Influence of Preoperative Chemoradiotherapy on the Number of Lymph Nodes Retrieved in Rectal Cancer

Objective: To evaluate the relation of preoperative chemoradiotherapy to the number of lymph nodes retrieved in curative intent surgery for rectal cancer. Summary Background Data: Current guidelines recommend evaluation of least 12 to 14 lymph nodes in rectal cancer. It is well known that lymph nodes retrieval is affected by many factors. Methods: This was a retrospective study of 615 patients who underwent curative intent surgery for primary rectal cancer. Preoperative chemoradiotherapy involving 50.4 Gy fractionated radiotherapy and concurrent chemotherapy was performed in patients with locally advanced rectal cancer (clinically T3 or T4). We explored associations between the number of lymph nodes retrieved in the pathologic specimen and patient demographics (age, gender, body mass index [BMI]), treatment (surgeon, sphincter-saving, preoperative chemoradiotherapy), and tumor-related variables (location, stage, histology). After adjustment for other factors, we compared the mean number of obtained lymph nodes between patients treated with preoperative chemoradiotherapy and those treated without preoperative chemoradiotherapy. Results: Univariate analysis demonstrated that age, BMI, preoperative chemoradiotherapy, location, and stage significantly related the number of lymph nodes retrieved. Multivariate analysis revealed age, BMI, preoperative chemoradiotherapy, and stage as independent factors influencing the number of lymph nodes retrieved. The mean number of lymph nodes adjusted for age, BMI, and stage was significantly lower in patients treated with preoperative chemoradiotherapy than in those treated without preoperative chemoradiotherapy (14.5 vs. 21.5, P < 0.001). The reduction rate by preoperative chemoradiotherapy was 32.6% (7/21.5). In patients who underwent preoperative chemoradiotherapy, advanced age (P < 0.001) and high BMI (P = 0.037) were associated with decreased number of retrieved lymph nodes. Conclusions: Preoperative chemoradiotherapy significantly decreased the number of retrieved lymph nodes by approximately 33%. Therefore, the recommended number of retrieved lymph nodes should be adjusted when rectal cancer is treated with preoperative chemoradiotherapy.Supported by National Cancer Center (grant 0610280).Lim SB, 2008, ANN SURG, V248, P243, DOI 10.1097/SLA.0b013e31817fc2a0Rullier A, 2008, AM J SURG PATHOL, V32, P45Morris EJA, 2007, J CLIN ONCOL, V25, P2573, DOI 10.1200/JCO.2007.11.0445Kim DY, 2007, INT J RADIAT ONCOL, V67, P378, DOI 10.1016/j.ijrobp.2006.08.063Tekkis PP, 2006, DIS COLON RECTUM, V49, P1673, DOI 10.1007/s10350-006-0691-2Marr R, 2005, ANN SURG, V242, P74, DOI 10.1097/01.sla.0000167926.60908.15Lim SB, 2005, EJSO, V31, P242, DOI 10.1016/j.ejso.2004.11.011Baxter NN, 2005, J NATL CANCER I, V97, P219, DOI 10.1093/jnci/dji020Baxter NN, 2005, INT J RADIAT ONCOL, V61, P426, DOI 10.1016/j.ijrobp.2004.06.259Sarli L, 2005, EUR J CANCER, V41, P272, DOI 10.1016/j.ejca.2004.10.010BAXENDALL M, 2005, J PATHOL A S1, V208, pA29Sauer R, 2004, NEW ENGL J MED, V351, P1731Scott N, 2004, J CLIN PATHOL, V57, P335THORN CC, 2004, COLORECTAL DIS, V6, P356Wright FC, 2003, ANN SURG ONCOL, V10, P903, DOI 10.1245/ASO.2003.01.012Luna-Perez P, 2003, ARCH MED RES, V34, P281, DOI 10.1016/S0188-4409(03)00041-9Gorog N, 2003, PATHOL ONCOL RES, V9, P180Johnson PM, 2002, J GASTROINTEST SURG, V6, P883Wichmann MW, 2002, ARCH SURG-CHICAGO, V137, P206GREENE FL, 2002, AJCC CANC STAGING MAJOHNSON PM, 2002, J GASTROINTEST SURG, V6, P889CUMMINGS BJ, 2002, TECH COLOPROCTOL, V6, P134Kapiteijn E, 2001, NEW ENGL J MED, V345, P638Tepper JE, 2001, J CLIN ONCOL, V19, P157Wong JH, 1999, J CLIN ONCOL, V17, P2896Pocard M, 1998, DIS COLON RECTUM, V41, P839Dworak O, 1997, INT J COLORECTAL DIS, V12, P19