Minimally Invasive Surgery for Rectal Adenocarcinoma Shows Promising Outcomes Compared to Laparotomy,a National Cancer Database Observational Analysis

Abstract

Purpose/Background:

The surgical approach to adenocarcinoma of the rectum remains a controversial topic. Although current data focus on the noninferiority of minimally invasive surgery (MIS) for rectal cancer compared with laparotomy, conclusions are drawn from smaller sample sizes and may be underpowered.

Methods/Interventions:

The National Cancer Database (NCDB) from 2010 to 2014 was reviewed for all cases of invasive adenocarcinoma of the rectum (SEER Histology Codes 8140) who underwent surgical resection for malignancy. Groups were separated based on laparotomy or an MIS approach and stratified by NCDB Analytic Stage. Multivariate Cox regression analysis was used to evaluate for survival after diagnosis of adenocarcinoma of the rectum.

Results/Outcomes:

The inclusion criteria identified 29,199 cases of adenocarcinoma of the rectum managed surgically. After controlling for differences in the cohorts, survival after diagnosis and definitive surgical treatment for adenocarcinoma of the rectum is improved when an MIS approach was used (adjusted hazard ratio [HR] = 0.82, 95% confidence interval [CI] = 0.77–0.88, P < .001). The protective effect of an MIS approach applied to Stages I, II, III, and IV adenocarcinoma of the rectum. The protective effect of a minimally invasive surgical approach applies to Stages I, II, III, and IV adenocarcinoma of the rectum. The rate of negative circumferential margins (86.2% versus 83.5%, P < .001), proximal and distal margins (94.7% versus 92.1%, P < .001), and lymph node yield >12 (73.2% versus 70.1%, P < .001) was higher in the minimally invasive group compared with laparotomy. The intraoperative conversion rate from MIS to laparotomy was 13.9%.

Conclusion/Discussion:

Minimally invasive resection for adenocarcinoma of the rectum shows promising survival benefit compared with open surgery after adjusting for measured confounds.

Introduction

There are ∼135,430 new cases of colorectal cancer reported in the United States each year accounting for 8% of all cancers deaths.¹ Although the surgical approach to rectal cancer remains hotly debated, a total mesorectal excision (TME) or tumor-specific mesorectal excision as initially described by Heald and later by Quirke remains the gold standard whether the operation was performed with laparotomy or with a minimally invasive approach.^2,3

As the field of minimally invasive surgery (MIS) has evolved, multiple randomized trials have evaluated the oncologic safety of a minimally invasive approach to colon and rectal cancer. The Clinical Outcomes of Surgical Therapy (COST) group originally investigated the oncologic safety of a minimally invasive approach to colonic malignancy and concluded that laparoscopy was safe and noninferior to laparotomy.^4,5 Subsequently, the United Kingdom Medical Research Council conventional versus laparoscopic-assisted surgery in colorectal cancer (MRC CLASICC trial) expanded the conclusions of the COST trial concluding that oncologic outcomes of a minimally invasive approach to rectal malignancy were similar to laparotomy.^6,7 In addition, the colorectal cancer laparoscopic or open resection (COLOR) II and comparison of open versus laparoscopic surgery for mid and low rectal cancer after neoadjuvant chemoradiotherapy (COREAN) trials also showed similar rates of successful TME comparing laparotomy and a minimally invasive approach.^8,9 By comparison, the American College of Surgeons Oncology Group (ACOSOG) Z6501 and Australian laparoscopic cancer of the rectum (ALACART) trials have raised concern that a minimally invasive approach to rectal malignancy does not meet the threshold for noninferiority and should not be recommended.^10,11 With the development of the robotic-assisted laparoscopic surgery, the robotic versus laparoscopic resection for rectal cancer (ROLARR) trial reported a high-quality TME for laparoscopic and robotic-assisted surgery but did not establish a benefit of a minimally invasive approach compared with laparotomy.¹²

Amidst these conflicting conclusions, many surgeons feel that a minimally invasive approach for rectal cancer is oncologically safe and potentially beneficial in terms of postoperative morbidity citing that the conflicting conclusions of previously published studies may be biased by data sets generated by handpicked surgeons. The purpose of this analysis was to utilize the comprehensive rectal cancer data set managed by the National Cancer Database (NCDB) to quantify the oncologic benefit of a minimally invasive approach versus laparotomy for rectal cancer across a wider range of surgeons and patients. The primary outcome of this analysis was survival after diagnosis of adenocarcinoma of the rectum based on laparotomy versus MIS.

