187P Long-term outcome of inguinal lymph node metastasis from rectal adenocarcinoma

Abstract

Aim/Background: Clinical picture of inguinal lymph node metastasis from rectal adenocarcinoma is unclear and treatment strategy is not established because of limited number of reported cases. Generally prognosis is reported to be poor. To clarify clinical picture and evaluate role of radical groin dissection, we reviewed our treatment results. Methods: Between 1993 and 2014, 19 patients with inguinal lymph node metastasis from rectal adenocarcinoma underwent radical groin dissection. We removed the lymph nodes and fat tissue completely from the region surrounded by the inguinal ligament, sartorius muscle, adductor longus muscle, and femoral nerve, artery, and vein. Results: There were 13 men and 6 women with a median age of 64 (39-80) years. Metastasis was metachronous in 15 patients, synchronous in 4, unilateral in 18, and bilateral in 1. Histologic diagnosis included adenocarcinoma in 18 cases and adenosquamous carcinoma in 1. Stages of primary tumor were stage I in 2 patients, stage III in 13, and stage IV in 4. A median distance between the anal edge of tumor and the anal verge was 1.5 (0-3) cm. All patients had a primary tumor involving the anal canal. Nine had lateral pelvic lymph node metastasis at initial surgery. A median disease-free interval was 11 (2-97) months. All patients underwent radical groin dissection for inguinal metastasis. Complications included lymphorrhea in 10 patients and wound infection in 3. During a median follow-up time of 60 (9-237) months, 14 patients developed recurrence. The initial site of recurrence included the lung in 6 patients, the external inguinal lymph node in 3, the paraaortic lymph node in 2, the liver in 1, and the brain in 1, opposite inguinal lymph node in 1. Five-year overall survival rate was 64%. There were no significant difference for overall survival rate between metachronous and synchronous metastasis.Three- and Five-year Disease-free survival rates were 64% and 32%, respectively. Conclusions: Involvement of the anal canal by a primary tumor and lateral pelvic lymph node metastasis may be risk factors of the inguinal lymph node metastasis. Radical groin dissection may be effective for prolonging survival. Countermeasures for lung and external iliac metastasis are necessary.