Effects of endoscopic mucosal resection and argon plasma coagulation on postoperative recovery and complications in elderly colon polyp patients

Abstract

BACKGROUND

Colon polyps represent a significant clinical challenge in elderly patients. While endoscopic mucosal resection (EMR) and argon plasma coagulation (APC) are widely used, their comparative effectiveness in elderly populations remains unclear, particularly regarding postoperative recovery and complication profiles.

AIM

To compare the postoperative recovery, complications and efficacy of EMR and APC in elderly patients with colonic polyps.

METHODS

We retrospectively analyzed clinical data from 224 elderly patients with colon polyps treated at our center between January 2021 and July 2024. All patients were divided into the EMR group and APC group according to the surgical method they received. By comparing the operation time, intraoperative bleeding situation, hospital stays, postoperative inflammatory response index, complication rate and recurrence status of the two groups, the effect of the two surgical methods was comprehensively evaluated.

RESULTS

The APC group exhibited superior outcomes in terms of operative time (10.63 minutes vs 13.27 minutes, P < 0.001), intraoperative bleeding situation (39.00% vs 52.42%, P = 0.031), and length of hospital stay (1.63 days vs 3.87 days, P < 0.001) compared to the EMR group. The one-time resection rate of the APC group (94.69%) was higher than that of the EMR group (89.14%) (P = 0.026). The overall effective rates of the two groups were 94.35% and 92.00%, respectively. Postoperative procalcitonin and C-reactive protein levels were lower in the APC group than in the EMR group (P < 0.001). The incidence of complications was comparable between the two groups (P = 0.159). The recurrence rate was lower in the APC group (2.00%) than in the EMR group (8.06%) (P = 0.045).

CONCLUSION

For elderly patients with colon polyps, APC showed certain advantages compared with EMR in promoting postoperative recovery, reducing the inflammatory response and the risk of complications. However, the study is limited by its single-center retrospective design and short follow-up period, and further multicenter prospective studies are needed to validate the findings.

Key Words: Colon polyps; Endoscopic mucosal resection; Argon plasma coagulation; Postoperative recovery; Complications; Elderly patients

Core Tip: This study compared endoscopic mucosal resection and argon plasma coagulation (APC) in elderly (≥ 50 years) colon polyp patients. APC demonstrated superior outcomes, including shorter operative time (10.63 minutes vs 13.27 minutes, P < 0.001), reduced intraoperative bleeding (39.00% vs 52.42%, P = 0.031), and lower inflammatory markers (procalcitonin and C-reactive protein, P < 0.001) compared to endoscopic mucosal resection. While both techniques showed similar overall efficacy, APC had a lower recurrence rate (2.00% vs 8.06%, P = 0.045). These findings suggest that APC may be preferable for small polyps (< 1.5 cm) in elderly patients due to faster recovery and reduced complications.

INTRODUCTION

As one of the most common lesions of the digestive system, the incidence of colon polyps increases significantly with age and is particularly prevalent in the elderly population[1]. In addition to presenting with symptoms such as abdominal discomfort and alterations in bowel habits, colon polyps may also have the potential for malignant transformation, which represents a significant risk to patients’ lives and health[2,3]. Therefore, timely and effective treatment is important for preventing colon cancer and improving the quality of life of elderly patients. Endoscopic mucosal resection (EMR) and argon plasma coagulation (APC) represent the principal endoscopic techniques employed in the treatment of colonic polyps[4-6]. Their widespread adoption in clinical practice is attributable to the benefits they offer in terms of reduced trauma, expedited recovery, and a relatively low incidence of complications. However, for this special group of elderly patients, the level of postoperative recovery and the risk of complications are important factors affecting the treatment effect[7]. Due to the decline of physiological function and the coexistence of multiple chronic diseases in elderly patients, postoperative recovery and complication management have become a challenge for clinicians[8].

EMR can remove polyps completely and reduce the risk of recurrence by excising the diseased mucosa and part of the muscle layer below[9,10]. APC uses high frequency current to excite plasma generated by argon gas to produce a thermal coagulation effect on the tissue surface to achieve the purpose of hemostasis and ablation of lesions[11]. However, the postoperative rehabilitation process for elderly patients is complex[12]. On the one hand, the metabolic capacity of elderly patients decreases and drug clearance slows down, which may result in an increase in drug side effects. On the other hand, they have numerous comorbidities, including hypertension, diabetes, and other chronic diseases, which may elevate the risk of surgery and impact postoperative recovery[13]. Therefore, evaluating and comparing the level of postoperative recovery and the risk of complications between EMR and APC in elderly patients with colonic polyps is important for optimizing treatment options and improving outcomes.

