Is Prophylactic Abdominal Drainage Necessary After Laparoscopic Colectomy For Colon Cancer? A Propensity Score-Matched Analysis

Background: In 2018, the Enhanced Recovery After Surgery (ERAS) Society recommended against routine drainage after colorectal surgery. However, the evidence is relatively old and few studies were performed in low-to-middle income country (LMIC) setting. This study aimed to compare outcomes of laparoscopic colectomy with and without prophylactic drainage for colon cancer. Methods: A retrospective study was performed from 2018 to 2021 with patients who underwent laparoscopic colectomy with D3 lymphadenectomy for colon cancer. The use of prophylactic drainage was depended on routine practice of surgeons. Outcomes were postoperative complications and postoperative hospital length of stay. The drain and no-drain groups were compared using propensity score-matched (PSM) analysis. Results: The study included 143 patients (59 in the drain group and 84 in the no-drain group). The PSM resulted in 94 patients (47 in each group). Median age was 62 years. The most frequent was right hemicolectomy (33.6%), followed by left hemicolectomy (32.2%), sigmoid colectomy (21%), extended right hemicolectomy (9.8%), transverse hemicolectomy (2.1%), and total colectomy (1.4%). Postoperative hospital stay was signicantly shorter in the no-drain group (median of 5 versus 6 days). The no-drain group also had lower rate of complications (23.8% versus 30.5% and 23.4% versus 34% before and after matching respectively) and less severe complications based on Clavien-Dindo classication, but the difference was not signicant. Conclusions: Laparoscopic colectomy without prophylactic drainage is safe in the treatment of colon cancer. This approach can shorten postoperative hospital stay and should be applied even in the LMIC setting. aspect: Laparoscopic Our study revealed the safety and effectiveness of laparoscopic colectomy without prophylactic drainage after surgery for colon cancer in a LMIC setting. Compared to laparoscopic colectomy with prophylactic drainage, the approach without prophylactic drainage yielded similar safety results when considering the prevention of postoperative complications. The rate of anastomotic leak, bleeding, abdominal abscess and reoperation due to complications was low and balanced between the two groups. With respect to the effectiveness, the two groups were not signicantly different in the time to atus, time to oral feeding and time of analgesics use, but the approach without prophylactic drainage signicantly shortened the length of postoperative hospital stay.


Introduction
In 2018, the Enhanced Recovery After Surgery (ERAS) Society's guidelines recommended that pelvic and peritoneal drains should not be used routinely in perioperative care in colorectal surgery. [1] However, with routine practices of many surgeons in a long period, prophylactic drainage after colectomy is not easily abandoned, particularly in low-to-middle income country (LMIC) setting. Prophylactic abdominal drains after colectomy have been used to early detect potential complications including bleeding and anastomotic leakage, and prevent uid accumulation. On the contrary, routine drainage can cause some disadvantages such as increased serous secretion, increased risk of intra-abdominal infection, bowel obstruction, and prolonged hospital length of stay. [2][3][4][5] There were a number of studies on the safety and effectiveness of prophylactic drainage after elective colorectal surgery and most of them showed similar complication rate between groups with and without routine drainage. [2,3,[5][6][7] Most authors agreed that prophylactic drains had no effect on clinical outcomes in elective colorectal surgery. Nevertheless, the majority of these studies were performed in upper-middle-or high-income countries, which healthcare facilities are better than in LMICs. Whether no prophylactic drainage after colectomy is safe in LMIC setting is still questioned. Also, the ERAS Society's recommendation was based on relatively old evidences, which most of the studies were performed around 20 years ago. [2,7] Meanwhile, there have been changes in colectomy, for example, the wide application of minimally invasive surgery, more radical surgery such as complete mesocolic excision and extended lymph node dissection (D3 lymphadenectomy), stapled anastomosis, and the use of new instruments in the surgery. Updated studies on whether the use of routine drainage is necessary after colorectal anastomosis are needed.
In our hospital, we started to apply the ERAS guidelines without routine drainage for colectomy since 2018 and the results are promising. Hence, this study aimed to compare outcomes of patients who underwent laparoscopic colectomy with and without prophylactic abdominal drainage in the treatment of colon cancer.

