Adding a longer course of androgen deprivation therapy (ADT) to postoperative radiotherapy can prolong metastasis-free survival (MFS) in patients with prostate cancer, according to data presented at ESMO Congress 2022.

In the phase 3 RADICALS-HD trial, a 2-year course of ADT improved MFS when compared with 6 months of ADT. However, 6 months of ADT did not improve MFS when compared with no ADT.

Researchers decided to test the efficacy of adding ADT to postoperative radiotherapy because the role of ADT in this setting “is uncertain, and current guidelines are largely silent on the matter,” said study presenter Chris Parker, MD, of the Royal Marsden Hospital NHS Foundation Trust in London, UK. 


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The RADICALS-HD trial included 2839 patients with prostate cancer who underwent radiotherapy after radical prostatectomy. Patients were randomly assigned to receive a short course of ADT (6 months), a long course of ADT (24 months), or no ADT. 

For the comparison between long-course ADT and short-course ADT, 1523 patients were randomly assigned to short-course ADT (n=761) or long-course ADT (n=762). 

For the comparison between no ADT and short-course ADT, 1480 patients were randomly assigned to short-course ADT (n=747) or no ADT (n=737).

Dr Parker noted that adverse clinical factors were more common in the long-short ADT comparison than in the short-none comparison.

Short vs None

At a median follow-up of 9 years, short-course ADT did not prolong MFS compared with no ADT (hazard ratio [HR], 0.89; 95% CI, 0.69-1.14; P =.35). The 10-year MFS rate was 79% in the no-ADT arm and 80% in the short-course ADT arm.

Likewise, there was no significant difference in freedom from distant metastases between the short-course and no-ADT groups (HR, 0.82; 95% CI, 0.58-1.15; P =.24). However, short-course ADT significantly delayed the time to salvage hormone therapy (HR, 0.54; 95% CI, 0.42-0.70; P <.0001). 

Overall survival (OS) was similar between the short-course and no-ADT groups (HR, 0.88; 95% CI, 0.65-1.19; P =.42). The 10-years OS rate was 86% in the no-ADT arm and 85% in the short-course ADT arm.

Long vs Short

Long-course ADT significantly improved MFS compared with the shorter course (HR, 0.77; 95% CI, 0.61-0.97; P =.03). The 10-year MFS rate was 78% with long-course ADT and 72% with short-course ADT. 

A long course of ADT also improved freedom from distant metastases (HR, 0.63; 95% CI, 0.47-0.85; P =.002) and time to salvage hormone therapy (HR, 0.73; 95% CI, 0.59-0.91; P =.005).

However, OS was similar between the short-course and long-course ADT groups (HR, 0.88; 95% CI, 0.66-1.17; P =.38). The 10-year OS rate was 82% in the short-course group and 85% in the long-course group.

Disclosures: Some of the study authors declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of disclosures.

Reference

Parker CC, Clarke N, Cook A, et al. Duration of androgen deprivation therapy (ADT) with post-operative radiotherapy (RT) for prostate cancer: First results of the RADICALS-HD trial (ISRCTN40814031). Presented at ESMO 2022; September 9-13, 2022. Abstract LBA9.

This article originally appeared on Cancer Therapy Advisor