From the Guidelines
Intermittent Androgen Deprivation Therapy (ADT) is generally preferable to continuous ADT for many patients with advanced prostate cancer, particularly those with non-metastatic disease or low-volume metastatic disease. With intermittent ADT, hormone therapy is administered until PSA levels drop significantly, then paused until PSA rises to a predetermined threshold, at which point treatment resumes. This approach offers several advantages, including reduced side effects like hot flashes, sexual dysfunction, and bone density loss during off-treatment periods, improved quality of life, and potential delay of hormone resistance.
Key Points
- The Canadian-led PR.7 trial provided phase III data comparing intermittent and continuous ADT in patients without metastasis, showing that intermittent ADT was noninferior to continuous ADT with respect to overall survival 1.
- Although more patients died of prostate cancer in the intermittent ADT arm, this was balanced by more non-prostate cancer deaths in the continuous ADT arm 1.
- Quality-of-life factors, including physical function, fatigue, urinary problems, hot flashes, libido, and erectile dysfunction, showed modest improvement in the intermittent ADT group 1.
- A study published in the Journal of the National Comprehensive Cancer Network found that intermittent ADT was not inferior to continuous ADT with respect to survival, and quality of life was better for the intermittent ADT arm 1.
Considerations
- The decision between intermittent and continuous ADT should be individualized based on disease characteristics, symptom burden, and patient preferences after discussing the benefits and limitations of each strategy.
- Continuous ADT remains preferred for high-volume metastatic disease or rapidly progressive cancer.
- Patients with a shorter PSADT (or a rapid PSA velocity) and an otherwise long life expectancy should be encouraged to consider ADT earlier, and may be candidates for intermittent ADT 1.
From the Research
Comparison of Intermittent and Continuous Androgen Deprivation Therapy (ADT)
- Intermittent ADT has been investigated as an alternative to continuous ADT in patients with prostate cancer, with the goal of delaying the development of castration resistance and reducing side effects 2, 3, 4, 5, 6.
- Studies have shown that intermittent ADT can be as effective as continuous ADT in certain patient populations, with similar overall survival and progression-free survival rates 4, 5.
- However, the results of these studies are not uniform, and some trials have suggested that continuous ADT may be more effective in certain situations 2.
- The use of intermittent ADT may be beneficial in reducing treatment-related side effects and improving quality of life, although the evidence for this is not strong 3, 4, 5.
- Factors such as disease burden, patient demographics, and treatment regimen may impact the effectiveness of intermittent ADT, and further study is needed to determine the optimal patient population for this treatment approach 5, 6.
Key Findings
- A randomized trial comparing intermittent and continuous ADT in patients with metastatic prostate cancer found no significant difference in overall survival or progression-free survival between the two groups 4.
- A review of phase 3 trials comparing intermittent and continuous ADT found that intermittent ADT can produce similar oncologic results to continuous ADT, with a modest benefit in terms of quality of life 5.
- Another review of clinical trials evaluating the efficacy of intermittent ADT versus continuous ADT suggested that intermittent ADT may be a viable option for certain patients with prostate cancer, although the evidence is not yet strong enough to support its widespread use 6.
Patient Selection
- Patient selection is critical when considering intermittent ADT, and factors such as disease burden, patient demographics, and treatment regimen should be taken into account 5, 6.
- Patients with a low disease burden and those who are highly responsive to ADT may be good candidates for intermittent ADT 4, 5.
- Further study is needed to determine the optimal patient population for intermittent ADT and to develop clear guidelines for its use 6.