Comparison of Complications and Long-term Permanent Stoma Rate in Robot-Assisted versus Laparoscopic Low Anterior Resection: A Propensity Score Matched Retrospective Cohort Study

doi:10.21203/rs.3.rs-4191663/v1

Aims

While some research points to the short-term advantages of robot-assisted low anterior resection (LAR) for mid-to-low rectal cancer, a detailed focus on outcomes like permanent stoma remains scant.

Methods

We conducted a retrospective analysis on a continuous series of non-metastatic mid-to-low rectal cancer patients. Between 2016 and 2020, these patients underwent either robot-assisted or traditional laparoscopic LAR at a singular center. We used a propensity score matching technique, and the participants were matched in a 1:2 ratio.

Results

Post-matching, our cohort consisted of 44 patients from the robot-assisted LAR group and 88 from the laparoscopic LAR group. The long-term results, such as overall survival, cancer-free survival, and local and distant recurrence rates, exhibited no significant differences between the two groups. However, the robot-assisted group exhibited a notably shorter average post-surgery hospitalization (10.8 vs. 16.7 days, p = 0.001), reduced incidence of anastomotic leakage (11.4% vs. 37.5%, p < 0.001), fewer patients requiring a permanent stoma (13.6% vs. 29.5% p = 0.044), and significantly lower occurrences of grade III Clavien Dindo Surgical Complications. The utilization of 3D laparoscopy was unanimous in the robot-assisted group (100% use) compared to just 40.9% in the laparoscopic group. Furthermore, the robot-assisted procedures had a diminished frequency of firing three or more staplers (2.3% vs. 26.1%, p = 0.001). A multivariate logistic regression indicated that robot-assisted LAR is independently associated with a reduced risk of permanent stoma (OR: 0.28, p = 0.033, 95% CI 0.087–0.901).

Conclusion

In patients with mid-to-low rectal cancer, robot-assisted LAR, despite comparable long-term survival and recurrence rates, displayed reduced complications, including fewer instances of anastomotic leakage and permanent stoma requirements than its laparoscopic counterpart. These findings imply the potential superiority of robot-assisted surgical techniques for mid-to-low rectal patients.

Rectal cancer

Robot-assisted

Laparoscopy

Permanent stoma

Survival

Complication

Surgical resection is a widely recognized and effective treatment option for rectal cancer, and significant advancements have been made in its management over time. One notable development has been transitioning from traditional laparotomy resection to minimally invasive surgery. In particular, robot-assisted minimally invasive surgery has gained immense popularity worldwide since its introduction in 2006.[1] Conventional laparoscopic procedures utilize long and rigid instruments and encounter inherent limitations when managing lower rectal cancers in the narrow pelvis. In contrast, robot-assisted resection offers distinct advantages over traditional laparoscopy. These advantages include overcoming counter-intuitive motion, reduced dexterity, and reliance on assistants for traction.[2] The robotic approach combines technological advantages, especially in demanding situations like dissecting a deep and narrow pelvis. The robotic digital platform offers enhanced surgical precision through advanced features, including an improved 3-dimensional view, EndoWrist surgical tools, stable camera movement, and reduced tremor. Moreover, flexible robotic arms enhance the overall quality of the surgical procedure.

While greater instrument flexibility can contribute to higher surgical quality in narrow spaces, it is essential to acknowledge that robot-assisted surgery comes with higher costs than laparoscopic surgery.[3] Hence, acquiring more substantial and compelling evidence becomes crucial to confidently determine the optimal utilization of robotic surgery in clinical practice, considering both its potential benefits and the financial implications it brings. However, randomized controlled trials focused on rectal resection have demonstrated comparable outcomes regarding total mesorectal excision (TME), postoperative morbidity, and conversion rates between robot-assisted and laparoscopic resections.[4–6] Several studies have indicated potential short-term advantages of robot-assisted low anterior resection (LAR) for mid-to-low rectal cancer.[7] However, there is conflicting evidence among these trials [8], making it challenging to draw definitive conclusions regarding the benefits of robot-assisted LAR in this specific context.

