Androgen deprivation therapy (ADT) is historically the standard of care for patients with oligorecurrent, hormone-sensitive prostate cancer — a setting where a small number of metastases emerge at some point following local treatment of the primary tumor. However, many men opt to postpone ADT due to substantial side effects of the therapy, and there is an unmet need for alternative therapeutic approaches that preserve patients’ quality of life while deferring systemic treatment.
A new wave of imaging technologies now allows for the direct detection of oligometastases and removal through local ablative techniques such as stereotactic body radiotherapy (SBRT); some of these technologies are emerging as new metastasis-directed therapies (MDTs) for patients with prostate cancer.
Indeed, a small number of prospective studies investigating the use of MDT — mostly SBRT — in men with oligorecurrent disease have suggested that the treatment is safe, and in 1 study, up to 50% of patients did not require ADT or other forms of systemic treatment for 2 years following MDT.1 Such findings have led to the idea that MDT could serve as an intermediate treatment between surveillance and systemic ADT.
While clinical trials are still investigating the long-term survival benefits of conducting upfront MDT prior to standard-of-care systemic therapy, a recent study estimated the cost-effectiveness of such a treatment approach and compared it to 2 hypothetical systemic approaches — ADT alone, or combining more advanced hormone therapies with ADT.2
Computational cost-effectiveness models suggested that at 10 years, upfront MDT followed by standard-of-care systemic therapy was similarly cost-effective as the other treatment approaches, suggesting that it could be a viable treatment strategy, particularly for patients who wish to defer systemic therapy. The findings were published in the International Journal of Radiation Oncology, Biology, Physics.
“Sometimes we think using fancy radiation is just adding cost, but it might actually be cost-effective if we are delaying the onset of more expensive other drugs,” said Amar U. Kishan, MD, an assistant professor and vice chair of clinical and translational research for the department of radiation oncology at the David Geffen School of Medicine at the University of California, Los Angeles, and a coauthor of the study.
In the study, Dr Kishan and his colleagues compared 3 hypothetical treatment strategies. In the first, patients with oligorecurrent, hormone-sensitive disease were to receive upfront SBRT, and upon progression, antihormonal drugs abiraterone acetate plus prednisone (AAP) together with ADT, followed by docetaxel chemotherapy plus ADT — combination approaches that have been associated with survival benefits in patients with de novo diagnoses of metastatic hormone-sensitive prostate cancer.3,4 In the second treatment scenario, patients received upfront AAP with ADT, followed by salvage docetaxel plus ADT. The third strategy entailed upfront treatment with docetaxcel plus ADT followed by salvage abiraterone plus ADT.