Materials and Methods

The NCDB from 2010 to 2014 was retrospectively reviewed for all cases of invasive adenocarcinoma of the rectum (SEER Histology Code 8140) that underwent definitive surgical resection. Only curative segmental resections (low anterior) and proctectomy with valid circumferential and proximal and distal margins were considered in this analysis; palliative procedures were excluded. Cases without valid staging, treatment, or follow-up data were excluded from the analysis. The minimally invasive cohort comprised definitive procedures performed laparoscopically, robotically, and cases converted from laparoscopic/robotic to laparotomy. This analysis utilized information provided by the NCDB database. These variables included the following: demographics, comorbidities, clinical and pathologic staging metrics, and surgical site-specific factors. The primary outcome of interest was survival after diagnosis of adenocarcinoma of the rectum based on surgical approach with curative intent. Secondary outcomes of this study focused on the impact of margin positivity and nodal yield on survival as well as additional beneficial effects of a minimally invasive approach to adenocarcinoma of the rectum. Negative circumferential margins were defined as ≥1 mm margin clearance from malignancy. Negative proximal and distal margins were defined as microscopically negative for malignancy.

Data extraction and statistical analysis were performed using IBM SPSS ver. 24. Survival estimates were calculated using Kaplan–Meier survival and compared using log-rank testing. Hazard ratios (HRs) were calculated to measure the degree of association between preoperative characteristics and survival by fitting the Cox proportional hazards regression model separately for each outcome. Cox regression analysis then incorporated the statistically significant differences based on surgical approach and evaluated the time from diagnosis to last day of patient follow-up with the outcome being the patients' vital status (alive or dead). P < .05 were considered statistically significant, 95% confidence intervals (CIs) were reported for all HRs, and power calculations were performed using G*Power 3.0.10. The NCDB is a joint project of the Commission on Cancer (CoC) of the American College of Surgeons and the American Cancer Society. The CoC's NCDB and the hospitals participating in the CoC NCDB were the source of the de-identified data used herein; they have not verified and are not responsible for the statistical validity of the data analysis or the conclusions derived by the authors.

Results

A total of 29,199 cases satisfied the inclusion criteria for this analysis; 16,602 had definitive surgery by laparotomy and 12,597 (9096 laparoscopic, 3501 robotic) by a minimally invasive approach. The utilization of MIS increased over the duration of study. The NCDB Analytic Stage was equally distributed over Stages I through III with a slightly higher incidence of Stage IV disease in the laparotomy cohort (8.3% versus 5.3%, P < .001) (Table 1). Chemotherapy and radiation treatment regimens were statistically different between laparotomy and MIS but similar with more cases in the MIS cohort undergoing neoadjuvant and adjuvant treatments. The median follow-up time for patients alive at last follow-up was 34.9 months.

Table 1.

Chi-Squared (Categorical) Comparison of National Cancer Database Analytic Stage Group (Pathological Stage When Present, Defaulting to Clinical Stage When Pathologic Data Are Lacking), Year of Diagnosis, and Treatment Regimen for Adenocarcinoma of the Rectum Surgically Treated by Laparotomy or a Minimally Invasive Technique

Trends and stages (n, %)	Laparotomy (n = 16,602)	Minimally invasive (n = 12,597)	P
NCDB analytic stage			<.001
Stage I	4563, 27.5%	3977, 31.6%
Stage II	4918, 29.6%	3512, 27.9%
Stage III	5730, 34.5%	4440, 35.2%
Stage IV	1391, 8.4%	668, 5.3%
Year of diagnosis			<.001
2010	3899, 23.5%	1708, 13.6%
2011	3547, 21.4%	2130, 16.9%
2012	3326, 20.0%	2479, 19.7%
2013	3068, 18.5%	2857, 22.7%
2014	2762, 16.6%	3423, 27.2%
Treatment regimen			<.001
No systemic therapy	3305, 19.9%	2568, 20.4%
Systemic therapy before surgery	7111, 42.9%	5180, 41.2%
Systemic therapy after surgery	2796, 16.9%	1970, 15.7%
Systemic therapy before and after surgery	3365, 20.3%	2867, 22.8%

Year of diagnosis denotes the initial physician diagnosis of adenocarcinoma of the rectum. Cases with missing staging data were omitted.

