PET Scans Can Guide Chemotherapy Choices for Hodgkin’s Lymphoma, Study Reports

PET Scans Can Guide Chemotherapy Choices for Hodgkin’s Lymphoma, Study Reports

A study published in the Journal of Clinical Oncology shows for the first time a chemotherapy regimen determination —made after a mid-point assessment of treatment — that successfully treats more patients with advanced Hodgkin’s lymphoma while minimizing the toxic effects of high-intensity chemotherapy.

For patients with advanced Hodgkin’s lymphoma, standard therapy in the U.S. is composed of a chemotherapy regimen made of four drugs. The approach cures about 70 percent of patients.

A more aggressive chemotherapy approach exists, but its efficiency as a lymphoma cure comes at a high price — possible infertility, heart problems, and secondary cancers.

Earlier studies have shown that the number of cancer cells detected by a scan taken partway through the chemotherapy treatment can predict the treatment’s outcome. In patients with advanced disease and detectable cancer cells after two rounds of chemotherapy, the cancer is much more likely to return within two years. In this group of patients, only an estimated 15 percent to 30 percent live for two years without disease progression.

In the new study, US Intergroup Trial of Response-Adapted Therapy for Stage III to IV Hodgkin’s Lymphoma Using Early Interim Fluorodeoxyglucose–Positron Emission Tomography Imaging: Southwest Oncology Group S0816,“ researchers used positron emission tomography (PET) scan, an imaging method that can visualize radioactively labeled sugar molecules. Cells that have a rapid metabolism, such as aggressively growing cancers, make up the bulk of the labeled sugar molecules detected by the scan.

After two cycles of standard chemotherapy, patients were scanned to see if any aggressive tumor cells were left in the lymph nodes. In patients with a lingering presence of cancer cells, treatment continued with a more aggressive regimen. Other patients remained on the standard treatment.

Of the 319 patients who completed the Phase 2 trial, PET scans detected cancer cells in 60 cases. The adjusted treatment regimen led to a calculated two-year progression-free survival of 79 percent, exceeding the researchers’ goals. The effect of the treatment switch in the high-risk group also surpassed the team’s expectations, with progression-free survival rising to 64 percent.

“The outcome of this large study was very encouraging and suggested that this approach could maximize cure rates for advanced Hodgkin’s lymphoma while minimizing toxicities for the majority of patients,” lead study author Dr. Oliver Press, a lymphoma physician, and scientist at the Fred Hutchinson Cancer Research Center and the University of Washington, said in a news release.

“Hodgkin’s lymphoma is one of the examples of a disease that [response-adapted therapy] makes the most sense in. Because we’re already curing a lot of patients with Hodgkin’s lymphoma, it suggests that there’s a subset of patients [in whom] we’d like to de-escalate treatment to limit toxicity, and also for that smaller fraction of people whom we’re not curing, to escalate treatment,” said Dr. Jonathan Friedberg, the study’s senior author, director of the James P. Wilmot Cancer Institute at the University of Rochester Medical Center and chair of the lymphoma committee at SWOG, the cancer clinical trials network that managed this study.

Both Press and Friedberg said they now use the PET-based approach to adapt treatment strategy for lymphoma patients, but would ultimately like to see the procedure evaluated in a Phase 3 clinical trial.

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Magdalena is a writer with a passion for bridging the gap between the people performing research, and those who want or need to understand it. She writes about medical science and drug discovery. She holds an MS in Pharmaceutical Bioscience and a PhD — spanning the fields of psychiatry, immunology, and neuropharmacology — from Karolinska Institutet in Sweden.

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