LOUIS—Androgen deprivation therapy (ADT) has been a mainstay of metastatic hormone-sensitive prostate cancer (mHSPC) for years. More recently, studies have shown improved survival in patients who receive either docetaxel or androgen signaling agents (ASIs) such as abiraterone or enzalutamide in combination with androgen deprivation therapy.
Whether the combination would provide a similar benefit in veterans, who tend to be older and have more co-morbidities, remains unknown. To answer the question, St. Louis University-led researchers identified veterans diagnosed with prostate cancer with SEER stage “distant” between 2018 and 2021, all of whom started ADT between one month before and four months following diagnosis. Patients were determined to have received combination therapy if treatment with docetaxel or an ASI also commenced during the same period.1
The team presented their results at the 2023 American Society of Clinical Oncology annual meeting in Chicago, June 2-6, 2023
Based on the highest prostate-specific antigen (PSA) level within three months of diagnosis, the researchers included any patient with a PSA of at least 100 ng/mL to have a PSA of 100 or more. The study excluded veterans who died within four months of diagnosis.
Of the 2,227 veterans with mHSPC, 25.8% identified as Black. The average age of all veterans in the study was 74 years. During the study period, 52% of veterans received only ADT, while 8.4% received docetaxel in addition to ADT and 39.6% of veterans received an ASI/ADT combo. Veterans receiving docetaxel were younger than those who received ASI, 67.7 years vs 72.9 years, respectively.
Both combination therapies provided a longer median overall survival of 40.9 months, while ADT alone had a median overall survival on 32.9 months (p < 0.001). There was no significant difference between the two combination therapies in terms of overall survival, with 37.9 months for the docetaxel combo and 36.6 for the ASI combination.
Half of veterans with PSA ≥100 received combination therapy compared to 46% of those with lower PSAs. Of the 1,071 veterans with PSA of 100 or higher, the median overall survival with combination therapy was 37.4 months compared to 27.5 months for ADT alone.
The researchers concluded that combination therapies were associated with longer overall survival in veterans with de novo metastatic hormone-sensitive prostate cancer compared to ADT monotherapy. Across the entire study cohort and those with PSA ≥ 100, the team found no difference in overall survival based on combination therapy selected. The researchers urged further studies of the impact of combination therapy that included tumor genetics or response to treatment to shed additional light on the best treatment for mHSPC.
- Babar A, Montgomery RB, Riekhof F, Etzioni RD, Almasalmeh N, Knoche EM, Sanfilippo KM, Schoen MW. Survival of de novo metastatic hormone sensitive prostate cancer in US Veterans based on treatment and PSA at diagnosis. 2023 ASCO annual meeting. June 2-6, 2023. Abstr. E17091. J Clin Oncol 41, 2023 (suppl 16; abstr e17091).
