Preoperative radiation response evaluated by 18-fluorodeoxyglucose positron emission tomography predicts survival in locally advanced rectal cancer.

Abstract

This study focuses on the prognostic survival value of postirradiation metabolic activity in primary rectal cancer as measured with 18-fluorodeoxyglucose positron emission tomography. From July 1995 to March 2002, all 59 patients underwent two series of fluorodeoxyglucose positron emission tomography: one before preoperative radiation (standardized uptake values-1), and the other two to three weeks after radiation (standardized uptake values-2). Standardized uptake values-1 and standardized uptake values-2 correspond to before and after radiation, respectively. In univariate analysis, the following emerged as significant prognostic variables: with or without residual tumor, pathologic differentiation, with or without recurrence, standardized uptake values-2, and with or without lymph node metastases. In multivariate analysis, residual tumor and standardized uptake values-2 were significant prognostic factors for survival. The median survival and the five-year overall survival rate comparing standardized uptake values-2 values <5 vs. >5 were 95 vs. 42 months and 70 vs. 44 percent, respectively (P = 0.042). A significant survival benefit was observed in patients with low fluorodeoxyglucose uptake after preoperative radiotherapy in primary tumors of rectal cancer.