FDG PET complete response (PET-CR) was found to be the strongest independent predictor of outcomes in patients with esophageal cancer treated with chemoradiotherapy alone, but not trimodality therapy, and patients who achieve a PET-CR may not benefit from esophagectomy, according to a study in the November issue of the Journal of Clinical Oncology.
Trimodality therapy consists of chemoradiotherapy, followed by esophagectomy which is generally performed four to six weeks after chemoradiotherapy. Surgery is deferred primarily due to medical inoperability or unresectable/metastatic disease after chemoradiotherapy, according to Arthur W. Blackstock, Jr., MD, program director of Comprehensive Cancer Center and chair of radiation oncology at Wake Forest University Baptist Medical Center in Winston-Salem, N.C., and colleagues.
The purpose of the study was to determine whether FDG PET can delineate patients with esophageal cancer who may not benefit from esophagectomy after chemoradiotherapy, according Blackstock and colleagues.
The researchers reviewed records of 163 patients with histologically confirmed stage I to IVA esophageal cancer receiving chemoradiotherapy with or without resection with curative intent. All patients received surgical evaluation. Initial and postchemoradiotherapy FDG PET scans and prognostic/treatment variables were analyzed. PET-CR after chemoradiotherapy was defined as standardized uptake value less than or equal to three.
Eighty-eight patients received trimodality therapy and 75 received chemoradiotherapy. A total of 105 patients were evaluable for postchemoradiotherapy FDG PET response. Thirty-one percent achieved a PET-CR, which predicted improved outcomes for chemoradiotherapy, but not trimodality therapy.
On multivariate analysis of patients treated with chemoradiotherapy, PET-CR was the strongest independent prognostic variable, noted Blackstock and colleagues. PET-CR predicted for improved outcomes regardless of histology, although patients with adenocarcinoma achieved a PET-CR less often.
Patients treated with trimodality therapy found no benefit with PET-CR, likely because FDG PET residual disease was resected, according to Blackstock and colleagues. Definitive chemoradiotherapy patients achieving PET-CR had excellent outcomes equivalent to trimodality therapy despite poorer baseline characteristics, added the authors.
Patients who achieve a PET-CR may not benefit from added resection given their excellent outcomes without resection. “Our results should be interpreted with caution and are not sufficient to change routine clinical practices. If prospective trials confirm that FDG PET response is highly predictive of local control and survival, then a prospective randomized trial evaluating a treatment algorithm that uses or defers surgery based on FDG PET response to chemoradiotherapy may be warranted,” concluded Blackstock and colleagues.