Premium
Pathologic stage is most prognostic of disease‐free survival in locally advanced rectal cancer patients after preoperative chemoradiation
Author(s) -
Quah HakMien,
Chou Joanne F.,
Gonen Mithat,
Shia Jinru,
Schrag Deborah,
Saltz Leonard B.,
Goodman Karyn A.,
Minsky Bruce D.,
Wong W. Douglas,
Weiser Martin R.
Publication year - 2008
Publication title -
cancer
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.052
H-Index - 304
eISSN - 1097-0142
pISSN - 0008-543X
DOI - 10.1002/cncr.23516
Subject(s) - medicine , concordance , stage (stratigraphy) , colorectal cancer , confidence interval , radiation therapy , t stage , cancer , rectum , neoadjuvant therapy , radiology , surgery , breast cancer , biology , paleontology
BACKGROUND. Preoperative chemoradiation is the standard treatment for locally advanced rectal cancer. However, it is uncertain whether pretreatment clinical stage, degree of response to neoadjuvant treatment, or pathologic stage is the most reliable predictor of outcome. This study compared various staging elements and treatment‐related variables to identify which factors or combination of factors reliably prognosticates disease‐free survival in rectal cancer patients receiving neoadjuvant combined modality therapy. METHODS. From a prospectively maintained single institution database, 342 consecutive patients with locally advanced rectal cancer staged by endorectal ultrasound were identified. Patients underwent rectal resection 4 to 8 weeks after a 5.5‐week course of pelvic radiotherapy/concurrent chemotherapy. The degree of tumor regression was histologically graded on each resected specimen using a previously reported response scale of 0% to 100%. Predictive models of disease‐free survival were created utilizing available pretherapy and postoperative staging elements in addition to the degree of tumor regression noted histologically. Model accuracy was measured and compared by concordance index, with 95% confidence interval (CI). RESULTS. Stratifying patients by degree of tumor regression predicted outcome with a concordance index of 0.65 (95% CI, 0.59–0.71), which was significantly better than models using preoperative stage elements (concordance index of 0.54; 95% CI, 0.50–0.58). However, the model found to be most predictive of disease‐free survival stratified patients by final pathologic T classification and N classification elements, with a concordance index of 0.75 (95% CI, 0.70–0.80). CONCLUSIONS. Tumor response to preoperative therapy is a strong predictor of disease‐free survival. However, outcome is most accurately estimated by final pathologic stage, which is influenced by both preoperative stage and response to therapy. Cancer 2008. © 2008 American Cancer Society.