Neoadjuvant chemoradiotherapy for borderline resectable low rectal cancer: short- and long-term outcomes at a single Japanese center.

Abstract

Rectal cancers pose a threat to the mesorectal fascia or invade neighboring structures or organs. Some tumors are potentially resectable but are likely to be positive at the resection margin for cancer involvement and are thus recognized as "borderline resectable (BR)" tumors. This study aimed to clarify the short- and long-term outcomes of neoadjuvant chemoradiotherapy (nCRT) for BR low rectal cancer at a single Japanese center. Data of 55 patients, who received nCRT followed by BR low rectal cancer surgery between April 2010 and December 2019, were evaluated for the short-term outcomes. The oncological outcomes of 42 patients who underwent surgery between April 2010 and December 2018 were evaluated. Thirty-six (65.5%) patients had cT4 tumors, and 53 (96.4%) patients had a clinical-stage III or IV. Lateral lymph node dissection was performed in 42 (76.4%) patients. The incidence of severe post-operative complications (Clavien-Dindo grade ≥ III) was 18.2%. Fifty-two (94.5%) patients had a pathological negative resection margin. The 3-year overall survival rate, disease-free survival rate, and cumulative incidence of local recurrence were 100%, 70.3%, and 5.3%, respectively. The short- and long-term outcomes of nCRT for BR low rectal cancer were acceptable. In particular, reasonable local control was achieved.