NCDB, National Cancer Database.

Cases in the MIS cohort were younger (61.0 years versus 62.2 years, P < .001) and were in general from areas with higher income (P < .001) and education (P < .001). Both cohorts started their treatment 33 days after diagnosis and an equal percentage from both cohorts received chemotherapy (80%, P = .292) and radiation therapy (72%, P = .858) in addition to surgical resection (Table 2). Time to definitive surgical resection was similar between cohorts (108.1 days versus 106.5 days, P = .057). A higher percentage of cases undergoing laparotomy had a proctectomy performed versus a low anterior resection (31.2% versus 22.5%, P < .001).

Table 2.

Pre- and Postoperative Characteristics of Patients Undergoing Surgical Therapy Adenocarcinoma of the Rectum by Laparotomy or a Minimally Invasive Technique

Demographic differences (n, %)	Laparotomy (n = 16,602)	Minimally invasive (n = 12,597)	P
Age (years)	62.2	61.0	<.001
Male	10,201, 61.4%	7801, 61.9%	.400
Charlson/Deyo score			.003
0	12,418, 74.8%	9621, 76.4%
1	3258, 19.6%	2361, 18.7%
≥2	926, 5.6%	615, 4.9%
Median income quartile by zip code
<$38,000	3227, 19.5%	1811,15.0%	<.001
$38,000–$47,999	4148, 25.1%	2843, 22.6%
$48,000–62,999	4391, 26.5%	3388, 27.0%
>$63,000	4785, 28.9%	4453, 35.4%
Percent no high school degree by zip code
>21%	3152, 19.0%	1977, 15.7%	<.001
13%–20.9%	4491, 27.1%	3146, 25.0%
7%–12.9%	5418, 32.7%	4161, 33.1%
<7%	3497, 21.1%	3285, 26.1%
Mean time from diagnosis to treatment (days)	32.1	32.8	.032
Radiation	11,951, 72.0%	9056, 71.9%	.858
Chemotherapy	13,290, 80.1%	10,021, 79.6%	.292
Mean time from diagnosis to surgery (days)	106.5	108.1	.057
Proctectomy	5181, 31.2%	2936, 22.5%	<.001

Categorical variables are reported as percentages and continuous variables are reported as averages. Cases with missing data were excluded from analysis.

Minimally invasive resection of adenocarcinoma of the rectum had higher rates of negative circumferential margins (malignancy <1 mm of margin; 86.2% versus 83.5%, P < .001) and negative proximal and distal margins (94.7% versus 92.1%, P < .001) versus laparotomy (Table 3) as well as a higher rate of >12 lymph nodes harvested (73.2% versus 70.1%, P < .001). Hospital length of stay was 1.6 days shorter for the MIS cohort (6.4 days versus 8.0 days, P < .001). Thirty-day readmission rate was the same between cohorts (9.0%, P = .880). Thirty-day (0.8% versus 1.6%, P < .001) and 90-day (1.7% versus 3.0%, P < .001) mortality favored the MIS cohort.

Table 3.

Unadjusted Peri- and Postoperative Outcomes After Definitive Surgical Resection of Adenocarcinoma of the Rectum

Peri- and postoperative data (n, %)	Laparotomy (n = 16,602)	MIS, no conversion (n = 10,841)	P	MIS, conversion (n = 1756)	P versus no conversion
Intraoperative conversion	N/A	1756, 13.9%	N/A	N/A	N/A
Circumferential resection margin negative	13,869, 83.5%	9349, 86.2%	<.001	1470, 83.7%	.005
Proximal and distal margin negative	15,291, 92.1%	10,264, 94.7%	<.001	1608, 91.6%	<.001
Lymph node yield >12	11,631, 70.1%	7935, 73.2%	<.001	1323, 75.3%	.063
Length of stay (days)	8.0	6.4	<.001	7.86	<.001
30-day readmission	1482, 9.0%	976, 9.0%	.880	196, 11.2%	.004
30-day mortality	217, 1.6%	63, 0.8%	<.001	23, 1.7%	.003
90-day mortality	414, 3.0%	133, 1.7%	<.001	37, 2.8%	.011

Categorical variables are reported as percentages, continuous variables are reported as decimals. Laparotomy and conversion are compared with MIS resection without conversion.

