Positron emission tomography (PET) scans during induction chemotherapy for esophageal cancer helps assess patient response to treatment and adjust their therapy, which could lead to an improved complete response rate prior to surgery, says a new study.
PET scans show cell activity and can help doctors gauge how active tumor cells are in a patient. Previous studies involving patients with esophageal cancer have shown that comparing PET scans prior to receiving chemotherapy and after receiving several weeks of chemotherapy can predict patients’ responsiveness to treatment.
Researchers led by Karyn A Goodman, MD, radiation oncologist at the University of Colorado, conducted a study that utilized a PET scan after initiation of two different induction therapy regimens to determine patient response to treatment. A total of 257 patients with resectable esophageal cancer were randomly assigned to induction chemotherapy with either modified FOLFOX-6 (folinic acid, fluorouracil, and oxaliplatin) or carboplatin/paclitaxel, followed by chemotherapy with radiation therapy and then surgery. All patients underwent a baseline PET scan followed by a repeat PET scan between days 36 and 42. Those patients responding well to their assigned treatment remained on that treatment, while those patients not responding well to their assigned treatment switched to the other treatment during their course of radiation. The primary endpoint of the study was an improvement in complete response from the expected rate (5%) to a rate of 20% by changing therapy.
Results of the study showed a mean complete response rate of 18% among PET non-responders (19% for those who switched from FOLFOX-6 to carboplatin/paclitaxel, 17% for those who switched from carboplatin/paclitaxel to FOLFOX-6). Previous studies had shown a complete response rate of 5% among patients that did not respond to induction chemotherapy. Complete response among PET responders was 26%, and for all patients it was 22.7%.
Previous studies have shown that a complete response at the time of surgery for patients who received induction chemotherapy was associated with better overall survival. Researchers hope that impending results from their study will further validate this conclusion.
“We know [pathologic complete response] is a prognostic marker and… we will be getting the additional information in terms of patient survival in this study in the next 6 months or so,” said Dr Goodman.
