Factors influencing postoperative complications in patients with gastric cancer: A retrospective study

Abstract

BACKGROUND

Gastric cancer is a malignancy with high morbidity and mortality rates. Surgical intervention, particularly gastrectomy, is essential for curative treatment but carries a substantial risk of complications. Identifying key risk factors and understanding complication profiles are crucial for improving outcomes and guiding perioperative management.

AIM

To analyze the incidence of postoperative complications in patients with gastric cancer and identify potential risk factors.

METHODS

We conducted a retrospective analysis of 500 patients who underwent gastrectomy between January 2018 and December 2022. Postoperative complications were classified using the Clavien-Dindo system.

RESULTS

The overall complication rate was 28.4% (142/500), with 15.2% (76/500) experiencing major complications (Clavien-Dindo grade ≥ III). Pulmonary complications were the most frequent (10.8%), followed by surgical site infections (8.6%), and anastomotic leakage (4.2%). Age 70 years or more, body mass index of 25 kg/m² or more, advanced tumor stage, total gastrectomy, and operative time 240 min or more emerged as independent risk factors.

CONCLUSION

Focused preoperative risk assessment, targeted interventions, and reduced operative time for older or obese patients requiring total gastrectomy or presenting with advanced disease are important to improve surgical outcomes.

Key Words: Gastric cancer; Postoperative complications; Risk factors; Gastrectomy; Retrospective study

Core Tip: This retrospective study examined 500 patients with gastric cancer undergoing gastrectomy and revealed an overall complication rate of 28.4 %, with 15.2% experiencing major complications. Key risk factors identified include age 70 years or more, body mass index of 25 kg/m² or more, advanced tumor stage, total gastrectomy, and prolonged operative time. Utilizing the Clavien-Dindo classification highlights the importance of identifying high-risk patients to implement targeted interventions, ultimately aiming to reduce complication rates and improve surgical outcomes in this vulnerable population.

INTRODUCTION

Gastric cancer is the fifth most common cancer and the third leading cause of cancer-related deaths worldwide, with an estimated 1089103 new cases and 768793 deaths in 2020[1]. Despite advancements in diagnostic techniques and treatment modalities, the prognosis of patients with gastric cancer remains poor, particularly for those with advanced stages[2]. Surgical resection remains the cornerstone of curative treatment for gastric cancer and is often combined with perioperative or adjuvant chemotherapy in advanced cases[3].

Existing research indicates that postoperative complications following gastric cancer surgery significantly affect patient survival, prolong hospital stay, and delay adjuvant therapy[4]. The reported complication rates vary widely from 10% to 46%, partly because of heterogeneous definitions and classification systems[5,6]. Moreover, factors such as age, nutritional status, tumor stage, and operative time have been implicated in predicting adverse outcomes; however, there is variability across studies[7]. Several factors have been suggested to influence the risk of postoperative complications, including patient-related (e.g., age, comorbidities, and nutritional status), tumor-related (e.g., tumor stage and location), and treatment-related factors (e.g., extent of resection and operative time)[8,9].

However, the relative impact of these factors and their interplay in determining the risk of complications remains unclear. Moreover, most previous studies have focused on specific complications or have used varying definitions and classification systems, making comparisons and generalizations challenging[10]. Comprehensive studies using standardized complication classification systems are required to provide a more accurate and comparable assessment of postoperative outcomes in patients with gastric cancer.

The Clavien-Dindo classification system has emerged as a widely accepted and validated tool for grading surgical complications[11]. This system categorizes complications based on the type of therapy required to treat them and provides a more objective and reproducible assessment of surgical morbidity. This standardized system facilitates more meaningful comparisons across studies and institutions.

Nevertheless, challenges remain. The precise interplay between the risk factors has not been exhaustively explored in large and diverse patient cohorts. To address these gaps, we applied the standardized Clavien-Dindo classification to a relatively large retrospective cohort of 500 patients with gastric cancer. This approach ensures comparability with other studies and highlights the potential risk factors for targeted preventive strategies.