MIS, minimally invasive surgery.

Minimally invasive resection of adenocarcinoma of the rectum was converted to laparotomy in 13.9% of cases (Table 3). Information detailing the reason for intraoperative conversion or when the procedure was converted was not available in the NCDB data set. MIS cases converted to laparotomy behaved similarly to the pure laparotomy cohort. Within the MIS cohort, robotic cases had a lower intraoperative conversion rate (7.6% versus 16.4%, P < .001) compared with laparoscopy.

Kaplan–Meier survival and log-rank testing for cases of resection of adenocarcinoma of the rectum showed a survival benefit for a minimally invasive approach across Stages I–IV (Table 4). In general, cases with higher stage disease had lower survival rates. When grouped by stage, MIS cases lived longer after diagnosis compared with laparotomy. Log-rank testing indicated that the estimated survival improvements associated with a minimally invasive approach were statistically significant over the 5-year follow-up period.

Table 4.

Kaplan–Meier and Log-Rank Survival After Diagnosis for Patients Undergoing Primary Surgical Therapy for Adenocarcinoma of the Rectum Reported to the National Cancer Database Based on Laparotomy or Minimally Invasive Surgery

	Stage I		Stage II		Stage III		Stage IV
Survival after diagnosis(Cohort size, survival, SD)	Laparotomy	MIS	Laparotomy	MIS	Laparotomy	MIS	Laparotomy	MIS
1 Year	3785, 95.4%, 0.3%	2920, 97.4%, 0.3%	4103, 94.5%, 0.4%	2534, 95.8%, 0.4%	4769, 94%, 0.3%	3213, 95.9%, 0.4%	1178, 89.1%, 0.9%	506, 91.1%, 1.3%
2 Years	3416, 91.7%, 0.5%	2676, 94.7%, 0.4%	3717, 88.4%, 0.5%	2277, 91.4%, 0.6%	4318, 85.8%, 0.5%	2937, 89.7%, 0.6%	1017, 70.5%, 1.4%	441, 75.2%, 2.0%
3 Years	2706, 86.5%, 0.6%	2021, 91%, 0.6%	2928, 81.8%, 0.7%	1709, 86.3%, 0.8%	3355, 77.2%, 0.7%	2191, 82.8%, 0.8%	700, 50.5%, 1.6%	303, 60.5%, 2.5%
4 Years	1819, 82.3%, 0.8%	1217, 88.3%, 0.8%	1893, 75.7%, 0.8%	993, 79.4%, 1.1%	2130, 69.6%, 0.8%	1248, 75.6%, 1.0%	346, 36.9%, 1.8%	149, 46.3%, 3.1%
5 Years	1015, 78.2%, 1.0%	603, 85.7%, 1.1%	1003, 70%, 1.1%	475, 73.8%, 1.5%	1101, 61.8%, 1.1%	569, 68.7%, 1.5%	151, 26.6%, 2.0%	53, 34.8%, 4.0%
Log rank (value, P)	32.602, <0.001		16.168, <0.001		32.942, <0.001		7.942, 0.005

Log-rank testing (P < .01) verified the statistically significant survival improvement with cases performed in a minimally invasive fashion across all stages of disease.

MIS, minimally invasive surgery; SD, standard deviation.

