By Nick Klenske
Metastatic castration-resistant prostate cancer (mCRPC) is an advanced, aggressive form of prostate cancer. Having spread to other parts of the body, the cancer does not respond to hormone therapy and is thus a leading cause of cancer-related deaths in men worldwide.
Although there is no cure for mCRPC, new treatments are helping people live longer.
One of those treatments is LuPSMA.
Approved by the U.S. Food and Drug Administration (FDA) in 2022, LuPSMA (177Lu-vipivotide tetraxetan) is a radioligand drug that targets a molecule on the surface of prostate cancer cells.
Providing well-tolerated systemic radiation delivery, LuPSMA can improve a patient’s quality of life, delay cancer progression and extend survival. However, in some cases, additional localized disease control may be required.
“When the cancer causes immediate health risks that demand rapid intervention, threatens the patient's ongoing treatment protocol, or involves unique disease sites, complementary localized treatments, alongside LuPSMA, could provide more comprehensive disease management, ensuring patients receive the most adaptive and responsive care possible,” said Sedra Mohammadi, MD, a research fellow in radiology at Massachusetts General Hospital.
In such cases, targeted external beam radiation therapy (EBRT), the most common type of radiation therapy used for treating cancer, could serve as an adjunct means of destroying any remaining cancer cells.
“EBRT can directly attack cancer cells, significantly slow tumor growth, reduce the likelihood of cancer recurrence and alleviate cancer-related symptoms,” Dr. Mohammadi explained.
Despite these advantages, Dr. Mohammadi said that little research has been done on the effects of using EBRT in combination with LuPSMA. To learn more, she led a study that investigated the combined use of these two therapies.
“Our goal was to better understand the indications, efficacy, safety and toxicity of using EBRT with LuPSMA in a real-world setting,” said Dr. Mohammadi, who shared the results of the study during a Wednesday session.
The study analyzed 52 patients who received both treatments, with a focus on the clinical factors driving EBRT use, treatment timing, outcomes and safety profile. Patients received radiation doses and techniques tailored to their specific disease conditions, with some receiving EBRT before, during or after LuPSMA. Three patients received the combination twice. While EBRT was administered to 33 patients for impending pathological fractures, 15 received it for intracranial and epidural diseases.
At a median follow-up of five months, 32 individuals showed symptom improvement, while 20 had died from disease progression. At the time of review, these 32 patients demonstrated a ≥50% reduction in prostate-specific antigen (PSA) from baseline at any time during EBRT/LuPSMA therapy —slightly lower but not substantially different compared to the general LuPSMA population.
Although the combined use of EBRT and LuPSMA did not significantly impact long-term systemic disease control, it did provide good local symptom control.
“This combination is particularly effective at managing CNS lesions, bone pain and preventing pathological fractures,” Dr. Mohammadi said.
Most importantly, the study clearly demonstrated that EBRT can be safely administered before, during, or after LuPSMA therapy.
“Our findings show that EBRT can provide targeted symptom relief and help manage specific complications while patients undergo systemic treatment, ultimately enhancing their quality of life,” Dr. Mohammadi concluded.
Access the presentation, “Utility of Combination External Beam Radiation with 177LU-OSMA-617 Therapy for Patient Management in the Real-World Setting,” (W6-SSNMMI06-2) on demand at RSNA.org/MeetingCentral.
© 2024 RSNA.
The RSNA 2024 Daily Bulletin is the official publication of the 110th Scientific Assembly and Annual Meeting of the Radiological Society of North America. Published online Sunday, December 1 — Friday, December 6.
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