Transanal Local Excision for Distal Rectal Cancer and Incomplete Response to Neoadjuvant Chemoradiation - Does Baseline Staging Matter?

BACKGROUND: Local excision may offer the possibility of organ preservation for the management of select patients after neoadjuvant chemoradiation. The oncological outcomes of this strategy have been largely associated with the risk of nodal metastases. Therefore, in addition to final ypT status, baseline staging has been suggested to potentially influence the outcomes of this treatment modality. OBJECTIVE: The aim of this study is to compare the pathological and oncological outcomes of patients following neoadjuvant chemoradiation and incomplete clinical response managed by transanal endoscopic microsurgery according to baseline staging. DESIGN: This study is a retrospective review of prospectively collected data. SETTINGS: The study was conducted at a single center. PATIENTS: Forty-six patients with distal rectal cancer cT2-4N0- 2M0 underwent 5-fluorouracil-based neoadjuvant chemoradiation. Assessment of response was performed at least 8 weeks from radiotherapy completion. Patients with a complete clinical response were not operated on immediately. Patients with an incomplete clinical response were managed by surgery. Those with small (<= 3 cm) residual cancers (ycT1-2N0M0) were managed by transanal endoscopic microsurgery. MAIN OUTCOME MEASURES: Patients undergoing local excision following chemoradiation were compared according to baseline staging. RESULTS: Fifteen patients (32%) were cT2N0 at baseline. Final ypT status was ypT0 in 3 (20%) patients, ypT1 in 2 (13%) patients, ypT2 in 9 (60%) patients, and ypT3 in 1 (7%) patient. There were no differences in final ypT status in comparison with patients with baseline cT3-4 or cN+ undergoing chemoradiation followed by transanal endoscopic microsurgery (p = 0.38). Local recurrence was observed in 1 patient with baseline cT2N0 (7%) and in 7 patients (23%) with stage II and II (p = 0.18). LIMITATIONS: This study was limited by the short follow-up, its limited sample size, and its retrospective and nonrandomized nature. CONCLUSIONS: Patients with baseline cT2N0 that do not develop complete response to chemoradiation (ycT02N0; <= 3 cm) frequently present unfavorable pathological features for transanal local excision (ypT2 or 3 in >66%). In the presence of incomplete clinical response following chemoradiation, patients with baseline cT2N0 have pathological and oncological outcomes similar to patients with baseline stage II or II and are probably not ideal candidates for local excision (see Video, Supplemental Digital Content 1, http://links.lww.com/DCR/A159).