Hence, the objectives of our study were to ascertain the incidence and spectrum of postoperative complications using the Clavien-Dindo classification, to identify independent risk factors linked to these complications, and to discuss how these findings might guide personalized perioperative management, including tailored follow-up and risk-based operative planning, and to better define the risk profiles of patients undergoing gastrectomy to optimize perioperative protocols and allocate resources to high-risk individuals, ultimately aiming to reduce morbidity and enhance survival outcomes.

MATERIALS AND METHODS

Study design and patient population

We conducted a retrospective cohort study of patients who underwent gastrectomy for gastric cancer at the First Affiliated Hospital of Chongqing Medical University, a high-volume tertiary care center, between January 1, 2018, and December 31, 2022. The study protocol was approved by the Institutional Review Board of the First Affiliated Hospital of Chongqing Medical University, and the need for informed consent was waived because of the retrospective nature of the study.

Inclusion criteria were: (1) Histologically confirmed gastric adenocarcinoma; (2) Age 18 years or more; and (3) Curative-intent gastrectomy (total or subtotal) with lymph node dissection. The exclusion criteria were: (1) Palliative surgery; (2) Emergency surgery; (3) Concurrent malignancy; and (4) Incomplete medical records.

Data collection

Patient data were extracted from electronic medical records and a prospectively maintained institutional database. The collected information included patient characteristics such as age, sex, body mass index (BMI), American Society of Anesthesiologists physical status classification, comorbidities, smoking history, and preoperative laboratory values. Tumor characteristics including location, clinical tumor node metastasis stage, and histological type were also recorded. The treatment details included neoadjuvant therapy, type of gastrectomy, extent of lymph node dissection, combined organ resection, operative time, estimated blood loss, and volume of blood transfusion. Postoperative outcomes, including length of hospital stay, 30-day readmission rate, and 30-day and 90-day mortality rates, were documented.

Definition and classification of postoperative complications

Postoperative complications were defined as any deviation from the normal postoperative course within 30 days of surgery or during hospitalization. All complications were graded according to the Clavien-Dindo classification system[11]. This system categorizes complications based on the type of therapy required to treat the complication: Grade I: Any deviation from the normal postoperative course without the need for pharmacological treatment or surgical, endoscopic, or radiological interventions; Grade II: Requires pharmacological treatment with drugs other than those allowing for grade I complications; Grade III: Requiring surgical, endoscopic, or radiological intervention; Grade IV: Life-threatening complication requiring intensive care or intensive care unit management; Grade V: Death of a patient.

Major complications were defined as Clavien-Dindo grade III or higher. In cases where a patient experienced multiple complications, the highest grade was used for analysis.

Specific complications were also recorded, including pulmonary complications (pneumonia, atelectasis requiring intervention, pleural effusion requiring drainage), cardiovascular complications (myocardial infarction, arrhythmia requiring intervention, pulmonary embolism), surgical site infections (classified as superficial incisional, deep incisional, or organ/space according to the centers for disease control and prevention criteria), anastomotic leakage (confirmed by radiological imaging or reoperation), pancreatic fistula (defined and graded according to the International Study Group of Pancreatic Fistula criteria), postoperative bleeding (requiring transfusion or reoperation), and delayed gastric emptying (requiring nasogastric tube reinsertion after postoperative day 3 or inability to tolerate oral intake by postoperative day 7).

Statistical analysis

Continuous variables are expressed as mean ± SD or median (interquartile range), depending on the distribution of data. Categorical variables are presented as frequencies and percentages. The Shapiro-Wilk test was used to assess the normality of continuous variables.

Univariate analysis was performed to identify potential risk factors for postoperative complications. The χ² test or Fisher’s exact test was used for categorical variables, and the student’s t-test or Mann-Whitney U test was used for continuous variables, as appropriate.

Variables with a P value < 0.1 in the univariate analysis were included in a multivariate logistic regression model to identify independent risk factors for postoperative complications. The results are presented as odds ratios (OR) with 95% confidence intervals (CI). The Hosmer-Lemeshow test was used to assess the goodness-of-fit of the logistic regression model.

