table 5).

Figure 4 Overall survival of gallbladder cancer patients according to histopathological features. A-F: Kaplan-Meier survival analyses illustrating differences in overall survival based on: Presence of preinvasive lesions (A), histologic differentiation subtype (B), presence of poorly cohesive components (C), depth of invasion (D), tumor size (E), and tumor budding (F). ICPN: Intracholecystic papillary neoplasm; BilIN: Biliary intraepithelial neoplasia; PCC: Poorly cohesive cells; SRC: Signet ring cells.

DISCUSSION

Early detection of GBC poses a significant challenge due to its typically asymptomatic presentation. The majority of cases are diagnosed incidentally following cholecystectomy performed for symptomatic conditions, such as gallstones[17]. For instance, in this study, half of GBC cases were identified incidentally by pathologists based on gallbladder specimens after cholecystectomy. Identification of clinical factors associated with GBC may enhance screening processes and risk stratification. A comparative analysis of benign, precancerous, and GBC groups revealed notable variations in clinical factors, including age (> 70 years), HTN, and cholangitis. Patients with GBC were significantly older and showed a higher prevalence of HTN and cholangitis. HTN is not traditionally recognized as a direct risk factor for GBC, its role within the context of metabolic syndrome and chronic systemic inflammation may contribute to carcinogenesis[18]. In contrast to previous studies reporting a high prevalence of gallstones among GBC patients, our findings indicated a lower incidence of gallstones in the GBC cohort[19]. This observation may be attributable to the fact that most patients undergoing cholecystectomy for benign conditions presented with symptoms, such as gallstone-related pain, whereas a subset of GBC cases underwent surgery primarily based on preoperative imaging findings, including gallbladder wall thickening or mass-like lesions. Biochemical analyses revealed higher levels of total cholesterol, triglycerides, and liver enzymes (AST, ALT, ALP) in the benign than the GBC group. Previous studies on bile duct cancers (including GBC) have reported significantly lower serum albumin levels in cancer patients compared with those with gallstones, along with elevated ALP levels, findings that are in concordance with our results[20]. Dyslipidemia, characterized by high triglyceride and high-density lipoprotein cholesterol levels, has been reported as an independent risk factor for GBC; however, this finding was contrary to our results[21,22]. The low triglyceride and cholesterol levels observed in patients with GBC may also reflect decreased appetite or reduced dietary intake associated with cancer development. Despite the increasing prevalence of hypercholesterolemia and dyslipidemia in South Korea[23], total cholesterol and triglyceride levels exhibited a declining trend among GBC patients over the study period.

In our study, the number of patients undergoing total cholecystectomy increased from 2004 to 2023, which could be attributed to improved access to healthcare services[24]. Although the proportion of GBC diagnoses among cholecystectomy cases remained relatively consistent, the absolute number of GBC cases gradually increased. This trend aligns with the growing incidence of GBC observed both across Asia and worldwide[25]. Previous studies have documented an increase in the incidence of GBC between 1999 and 2019, alongside an escalation in cancer-related mortality in both men and women. In the current research, approximately 30%-46% of GBC patients were diagnosed at advanced stages (stage III or IV), with no significant temporal changes. A previous Korean study reported a decrease in the proportion of advanced-stage diagnoses and a gradual improvement in the 5-year relative survival rate, increasing from 21.8% to 30.6% between 1999 and 2019[26]. Globally, the reported 5-year overall survival rates ranged from 7.3% to 22.4% in Europe and North America, 10.2% to 16.5% in China, and 17.2% to 39.8% in Japan[27]. The overall 5-year survival rate of GBC patients in our study was 52%, exceeding that reported in previous studies. Over the 15-year period, this rate did not change significantly, which may be attributable to minimal advances in surgical or therapeutic protocols in our institution during this time. These differences may be influenced by the stage at diagnosis and level of access to timely medical care and surgical intervention.

The number of precancerous lesions showed no significant temporal increase, peaking in 2009-2013, followed by a gradual decline in proportion over subsequent periods. The persistently high proportion of advanced-stage diagnoses may be attributed to the challenges associated with detecting GBC through radiologic evaluation. However, the observed decrease in precancerous lesions may reflect the increased awareness and proactive management of benign gallbladder conditions.

