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.


BACKGROUND
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.
Ha
Yun Hyung
YH
Center for Colorectal Cancer, Research Institute & Hospital, National Cancer Center, Goyang-si, Gyeonggi-do, Korea.
Jeong
Seung-Yong
SY
Lim
Seok-Byung
SB
Choi
Hyo Seong
HS
Hong
Yong Sang
YS
Chang
Hee Jin
HJ
Kim
Dae Yong
DY
Jung
Kyung Hae
KH
Park
Jae-Gahb
JG
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use; D003131:Combined Modality Therapy; D005260:Female; D006801:Humans; D008197:Lymph Node Excision; D008207:Lymphatic Metastasis; D008297:Male; D008875:Middle Aged; D011879:Radiotherapy Dosage; D012004:Rectal Neoplasms / Q000188:drug therapy / Q000473:pathology* / Q000532:radiotherapy / Q000601:surgery*; D012044:Regression Analysis; D012189:Retrospective Studies; D012307:Risk Factors