Reduced Length of ADT and ARTA With XRT in High-Risk Prostate Cancer (RELAX): A Randomised Trial

Aim of the study to improve the treatment of high-risk non-metastatic prostate cancer by comparing reduced duration of hormone therapy to the standard duration of two years, when combined with curative intent standard of care radiotherapy to prostate and pelvic nodes. The reduced duration will be intensified with addition of newer hormonal agents such as abiraterone or enzalutamide tablets, which have been shown to improve disease control in locally advanced prostate cancer. This is hoped to reduce the side effects of prolonged hormone therapy, while maintaining similar rates of disease control and survival. The effectiveness of both treatment approaches will be assessed in terms of cancer control, survival, and overall quality of life of patients. Additionally, the study will examine the side effects associated with each treatment regimen, which could provide valuable insights into impact of treatment duration on patients. If a person decides not to participate, they will still receive the standard two years of hormonal therapy and radiation therapy outside the study. This ensures that all patients receive appropriate care regardless of their involvement in the research. Participation is voluntary, and will not affect patient care.

Sex

Male

Minimum age

19 Years

Maximum age

99 Years

Inclusion Criteria:-

* Patients with biopsy proven prostate adenocarcinoma, deemed suitable for curative- intent radiotherapy
* Clinicoradiological stage T1-T4N0M0 using PSMA-PETCT and MRI
* High risk or very high risk (as per NCCN 2023): stage T3a + OR Gleason Score 4+4 or 4+5 OR PSA 20 +
* Patient fit and able to receive ADT for 2 years
* Patient fit and able to receive ARTA for 6 months
* ECOG performance status 0-2
* Patient able and willing for informed consent and reliable for follow-up

Exclusion Criteria:-

* Primary Gleason pattern 5 (Gleason score 5+4 or 5+5)
* Life expectancy deemed to be less than 2 years
* Uncontrolled comorbidities such as diabetes or hypertension causing ineligibility to receive ARTA
* Bulky primary disease with extensive infiltration into bladder/rectum/pelvic muscle
* Prior ADT more than 3 months before screening or prior orchiectomy
* Prior prostatectomy
* Unsuitable for curative dose of radiotherapy (severe urinary obstructive symptoms, inflammatory bowel disease, prior pelvic radiotherapy etc.)
* Presence of adverse pathological variants (such as small cell histology)
* Unable or unwilling to consent and follow up

• DERIVEDMurthy V, Maitre P, Priya S, Dhingra S, Dhanawat A, Shah M, Bhattacharya K, Adepu A, Singh P, Phurailatpam R, Patil D, Noronha V, Prabhash K, Misra A, Arora A, Pal M, Prakash G, Menon S, Joshi A. Reduced Length of ADT and ARTA With XRT in High-Risk Prostate Cancer (RELAX): A Randomised Controlled Trial. Clin Oncol (R Coll Radiol). 2026 Jun 27;57:104280. doi: 10.1016/j.clon.2026.104280. Online ahead of print. PMID 42567090