After controlling for the difference between cohorts, Cox survival analysis (n = 22,931) identified a statistically significant association between a minimally invasive approach and 18% reduced hazard for mortality (HR = 0.82, 95% CI = 0.77–0.88, P < .001) (Table 5) over the 5-year period. The reduced hazard for mortality of a minimally invasive approach was statistically significant (P < .05) for Stages I–IV disease (Table 6, Fig. 1) and had the largest protective effect for Stage I disease (HR = 0.72, 95% CI = 0.62–0.84, P < .001). Increasing age, increasing comorbidity burden, increasing stage, and living in an area with a lower socioeconomic status had increased hazard for mortality. Cases where proctectomy was performed by either modality had a higher hazard rate of mortality (HR = 1.17, 95% CI = 1.10–1.25, P < .001). Resections with negative circumferential margins (HR = 0.76, 95% CI = 0.70–0.83, P < .001), negative proximal and distal margins (HR = 0.53, 95% CI = 0.48–0.59, P < .001), or a lymph node yield >12 (HR = 0.87, 95% CI = 0.82–0.93, P < .001) had reduced hazard of mortality.

FIG. 1.

Cox regression analysis for adenocarcinoma of the rectum managed surgically based on NCDB Analytic Stage. After controlling for differences in each cohort, an MIS approach has a higher survival compared with laparotomy for all stages of disease. MIS, minimally invasive surgery; NCDB, National Cancer Database.

Table 5.

Cox Regression Analysis for Survival After Diagnosis and Definitive Surgical Resection of Adenocarcinoma of the Rectum Based on Variables of Interest and Those Showing Statistically Significant Differences Between Groupings on Univariate Analysis

Cox survival analysis (n = 22,931)	HR	95% CI	P
Age (years by decade)	1.50	1.46–1.53	<.001
Charlson/Deyo score versus score 0
Charlson/Deyo score 1	1.26	1.17–1.35	<.001
Charlson/Deyo score 2	1.91	1.72–2.12	<.001
Percent no high school degree versus >21%
13.0%–20.9%	1.04	0.95–1.15	.368
7.0%–12.9%	0.99	0.90–1.10	.906
Less than 7.0%	1.02	0.90–1.15	.763
Median income quartile versus <$38,000
$38,000–$47,999	0.91	0.83–1.00	.048
$48,000–$62,999	0.86	0.78–0.95	.003
>$63,000	0.81	0.72–0.91	<.001
NCDB analytic stage versus Stage 1
NCDB analytic Stage II	1.43	1.31–1.57	<.001
NCDB analytic Stage III	2.02	1.85–2.20	<.001
NCDB analytic Stage IV	5.36	4.84–5.93	<.001
Proctectomy	1.17	1.10–1.25	<.001
Minimally invasive surgery	0.82	0.77–0.88	<.001
Lymph node yield >12	0.87	0.82–0.93	<.001
Negative proximal and distal margin	0.53	0.48–0.59	<.001
Negative circumferential margin	0.76	0.70–0.83	<.001
Intraoperative conversion	0.57	0.90–1.20	.572

NCDB, National Cancer Database.

Table 6.

Cox Regression Analysis for Survival After Diagnosis and Definitive Surgical Resection of Adenocarcinoma of the Rectum Based on National Cancer Database Analytic Stage and Surgical Approach Using the Same Multivariate Regression Model Detailed in Table 5. Hazard Ratios Determined from Data Within Specific Stage Group

Cox survival analysis impact of MIS versus laparotomy based on NCDB analytic stage	HR	95% CI	P
Stage I (n = 6684) MIS versus laparotomy	0.72	0.62–0.84	<.001
Stage II (n = 6616) MIS versus laparotomy	0.88	0.77–0.99	.040
Stage III (n = 7953) MIS versus laparotomy	0.83	0.75–0.92	<.001
Stage IV (n = 1675) MIS versus laparotomy	0.84	0.72–0.92	.040

Minimally invasive surgery for rectal adenocarcinoma shows promising outcomes compared with laparotomy, a National Cancer Database Observational Analysis.

MIS, minimally invasive surgery; NCDB, National Cancer Database.

Discussion

The results of this analysis showed a promising association of lower hazard for mortality after a minimally invasive resection of adenocarcinoma of the rectum compared with a similar curative resection performed by laparotomy. Based on the results of the multivariate regression model, the reduced hazard for mortality may have been related to the higher rates of negative circumferential margins, negative proximal and distal margins, and higher lymph node yield when a minimally invasive approach was utilized. Compared with existing studies like ACOSOG Z6501 and ALACART, this analysis was sourced from the NCDB rectal cancer registry that provided a broader patient demographic and range of malignancy and represented a broader range of surgical experience with a minimally invasive approach to rectal cancer. Establishing a clearer understanding of the costs and benefits of different surgical approaches to rectal cancer is an important step in improving outcomes especially as a minimally invasive approach has become the standard of care for other colorectal pathology.

