Radiation boost for synchronous solitary inguinal lymph node metastasis during neoadjuvant chemoradiotherapy for locally advanced rectal cancer.

Background: Some patients with locally advanced rectal cancer (LARC) present with inguinal lymph node metastases without evidence of other systemic disease, known as solitary inguinal lymph node metastasis (SILNM). These patients may represent a distinct subset who have a more favorable prognosis and should be treated with curative intent. The optimal treatment strategy for these patients has not been determined.

Associations between clinical characteristics and tumor response to neoadjuvant chemoradiotherapy in rectal cancer.

Following standard neoadjuvant chemoradiotherapy and total mesorectal excision, some patients with locally advanced rectal cancer achieve good response (pathological T0-2N0), while others show nonresponse (pathological T3-4N0 or node-positive). To date, the clinicopathological predictors of good response and the necessity of adjuvant chemotherapy treatment (ACT) in good responders remain unclear. In this retrospective study, clinicopathological characteristics were surveyed to investigate the correlation with good response; furthermore, a propensity score matching (PSM) model was designed to balance the confounding factors between good responders treated with ACT or observation.