To identify predictive factors for locoregional recurrence (LR), distant metastasis (DM), and overall survival (OS) in patients treated with chemoradiation and surgery for rectal cancer.
Between 1989 and 2001, 470 patients with rectal cancer were treated with preoperative (89%) or postoperative (11%) chemoradiation and mesorectal excision. Median radiation dose was 45 Gy; 97% received concurrent infusional 5-fluorouracil, and 65% received adjuvant chemotherapy. Median follow-up interval was 5.7 years.
The 5-year rates of freedom from LR, freedom from DM, and OS were 90%, 79%, and 80%, respectively. On univariate analysis, significant predictors of LR were female sex, clinical T stage, pathologic T and N stages, and positive radial margin. Significant univariate predictors of DM were circumferential extent of tumor, tumor immobility, lymphovascular invasion, perineural involvement, and pathologic T and N stages. Significant univariate predictors of lower OS were age, circumferential extent of tumor, shorter distance from anal verge, tumor size, tumor immobility, anal canal involvement, lymphovascular invasion, perineural involvement, positive radial margin, and pathologic T and N stages. On Cox multivariate analysis, female sex and pathologic T and N stages independently predicted for LR; pathologic T and N stages independently predicted for DM; and age, circumferential extent of tumor, positive radial margin, and pathologic T and N stages independently predicted for lower OS.
Pathologic T and N stages significantly predicted for all 3 end points (LR, DM and OS) on multivariate analysis. Investigations of more aggressive adjuvant chemotherapy appear warranted for pathologic stage T3/T4 or N1/2 rectal cancer.
From the *Department of Radiation Oncology, †Department of Surgical Oncology, and ‡Department of Gastrointestinal Medical Oncology, The University of Texas M. D. Anderson Cancer Center, Houston, TX.
Supported in part by grants CA06294 and CA16672 from the National Cancer Institute, Department of Health and Human Services.
Presented in part at the American Society of Clinical Oncology Annual Meeting, May 13–17, 2005.
Reprints: Prajnan Das, Department of Radiation Oncology, The University of Texas M. D. Anderson Cancer Center, 1515 Holcombe Boulevard, Unit 97, Houston, TX 77030. E-mail: PrajDas@mdanderson.org.