All statistical analyses were performed using IBM SPSS Statistics for Windows (version 26.0; IBM Corp., Armonk, NY, United States). Statistical significance was defined as a two-sided P value of < 0.05.

RESULTS

Patient characteristics

A total of 500 patients who underwent gastrectomy for gastric cancer between January 2015 and December 2019 were included in this study. The mean age of the patients was 63.7 ± 11.2 years, and 312 (62.4%) were male. Baseline characteristics of the study population are summarized in Table 1.

Table 1 Baseline characteristics of the study population (n = 500), mean ± SD/n (%).

Characteristic	Value
Age (years)	63.7 ± 11.2
Male sex	312 (62.4)
BMI (kg/m²)	23.8 ± 3.6
ASA score
I	98 (19.6)
II	276 (55.2)
III	118 (23.6)
IV	8 (1.6)
Comorbidities
Hypertension	187 (37.4)
Diabetes	95 (19.0)
Cardiovascular disease	73 (14.6)
COPD	41 (8.2)
Smoking history	156 (31.2)
Preoperative laboratory values
Hemoglobin (g/dL)	12.3 ± 1.8
Albumin (g/dL)	3.8 ± 0.5
CRP (mg/L), median (IQR)	5.2 (2.1-12.7)
Tumor location
Upper third	112 (22.4)
Middle third	178 (35.6)
Lower third	210 (42.0)
Clinical TNM stage
I	156 (31.2)
II	178 (35.6)
III	166 (33.2)
Lauren classification
Intestinal	247 (49.4)
Diffuse	193 (38.6)
Mixed	60 (12.0)
Neoadjuvant therapy	87 (17.4)

BMI: Body mass index; ASA: American Society of Anesthesiologists; COPD: Chronic obstructive pulmonary disease; CRP: C-reactive protein; IQR: Interquartile range; TNM: Tumor node metastasis.

Surgical characteristics

The surgical characteristics of the study population are presented in Table 2.

Table 2 Surgical characteristics (n = 500), n (%).

Characteristic	Value
Type of gastrectomy
Total	187 (37.4)
Subtotal	313 (62.6)
Combined organ resection	68 (13.6)
Operative time (minute), median (IQR)	225 (185-270)
Estimated blood loss (mL), median (IQR)	200 (150-300)
Intraoperative blood transfusion	53 (10.6)

IQR: Interquartile range.

Postoperative complications

The overall complication rate was 28.4% (142/500), with 15.2% (76/500) of patients experiencing major complications (Clavien-Dindo grade ≥ III). The distribution of complications according to the Clavien-Dindo classification is shown in Table 3. The most common types of complications are presented in Table 4.

Table 3 Distribution of complications according to Clavien-Dindo classification.

Clavien-Dindo grade	n (%)
No complications	358 (71.6)
I	37 (7.4)
II	29 (5.8)
IIIa	42 (8.4)
IIIb	21 (4.2)
IVa	9 (1.8)
IVb	2 (0.4)
V	2 (0.4)

Table 4 Types of postoperative complications.

Complication	n (%)
Pulmonary complications	54 (10.8)
Surgical site infections	43 (8.6)
Anastomotic leakage	21 (4.2)
Pancreatic fistula	18 (3.6)
Postoperative bleeding	15 (3.0)
Delayed gastric emptying	14 (2.8)
Cardiovascular complications	12 (2.4)

Risk factors for postoperative complications

Older patients (≥ 70 years) or had a BMI of 25 kg/m² or more showed a higher complication rate. Advanced tumor stage (especially stage III) also significantly increased the risk, presumably because of more extensive surgical procedures and compromised nutritional status. Total gastrectomy has a higher incidence of complications than subtotal resection, suggesting that complete stomach removal confers greater technical demands and physiological stress. Additionally, operations extending beyond 240 minutes were correlated with more frequent morbidity, indicating that prolonged intraoperative manipulation could exacerbate tissue trauma and hemodynamic fluctuations.

As shown in Table 5, multivariate logistic regression confirmed 5 independent predictors: Age 70 years or more (OR = 1.78, P = 0.003), BMI: 25 kg/m² or more (OR = 1.56, P = 0.027), advanced tumor stage (OR = 1.92, P = 0.001), total gastrectomy (OR = 1.75, P = 0.005), and operative time ≥ 240 minutes or more (OR = 1.63, P = 0.015).