Despite the remarkable success of EMR and APC in the treatment of colonic polyps, there is still a lack of information regarding the effectiveness and safety assessment of their application in elderly patients. By retrospectively analyzing the clinical data of 224 elderly patients with colonic polyps, this study aimed to assess the differences between the two treatments, EMR and APC, in terms of the level of postoperative recovery and the risk of complications. This study is expected to provide new ideas and methods for the treatment of elderly patients with colonic polyps, optimize the treatment plan, improve the therapeutic effect and reduce the complication rate. By deeply analyzing the influencing factors of the level of postoperative recovery and the risk of complications, this study will provide useful references and lessons for research in related fields, and promote the further development of endoscopic technology in the treatment of geriatric gastrointestinal diseases. At the same time, this study will also provide a scientific basis for clinical decision-making, guiding doctors to choose treatment options more precisely and providing patients with safer and more effective treatment services.

MATERIALS AND METHODS

Patient population

This study used a single-center, retrospective study design. The study included 224 elderly patients who were treated for colon polyps at our center between January 2021 and July 2024. Patients were divided into the EMR group (124 cases) and APC group (100 cases) according to the different surgical methods. All patients met the following inclusion criteria: (1) Age ≥ 50 years old; (2) The colon polyp was confirmed by imaging examination and pathological biopsy; (3) Patients with polyps < 1.5 cm in diameter; (4) EMR and APC are indicated for surgical treatment; and (5) Patients with complete clinical data. The exclusion criteria were as follows: (1) Patients with malignant tumors; (2) Patients with hematological diseases or abnormal coagulation function; (3) Severe cardiopulmonary dysfunction; (4) Unable to tolerate surgery or refused EMR/APC treatment; and (5) Preoperative chemotherapy or other antitumor therapy. This study has been approved by the Ethics Committee of Jiujiang University Affiliated Hospital (Approval No. jjumer-b-2024-0720).

Treatment method

All patients received routine clinical examinations (including routine blood tests, biochemistry, coagulation function, and electrocardiogram) before surgery to determine the patients’ various surgical indications. Two days before the surgery, the patients’ diet was well managed, avoiding legumes and indigestible foods such as fish and meat. Patients were instructed to abstain from food and water for 8 hours and 2 hours, respectively, before the operation, and were urged to urinate and defecate to ensure that the gastrointestinal tract was clean and unobstructed.

EMR: The EMR procedure was conducted with the use of a standard colonoscope. The bowel was typically prepared prior to the procedure, the patient was positioned in the left lateral decubitus position, and the colonoscope was inserted after the administration of intravenous anesthesia. The polyp was then located under direct vision and a loop device was applied to the tip or base of the polyp. Subsequently, saline was injected to separate the submucosa from the muscularis propria, creating a ‘water cushion’. The polyp was then excised using the loopers or a scalpel, ensuring that at least 2 mm of normal mucosa was included around the polyp. After excision, hemostasis was performed using hemostatic clips or APCs.

APC: Similarly, the APC procedure was conducted with a standard colonoscope, employing the same preoperative preparations as those utilized for EMR. The polyp was located under direct vision and the APC probe was aimed at the surface of the polyp. The appropriate power and gas flow were set to perform continuous or intermittent coagulation until the surface of the polyp turned white or burnt-yellow, indicating that the diseased tissue had been coagulated and was necrotic. No special treatment was required following the procedure; however, the wound should be monitored for bleeding and treated with hemostatic clips or APC if necessary.

Postoperative management and follow-up

Postoperative patients were routinely fasted for 24 hours; intravenous fluid replacement and antibiotics were given to prevent infection. Twenty-four hours later, the diet was gradually resumed, with fluids or semi-fluids as the mainstay, and stimulating foods were avoided. After the operation, the patient’s vital signs were closely monitored, and observations were carried to determine whether the patient had abdominal pain, abdominal distension, blood in stool and other complications. After discharge, patients returned to the hospital for regular follow-ups, including colonoscopy, routine blood tests, coagulation function, etc., in order to assess the postoperative recovery, and to timely detect and manage complications. All patients were followed up for at least 12 months to assess postoperative recovery and the occurrence of complications. The determination of a patient’s relapse was made jointly by two clinicians based on the patient’s signs and clinical findings.

