Background: The number of lymph nodes retrieved and examined from a resected colon cancer specimen may be crucial for correct staging. We examined if efforts to increase the lymph node harvest to more than 12 lymph nodes per specimen would upstage some patients from TNM stage II to III.
Methods: Three hospitals compared results from 2000 with those of 2007 in 421 resected patients with stage II and III colon cancer. Hospital A endeavored to improve the surgical procedure while the pathologists enhanced the quality of lymph node sampling. Hospital B did not make any marked changes, while hospital C introduced the GEWF lymph node solvent (glacial acetic acid, ethanol, distilled water, and formaldehyde) in their pathology method.
Results: In 2000, 12 or more lymph nodes were harvested in 39.6, 45.0, and 21.1% of the specimens from the three hospitals, while the figures for 2007 were 85.7, 42.0, and 90.3%, respectively. The significant increase in lymph node harvest in two of the hospitals in 2007 compared to 2000 (p < 0.001) did not affect the share of patients with stage III in 2007 (38.7%) compared to 2000 (44.1%) (p = 0.260). The number of positive lymph nodes and the lymph node ratio (LNR) decreased from 2000 to 2007. A lymph node yield of 12 or more was not associated with an increased probability of positive lymph nodes in a multivariable logistic regression analysis.
Conclusion: More radical surgery and dedicated pathologists and the use of the GEWF solvent significantly increased the lymph node yield but did not upstage patients from TNM stage II to III.