Study design and patients
This is a retrospective study performed at Gia Dinh People's hospital, a referral teaching hospital in Ho Chi Minh City, Vietnam. The study was approved by the ethics committees of the hospital (No. 35/NDGD-HDDD on 22 April 2021) and University of Medicine and Pharmacy at Ho Chi Minh City (No. 114/HDDD-DHYD on 17 February 2021). All patients who underwent laparoscopic colectomy for the treatment of colon cancer from January 2018 to June 2021 were selected and divided into two groups: one with prophylactic drainage after surgery (drain group) and the other without prophylactic drainage (no-drain group). We excluded patients with the conversion to open surgery. Informed consent was waived since all data were retrospective collected.
The use of prophylactic drainage after surgery was decided by the operating surgeon and this was mainly depended on the routine practice of the surgeons rather than any clinical criterion. Patients in both groups were treated with the same protocol for preoperative preparation, intraoperative approach (except for prophylactic drainage after surgery), and postoperative evaluation. Preoperative bowel preparation was done or not depending on the operating surgeons. All patients underwent laparoscopic or laparoscopyassisted colectomy with hand-sewn or stapled anastomosis. The colectomy along with D3 lymphadenectomy were performed in accordance with the Japanese Society's guidelines for Cancer of the Colon and Rectum. [8] In the drain group, 28F natural latex rubber tubes without vacuum devices (passive drains) were used to place near the anastomosis. The drains were removed when the output was less than 20 ml per day and the color of the output uid was normal (light pink or light yellow). Antimicrobial prophylaxis was administered for all patients in both groups.
Patient's characteristics were collected using the hospital medical records, including preoperative variables (age, sex, body mass index [BMI], comorbidities, history of abdominal surgery, American Society of Anesthesiologists [ASA] score, hemoglobin, serum albumin), intraoperative variables (surgical method, operating time, combined surgery, the amount of blood loss, anastomosis technique, the number of drains), and pathological ndings (tumor's location and stage according to the American Joint Committee Cancer [AJCC] tumor/node/metastasis [TNM] classi cation and staging system). Outcomes of interest were postoperative complications (abdominal uid collection, abscess, bleeding, anastomotic leakage, bowel obstruction, surgical site infection, and other organ complications), length of postoperative hospital stay, and time to atus and oral feeding. All complications were recorded within 30 days after surgery and were evaluated using the Clavien-Dindo classi cation. [9] Statistical analysis Data were summarized by each group using median and interquartile range (IQR) for continuous variables and count and percentage for categorical variables. The comparison between the two groups was performed using Mann-Whitney-U test and Fisher's exact test for continuous and categorical variables respectively. We used propensity score-matched (PSM) analysis to adjust for differences in baseline and operating characteristics between the two groups. The propensity score was developed from a logistic regression model with covariates age, sex, BMI, ASA score, TNM stage, the type of surgery (elective or emergency), type of colon resection, and preoperative bowel preparation. Matched cases were selected at a ratio of 1:1 using the nearest neighbor method with a caliper of 0.1. We used the statistical software R version 4.1.0 to analyze the data and the 'MatchIt' package for the PSM analysis. [10] Results A total of 143 patients with colon cancer underwent laparoscopic colectomy from January 2018 to June 2021 were included in the study: 59 patients with prophylactic drainage and 84 patients without prophylactic drainage after the surgery. The PSM strategy resulted in 94 patients (47 patients in each group). The characteristics of the patients and tumors were more balanced between the two groups after matching ( Table 1, Table 2).   In our study, the tumors located in all sections of the colon. Before matching, the most frequent were the sigmoid colon (25.4% and 20.2% in the drain and no-drain groups respectively), followed by the descending colon (22% and 17.9%) and left colic exure (15.3% and 7.1%). According to the TNM staging system, most of the patients were graded as stage III postoperatively (57.6% and 71.4% in the drain and no-drain groups before matching). After matching, tumor's location and stage were balanced between groups ( Table 2).
Preoperative bowel preparation was performed in 18.6% and 10.7% of the patients in the drain and nodrain groups before matching. The operating time was similar in the two groups (median was 210 and 198 mins before matching and 205 and 198 after matching in the drain and no-drain groups respectively). Before matching, the most frequent types of colectomy were right hemicolectomy (48 patients, 33.6%), followed by left hemicolectomy (46 patients, 32.2%). Median intraoperative blood loss was 50 ml in both groups and 11 patients (5 in the drain group and 6 in the no-drain group) required blood transfusion. Most operative characteristics were balanced between groups after matching ( Table  3). The median (IQR) time of drainage in the drain group was 5 (4.2; 6) days.