In addition to showing a reduced hazard for mortality among the MIS cohort, this analysis also generated a quantifiable impact of negative circumferential margins, proximal and distal margins, lymph node yield >12, and the mortality detriment from proctectomy versus segmental resection. Although current rectal cancer operative techniques are dominated by completeness of TME, little has been done in large data sets to evaluate the components of a complete mesorectal excision (radial margin, proximal and distal margin, or lymph node yield). In order of prognostic importance, regression analysis indicated that negative proximal and distal margins had the largest impact on decreasing hazard for mortality after diagnosis (HR = 0.53), followed by negative circumferential margins (HR = 0.76), and finally lymph node yield >12 (HR = 0.87).

Comparatively, the improved rate of circumferential margin clearance after a minimally invasive approach versus laparotomy reported in this analysis (86.2% versus 83.5, P < .001) contrasts clearances rates reported in ACOSOG Z6501 (87.9% versus 92.3%, P = .11) and ALACART (93% versus 97%, P = .06).^10,11 A comparison regarding proximal and distal margin clearance was difficult as ACOSOG Z6501 and ALACART reported margin clearance in >98% of cases for both techniques, whereas this analysis reports improved proximal and distal margin clearance for the minimally invasive approach (94.7% versus 92.1%, P < .001). A direct comparison of lymph node yield was also difficult as for nodal yield as ACOSOG Z6501 reported an average number of nodes examined (higher average in the laparoscopic group) and ALACART reported a nodal stage. Although these three metrics are components of a complete mesorectal excision, regression analysis indicated that margin clearance carried the greatest hazard for mortality. This is likely because nodes examined does not equate to positive nodal disease, whereas positive margins equate to higher rates of local recurrence even with adjuvant therapy.

Although pathologic stage was well defined and similar across both cohorts in this analysis, tumor location within the rectum was difficult to control because of the granularity of information provided by NCDB. As a surrogate, the rate of proctectomy was used to identify lower rectal malignancy. Given the increased complexity of proctectomy versus segmental resection, the 17% increase in hazard for mortality associated with proctectomy in both cohorts was expected. Rate of minimally invasive proctectomy reported by NCDB (22.5%) was similar to the MIS cohort of ACOSOG Z6501 (24.2%) and both were significantly higher than the rate reported by ALACART (11%).^10,11 Despite controlling for proctectomy rates in the multivariate regression modeling, it is possible that the improved survival seen in the MIS cohort is secondary to survival bias from treating a higher percentage of less technically challenging upper and middle rectal pathology. It is also possible that surgeon bias on use of proctectomy versus low anterior resection, middle and upper rectal lesions may influence the results of this analysis.

Intraoperative conversion rates reported in this analysis (13.9%) were higher than both ACOSOG Z6501 (11%) and ALACART (9%) but similar to that reported by COLOR II (16%).^9–11 Within the MIS cohort of this analysis, robotic-assisted cases had a lower overall conversion rate (7.6%) versus straight laparoscopic cases (16.4%) but survival after diagnosis was similar on subset analyses. Of the MIS converted cases, pathologic outcomes were similar to cases performed by pure laparotomy. This fact suggests that conversion occurred before completion of the mesorectal excision but cannot be confirmed based on the NCDB data set. Furthermore, lower conversion rates seen with robotic-assisted approaches might indicate improved outcomes, but cohort and effect sizes within the subgroups of converted versus nonconverted within minimally invasive approaches prevented a sufficiently powered subset analysis. Future releases of the NCDB may be able to answer this question.

The limitations of this study stem from the data provided by the NCDB data set. Most importantly, the location of the rectal malignancy was granular and based on identification within the rectal cancer data set, the rectosigmoid data set was excluded, and whether a proctectomy was performed. Staging information and the incidence of neoadjuvant chemotherapy were similar between cohorts but time to adjuvant therapy was difficult to determine in patients who also had neoadjuvant therapy. Furthermore, time to intraoperative conversion and reason for conversion was not available. These limitations seem inevitable when sourcing data from prospectively entered retrospective observational data sets but are offset by the cohort size and detailed pathologic staging provided by the NCDB data set. Given that pursuing a similarly powered prospective trial would be difficult, the authors believe that a detailed observational study from a national level oncologic data set provides an attractive approach to study real-life outcomes for procedures performed by all surgeons, not only a handpicked few.

