A NSQIP analysis of trends in surgical outcomes for rectal cancer: What can we improve upon?

BACKGROUND

There is significant variation in rectal cancer outcomes in the USA, and reported outcomes have been inferior to those in other countries. In recognition of this fact, the American College of Surgeons (ACS) recently launched the Commission on Cancer (CoC) National Accreditation Program for Rectal Cancer (NAPRC) in an effort to further optimize rectal cancer care. Large surgical databases will play an important role in tracking surgical and oncologic outcomes. Our study sought to explore the trends in surgical outcomes over the decade prior to the NAPRC using a large national database.

METHODS

The ACS National Surgical Quality Improvement Program (NSQIP) database from 2005 to 2017 was used to select colorectal cancer cases which were divided into abdominal-colonic (AC) and pelvic-rectal (PR) cohorts based upon the operation performed. Outcomes of interest were occurrence of any major surgical complication, mortality within 30 days of procedure, and postoperative length of stay (LOS). Chi-square and two sample t-tests were used to evaluate association between various risk factors and outcomes. Modified Poisson regression was used to compare and estimate the unadjusted and adjusted effect of procedure type on the outcomes. STATA 15.1 was used for analysis and statistical significance was set at 0.05.

RESULTS

A total of 34,159 patients were analyzed. AC cases constituted 50.7% of the overall cohort. The two groups were relatively similar in demographic distribution, but the PR patients had higher rates of hypoalbuminemia and were sicker (ASA class 3 or greater). Rates of non-sphincter preserving operations ranged from 30 to 34%. Higher complication rates in the PR cohort were mainly infectious and surgical site complications, while rates of deep vein thrombosis and pulmonary embolism were similar between the two cohorts. On bivariate analysis, rates of mortality were similar between the two groups (AC: 1.02% vs PR: 0.91%, p = 0.395), while PR patients were found to be 1.36 times (95% CI: 1.32-1.41) more likely to have major complications and 1.40 times (95% CI: 1.35-1.44) more likely to have an extended LOS as compared to the AC patients. After multivariable analysis, PR patients continued to have a higher likelihood of major complications (IRR: 1.31, 95% CI 1.25-1.36) and extended LOS (IRR: 1.38, 95% CI: 1.33-1.43). 10-year trends showed a significant reduction in the percentage of patients with prolonged lengths of hospitalization as well as a reduction of nearly 20% in the mean LOS, but without improvement in morbidity or mortality.

CONCLUSIONS

Patients undergoing PR operations were more likely to have had major complications than were patients who underwent AC procedures; unfortunately no improvement in the rate of these complications or in mortality occurred. Perhaps the significant reduction in LOS is due in part to an increased prevalence of minimally invasive surgery and/or enhanced recovery protocols. Data were found to be lacking within NSQIP for several important variables including key oncologic data, stratification by surgical volume, and patient geographic location. We anticipate that the NAPRC should help improve PR surgical and oncologic outcomes including decreasing morbidity and mortality rates during the next decade.