Prognostic significance of lymph node ratio in patients undergoing abdominoperineal resection of rectum

Lymph node ratio (LNR) has been shown to be an independent prognostic factor in stage III colorectal cancer. Abdominoperineal resection (APR) of rectum is historically associated with poorer oncological outcomes compared to other colorectal resections, and significance of LNR in this group of patients has not been studied. Our aim was to determine impact of LNR on oncological outcomes in a series of patients with rectal cancers undergoing APR. A series of patients who had undergone APR and had lymph node metastasis were identified from a prospectively maintained clinical, histopathological and radiological database. LNR was calculated, and Cox regression was used to determine the impact of factors affecting local recurrence, distal metastases and overall survival. Fifty-eight (42 males) patients were identified to have rectal cancer with lymph node involvement. LNR was an independent predictor of distal metastasis and overall survival at cutoff levels of 0.17, 0.41 and 0.69. Lymph node ratio is an independent predictor of survival outcomes in patients with stage III tumours undergoing APR. LNR may help improve stratification of this group of patients.