Within the GBC cohort, the average male-to-female incidence rate ratio was 1.08, indicating no significant differences in GBC incidence between genders. On a global scale, GBC occurs more frequently in females, with reported incidence rates being three to six times higher than in males[4]. However, studies conducted in South Korea have demonstrated lower sex ratios, with rates reported at 0.96 and 1.33, respectively[26,28]. Consistent with the stable proportion of GBC cases over time, no significant temporal changes were observed in the clinical characteristics of GBC patients. Nevertheless, several clinical factors [including age (> 70 years), ALP, γ-GT, amylase, BMI, total cholesterol, triglycerides, albumin levels, and the presence of cholangitis] were found to be associated with prognosis. These factors may serve as potentially useful prognostic indicators and aid in predicting patient survival. Cholesterol, triglyceride, and albumin levels demonstrated an inverse association with adverse prognosis, suggesting that higher levels of these metabolic factors may be associated with improved survival outcomes.

In our study, the distribution of the several histopathological features of GBC patients varied over time. The proportion of GBCs with intestinal differentiation increased during the 2019-2023 compared to 2004-2008. Although the changes were not statistically significant, the percentage of ICPN gradually increased in the first three periods before experiencing a decline in the final period, which diverges from the trends observed for BilIN and adenoma. Additionally, while liver involvement did not show statistical significance, its proportion more than doubled in 2019-2023 compared to 2014-2018. Other prognostic factors that showed no significant temporal variation may reflect limited statistical power during the early time periods due to smaller sample sizes. Although the temporal differences were not statistically significant, the overall patient profile remained stable across two decades, suggesting consistent underlying epidemiology. A modest decline in triglyceride and cholesterol levels may reflect cancer-related systemic effects, while slight increases in HTN, DM, and cholangitis likely mirror broader population health trends. The small increase in early-stage detection, though not significant, may still hold clinical relevance.

Advanced-stage tumors showed significantly higher rates of liver involvement, poorly cohesive and undifferentiated components, greater depth of invasion, tumor size, and tumor budding. In contrast, histologic subtype and non-neoplastic epithelial changes did not differ by stage. These features strongly support their role as markers of aggressive tumor biology. The presence of preinvasive lesions, intestinal histologic differentiation, poor differentiation histology including poorly cohesive components, liver invasion, increased depth of invasion, bigger tumor size, and tumor budding were all associated with poorer overall survival in patients with GBC. GBCs harboring ICPN or papillary neoplasia as preinvasive lesions were linked to poorer prognosis and exhibited distinct expression patterns of tumor suppressor proteins, suggesting a biologically different profile compared to tumors lacking such lesions[29]. Similarly, in periampullary adenocarcinoma, the pancreaticobiliary subtype has been associated with poorer outcomes compared to the intestinal subtype[30]. Our study highlights the prognostic value of several pathological factors in GBC. Notably, since these features can only be assessed following surgical resection, they are not applicable as predictive markers for preoperative decision-making, but could serve as useful prognostic markers in a postoperative setting.

In our study, metabolic factors including albumin, and lipid profiles and histologic factors were evaluated multivariate analysis with age and stages. They showed significant associations with GBC in the univariate analysis, however, many of these relationships were lost significance in the multivariate models after adjustment for tumor stage. This discrepancy suggests that tumor stage may act as a major determinant influencing these variables. We propose advanced-stage GBC is often accompanied by systemic changes including metabolic alterations and cachexia. Therefore, factors that appear to correlate with GBC in unadjusted analyses may, in fact, be driven primarily by stage-related physiological derangements rather than independent etiologic roles.

CONCLUSION

Our findings may be limited in generalizability but still provide meaningful insights. Age, HTN, cholangitis, and metabolic factors were identified as risk factors, supporting the importance of early identification of GBC. The clinicopathologic characteristics of GBC further highlight the value of recognizing high-risk profiles and underscore the prognostic significance of detailed histopathological evaluation. Treatment strategies for biliary tract cancers have evolved, with targeted agents such as HER2 and IDH1 inhibitors demonstrating promising efficacy in advanced-stage disease[31]. Because biliary tract cancers exhibit diverse genetic alterations and biological behaviors depending on subtype and anatomical location, dedicated studies focusing specifically on GBC remain essential[32]. Overall, this research contributes to a deeper understanding of the evolving landscape of GBC and provides a foundation for improving risk stratification and patient outcomes in clinical practice.