PET May Help Plot Course of Hodgkin’s Lymphoma Treatment

Positron emission tomography (PET) may predict treatment outcomes for patients with Hodgkin’s lymphoma, according to a study published in the New England Journal of Medicine.

Researchers from the United Kingdom sought to undertake a prospective, randomized, controlled trial to determine if interim PET-CT could be an effective measure of early response to chemotherapy in order to guide treatment for patients with advanced Hodgkin’s lymphoma. The primary outcome was the difference in the 3-year progression-free survival rate between randomized groups.

A total of 1,214 patients were originally recruited for the study; 1,119 underwent an interim PET-CT scan after two cycles of doxorubicin, bleomycin, vinblastine, and dacarbazine (ABVD). More than half (54.5%) were male, and the overall patient median age was 33; 41.6% of the patients had stage II disease, 30.2% stage III disease, and 28.3% stage IV disease. The images were centrally reviewed with the use of a 5-point scale for PET findings.

The interim PET-CT scanning was performed nine to 13 days after the preceding dose of chemotherapy. PET findings were scored as 1 (no uptake), 2 (slight uptake but lower than uptake in the normal mediastinal blood pool), or 3 (uptake equal to or slightly above uptake in the blood pool but less than uptake in the liver) was regarded as indicating negative findings, and a score of 4 (uptake moderately higher than uptake in the liver), or 5 (uptake markedly higher than uptake in the liver) was regarded as indicating positive findings.

 “Patients with negative PET findings after two cycles were randomly assigned to continue ABVD (ABVD group) or omit bleomycin (AVD group) in cycles 3 through 6,” the authors wrote. “Those with positive PET findings after two cycles received BEACOPP (bleomycin, etoposide, doxorubicin, cyclophosphamide, vincristine, procarbazine, and prednisone).”  

The results showed that 937 of the 1119 patients (83.7 %) who underwent an interim PET-CT scan according to protocol had negative findings.

Follow-up at median 41 months:

The absolute difference in the three-year progression-free survival rate (ABVD minus AVD) was 1.6 percentage points. Patients in the ABVD group did experience more severe respiratory adverse events than in the AVD group.

The 172 patients who had positive findings on the interim scan were given BEACOPP, and 74.4% had negative findings on a third PET-CT scan. There was a three-year progression-free survival rate of 67.5% and an overall survival rate of 87.8 %. Sixty-two patients died during the trial (24 from Hodgkin’s lymphoma), for a three-year progression-free survival rate of 82.6% and an overall survival rate of 95.8%.

“The good news is that the majority of people diagnosed with Hodgkin lymphoma can be cured - in this trial more than 95 percent of patients are alive after three years,” lead author Professor Peter Johnson, MA, MD, Cancer Research UK’s chief clinician based at the University of Southampton, said in a release. “But we worry about the long-term side effects from the treatments we use. As we've done in this trial, personalizing treatment based on how well it works is a major development for patients with Hodgkin lymphoma, and sets a new standard of care.”

"Knowing which patients have a more difficult to treat form of the disease means we can select those who need stronger chemotherapy, while sparing everyone else the severe side effects such as infertility. This approach, along with a reduction in the need for radiotherapy, should substantially reduce damage to healthy tissues and the risk of second cancers caused by treatments."