K. Hrebinko1, K. M. Reitz1, M. Mohammed1, D. Medich2, J. Celebrezze2, J. Salgado Pogacnik3, J. Holder-Murray2 1University Of Pittsburgh,Department Of Surgery,Pittsburgh, PA, USA 2University Of Pittsburgh,Division Of Colon And Rectal Surgery,Pittsburgh, PA, USA 3University Of Texas Southwestern Medical Center,Department Of Surgery,Dallas, TX, USA
Introduction: Neoadjuvant chemoradiation for locally advanced rectal cancer increases the feasibility of sphincter preservation without jeopardizing oncologic outcomes. Prospective trials evaluating the interval from chemoradiation to surgery favor a longer duration (i.e. 6 or 8 weeks) to optimize sphincter preservation and pathologic complete response. We hypothesize that a longer than typical duration between neoadjuvant chemoradiation and surgery is associated with an increased rate of sphincter preservation in locally advanced rectal cancer.
Methods: We identified patients from 2010-2017 who underwent resection for primary rectal cancer following neoadjuvant chemoradiotherapy from an institutional database. Baseline characteristics and outcomes were compared with rank-sum and Chi-squared testing, as appropriate. The primary outcome was sphincter preservation for patients who had a long (L, ≥ 12 weeks) or short (S, < 12 weeks) interval between completion of chemoradiation and surgery. A multivariable logistic regression model was used to generate the odds of sphincter preservation controlling for clinically significant confounders.
Results: 162 patients met inclusion criteria. Average time to surgery was 10.9 (n=105) and 15.0 (n=57) weeks in short (S) and long (L) cohorts, respectively. Baseline characteristics were similar between groups (Table 1). There was no difference in pretreatment clinical tumor (p=0.80) or nodal (p=0.59) stage between cohorts. Patients with a long interval had a higher rate of sphincter preservation (L: 48 (89%), S: 74 (76%), p=0.047). After controlling for age, pretreatment stage, and ASA classification, the long interval continued to significantly improve sphincter preservation (OR 5.8 [95%CI 1.28-24.0], p=0.016) while a higher ASA score (OR 0.18 [0.06-0.56], p=0.003) correlated with less preservation. There was no significant difference in the rate of pathologic complete response (L: 17 [29.8%], S: 27 [25.7%], p=0.570), conversion to open (L: 9 [15.8%], S: 23 [21.9%], p=0.35), or post-operative complications (p=0.47) between groups. Median operative time (L: 151min [IQR 129-227], S: 221 [136-270], p<0.001) and blood loss (L: 100mL [10-200], S: 150 [75-300], p=0.006) were greater in < 12 weeks cohort. There was a trend toward decreased mortality in the ≥ 12 weeks group (L: 6 [11.3%] vs. S: 18 [18%], p=0.280).
Conclusion: This is the first study to examine rectal cancer outcomes between patients with typical versus extended time intervals between completion of neoadjuvant therapy and surgery. We demonstrate that an extended ≥ 12-week interval may improve the ease of operation and likelihood of sphincter preservation without compromising oncologic outcomes or survival.
