Radiat Oncol J.  2012 Sep;30(3):99-107.

Clinical predictive factors of pathologic tumor response after preoperative chemoradiotherapy in rectal cancer

• Choi CH
• Kim WD
• Lee SJ
• Park WY

Abstract

PURPOSE
The aim of this study was to identify clinical predictive factors for tumor response after preoperative chemoradiotherapy (CRT) in rectal cancer.
MATERIALS AND METHODS
The study involved 51 patients who underwent preoperative CRT followed by surgery between January 2005 and February 2012. Radiotherapy was delivered to the whole pelvis at a dose of 45 Gy in 25 fractions, followed by a boost of 5.4 Gy in 3 fractions to the primary tumor with 5 fractions per week. Three different chemotherapy regimens were used (5-fluorouracil and leucovorin, capecitabine, or tegafur/uracil). Tumor responses to preoperative CRT were assessed in terms of tumor downstaging and pathologic complete response (ypCR). Statistical analyses were performed to identify clinical factors associated with pathologic tumor response.
RESULTS
Tumor downstaging was observed in 28 patients (54.9%), whereas ypCR was observed in 6 patients (11.8%). Multivariate analysis found that predictors of downstaging was pretreatment relative lymphocyte count (p = 0.023) and that none of clinical factors was significantly associated with ypCR.
CONCLUSION
Pretreatment relative lymphocyte count (%) has a significant impact on the pathologic tumor response (tumor downstaging) after preoperative CRT for locally advanced rectal cancer. Enhancement of lymphocyte-mediated immune reactions may improve the effect of preoperative CRT for rectal cancer.

Keyword

Rectal cancer; Preoperative chemoradiotherapy; Predictive factors; Tumor response

MeSH Terms

Chemoradiotherapy
Deoxycytidine
Fluorouracil
Humans
Leucovorin
Lymphocyte Count
Multivariate Analysis
Pelvis
Rectal Neoplasms
Capecitabine
Deoxycytidine
Fluorouracil
Leucovorin