WINSTON-SALEM, N.C., April 12 – Positron emission tomography (PET) scans can identify esophageal cancer patients who responded well to neoadjuvant chemoradiation, possibly sparing them from esophagectomy, a study here suggested.
Other imaging techniques, such as computed tomography and endoscopic ultrasound, have been unable to identify responders to chemoradiation accurately, said Edward A. Levine, M.D., and colleagues at Wake Forest University here.
PET scans before chemoradiation also identified a subgroup of patients likely to have a significant response to treatment, Dr. Levine and colleagues reported in April issue of Annals of Surgery.
The study involved 64 patients with esophageal cancer. The investigators used PET to gauge disease severity by measuring tissue uptake of injected 18-flouro-deoxy-glucose (18 FDG). Patients underwent PET scans before chemoradiation and then again four to six weeks afterward, before esophagectomy.
Nearly 78% of patients with an uptake value of 15 standard units or more before chemoradiation had a significant response to the treatment, compared with about 24% of patients with an uptake value of less than 15 (P=.005).
After chemoradiation, 71% patients whose uptake value decreased by 10 or more units had a significant response to the therapy, compared with 33% of those whose value decreased by less than 10 units (P=.004).
Surgical pathology reports were compared with the PET scan results, indicating that the PET measurements had a sensitivity of 83% and a specificity of 88% for detecting metastatic disease after chemoradiation treatment.
The positive predictive value of PET was 55.6% and the negative predictive value of 96.7%, the investigators reported.
“While additional multicenter prospective studies are needed, the research clearly shows that PET is a useful tool for identifying patients who respond well to chemoradiation,” Dr. Levine said.
These results also showed the predictive power of pre-treatment PET imaging for identifying patients likely to have a significant tumor response to chemoradiation, added Dr. Levine.
“The evidence suggests the potential for PET to change clinical practice, perhaps helping some patients avoid surgery,” he concluded.
Primary source: Annals of Surgery
Levine EA et al. Predictive value of 18-flouro-deoxy-glucose positron emission tomography in the identification of responders to chemoradiation therapy for the treatment of locally advanced esophageal cancer. Annals of Surgery. 2006; 243(4):472-479.