The impact of lymph node dissection in patients with colorectal cancer

Abstract

17055 Background: The role of extended lymphadenectomy on survival of patients with colorectal cancer is unclear. Survival in these patients is inversely proportional to the stage of disease. The prognostic significance of inadequate lymph node dissection is not understood. To understand the impact of the number of lymph nodes removed at the time of surgery on survival, we conducted a retrospective study of patients with colorectal cancer treated at the Central Arkansas Veterans Healthcare System, Little Rock, AR. Methods: Data on 531 patients with a diagnosis of colorectal cancer from January 1991 to October 2005 was obtained from the tumor registry. The number of lymph nodes dissected the number of positive and negative lymph nodes for each patient, treatment received and overall survival was analyzed. The number of resected nodes was grouped as follows: none (LNG0), 1–5 (LNG1), 6–10 (LNG2), and > 10 (LNG3). Log rank test was used to evaluate difference in survival between the groups. Results: There were 451 Caucasians, 80 African Americans, 523 males and 8 females in the study. The median age was 69 yrs (range: 29–100). Rectal cancer patients had fewer nodes dissected compared to colon cancer (p <0.001). There was no survival difference between LNG0, LNG1, LNG2 and LNG3 (p=0.435). The number of lymph nodes removed did not have an impact on survival among those who had node negative disease (0.435) and node positive (0.458) disease. LNG0 patients had the same prognosis as those with node negative disease (P=0.435) who had better survival compared to node positive disease. (p=0.029). However, LNG0 patients had similar survival compared to LNG1 subset of patients and those in LNG3 had a trend towards better survival, though not statistically significant. LNG0 subjects received less chemotherapy (p=0.018) and radiation therapy (p=0.01) compared to those who had lymphadenectomy. Conclusions: The number of nodes removed at the time of surgery did not affect survival in subjects with node negative and node positive disease. Patients who did not have any identifiable nodes at the time of surgery had the same prognosis as those who had node negative disease. Patients with more than 10 negative nodes dissected had a trend towards better survival although not statistically significant. No significant financial relationships to disclose.