Nevertheless, there is a lack of studies that specifically investigate the long-term outcomes related to the permanent stoma in patients undergoing these procedures. Therefore, this study aims to evaluate the safety, efficacy, and long-term stoma status of robot-assisted low anterior resection (LAR) compared to laparoscopic surgery for middle or low rectal cancers. This assessment will be conducted while accounting for other confounding factors using a propensity score-matched method. The aim is to provide comprehensive insights into the impact of the surgical approach on the permanent stoma outcomes in these patients.

The Chang Gung Medical Foundation Institutional Review Board approved this study (IRB No. 202301006B0). We collected and analyzed the data of 1162 rectal cancer patients who underwent surgery at the Division of Colorectal Surgery, Chang Gung Memorial Hospital, Linkou, from January 1, 2016, to December 31, 2020 (Fig. 1). Before the surgery, we performed preoperative evaluations such as colonoscopy, chest-pelvis computed tomography, pelvic magnetic resonance imaging (MRI), rectal sonography (if needed), and essential laboratory tests (including serum carcinoembryonic antigen). We also prospectively recorded each patient’s clinical characteristics, such as age, sex, comorbidities (cardiovascular disease, cirrhosis, etc.), tumor location, and the neoadjuvant chemoradiation regimens.

The surgeon decided whether to use neoadjuvant concurrent chemoradiation (CCRT) or short-course radiotherapy for patients with locally advanced rectal cancer (cT3, cT4, or positive cN stage). Patients receiving neoadjuvant CCRT had a 5-fluoropyrimidine-based regimen (5-fluorouracil, capecitabine, or tegafur) and 50.4 Gy of radiotherapy in 28 fractions. They had surgery 6 to 8 weeks after finishing the therapy. Patients with short-course radiotherapy got a dose of 25 Gy in 5 fractions to the pelvis and tumor. They had surgery 8 to 10 days after radiotherapy or additional 5-fluoropyrimidine-based neoadjuvant chemotherapy before the surgery. The surgeon chose a 5-fluoropyrimidine-based regimen (5-fluorouracil, capecitabine, or tegafur) for the adjuvant chemotherapy. Whether to give oxaliplatin to the patient is based on each surgeon’s decision.

All of the robotic device used in this study was the Da Vinci® Xi surgical system (Intuitive Surgical, Sunnyvale, CA, USA), and we used 4 robotic arms and one assistant arm in all of the robotics-assisted surgery. The anastomotic methods in this study were the ILS curved 29-mm intraluminal stapler (CDH 29, Ethicon Endo-Surgery) with or without hand-sewn reinforcement or coloanal hand-sewn anastomosis, each surgeon determined the choice of anastomosis during the surgery. The cartridges were used for transactions on the distal side of the rectum. Additional firing would be applied if the transaction was incomplete with one cartridge. The common reasons for multiple firings were the narrow pelvis, inability to visualize the cartridge application, limited angle for applying the cartridges, and the number of cartridge firings strongly associated with anastomotic leakage.[9] We used ECHELON FLEX™ ENDOPATH® Staplers (Ethicon, Johnson & Johnson, New Brunswick, NJ) with 60 mm or 45 mm green cartridges in both the robotic-assisted and laparoscopy groups. Each surgeon determined the size of the cartridge intraoperatively. After the anastomosis, we routinely performed air-leak tests. If air leakage was detected, we would add an additional suture and re-perform the test. A re-anastomosis and preventive stoma would be performed if the air leakage was still persisted. The surgeons in our center usually create a preventive stoma in patients with lower rectal cancer, narrow pelvic cavity, those who received neoadjuvant radiotherapy, and malnutrition status.[10–13] However, the final decision depended on each surgeon during the surgery.