Table 5 Univariate analysis and multivariate analysis of risk factors for postoperative complications, n (%).

Risk factor	Complication (n = 142)	No complication (n = 358)	Univariate P value	Multivariate OR (95%CI)	Multivariate P value
Age ≥ 70 years	58 (40.8)	92 (25.7)	0.001	1.78 (1.21-2.62)	0.003
BMI ≥ 25 kg/m²	51 (35.9)	89 (24.9)	0.015	1.56 (1.05-2.31)	0.027
ASA score ≥ III	52 (36.6)	74 (20.7)	< 0.001	Not identified	Not identified
Diabetes	37 (26.1)	58 (16.2)	0.012	Not identified	Not identified
Preop albumin < 3.5 g/dL	45 (31.7)	76 (21.2)	0.015	Not identified	Not identified
Advanced tumor stage (III)	62 (43.7)	104 (29.1)	0.002	1.92 (1.29-2.86)	0.001
Total gastrectomy	68 (47.9)	119 (33.2)	0.003	1.75 (1.18-2.59)	0.005
Combined organ resection	28 (19.7)	40 (11.2)	0.014	Not identified	Not identified
Operative time ≥ 240 minutes	71 (50.0)	129 (36.0)	0.004	1.63 (1.10-2.42)	0.015
Blood loss ≥ 300 mL	53 (37.3)	97 (27.1)	0.026	Not identified	Not identified

BMI: Body mass index; ASA: American Society of Anesthesiologists; OR: Odds ratio; CI: Confidence interval.

Postoperative outcomes

The median length of hospital stay was 10 days (interquartile range: 8-14 days). Patients who experienced complications had significantly longer hospital stays than those without complications (median: 15 vs 9 days, P < 0.001).

The 30-day readmission rate was 7.2% (36/500), which was higher in patients who experienced complications than in those who did not (15.5% vs 3.9%, P < 0.001). The 30-day mortality rate was 0.4% (2/500), and the 90-day mortality rate was 1.2% (6/500).

DISCUSSION

This retrospective study of 500 patients who underwent gastrectomy for gastric cancer provided a comprehensive analysis of the postoperative complication rates and associated risk factors. Our findings contribute to the growing body of evidence on surgical outcomes of gastric cancer and offer insights into improving perioperative management and patient selection.

The overall complication rate in our study was 28.4%, with 15.2% of patients experiencing major complications (Clavien-Dindo grade ≥ III). These rates are consistent with those reported in recent literature, which range from 20% to 46%[12,13]. The variability in the reported complication rates can be attributed to differences in patient populations, surgical techniques, and complication definitions across studies. Our use of the standardized Clavien-Dindo classification system enhances the comparability of our results with those of other studies using this widely accepted grading system.

Pulmonary complications were the most frequent (10.8%), followed by surgical site infections (8.6%), and anastomotic leakage (4.2%). This distribution is similar to that reported in other large series[14,15]. The high incidence of pulmonary complications underscores the importance of optimizing preoperative pulmonary function and implementing aggressive postoperative pulmonary care protocols. Similarly, the notable rate of surgical site infections highlights the need for strict adherence to infection prevention measures and appropriate use of prophylactic antibiotics.

Our multivariate analysis identified five independent risk factors for postoperative complications: Age 70 years or more, BMI 25 kg/m² or more, advanced tumor stage, total gastrectomy, and operative time 240 minutes or more. These findings have important implications for preoperative risk assessment and perioperative management.

The increased risk of complications in older patients (OR = 1.78, 95%CI: 1.21-2.62) is consistent with previous studies[16,17]. This may be attributed to decreased physiological reserves, increased comorbidities, and reduced functional capacity in Elderly patients. Our findings emphasize the need for comprehensive geriatric assessment and optimization before surgery as well as tailored perioperative care for this vulnerable population.

