American Society for Radiation Oncology, Sept. 27-Oct. 1

The annual meeting of the American Society for Radiation Oncology was held from Sept. 27 to Oct. 1 in San Francisco, drawing more than 11,000 participants from around the world, including physicians, oncology nurses, radiation therapists, biologists, physicists, and other cancer researchers. The conference featured educational courses focusing on radiation, surgical, and medical oncology.

In the NRG GU006 double-blind, placebo-controlled, randomized trial, Daniel E. Spratt, M.D., of the Case Western Reserve University School of Medicine in Cleveland, and colleagues validated a predictive biomarker — referred to as PAM50 — for hormone therapy benefit in patients with prostate cancer receiving secondary radiotherapy (SRT).

The authors evaluated the benefit of apalutamide based on a novel gene expression signature, PAM50, for men with recurrent prostate cancer receiving SRT. The researchers successfully demonstrated that patients with luminal B tumors derived benefit from apalutamide, while patients with nonluminal B tumors did not. Apalutamide was well tolerated, and only a few patients had grade 3 or higher side effects related to the modern radiotherapy used in the trial.

“Patients with recurrent prostate cancer planning to receive SRT should undergo PAM50 testing, and patients with luminal B tumors should be counseled on the benefits of adding hormone therapy to SRT,” Spratt said. “In contrast, nonluminal B patients should be counseled on the lack of demonstrated benefit of hormone therapy with SRT.”

One author disclosed financial ties to the pharmaceutical industry.

Press Release

In the phase 2 LUNAR trial, Amar U. Kishan, M.D., of the University of California in Los Angeles, and colleagues found that adding two cycles of the investigational prostate-specific membrane antigen (PSMA)-targeting drug ¹⁷⁷Lu-PNT2002 to targeted radiation in men with one to five lesions outside the prostate (after prior treatment of their prostate) improves progression-free survival (PFS).

The authors randomly assigned patients with hormone-sensitive, oligometastatic prostate cancer and one to five distant lesions visible on a PSMA positron emission tomography/computed tomography scan to either stereotactic body radiation therapy (SBRT) alone or two cycles of ¹⁷⁷Lu-PNT2002 followed by SBRT.

This trial was a key proof-of-concept study demonstrating that ¹⁷⁷Lu-PNT2002 was able to act on occult disease. Specifically, adding two cycles of ¹⁷⁷Lu-PNT2002 to targeted radiation in men with one to five lesions outside the prostate (after prior treatment of their prostate) improved PFS by more than 10 months and allowed men to defer hormone therapy for up to two years on average with no significant added toxicity.