Depending on the type and stage of lymphoma, physicians may choose to avoid having their patients undergo radiation therapy for fear of potential toxic effects in organs. How has modern radiation therapy evolved of late in terms of what it can do to organs at risk?
A study published earlier this year in JAMA Network Open discusses this question, as researchers looked to find what applying modern radiation technology to patients with early-stage favorable Hodgkin lymphoma would do to organs at risk. The study included patients who could be treated with a combination of doxorubicin, bleomycin, vinblastine, and dacarbazine without the use of radiation therapy. The median age at diagnosis for the 42 adults who participated in the study and who received treatment between 2010 and 2019 was 35; 24 patients had stage II disease and 18 had stage I disease.
Patients underwent 2 cycles of chemotherapy: 36 patients received the combination of doxorubicin, bleomycin, vinblastine, and dacarbazine; 5 patients received doxorubicin, vinblastine, and dacarbazine; and 1 patient received doxorubicin, bleomycin, and dacarbazine. After chemotherapy, patients received consolidative radiation therapy: 86% of patients were given intensity-modulated radiation therapy or volumetric-modulated radiation therapy; 12% of patients were administered 3-dimensional conformal radiation therapy; and 1 patient received proton therapy. The doses administered to patients across all organs that required treatment were all below standard dose constraints recommended for both solid tumors and lymphoma.
The researchers found promising results from studying these patients. In addition to an impressive 3-year progression-free survival rate of 91.2% (2 patients experienced relapse and 1 died for a reason unrelated to Hodgkin lymphoma), they found that toxic effects in organs at risk were limited. Using Common Terminology Criteria for Adverse Effects guidelines, they did not find any grade 4 or 5 toxic effects, and the only grade 3 toxic effect found occurred prior to radiation therapy.
What the researchers suggested after studying these findings, as well as historical data, was that hesitancy to use radiation therapy in patients with early-stage favorable Hodgkin lymphoma was based on outcomes in patients who were given higher doses and had a higher incidence of a second cancer. They believe that while the study had a small number of patients, the findings may still suggest that lower doses of radiation therapy in tandem with doxorubicin, bleomycin, vinblastine, and dacarbazine treatment could be an effective and safe strategy for patients with early-stage favorable Hodgkin lymphoma.
Pinnix CC, Gunther JR, Fang P, et al. Assessment of radiation doses delivered to organs at risk among patients with early-stage favorable Hodgkin lymphoma treated with contemporary radiation therapy. JAMA Netw Open. 2020;3(9):e2013935. doi:10.1001/jamanetworkopen.2020.13935