Radiotherapy after chemoimmunotherapy may be omittable for certain patients with lymphoma
Click Here to Manage Email Alerts
Key takeaways:
- PFS rates at 30 months appeared similar between patients in the radiation and observation groups.
- Longer follow-up is necessary to assess late toxicity.
CHICAGO — Radiation therapy can be safely omitted for patients with primary mediastinal B-cell lymphoma who demonstrate a complete metabolic response after chemoimmunotherapy, according to data presented at ASCO Annual Meeting.
IELSG37 — the largest prospective, international study in primary mediastinal B-cell lymphoma, according to researchers — showed patients may be spared from late toxicities without compromising the potential for cure.
“The main take home message is that mediastinal radiotherapy in patients with complete remission after front-line immunochemotherapy can be safely omitted,” Emanuele Zucca, MD, consultant and head of the lymphoma unit at Oncology Institute of Southern Switzerland, said during a presentation.
Background and methodology
Patients with primary mediastinal B-cell lymphoma (PMBCL) have a good prognosis if remission is achieved with dose-intensive immunotherapy; however, mediastinal radiotherapy carries increased risk for second malignancies and certain forms of heart disease.
Researchers conducted IELSG37 to assess whether radiotherapy can be omitted in patients who achieve a complete metabolic response after immunochemotherapy.
Eligible patients included those with newly diagnosed PMBCL.
PFS at 30 months from randomization served as the primary endpoint. OS at 5 years from registration and long-term toxicity served as secondary endpoints.
Of 545 enrolled patients, 268 (median age, 35.5 years; 61.6% women) achieved complete metabolic response and were randomly assigned to undergo observation (n = 132) or receive radiotherapy (n = 136).
Median follow-up was 63 months (interquartile range, 48-69).
Results
Researchers reported 30-month PFS rates of 98.5% (95% CI, 94.2-99.6) in the radiotherapy group and 96.2% (95% CI, 91.1-98.4) in the observation group.
HRs for estimated relative effect of radiotherapy vs. observation were 0.47 (95% CI, 0.12-1.89) without adjustments and 0.68 (95% CI, 0.16-2.91) when stratified for factors such as sex, chemotherapy, country and PET response score.
Researchers reported 30-month OS rates of 99.3% (95% CI, 94.9-99.9) with radiotherapy and 99.2% (95% CI, 94.7-99.9) with observation.
Longer follow-up is necessary to assess late toxicity, Zucca said.
“These findings are particularly important for this aggressive type of lymphoma, which occurs more often in young adults,” Corey W. Speers, MD, PhD, vice chair of research and associate professor at University Hospitals Seidman Cancer Center and Case Western Reserve University, said in an ASCO press release. “These reassuring data demonstrate that patients with primary B-cell lymphoma who have a rapid response to initial dose-intensive chemoimmunotherapy have excellent outcomes with a very low likelihood of the cancer coming back, regardless of whether they receive consolidative radiation therapy as a part of their treatment.”
References:
- Radiation treatment may not be necessary after chemoimmunotherapy for primary mediastinal B-cell lymphoma (ASCO press release). Available at: Published June 6, 2023. Accessed June 6, 2023.
- Zucca E, et al. Abstract LBA7505. Presented at: ASCO Annual Meeting 2023; June 2-6, 2023: Chicago.
Collapse
Zucca E, et al. Abstract LBA7505. Presented at: ASCO Annual Meeting 2023; June 2-6, 2023: Chicago.
Click Here to Manage Email Alerts