The anastomotic leakage was diagnosed clinically and radiologically as one of the following: diffuse peritoneal signs, gross fecal content from the wound or the drainage tube, pelvic abscess with fever and sepsis, pus-like discharge from anus and rectovaginal fistula. Although most patients had radiological tests when leakage was suspected, some patients with diffuse peritonitis after intestinal resection with anastomosis underwent immediate exploratory laparotomy. Once the leakage occurred, our first attempt was laparoscopic exploration for fecal diversion and drainage. However, we would opt for laparotomy exploration in patients with unstable hemodynamic status, which made them unsuitable for laparoscopic exploration. We also recorded other complications, such as surgical wound infections, postoperative ileus, and genitourinary system involvement. Postoperative ileus was defined after ruling out anastomotic leakage clinically and radiologically.

After the surgery, we documented the pathological stage, cancer histology, length of hospital stay, stoma status, and complications. We followed a standardized protocol to arrange postoperative follow-up. "Local recurrence" refers to the reappearance of cancer in the pelvic region following surgery. On the other hand, "distal metastasis" is characterized by the recurrence of cancer beyond the pelvic area, such as in the liver, lungs, or other lymph nodes. Before closing the stoma, a digital rectal examination was conducted to assess the connection between the two ends of the intestine and to examine for any infection near the anus. An extra colonoscopy or lower gastrointestinal series was performed when the digital rectal examination results were inconclusive.

We compared patients who had laparoscopy anterior resection and robot-assisted anterior resection. We did not include patients with Transanal Total Mesorectal Excision or laparotomy surgery. We also excluded patients with a non-curative resection, metastatic disease, recurrent cancer, emergency surgery, or non-adenocarcinoma types such as sarcoma, melanoma, and gastrointestinal stromal tumor. We excluded patients with upper rectal cancer (> 10 cm from the anal verge) because they had a low chance of anastomosis leakage and stoma creation. We also omitted patients who had abdominoperineal resection or Hartmann’s procedure because they did not have anastomosis and had immediate permanent stoma after the surgery. The permanent stomas included stomas that were not closed or reopened. The stomas that were not closed were those that did not have a reversal procedure until the end of the follow-up period. Stomas reopened, had a recreation procedure after a previous closure, and remained open until the end of the follow-up.

We performed statistical analysis using SPSS statistics software (version 24.0; SPSS Inc., Chicago, IL, USA). We compared continuous variables between the groups using an independent samples t-test and categorical variables using a chi-square or Fisher’s exact test. We calculated the survival curve between the groups by Kaplan–Meier analysis and used the log-rank test to compare it. We used multivariate logistic regression to identify the independent factors predicting permanent stoma. The p-value < 0.05 is considered statistically significant.

A total of 1162 rectal cancer patients were included in this study. After exclusion, a total number of 424 non-metastatic mid-to-low rectal patients were included and divided into the robot-assisted group (n = 44) and laparoscopy group (n = 380) (Figure 1). A comparative analysis of clinical and pathological factors revealed that the robot-assisted group had a greater prevalence of low rectal tumors (located less than 5 cm from the anal verge) and received more neoadjuvant radiation treatments, either long or short-course, and chemotherapy (Table 1). Post propensity score matching at a 1:2 ratio with a 0.05 caliper, the study analyzed 44 patients from the robot-assisted group and 88 from the laparoscopy group. The average monitoring period was 40.27 months, peaking at 73.8 months (Figure 1). After adjustments, there were negligible differences in clinicopathological factors between both groups.

