September 22, 2008 - Changes in gene expression during chemoradiation can predict the likelihood of response to therapy for women with locally advanced cervical cancer according to new research from the Radiation Therapy Oncology Group (RTOG) presented at ASTRO 2008.
RTOG, an NCI-funded national clinical trials group, is a clinical research component of the American College of Radiology (ACR).
RTOG investigators examined tissue samples from 22 patients, including 13-paired samples, obtained prior to treatment and midway through treatment. The investigators found that changes in the gene signature pattern of seven genes predicted whether the woman’s cervical cancer would respond to treatment with a COX-2 inhibitor combined with chemoradiotherapy. Investigators did not find a pre-treatment or mid-treatment marker that predicted local control on its own, but rather it was the changes in gene expression from pre- to mid-treatment that predicted future response in 100 percent of the samples. The results were validated by leave one out and two-fold cross validation.
According to Joanne Weidhaas, M.D., Ph.D., lead author of the research from the Yale University Cancer Center, “This is an important first step towards tailoring therapy to individual patients. If we can predict midway through treatment how well a patient will respond to their therapy we can make treatment alterations earlier with a greater probability of improving outcome.”
The tissue samples were from patients entered on RTOG 0128, a phase I/II study of chemoradiation given with a COX-2 inhibitor for women with locally advanced cervical cancer. The women enrolled on this study received a five-week course of external radiation together with chemotherapy followed by brachytherapy that involved the insertion of two to five radioactive implants into the tumor site. Biopsies were done prior to the start of treatment and again at the time of the first brachytherapy application.