Objective: To identify the risk factors associated with lymph node metastasis in rectal cancer after neoadjuvant chemoradiotherapy (CRT).
Methods: From January 2005 to December 2013, the clinical data of 178 patients with advanced rectal cancer undergoing radical excision after neoadjuvant CRT in our department were reviewed retrospectively. A total of 11 clinicopathologic factors relating to lymph node metastasis were studied using univariate and multivariate Logistic regression analyses.
Results: There were 74(41.6%) cases with lymph node metastasis, while 104 cases without lymph node metastasis. Univariate analysis showed that age(P=0.000 2), post-CRT CEA level(P=0.011 2), ypT stage(P=0.000 0), pathologic type(P=0.004 0), and tumor regression grade(TRG)(P=0.033 8) were significantly associated with lymph node metastasis. Multivariate analysis showed that age(OR=2.385, 95% CI:1.372 ~ 4.147, P=0.002 1), post-CRT CEA level(OR=2.310, 95% CI:1.005 ~ 5.307, P=0.048 6) and ypT stage(OR=2.592, 95% CI:1.236 ~ 5.432, P=0.011 7) were independent risk factors. However, 15.8% of the patients who achieved TRG1 had lymph node metastasis and TRG failed to independently correlate with lymph node metastasis in rectal cancer after neoadjuvant CRT.
Conclusions: There was a higher ratio of lymph node metastasis in rectal cancer patients who were young, CEA≥5 μg/L or deep invasion after neoadjuvant CRT. Therefore, neoadjuvant CRT should be carefully considered in these patients.