However, the data indicated that the robot-assisted LAR patients experienced a reduced hospital stay, averaging 10.8 days compared to 16.7 days in the laparoscopy group (p = 0.001). They also demonstrated more utilization of total 3D laparoscopy and had fewer instances where resection staples were fired more than three times in the robot-assisted group (2.3% vs. 26.1%, p = 0.001, Table 2). The anastomotic choice of the intraluminal stapler and pull-through hand-sewn anastomosis between both groups was similar (p = 0.882, Table 2). Even though a more significant portion of the laparoscopy group received preventive stomas (63.6% vs. 43.2%, p = 0.025), the robot-assisted group reported a notably lesser rate of long-term permanent stomas (13.6% vs. 29.5%, p = 0.044). In patients with a permanent stoma, 16 out of 26 in the laparoscopy group were associated with anastomosis-related factors such as leakage, fistula, stenosis, or abscess In contrast, 8 patients were linked to cancer recurrence.2 In contrast, 3 out of 6 patients in the robot-assisted group were related to anastomosis-related factors, and 2 patients were associated with cancer recurrence (Table 3). Additionally, robot-assisted patients recorded decreased instances of anastomotic leakage (11.4% vs. 37.5%, p < 0.001) and a reduced frequency of Clavien-Dindo grade III complications (4.5% vs. 34.1%, p < 0.001).

Both the robot-assisted and laparoscopy groups displayed comparable long-term overall and cancer-free survival rates (Figure 2). The recurrence locations, including local recurrence, various distant metastasis sites, and the count of metastasis locations (single or multiple), were consistent between the two groups (Table 4). In multivariate analysis, the robot-assisted LAR showed a significantly lower risk of permanent stoma (OR: 0.28, p = 0.033, 95% CI 0.087-0.901) after adjusted with other confounding factors (Table 5).

With the rising adoption of robotic surgery in rectal cancer procedures, several studies have compared its efficacy to laparoscopy.[5, 6, 8, 14] For rectal cancer patients, avoiding a permanent stoma is crucial as it significantly impacts their self-image, mental well-being, and physical and emotional functions.[15] Nevertheless, no studies have specifically explored the long-term stoma status of patients currently. Thus, our research stands out as the first to examine the long-term stoma status in mid-and-low rectal cancer patients who underwent either robot-assisted or laparoscopic LAR. Our findings indicate that robot-assisted LAR results in shorter post-operative hospital stays, reduced anastomotic leakage, lower permanent stoma use and fewer grade III Clavien-Dindo complications.

While the long-term survival and complication rates were comparable between robot-assisted and laparoscopic anterior resections in patients with rectal cancer [8], studies have indicated certain advantages of robotic-assisted resection, specifically in cases of mid-to-low rectal cancer, obese or male patients.[4, 14, 16] Existing research has primarily focused on comparing survival, complications, and the use of permanent stomas between robotic-assisted laparoscopy LAR, with fewer studies examining the long-term implications of permanent stoma use. In our study, patients who underwent robot-assisted LAR exhibited similar long-term survival and recurrent rates but experienced significantly lower rates of anastomotic leakage (37.5% vs. 11.4%, p < 0.001), fewer grade III Clavien Dindo Surgical Complications (34.1% vs. 4.5%, p < 0.001), and a lower incidence of permanent stomas (29.5% vs. 13.6%, p = 0.044). These differences can be attributed to improved visibility during 3D laparoscopic surgery and reduced stapler usage.[17, 18] Furthermore, in robot-assisted surgery, the surgeon can independently control the endoscope during the procedure, reducing the need for assistance. Overall long-term survival, cancer-free survival, local recurrence, and distant recurrence rates were comparable between the two groups, indicating that both robotic-assisted and laparoscopic LAR can achieve a similar quality of cancer resection, as supported by current studies.[8, 19, 20] Although the laparoscopic LAR group in this study had a higher proportion of close or involved surgical margins, the local recurrence rate did not significantly differ between the two groups. This outcome may be attributed to radiotherapy and an equal or longer distal margin in laparoscopic LAR.

