Background: The National Comprehensive Cancer Network and the American Joint Committee on Cancer recommend retrieving > 12 lymph nodes for adequate colorectal cancer (CRC) staging. Nodal status and presence of metastasis is an important prognostic factor and may guide decision making for adjuvant chemotherapy. Recent data have shown variable results for survival based on the number of lymph nodes sampled and the ratio of positive lymph nodes of the total sampled. In our study, we aimed to assess the influence of lymph node retrieval and positive lymph node status on overall survival of male veteran patients with CRC.
Methods: A retrospective chart review study at a VA medical center in a large metropolitan area was conducted. Charts of patients diagnosed with colon cancer from January 1, 2008, to January 1, 2012, were reviewed, and data on age, diagnosis of cancer, symptoms, histologic type of tumor, stage, number of lymph nodes harvested, number of lymph nodes positive for cancer, tumor invasion, date of diagnosis, and date of death were recorded. Descriptive statistics, including average/median, range, and standard deviation were calculated. Lymph node ratio (LNR) was calculated from the number of lymph nodes positive for cancer of the total number of lymph nodes harvested. Survival was calculated from date of diagnosis to date of death. Differences in survival were assessed through t tests for different groups. Pearson’s correlations and regression analysis were carried out for survival for the 4 groups of interest (< 12 nodes harvested, ≥ 12 nodes harvested. Lymph node ratio < 0.2, and LNR > 0.2)
Results: Data from 84 patients were obtained with a median survival of 299 days. On diagnosis, 26 (31%) were stage I, 21 (25%) were stage II, 16 (18%) were stage III, and 21 (25%) were stage IV. Twenty-three (27.3%) patients had local invasion at time of diagnosis. An average of 14.5 lymph nodes (range 4-29) were sampled per patient. Twenty-two (26%) patients had < 12 nodes sampled, and 42 (50%) had ≥ 12 nodes sampled. The average LNR for the whole group was 0.07 (SD ± 0.15). There was no significant difference in sur-vival between the patient groups who had < 12 LNs sampled vs those who had 12 or more LNs sampled (mean 316.6 days vs 543.6 days, t = 0.82, df 11, P = .42). There was no significant difference in survival between the patient groups who had LNR < 0.2 vs those who had LNR > 0.2 (mean 450.7 days vs 580.0 days, t = 0.50, df 9, P = .62).There were no significant differences in survival based on mode of diagnosis (screening colonoscopy vs presence of symptoms) or presence of local invasion at diagnosis.
Conclusion: This study did not find that number of harvested LNs as well as LNR had an impact on survival.
