To continue androgen deprivation therapy or not?
The concept of intermittent androgen deprivation therapy (IADT) is well established. After a patient has been initiated on ADT for an induction period of between 6-12 months, they may then be offered a treatment holiday. The benefit of this treatment approach is to minimise treatment related side effects (such as compromised sexual function, hot flushes, depression, fatigue and cardiovascular risk) and improve quality of life. It may also resensitise the tumour and prolong survival to castration resistance (discussed in previous blogs). There is also a cost benefit.
Who qualifies for IADT?
Patients who achieve a PSA less than 4 ng/mL during the initial induction period, have poor tolerability to continuous ADT, have non-metastatic disease, or metastasis that is limited to lymph nodes (glands) and are not candidates for chemotherapy such as docetaxel, have locally advanced disease, ideally older but highly motivated, have Gleason scores >7, and have longer PSA doubling time. IADT may lead to slower time to cancer progression and improved overall survival.
What is a typical IADT protocol?
There is no formal recommendation for the optimal protocol, but this is a guide: After the initial induction period where the PSA has reached less than 4 ng/mL for metastatic disease or less than 0.5ng/ml for those who have recurrent disease after primary treatment (surgery or radiation), the off-treatment phase can begin. During this time disease progression is monitored by testing PSA and testosterone levels every 3-6 months and a clinical review. If the PSA reaches 4-10 ng/ml for non-metastatic cancer and 10-20ng/ml for metastatic cancer or if the patient exhibits evidence of radiological or symptomatic progression, then treatment has to be re-initiated. Further imaging studies such as CT, bone scan or PET-based imaging may be requested. If there is no progression then a new induction phase is implemented for another 6 months before an ADT holiday can be trialled again.
The American Urological Association and National Comprehensive Cancer Network guidelines suggest IADT may be offered for patients with biochemical failure without metastases, and the European Association of Urology considers IADT for asymptomatic metastatic patients. This variation in recommendations has influenced the implementation of IADT by practitioners. There is limited research into the patterns of IADT usage. Cheung et al from the University of Toronto investigated a cohort of 8544 eligible patients and discovered that only 16,4% received IADT1. This statistic varied per region from 11.4%-24.8%. Those who had recurrence after radiation, or a prostatectomy were more likely to be placed on IADT with a prevalence of 26.6%. Those who had higher incomes were also more likely candidates, whereas those in rural areas experienced variation in their access to services and poorer survival. Radiation oncologists were more likely to prescribe IADT over urologists and number of years in practice was a positive influencer. Some of the cited reasons for initiating IADT by doctors was patient age, lower PSA, desire to maintain sexual function, associated illnesses, and patient request, which may reflect attempts to minimize side effects in lower-risk patients.
Where indicated, IADT has a potential impact on patients’ quality of life and cancer outcomes. Further research is required, particularly in the Australian context, to ascertain local prescribing patterns and impact on overall survival. This may shape treatment guidelines and redress any inequalities in care. Current trials are investigating combination treatments including targeted interventions (radiation and intratumoural therapy) and medications (abiraterone or immunotherapy such as nivolumab) to increase the time before re-initiation of ADT by controlling the primary disease2.
References
- Cheung DC, Alibhai SMH, Martin LJ et al. Real-world practice patterns and predictors of continuous versus intermittent androgen deprivation therapy use for prostate cancer in older men. Journal of Urology 2021; 206: 933-941.
- Perera MP, Roberts MJ, Klotz L, Higano CS, Papa N, Sengupta S, Bolton D, Lawrentschuk N. Intermittent versus continuous androgen deprivation therapy for advanced prostate cancer. Nature Reviews Urology 2020; 17: 469-481.
|
|
About the Author Kalli Spencer MBBCh, FC Urol (SA), MMed (Urol), Dip.Couns (AIPC) Kalli is an internationally renowned Urological Surgeon, specialising in oncology and robotic surgery. He trained and worked in South Africa, before relocating to Australia where he has worked at Macquarie University Hospital and Westmead Hospital. His passion for what he does extends beyond the operating room, through public health advocacy, education and community awareness of men’s health, cancer and sexuality. Kalli has been involved with the Prostate Cancer Foundation of Australia for many years, advocating for improved cancer care and facilitating community prostate cancer support groups. |
Prostate Cancer Specialist Telenursing Service:
If your life has been impacted by prostate cancer, our Specialist Telenursing Service is available to help. If you would like to reach out to the PCFA Prostate Cancer Specialist Telenurse Service for any questions you have about your prostate cancer experience, please phone 1800 22 00 99 Monday - Friday 9am - 5pm, Wednesday 10am-8pm (AEST).
Prostate Cancer Support Groups:
PCFA is proud to have a national network of affiliated support groups in each state and territory of Australia consisting of men and women who have a passion for assisting others who encounter prostate cancer. This network is made up of over 170 affiliated groups who meet locally to provide one-to-one support, giving a vision of life and hope after treatment. Call us on 1800 22 00 99 to find your local group.
MatesCONNECT Telephone-based peer support:
MatesCONNECT is a telephone-based peer support program for men affected by prostate cancer. If you’ve recently been diagnosed with prostate cancer, our MatesCONNECT service can connect you to a trained volunteer who understands what you’re going through. All of our volunteers have been through prostate cancer. Simply call us on 1800 22 00 99 to be connected with a volunteer.
Newly diagnosed? or need to find more information -Access the PCFA resources here!
1 Comment
