Surgical treatment for isolated inguinal lymph node metastasis in lower rectal adenocarcinoma patients improves outcome

Purpose No consensus has been formed on the optimal treatment strategy for the prognosis of patients with inguinal lymph node (ILN) metastasis from lower rectal adenocarcinoma. We, therefore, retrospectively analyzed outcomes of patients with ILN metastasis from lower rectal adenocarcinoma. Methods Of 323 patients with lower rectal adenocarcinoma treated at a single institution between November 1993 and March 2010, 10 had synchronous or metachronous ILN metastasis, as confirmed by curative resection (R0) of the primary lesion. Outcomes of these 10 patients were assessed. Results The 10 patients with ILN metastasis were divided into two groups: group A (two patients who did not undergo ILN resection surgery because of metastases at other sites) and group B (eight patients with no other metastases who underwent surgery). Both patients in group A, with median overall survival of 5.2 months, died due to the other metastases, whereas five out of eight patients in group B survived ( P = 0.001). Group B patients were further subclassified into synchronous (group B1) and metachronous (group B2) metastasis ( n = 4 each) groups. Two patients in group B1 died of other metastases, which was diagnosed later, whereas three patients in group B2 survived. Conclusions Some patients with isolated inguinal lymph node metastasis show a good prognosis after lymph node excision and, therefore, should be treated surgically. Patients with metachronous metastases have a better prognosis than patients with synchronous ILN metastases. Nevertheless, assessment of additional patients for prognosis and treatment strategy is warranted.