Modern Radiation Therapy Limits Radiation Doses to Organs at Risk in Hodgkin Lymphoma

Combined modality therapy with 2 cycles of doxorubicin, bleomycin, vinblastine, and dacarbazine (ABVD) and consolidative 20 Gy radiation therapy (RT) for early-stage favorable Hodgkin lymphoma (ESFHL) yielded excellent outcomes and limited excess radiation doses to organs at risk, according to study results published in JAMA Network Open.

Despite the maximal efficacy of combined modality therapy in ESFHL, RT is often avoided because of the fear of late adverse effects. However, modern involved-site RT may be able to limit these toxic effects.

Chelsea Pinnix, MD, PhD, of the department of radiation oncology at the University of Texas MD Anderson Cancer Center in Houston, and colleagues aimed to determine the radiation doses delivered to organs at risk with consolidative modern involved-site RT in patients with ESFHL treated with 20 Gy after 2 cycles of ABVD.

The investigators screened the radiation oncology database maintained by the University of Texas MD Anderson Cancer Center for medical records of adult patients with ESFHL (German Hodgkin Study Group criteria) who had been treated with combined modality therapy from 2010 to 2019. Patients were included if they had achieved complete response after 2 cycles of ABVD assessed by positron emission tomography–computed tomography and received consolidative RT. Radiation doses to organs at risk were calculated, and progression-free survival (PFS) and overall survival (OS) were the assessed outcomes.

In total, 42 patients with ESFHL (median age at diagnosis, 35 years [range, 18-74]; men/women, 57%/43%) were included. More than half of the patient population (57%) had stage II disease. At a median follow-up duration of 44.6 months (95% CI, 27.6-61.6), the 3-year PFS rate was 91.2% (95% CI, 74.9-97.1), while the OS rate was 97.0% (95% CI, 80.4-99.6).

Among all patients, the mean radiation dose was 0.8 Gy (standard deviation [SD], 1.5 Gy; range, 0-4.8 Gy) to the heart, and among the 18 female patients, 0.1 Gy (SD, 0.2) to both breasts (left breast range, 0-1.0; right breast range, 0-0.9). Among all patients, the total lung mean dose was 1.3 Gy (SD, 1.9; range, 0-5.8). Mean doses to the parotid, salivary, and thyroid glands were well below the standard radiation dose constraints established by a comprehensive review of the association of radiation dose and volume with organ function and toxic effects.

The study was limited by the small sample size, exclusion of pediatric patients, short follow-up durations, and single-center design. The authors noted that additional studies of patients who receive combined modality therapy should include detailed RT dosimetric information to quantify the radiation doses to organs at risk and determine the long-term toxic effects.

“The favorable dosimetric profiles, with mean doses of less than 5 Gy to surrounding normal structures, suggests that long-term toxic effects may be lower than what has been reported in historic series. We advise that treatment strategies for patients with ESFHL, including the incorporation of RT, be considered on a case-by-case basis,” wrote the authors.

Disclosures: Some authors have declared affiliations with or received funding from the pharmaceutical industry. Please refer to the original study for a full list of disclosures.