Observation indicators

Treatment effect was categorized into three levels: Marked effect, effective and ineffective. Marked effect was defined as complete removal of the polyp, no other symptoms, and a review of normal indicators. Effective was defined as complete removal of the polyp with significant improvement in all indicators. Ineffective was defined as complete removal of the polyp, but clinical symptoms had not improved and all indicators remained abnormal. The ‘total effective rate’ was defined as the proportion of patients who achieved either ‘marked effect’ or ‘effective’ outcomes, excluding those classified as ‘ineffective’. Surgical treatment indices included operation time, intraoperative blood loss, gastrointestinal function recovery time and hospital stay. In addition, indicators of one-time resection rate, preoperative and postoperative levels of procalcitonin (PCT) and C-reactive protein (CRP) were collected from patients. The complication indices mainly included bleeding, incision infection, postoperative abdominal pain, abdominal perforation and so on. The recurrence status of patients was mainly analyzed at 6 months and 12 months after surgery.

Statistical analysis

Statistical analysis software SPSS 23.0 was used for data analysis. The counting data were described in the form of mean ± SD, and the difference between groups was analyzed using the t-test. The measurement data were described by frequency and percentage, and χ² test and Fisher’s exact test probability method were used to analyze the difference between the groups. All statistical tests were conducted bilaterally, and P < 0.05 was considered statistically significant.

RESULTS

Comparison of general data between the two groups

The mean age of the EMR group was 55.35 ± 2.94 years, while that of the APC group was 55.72 ± 2.97 years, with no significant difference (P = 0.349; Table 1). There was no significant difference in gender composition between the two groups (P = 0.471). The mean diameter of polyps was 1.22 ± 0.19 cm in the EMR group and 1.25 ± 0.17 cm in the APC group, with no significant difference (P = 0.216). In addition, there were 104 (83.87%) cases of multiple polyps in the EMR group and 81 (81.00%) cases in the APC group, with no significant difference (P = 0.573). There was no significant difference in the types of polyps between the two groups (P = 0.892). These characteristics indicate that the two groups of patients have certain comparability.

Table 1 Comparison of general data between the two groups, mean ± SD/n (%).

Variables	Total (n = 224)	EMR (n = 124)	APC (n = 100)	Statistic	P value
Age (years)	55.51 ± 2.96	55.35 ± 2.94	55.72 ± 2.97	t = -0.94	0.349
Gender				χ2 = 0.52	0.471
Female	86 (38.39)	45 (36.29)	41 (41.00)
Male	138 (61.61)	79 (63.71)	59 (59.00)
Polyp diameter (cm)	1.23 ± 0.18	1.22 ± 0.19	1.25 ± 0.17	t = -1.24	0.216
Polyp number				χ2 = 0.32	0.573
Single polyp	39 (17.41)	20 (16.13)	19 (19.00)
Multiple polyps	185 (82.59)	104 (83.87)	81 (81.00)
Polyp type				χ2 = 0.23	0.892
Mucosal elevation	167 (74.55)	94 (75.81)	73 (73.00)
Sessile polyp	38 (16.96)	20 (16.13)	18 (18.00)
Pedunculated polyp	19 (8.48)	10 (8.06)	9 (9.00)

EMR: Endoscopic mucosal resection; APC: Argon plasma coagulation.

Comparison of surgical indices between the two groups

The mean operative time (10.63 minutes vs 13.27 minutes, P < 0.001), incidence of intraoperative bleeding (39.00% vs 52.42%, P = 0.031) and hospital stay (1.63 days vs 3.87 days, P < 0.001) in the APC group were significantly better than those in the EMR group (Table 2).

Table 2 Comparison of surgical treatment indices, mean ± SD/ n (%).

Variables	Total (n = 224)	EMR (n = 124)	APC (n = 100)	Statistic	P value
Operation time (min)	12.09 ± 3.34	13.27 ± 3.82	10.63 ± 1.76	t = 6.84	< 0.001
Intraoperative bleeding	104 (46.43)	65 (52.42)	39 (39.00)	χ2 = 4.63	0.031
Hospital stays (days)	2.87 ± 1.20	3.87 ± 0.40	1.63 ± 0.49	t = 37.78	< 0.001

EMR: Endoscopic mucosal resection; APC: Argon plasma coagulation.

Comparison of one-time resection rates

In the EMR group, a total of 267 polyps were identified in 124 patients, of which 238 (89.14%) were removed in a single procedure. In the APC group, 226 polyps were observed in 100 patients, with 214 (94.69%) of these removed in a single procedure. The rate of one-time resection in the APC group was significantly higher than that observed in the EMR group (P = 0.026; Table 3).

Table 3 Comparison of one-time resection rates, n (%).

Group	Number of polyps	One-time excision	Two or more resections
EMR	267	238 (89.14)	29 (10.86)
APC	226	214 (94.69)	12 (5.31)
χ2		4.95
P value		0.026

EMR: Endoscopic mucosal resection; APC: Argon plasma coagulation.

