A large clinical trial has demonstrated that men with prostate cancer who require radiation therapy after surgery can safely receive a shorter, more intensive course of treatment without experiencing long-term quality of life differences compared to conventional approaches.
The study, conducted by NRG Oncology across more than 90 treatment centers nationwide, found that hypofractionated post-operative prostate bed radiotherapy (HYPORT) delivered over 5 weeks produced similar patient-reported outcomes as the standard 7-week conventional post-prostatectomy radiotherapy (COPORT) regimen.
Treatment Comparison and Study Design
The phase 3 trial randomized 296 men into two treatment groups. The HYPORT group received 62.5 Gy to the prostate bed in 25 fractions of 2.5 Gy over 5 weeks, while the COPORT group received 66.6 Gy in 37 fractions of 1.8 Gy over 7 weeks. Both approaches delivered the same overall radiation dose but with different intensities and timeframes.
"Radiotherapy is a curative treatment alternative to surgery for men with prostate cancer and short courses are used all the time," explained lead investigator Dr. Mark Buyyounouski, a radiation oncologist at Stanford University. "Radiotherapy may also be indicated after surgery, but a short course has not been tested until now."
The trial was designed to be inclusive, representing patients commonly treated in community settings. Participants included both those receiving radiation immediately after surgery and those who waited until they had rising PSA levels. Patients with some invasion of cancer into nearby tissue were eligible, though those with lymph node involvement were excluded.
Patient-Reported Outcomes
The study relied on patient-reported outcomes rather than physician assessments of toxicity, using the Expanded Prostate Cancer Index Composite (EPIC) questionnaire to measure urinary and bowel symptoms before radiation and at 6, 12, and 24 months after treatment.
"Physician-reported toxicities can sometimes lead us astray," noted Dr. Buyyounouski. "Not everything that can be counted [by us] counts to patients. So we wanted to know: When do [people] tell us that they're feeling good again?"
Approximately three-quarters of participants completed all questionnaires. The results showed that while patients receiving HYPORT reported more bowel side effects immediately following treatment, these differences disappeared by the 6-month follow-up. Urinary side effects were equivalent between groups throughout the study period.
By two years post-treatment, both groups continued to report similar and relatively low levels of symptoms, with no differences in cancer recurrence rates observed between the two approaches.
Clinical Significance and Patient Benefits
The findings represent a significant advancement in prostate cancer care, potentially making treatment more accessible to patients who might otherwise face barriers to completing a full course of radiation therapy.
"For a lot of patients, coming in every [weekday] for 7 weeks has a major impact on their lives," said Dr. Deborah Citrin of NCI's Center for Cancer Research, who was not involved in the study. "There's a lot of interest in hypofractionation because getting treatment done more quickly is so much easier, financially and otherwise."
Dr. Buyyounouski emphasized the practical implications: "There's transportation costs, gas, parking, co-pays. And there are costs associated with the things you're not doing, like time away from work or responsibilities at home. It's more than just the medical bills."
Implementation Considerations
For patients considering HYPORT, the researchers noted that the technology used in the trial is widely available across the country. The only specific requirement is the use of image guidance during treatment, which helps clinicians precisely target radiation delivery.
"We want people to know that this is available near you," Dr. Buyyounouski said, though he cautioned that the results may not apply to all post-prostatectomy patients, such as those requiring radiation to their lymph nodes.
Future Directions
Several ongoing clinical trials are exploring whether prostate radiation therapy can be compressed even further for select patients. For example, researchers are currently testing hypofractionated radiation delivered over just 2 to 4 weeks.
Recent advances in prostate imaging, including FDA-approved PSMA-based PET-CT imaging, may also allow for more personalized radiation therapy approaches that could potentially reduce side effects by targeting smaller areas of tissue more effectively.
"Ongoing research in radiation oncology is often aimed at making radiation therapy more convenient, less toxic, and less expensive for patients, while maintaining excellent cure rates," Dr. Citrin noted.
The results of this study were presented at the 2021 American Society for Radiation Oncology Annual Meeting, offering new evidence that could change standard practice and improve the treatment experience for many prostate cancer patients.