IQR, interquartile range
There were no signi cant differences in time to oral feeding, time of analgesics use, and time to atus between the two groups in both the analyses before and after matching. Postoperative hospital length of stay, however, was signi cantly shorter in the no-drain group compared to the drain group in both the unmatched and matched cohorts (median of 5 versus 6 days). The drain group had higher rate of postoperative complications and more severe complications based on Clavien-Dindo classi cation in both the analyses before and after matching, however the difference did not reach statistical signi cance.
The most frequent complication was uid accumulation but all required medical treatment only. Other complications were uncommon (Table 4).

Discussion
Our study revealed the safety and effectiveness of laparoscopic colectomy without prophylactic drainage after surgery for colon cancer in a LMIC setting. Compared to laparoscopic colectomy with prophylactic drainage, the approach without prophylactic drainage yielded similar safety results when considering the prevention of postoperative complications. The rate of anastomotic leak, bleeding, abdominal abscess and reoperation due to complications was low and balanced between the two groups. With respect to the effectiveness, the two groups were not signi cantly different in the time to atus, time to oral feeding and time of analgesics use, but the approach without prophylactic drainage signi cantly shortened the length of postoperative hospital stay.
Prophylactic drainage is expected to provide some bene t. The rst is to remove collected uid after surgery, which is thought to reduce the risk of intra-abdominal infection. [11,12] The second is to early detect postoperative complications such as intra-abdominal bleeding or anastomotic leakage. Another potential bene t is to minimize the severity of leakage when occurring and possibly avoid reoperation. [13,14] Our study showed that there was no difference in uid accumulation and intra-abdominal infection between the two groups. Thus, similar to other studies, [1,15] our results suggest that prophylactic drainage for the prevention of intraperitoneal uid accumulation is not necessary.
Abdominal drainage might have a role in the diagnosis and treatment of anastomotic leakage. In our study, one patient in the drain group was diagnosed with anastomotic leakage at day 6 postoperatively without clinical signs of peritonitis except that there was fecal uid in the drain's output. Conservative treatment was successful for that patient. Whereas two patients in the no-drain group with anastomotic leakage required reoperation, one with a misdiagnosis of postoperative paralytic ileus and the other with a diagnosis of localized peritonitis in the right upper quadrant. Prophylactic drainage in these two patients might help to early diagnose anastomotic leakage or prevent reoperation. Therefore, routine drainage may still play a role in the diagnosis and treatment of anastomotic leakage. Nevertheless, it should be highlighted that with the application of the ERAS protocol and the advancement of surgical techniques and instruments, anastomotic leakage is very rare. Thus, routine drainage for all patients should be considered and further studied in terms of the diagnosis and prevention of anastomotic leakage.
On the other hand, routine drainage may cause some problems. In our study, three patients in the drain group had intestinal obstruction; one patient resolved after drain removal and two patients required reoperation. Whether the drainage tube causes intestinal obstruction is still unclear, but this complication was mentioned before. [4,16] In addition, routine drainage can cause other problems such as pain, discomfort and limitation of returning to normal activities of the patients.
Routine abdominal drainage is still under debate in colectomy for colon cancer. Some studies showed no signi cant difference between the groups with and without prophylactic drainage in terms of postoperative complications such as anastomotic leakage, mortality, wound infection, pelvic sepsis, postoperative bowel obstruction and reintervention for abdominal complication. [5,7,13,[17][18][19][20] Several other studies favored routine drainage after colorectal surgery because a prophylactic drain could reduce the incidence of colorectal anastomotic leakage and the rate of reintervention due to complications. [21][22][23] However, since most level-I evidence studies (well-designed randomized controlled trial and systematic review and meta-analysis) recommended against the use of prophylactic drainage, we agree with the ERAS guidelines that routine drainage should not be used after colorectal anastomosis. Since most of the studies were performed in the upper-middle-or high-income countries, our study supports this recommendation in the LMIC setting.
There are several limitations in this study. First, the sample size of the study is relatively small. Second, there was potential selection bias in the comparison between the two groups, which is a nature of a nonrandomized comparative study. We tried to overcome this issue by using the PSM analysis, but potential bias might not be ruled out completely. Third, this study came from a single center with a single surgical team. This might limit the generalizability of the results to other settings.
In conclusion, laparoscopic colectomy without prophylactic drainage is safe in the treatment of colon cancer. This approach does not increase postoperative complications but shortens the length of postoperative hospital stay when compared to the surgery with routine prophylactic drainage. We suggest against the use of prophylactic drainage after laparoscopic colectomy for colon cancer even in the LMIC setting. Declarations