Local excision and selective radical resection after neoadjuvant chemoradiation for rectal cancer.

Abstract

e14107 Background: 20% of rectal cancer patients with a clinical complete response (CR) after neoadjuvant chemoradiation will have a pathologic CR at radical resection (RR). Local excision (LE) of the primary tumor can identify patients who achieved a pathologic CR/may not require RR. The objective of this study was to explore the predictive/therapeutic value of LE and optimal surgical strategy in this patient population. Methods: We developed a decision analysis/Markov model to compare outcomes following selective versus routine RR in rectal cancer patients with a clinical CR after chemoradiation. All patients in the selective RR strategy underwent LE: patients with a pathologic CR were observed/those with residual disease underwent subsequent RR. Sensitivity/specificity of LE and morbidity/mortality/recurrence/salvage/survival estimates were obtained from the medical literature. Outcomes were quality-adjusted using health state preferences. Results: Quality-adjusted life years (QALYs) after selective RR were 6.22 compared to 6.03 after routine RR (69 additional healthy days gained). Patients with a “true” pathologic CR (at the primary tumor site/mesorectum) gained the greatest benefit (8.46 versus 7.68 QALYs, respectively). Selective RR was the optimal strategy even after model estimates were varied widely over reported ranges. Routine RR became the preferred strategy only if mortality of local excision and probability of pathologic CR were assumed to be >3% and <1%, respectively. Conclusions: Selective RR (based on findings at LE) maximizes quality-adjusted life expectancy compared to routine RR in rectal cancer patients with a clinical CR after neoadjuvant chemoradiation. Routine RR in this increasingly common clinical situation should be strongly reconsidered.