The use of a permanent stoma can significantly impact a patient's quality of life, leading to changes in body image and affecting their physical, mental, emotional, and social well-being [21]. Therefore, preserving organ function and avoiding the need for a permanent stoma are significant goals in treating rectal cancer. This study is the first to reveal a lower rate of permanent stoma use in rectal cancer patients undergoing robotic-assisted LAR than laparoscopic LAR. Although the Robotic vs. Laparoscopic Resection for Rectal Cancer (ROLARR) trial showed potential benefits of lower conversion rate in robot-assisted LAR in selected groups such as male or obese patients [4], studies comparing robot-assisted LAR and laparoscopic LAR did not report findings regarding the rate of permanent stomas in patients with mid-to-low rectal cancer.[4, 7, 8, 22–24] In our study, patients in both the robot-assisted LAR group and the laparoscopy group who had a permanent stoma were mainly affected by cancer recurrence and anastomotic complications (Table 3). These findings were compatible with our earlier study that the cancer recurrence and anastomotic complications such as stenosis or malunion were the primary factors contributing to permanent stomas in rectal cancer patients who underwent curative resection. [25] Therefore, the "quality of resection," which relates to local recurrence rate and cancer-free survival, is similar between robotic-assisted and laparoscopic LAR [8, 16]; the "quality of anastomotic creation" may be superior in the robotic-assisted group due to improved operative field visibility, flexible instruments, and reduced use of resecting staplers. Hence, robot-assisted LAR effectively reduces anastomotic complications and indirectly elevate the rate of closure of temporary stomas while maintaining a comparable local recurrence rate to laparoscopic LAR.

The first recorded cases of laparoscopic colorectal surgery in our hospital were in 2007. However, according to the chart review, the first case of robot-assisted colorectal surgery was in 2010. However, the conversion rate between the laparoscopy group and the robot-assisted group was similar in our study (2.3% vs. 0%, p = 0.314), and there was a lower complication rate in the robot-assisted group after propensity score matching. These results imply the advantage of robotic-assisted surgery and the short learning curve once abundant laparoscopic experiences are obtained beforehand.

Although we used the same laparoscopy stapler in both groups in our study, the robotic-assisted group is still associated with a lower rate of multiple cartridge firing. The lower multiple firing rates in the robotic-assisted group can be attributed to a better-approaching angle and a better perspective with the more flexible robotic arms in the pelvic cavity; we can be more assured of applying the cartridge than when approached with laparoscopic instruments. Moreover, one randomized controlled trial showed a similar number of cartridges used between laparoscopy staplers and robotic staplers in robotic-assisted rectal surgery [26], which implies that the approaching method is more important than the choice of laparoscopy or robotic staples.

This study had several limitations. Firstly, the retrospective study design with propensity score adjustment introduced potential selection bias that cannot be entirely ruled out. The decision to perform either robot-assisted LAR or laparoscopic LAR was left to each surgeon's discretion, leading to variations in treatment approaches. Factors such as the choice between long-course chemoradiation or short-course radiotherapy, the inclusion of concurrent chemotherapy, the addition of oxaliplatin to the chemotherapy regimen, and the waiting time before surgery all differed based on individual surgeon preferences. Moreover, the higher cost of robot-assisted surgery may have influenced patient selection. Patients with higher socioeconomic status may have been more likely to afford robot-assisted LAR, leading to a preference for individuals with better overall health conditions. This could have contributed to the lower leakage rate observed in the robot-assisted LAR group compared to the laparoscopic LAR group. In the duration of the data collection for this study, "enhanced recovery after surgery (ERAS)" was not incorporated as routine practice. However, our postoperative hospital stay (robotic-assisted group: 10.8 ± 4.8 days, laparoscopy group: 16.7 ± 13.9 days) is similar to that of other similar studies focusing on mid-to-low rectal cancer (13 days vs. 14 days) [27] With the incorporation of ERAS, the length of postoperative hospital stay may be shortened in recent years. In addition, due to a lack of postoperative quality of life data in our medical records, we were unable to provide relevant data in this study. However, many reports have demonstrated a negative impact of long-term stomas on rectal patients[28], including temporary stomas.[29]

While long-term survival and cancer-free survival rates are comparable, robot-assisted LAR patients have a reduced rate of postoperative complications, shorter hospital stay and permanent stoma usage than those undergoing laparoscopic LAR.