Comparison of treatment effect

The total effective rate was 94.35% in the EMR group and 92.00% in the APC group, and there was no significant difference between the two groups (Table 4).

Table 4 Comparison of treatment effects, n (%).

Group	Cases	Marked effect	Effective	Ineffective	Total effective
EMR	124	64 (51.61)	53 (42.74)	7 (5.65)	117 (94.35)
APC	100	47 (47.00)	45 (45.00)	8 (8.00)	92 (92.00)
χ2					0.49
P value					0.483

EMR: Endoscopic mucosal resection; APC: Argon plasma coagulation.

Comparison of inflammation levels before and after treatment

Compared with the preoperative period, PCT levels were significantly higher in both the EMR and APC groups after surgery (P < 0.001; Table 5). There was no significant difference in the preoperative PCT levels between the two groups (P = 0.075), and the postoperative PCT levels in the APC group were significantly lower than those in the EMR group (P < 0.001). Postoperative CRP levels were significantly increased in both groups (P < 0.001). Postoperative CRP levels were significantly lower in patients in the APC group than in the EMR group (P < 0.001).

Table 5 Comparison of inflammation levels before and after surgery, mean ± SD.

Group	PCT (mg/L)			CRP (ng/mL)
	Before	After	P value	Before	After	P value
EMR	43.31 ± 4.77	68.85 ± 7.74	< 0.001	0.33 ± 0.12	0.83 ± 0.21	< 0.001
APC	44.51 ± 5.41	55.16 ± 6.39	< 0.001	0.35 ± 0.15	0.55 ± 0.17	< 0.001
P value	0.075	< 0.001		0.544	< 0.001

EMR: Endoscopic mucosal resection; APC: Argon plasma coagulation; PCT: Procalcitonin; CRP: C-reactive protein.

Comparison of complications

A total of 9 (7.26%) patients in the EMR group had complications. There were 4 (3.23%) cases of bleeding, 3 (2.42%) cases of incision infection, 2 (1.61%) cases of postoperative abdominal pain and no abdominal perforation (Table 6). Complications occurred in 3 (3.00%) patients in the APC group. Among them, 2 (2.00%) cases experienced hemorrhage and 1 (1.00%) case experienced postoperative abdominal pain. There was no significant difference in the overall complication rate between the two groups (P = 0.159).

Table 6 Comparison of complications, n (%).

Group	Cases	Bleeding	Incision infection	Postoperative abdominal pain	Abdominal perforation	Total complications
EMR	124	4 (3.23)	3 (2.42)	2 (1.61)	0 (0.00)	9 (7.26)
APC	100	2 (2.00)	0 (0.00)	1 (1.00)	0 (0.00)	3 (3.00)
χ2						1.98
P value						0.159

EMR: Endoscopic mucosal resection; APC: Argon plasma coagulation.

Postoperative recurrence

In the EMR group, there were 2 (1.61%) patients with recurrence at 3 months after surgery and 10 (8.06%) patients with recurrence at 6 months (Table 7). No one in the APC group had a recurrence at 3 months after surgery, and 2 (2.00%) had a recurrence at 6 months.

Table 7 Comparison of postoperative recurrence rates, n (%).

Group	Cases	6th month	12th month
EMR	124	2 (1.61)	10 (8.06)
APC	100	0 (0.00)	2 (2.00)
χ2			4.02
P value		0.504	0.045

EMR: Endoscopic mucosal resection; APC: Argon plasma coagulation.

DISCUSSION

The objective of this study was to evaluate the discrepancy in postoperative recovery and the incidence of complications between EMR and APC in the treatment of elderly patients with colonic polyps. By retrospectively analyzing the clinical data of 224 elderly patients treated at our center between January 2021 and July 2024, we obtained some insightful and clinically instructive findings. In the following section, we will discuss the main results in detail and attempt to elucidate the underlying reasons for these findings. A comparison of the general data of the patients revealed no significant differences between the EMR and APC groups in terms of age, gender, polyp diameter and polyp number. This indicates that the two groups were comparable in terms of baseline characteristics, thereby enhancing the reliability of the findings. A comparison of surgical treatment indicators revealed that the APC group exhibited significantly superior outcomes in terms of operative time, intraoperative bleeding, and hospital stay compared to the EMR group. This finding may be attributed to the characteristics of the APC technique, in which the plasma generated by argon gas excited by a high-frequency current produces a thermocoagulation effect on the tissue surface to achieve hemostasis and ablation of the lesion[14,15]. Compared with EMR, APC is easier and faster to perform and less damaging to the tissues, thus possibly reducing the procedure time and intraoperative bleeding, and consequently the length of hospital stay[16]. In a comparison of the one-time polyp removal rates, the APC group also exhibited higher removal rates. This may be attributed to the fact that the coagulation effect of APC is capable of acting in a more uniform manner on the polyp surface, thereby facilitating the complete ablation of polyp tissue[17]. In contrast, EMR necessitates a more exacting degree of control over the depth and extent of the incision when removing polyps, in order to prevent damage to the surrounding normal tissues. Consequently, in certain instances, this may necessitate the performance of multiple resections in order to achieve complete removal[18,19].