The association between higher BMI and increased complication risk (OR = 1.56, 95%CI: 1.05-2.31) aligns with previous reports[18,19]. Obesity can complicate surgical techniques, prolong operative times, and impair wound healing. Preoperative weight optimization and careful consideration of the surgical approach in obese patients may help mitigate this risk.

In addition to weight optimization, comprehensive preoperative evaluation is crucial. Recent research indicates that patients should undergo colonoscopy when diagnosed with gastric neoplasms, especially patients with gastric cancer, a low BMI, and a history of smoking[20]. This finding highlights the importance of thorough preoperative screening for potential comorbidities.

Patients with advanced-stage tumors had a higher risk of complications (OR = 1.92, 95%CI: 1.29-2.86). This may be due to more extensive surgery, poorer nutritional status, and systemic effects of advanced malignancy[21]. These findings underscore the importance of early detection and treatment of gastric cancer as well as the need for careful patient selection and preoperative optimization in advanced cases.

Furthermore, emerging evidence suggests that oral health may play a role in gastric cancer risk. A recent study reported that patients with poor oral health, especially those with periodontitis, have a higher risk of gastric cancer. Patients should be concerned about oral health. Improving oral health may reduce the risk of gastric cancer[22]. This underscores the importance of comprehensive health assessments and potential preventive strategies for gastric cancer management.

Total gastrectomy was associated with a higher complication risk compared to subtotal gastrectomy (OR = 1.75, 95%CI: 1.18-2.59). This is likely due to the more extensive nature of surgery, potentially longer operative times, and the physiological impact of complete gastric removal[23]. When oncologically appropriate, subtotal gastrectomy may help reduce complication rates in selected patients.

Prolonged operative time was an independent risk factor for complications (OR = 1.63, 95%CI: 1.10-2.42). This may reflect case complexity, technical difficulties, and surgeon experience[24]. Efforts to optimize surgical efficiency, such as standardized operative protocols and enhanced training programs, may help reduce operative time and associated complications.

These findings suggest personalized management strategies, such as prehabilitation for older patients or those with a high BMI, and a focus on nutrition and comorbidity optimization may prevent postoperative complications. Patients with advanced-stage gastric cancer require careful monitoring and conservative surgery. Patients undergoing total gastrectomy require intensive perioperative support including nutrition and infection prevention measures. Reducing operative time through standardized protocols should be a goal in high-volume centers to lower complication risks. As more centers adopt the Clavien-Dindo framework, multi-institutional registries can streamline complication data, facilitating meaningful comparisons and enhancing evidence-based practice.

These findings have important clinical implications. The identified risk factors can aid in more accurate preoperative risk assessment, facilitating informed decision-making and patient counseling. Targeted interventions for modifiable risk factors, such as preoperative nutritional support, prehabilitation programs for older patients, and weight optimization for patients with obesity, may help reduce complication rates. Moreover, recent evidence suggests that older patients with gastric cancer who received the enhanced recovery after surgery protocol after surgery had a lower risk of mortality[25]. The higher risk associated with total gastrectomy and the prolonged operative time underscores the importance of careful surgical planning and technique optimization. Moreover, by identifying high-risk patients, healthcare resources can be allocated more efficiently, potentially improving overall outcomes and reducing healthcare costs.

This study has several limitations. The retrospective nature of this study introduces the potential for selection bias and limits the ability to establish causal relationships. As this was a single-center study, our findings may not be generalizable to all populations or healthcare settings. Multicenter studies are required to validate these results. We focused on short-term postoperative outcomes, and future studies should assess the impact of complications on long-term oncological outcomes. Despite comprehensive data collection, there may have been unmeasured factors influencing complication rates that were not accounted for in our analysis. Lastly, over the study period, changes in surgical techniques or perioperative management may have influenced the complication rates.

CONCLUSION

In conclusion, by enhancing our understanding of the risk factors associated with postoperative complications in gastric cancer surgery, this study contributes to ongoing efforts to improve patient outcomes. The implementation of risk-stratified management strategies coupled with the continued refinement of surgical techniques and perioperative care protocols holds promise for reducing complication rates and improving overall outcomes in patients undergoing gastrectomy for gastric cancer.