Disclosure

Hsin Hsu, Jeng-Fu You, Chun-Kai Liao, Tzong-yun Tsai, Wen-Sy Tsai, Cheng-Chou Lai, Pao-Shiu Hsieh, Chien-Yuh Yeh, Shu-Huan Huang have no conflicts of interest or financial ties to disclose.

Author Contribution

Hsin Hsu and Shu-Huan Huang wrote the main manuscript text. Hsin Hsu and Shu-Huan Huang prepared figures 1-2 and table 1-5. All authors reviewed the manuscript.

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Table 1. Clinicopathological factors between robotic-assisted and laparoscopy low anterior resection before and after propensity score matching

BMI: body mass index. CVA: Cerebrovascular accident. eGFR: estimated Glomerular filtration rate. CEA: carcinoembryonic antigen RT: radiation therapy

	Before propensity score matching			After propensity score matching
	Robot-assisted	Laparoscopy	P value	Robot-assisted	Laparoscopy	P value
Case number	44	380		44	88
Age (Std. dev)	63.5 (11.9)	62.1 (12.4)	0.465	63.5 (11.9)	59.4 (11.6)	0.061
Sex (%) M F	30 (68.2) 14 (31.8)	236 (62.1) 144 (37.9)	0.430	30 (68.2) 14 (31.8)	69 (78.4) 19 (21.6)	0.201
BMI (Std. dev)	24.6 (3.8)	24.5 (3.4)	0.741	24.6 (3.8)	24.7 (3.7)	0.912
CVA (%)	0	18 (4.7)	0.140	0	2 (2.3)	0.314
Liver cirrhosis (%)	0	5 (1.3)	0.444	0	0	n/a
eGFR ≤ 45 mL/min/1.73m² (%)	1 (2.3)	16 (4.2)	0.535	1 (2.3)	3 (3.4)	0.720
T stage (%) 0-2 3 4	22 (50) 21 (47.7) 1 (2.3)	148 (38.9) 206 (54.2) 26 (6.8)	0.246	22 (50) 21 (47.7) 1 (2.3)	29 (33) 53 (60.2) 6 (6.8)	0.125

Table 1. (continued)

	Before propensity score matching			After propensity score matching
	Robot-assisted	Laparoscopy	P value	Robot-assisted	Laparoscopy	P value
Case number	44	380		44	88
N stage (%) 0 1 2	32 (72.7) 7 (15.9) 5 (11.4)	227 (59.7) 92 (24.2) 61 (16.1)	0.245	32 (72.7) 7 (15.9) 5 (11.4)	46 (52.3) 26 (29.5) 16 (18.2)	0.077
Tumor diameter cm (Std. dev)	3.5 (1.5)	3.7 (1.8)	0.557	3.5 (1.5)	4.1 (2.1)	0.074
Tumor ≤ 5 cm from anal verge (%)	20 (45.5)	70 (18.4)	<0.001	20 (45.5)	29 (33)	0.161
Lymph Node < 12 (%)	4 (9.1)	15 (3.9)	0.118	4 (9.1)	5 (5.7)	0.464
Involved or closed circumferential margin (%)	8 (18.2)	114 (30)	0.101	8 (18.2)	34 (38.6)	0.017
Distal resected margin (Std. dev)	1.6 (1.1)	2.2 (5.2)	0.438	1.6 (1.1)	2.2 (1.5)	0.016

Table 1. (continued)

