(UroToday.com) The 2023 American Society of Clinical Oncology (ASCO) annual meeting held in Chicago, IL between June 2nd and June 6th was host to a prostate, testicular, and penile cancers poster session. Dr. Wee Loon Ong presented the results of TRANSPORT, evaluating testosterone recovery following androgen suppression and prostate radiotherapy, using updated individual patient data meta-analyses from the MARCAP consortium.
While concurrent testosterone suppression has been shown to improve survival outcomes in prostate cancer patients receiving pelvic radiotherapy, there are significant concerns regarding testosterone recovery following cessation of therapy. The kinetics of testosterone recovery vary significantly following cessation of androgen deprivation therapy (ADT) of various durations. In particular, time to testosterone recovery is of utmost interest given its impact on quality of life. In this study, Dr. Ong and colleagues sought to characterize testosterone recovery kinetics and identify factors predicting time to recovery following ADT use.
This analysis included patients from trials of prostate radiotherapy plus ADT in the Meta-Analysis of Randomized trials in Cancer of the Prostate (MARCAP) consortium for which prospectively collected serial testosterone data is available. Two outcomes were evaluated:
- Time to non-hypogonadal testosterone, defined as >8 nmol/L
- Time to full testosterone recovery, defined as >10.5 nmol/L
Time-to-event rates were estimated using Kaplan-Meier curves and defined from the time of first available testosterone at trial enrolment. The effect of interactions between duration of ADT and patients’ age on testosterone recovery was evaluated.
This cohort included 1,439 men with non-castrate testosterone at baseline (>1.7nmol/L) who met the study inclusion criteria, of whom 220, 765, and 454 had received 3, 6, and 18 months of ADT, respectively. Full testosterone recovery was observed in 67% of men at last follow-up. In the overall cohort, the median times to non-hypogonadal and full testosterone recoveries were as follows:
- 3-months ADT: 5.5 months (range: 1.6 – 76.3) and 6.2 months (1.8 – 75.7)
- 6-months ADT: 12.2 months (0.8 – 53.6) and 15.2 months (0.8 – 86)
- 18-months ADT: 30.1 months (2.8 – 90.4) and 36 months (18.1 – 85.5)
In the subset of 1,160 men with normal testosterone at baseline (i.e., >10.5 nmol/L), 69% had full testosterone recovery, with median times as follows:
- 3-months ADT: 5.5 months (1.8 – 75.7)
- 6-months ADT: 12.7 months (1.8 – 86)
- 18-months ADT: 30.8 months (18.1 – 84.1).
For any given duration of ADT, men aged above 65 years were less likely to have full testosterone recovery compared to those aged under 65 years:
- 3-months ADT: HR= 0.67 (95% CI: 0.46 – 0.99)
- 6-months ADT: HR=0.80 (95% CI: 0.67 – 0.96)
- 18-months ADT: HR= 0.64 (95%CI: 0.51-0.91)
There was no evidence of interaction between the effect of ADT duration on time to full testosterone recovery and age (interaction P=0.3 for entire cohort).
Dr. Ong concluded that this is the largest pooled analysis of prospectively collected serial testosterone data from randomized trials, indicating substantial delay in full testosterone recovery in men receiving longer durations of ADT. Approximately one-third of the men did not achieve full testosterone recovery, which may have life-long impact on quality of life.
Presented by: Wee Loon Ong, MBBS, Clinical Fellow, Department of Radiation Oncology, Sunnybrook Health Science Centre, University of Toronto, Toronto, ON
Written by: Rashid Sayyid, MD, MSc – Society of Urologic Oncology (SUO) Clinical Fellow at The University of Toronto, @rksayyid on Twitter during the 2023 American Society of Clinical Oncology (ASCO) Annual Meeting, Chicago, IL, Fri, June 2 – Tues, June 6, 2023.