Moving forward, subsequent analyses could focus on further clarifying the prognostic implications of margin clearance and lymph node yield. Furthermore, identifying the benefits of robotic-assisted surgery versus laparoscopy would further flesh out the benefits of a minimally invasive approach for adenocarcinoma of the rectum.

Conclusion

Minimally invasive resection for adenocarcinoma of the rectum shows an observed survival benefit compared with open surgery after adjusting for measured confounds. A minimally invasive approach should be considered for surgical disease.

Funding Sources

This study was performed without grant support or support from other financial relationships.

Authors' Contributions

M.S., C.S., B.U., V.O.: conception; M.S., R.A.: data acquisition; M.S., R.A.: analysis; M.S., V.O., B.U., C.S., R.A., F.B.: manuscript preparation; M.S., R.A., V.O., B.U., C.S., F.B.: review.

Footnotes

Disclosure Statement

V.O.: Consultant for intuitive surgical. No competing financial interests exist for other authors.

References

Siegel

, Miller

, Fedewa

, et al. Colorectal cancer statistics, 2017. CA Cancer J Clin, 2017; 67:177–193.

Quirke

, Durdey

, Dixon

, Williams

. Local recurrence of rectal adenocarcinoma due to inadequate surgical resection. Histopathological study of lateral tumour spread and surgical excision. Lancet (London, England), 1986; 2:996–999.

Heald

, Husband

, Ryall

. The mesorectum in rectal cancer surgery—The clue to pelvic recurrence?. Br J Surg, 1982; 69:613–616.

Clinical Outcomes of Surgical Therapy Study Group, Nelson

, Sargent

, et al. A comparison of laparoscopically assisted and open colectomy for colon cancer. N Engl J Med, 2004; 350:2050–2059.

Fleshman

, Nelson

, Peters

, et al. Early results of laparoscopic surgery for colorectal cancer. Retrospective analysis of 372 patients treated by Clinical Outcomes of Surgical Therapy (COST) Study Group. Dis Colon Rectum, 1996; 39,(10 Suppl):S53–S58.

Guillou

, Quirke

, Thorpe

, et al. Short-term endpoints of conventional versus laparoscopic-assisted surgery in patients with colorectal cancer (MRC CLASICC trial): Multicentre, randomised controlled trial. Lancet (London, England), 2005; 365:1718–1726.

Green

, Marshall

, Collinson

, et al. Long-term follow-up of the Medical Research Council CLASICC trial of conventional versus laparoscopically assisted resection in colorectal cancer. Br J Surg, 2013; 100:75–82.

Jeong

S-Y

, Park

, Nam

, et al. Open versus laparoscopic surgery for mid-rectal or low-rectal cancer after neoadjuvant chemoradiotherapy (COREAN trial): Survival outcomes of an open-label, non-inferiority, randomised controlled trial. Lancet Oncol, 2014; 15:767–774.

Bonjer

, Deijen

, Abis

, et al. A randomized trial of laparoscopic versus open surgery for rectal cancer. N Engl J Med, 2015; 372:1324–1332.

10.

Fleshman

, Branda

, Sargent

, et al. Effect of laparoscopic-assisted resection vs open resection of stage II or III rectal cancer on pathologic outcomes: The ACOSOG Z6051 randomized clinical trial. JAMA, 2015; 314:1346–1355.

11.

Stevenson

ARL

, Solomon

, Lumley

, et al. Effect of laparoscopic-assisted resection vs open resection on pathological outcomes in rectal cancer: The ALaCaRT randomized clinical trial. JAMA, 2015; 314:1356–1363.

12.

Jayne

, Pigazzi

, Marshall

, et al. Effect of robotic-assisted vs conventional laparoscopic surgery on risk of conversion to open laparotomy among patients undergoing resection for rectal cancer: The ROLARR randomized clinical trial. JAMA, 2017; 318:1569–1580.