PET Scans Inform, Improve Treatment in Esophageal Cancer
Altering chemotherapy during neoadjuvant chemoradiotherapy based on response to induction chemotherapy by PET imaging can improve pathologic complete response.
Among patients with resectable stage II to III esophageal and gastroesophageal junction (GEJ) adenocarcinoma, altering chemotherapy during neoadjuvant chemoradiotherapy based on response to induction chemotherapy by PET imaging can improve pathologic complete response, according to a study being presented at the 2017 Gastrointestinal Cancers Symposium.1
"In this study, we are adding induction chemotherapy before chemoradiation and showing that using PET scans after the induction chemotherapy to assess response can help doctors make quick course corrections to maximize patient benefit from chemotherapy," Karyn A. Goodman, MD, a radiation oncologist at the University of Colorado School of Medicine in Aurora, CO, said in a press release. "Although our approach does lengthen a patient's time before surgery, we found that assessing treatment efficacy by PET scans can improve the efficacy of the treatment as shown by the ability to achieve a pathologic complete response, meaning there were no traces of cancer in the tissue specimen taken at the time of surgery."
Patients with stage II to III esophageal and GEJ cancers typically undergo 5.5 weeks of neoadjuvant chemoradiotherapy followed by surgery. There are several options for chemotherapy available for use during chemoradiotherapy, though there is no reliable method for clinicians to predict whether a particular regimen will be effective.
Because PET imaging is routinely used to guide treatment decisions for patients with lymphoma, researchers evaluated the benefit of PET imaging for informing pre-surgery treatment decisions for esophageal cancer and the impact of PET imaging-informed treatment changes on outcomes.
Investigators enrolled 257 patients with stage II to III esophageal and GEJ adenocarcinoma after receiving an initial PET scan. Patients were randomly assigned to receive induction chemotherapy with modified FOLFOX-6 or carboplatin plus paclitaxel.
After the first few cycles of induction therapy, patients underwent a repeated PET scan. If the PET scan revealed that the induction regimen was not effective, chemotherapy was changed to the other of the 2 regimens during chemoradiation. Otherwise, patients continued with the same regimen.
Thirty-nine of the 129 patients assigned to FOLFOX induction and 49 of the 128 given carboplatin/paclitaxel induction switched chemotherapy regimens following the second PET scan. Among those who switched to an alternative regimen, 15.6% achieved a pathologic complete response, compared with 5% in historical data from patients who did not switch neoadjuvant chemotherapy despite being unresponsive to induction chemotherapy as measured by PET imaging.
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Although these findings suggest that PET scans can help guide treatment decisions for patients with esophageal and GEJ cancers, further research is needed to determine the most effective regimen for this population.
- Goodman KA, Niedzwiecki D, Hall N, et al. Initial results of CALGB 80803 (Alliance): A randomized phase II trial of PET scan-directed combined modality therapy for esophageal cancer. J Clin Oncol. 2017;35(suppl):4S. Abstract 1.