	Before propensity score matching			After propensity score matching
	Robot-assisted	Laparoscopy	P value	Robot-assisted	Laparoscopy	P value
Case number	44	380		44	88
Albumin < 3.5 g/dL	2 (4.5)	8 (2.1)	0.313	2 (4.5)	4 (4.5)	1
CEA > 5 ng/mL	7 (15.9)	91 (23.9)	0.231	7 (15.9)	21 (23.9)	0.292
Neoadjuvant RT^@ (%)	15 (34.1)	51 (13.4)	<0.001	15 (34.1)	41 (46.6)	0.171
Adjuvant or neoadjuvant chemotherapy	25 (56.8)	162 (42.7)	0.012	25 (56.8)	66 (75)	0.102
Chemotherapy with Oxaliplatin*	3 (23.1)	58 (49.2)	0.074	7 (28)	29 (43.9)	0.165

@ including short-course and long-course radiation therapy

* percentage of patients with chemotherapy

Table 2. Complications and surgical factors between robotic-assisted and laparoscopy low anterior resection

	Robot-assisted	Laparoscopy	P-value
Case number	44	88
Hospital stay (Std. dev)	10.8 (4.8)	16.7 (13.9)	0.001
3D laparoscopy (%)	44 (100)	36 (40.9)	<0.001
Resection staple ≥ 3 (%)	1 (2.3)	23 (26.1)	0.001
Anastomosis type Intraluminal stapler Hand-sewn	34 (77.3) 10 (22.7)	69 (78.4) 19 (21.6)	0.882
Preventive stoma (%)	19 (43.2)	56 (63.6)	0.025
Permanent stoma (%)	6 (13.6)	26 (29.5)	0.044
Converse to open surgery (%)	0	2 (2.3)	0.314
Complication by types (%) Anastomosis leakage Ureteral injury Ileus Urinary retention Respiratory failure	5 (11.4) 1 (2.3) 0 2 (4.5) 0	33 (37.5) 1 (1.1) 1 (2.3) 2 (2.3) 0	<0.001 0.614 0.478 0.473 n/a
Complication by Grades* (%) 1 2 3 4	1 (2.3) 5 (11.4) 2 (4.5) 0	5 (5.7) 2 (2.3) 30 (34.1) 0	<0.001

* Clavien-Dindo complication scale

Table 3. Related conditions for patients with a permanent stoma

Robot

Laparoscopy

Total case number

6

26

Cancer recurrence

Local recurrence

Distant metastasis

Metachronous cancer

1

4

Anastomosis related

Stricture

Stenosis

Fistula

Abscess

Leakage

2

1

2

6

2

5

Patient related

Lost of follow-up

Loose anal tone

1

Table 4. Recurrence site between robotic-assisted and laparoscopy low anterior resection

	Robot-assisted	Laparoscopy	P-value
Case number	44	88
Multiple metastasis (%)	4 (9.1)	4 (4.5)	0.302
Lung (%)	7 (15.9)	10 (11.4)	0.462
Liver (%)	3 (6.8)	3 (3.4)	0.375
Local recurrence (%)	4 (9.1)	6 (6.8)	0.642
Intra-abdominal (%)	1 (2.3)	0	0.156
Brain (%)	0	0	n/a
Bone (%)	0	0	n/a
Systemic lymph node (%)	1 (2.3)	6 (6.8)	0.272
Other sites (%)	2 (4.5)	1 (1.1)	0.215

Table 5. Multivariate logistic regression for permanent stoma

	OR	p-value	95% CI
Laparoscopy Robot	1 0.28	0.033	0.087-0.901
Age > 80	11.23	0.006	1.970-64.111
Male Sex	1.20	0.742	0.401-3.607
Staple ≥ 3	1.27	0.062	0.069-2.066
T stage 0-2 3 4	1 1.14 3.78	0.806 0.182	0.398-3.275 0.537-26.649
N stage 0 1 2	1 1.86 2.28	0.251 0.202	0.644-5.391 0.642-8.094
< 5 cm from anal verge	1.37	0.523	0.520-3.621
Involved or closed circumferential margin	1.65	0.319	0.618-4.392

No competing interests reported.

Comparison of Complications and Long-term Permanent Stoma Rate in Robot-Assisted versus Laparoscopic Low Anterior Resection: A Propensity Score Matched Retrospective Cohort Study

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