Although APC demonstrated advantages in terms of operation time and polyp removal rate at one point in time, a comparison of treatment outcomes revealed no significant difference in the total effective rate between the EMR and APC groups. This indicates that both treatments are equally effective in the removal of polyps and the alleviation of patient symptoms[20,21]. It is noteworthy that the comparison of postoperative inflammatory markers revealed a significant reduction in both PCT and CRP levels in the APC group relative to the EMR group. APC coagulates the tissue surface by excitation of plasma generated by argon gas, a technique that allows precise control of the coagulated area and reduces damage to surrounding normal tissue[22]. Due to its non-contact and precise nature, APC may offer advantages in reducing postoperative inflammatory responses, which could result in lower levels of PCT and CRP[23]. Secondly, the coagulation effect of APC may facilitate the postoperative wound healing process at a faster rate and reduce the release of postoperative inflammatory mediators.

A comparison of the incidence of complications revealed that the EMR group exhibited a marginally elevated rate in this regard relative to the APC group. However, no statistically significant discrepancy was identified between the two groups. The complications observed in the EMR group were primarily bleeding, incision infection and postoperative abdominal pain[24]. These findings suggest that the greater tissue damage associated with the EMR procedure and the slower postoperative recovery may be contributing factors[25]. Nevertheless, the complication rates of both treatments were low, and no serious complications such as abdominal perforation occurred, which indicates that both EMR and APC are safe procedures for the treatment of elderly patients with colonic polyps[26]. Ultimately, a comparison of postoperative recurrence revealed that the EMR group exhibited a higher recurrence rate than the APC group at both 6 months and 12 months intervals following surgery[27]. Although the difference between the two groups was not statistically significant, this trend nevertheless merits further investigation. This may be attributable to the fact that EMR may leave some diseased tissue behind when removing polyps, whereas the coagulation effect of APC is capable of more thoroughly ablating polyp tissue, thus reducing the risk of recurrence[28,29]. Nevertheless, given the brief follow-up period and the restricted sample size of the present study, further investigation is required to substantiate this conclusion.

There are some limitations in this study. Firstly, this was a single-center, retrospective study with a relatively homogeneous sample source, which may not be representative of different populations. Consequently, the results may not be generalizable or extrapolatable to other populations. Second, patients treated with EMR and APC may differ in severity of disease, comorbidities, or other unmeasured confounders, which may affect comparisons of treatment outcomes and complications. Finally, although all patients were followed for at least 6 months, this follow-up time may not be sufficient to fully assess some late complications or recurrences that may occur after a longer period of time. In subsequent studies, the results of this investigation can be further corroborated and the aforementioned constraints can be addressed by expanding the sample size, conducting a multicenter study, extending the follow-up period, controlling for additional confounding variables, and conducting a prospective randomized controlled trial.

CONCLUSION

A retrospective analysis of the clinical data of 224 elderly patients with colonic polyps revealed that APC exhibited several superior aspects compared to EMR in the treatment of these patients. In particular, APC has the advantage of a shorter operative time and less intraoperative bleeding. Furthermore, it has been demonstrated to promote postoperative recovery, as evidenced by lower postoperative levels of PCT and CRP, indicating a less severe inflammatory response. This contributes to shorter hospital stays. Although no significant difference was observed in the incidence of complications between the two groups, the APC group exhibited a slightly lower rate of complications and no serious adverse events, further substantiating the safety and efficacy of this approach. These findings support APC as a safe and effective option for selected elderly patients, but its applicability to larger polyps or complex cases requires further study. Nevertheless, as this was a single-center, retrospective study with a limited sample size and a relatively short follow-up period, these findings require further validation in future multicenter, prospective studies and assessment for long-term efficacy and safety. The principal clinical and practical significance of this study is to provide a safer and more effective treatment option for elderly patients with colonic polyps. This may help to reduce surgical trauma, accelerate postoperative recovery and potentially reduce the risk of complications, thereby improving patients’ quality of life.