Postsurgical Radiotherapy Not Necessary for Prostate Cancer

For men with early-stage prostate cancer, the standard of care for many years has been radical prostatectomy followed by adjuvant radiotherapy to prevent disease recurrence. However, the benefits of radiotherapy in this setting are not well documented and can be associated with numerous toxic effects. At the ESMO Congress 2019, results from a large clinical trial and a supporting prospective meta-analysis suggested that postsurgical radiotherapy might not be necessary or ideal.

During the Presidential Session, Chris Parker, MD (Royal Marsden NHS Foundation Trust, London, United Kingdom), presented results from the RADICALS-RT study. A large, randomized study comparing adjuvant radiotherapy to observation in 1,396 patients with prostate cancer who had undergone a radical prostatectomy and had postoperative prostate-specific antigen (PSA) levels of ≤0.2 ng/mL. Salvage radiotherapy was offered to patients in the observation arm who developed signs of disease recurrence, defined as two consecutive rises of PSA and PSA levels of >1 ng/mL or three consecutive rises in PSA. At a median follow-up of 5 years, only 33% of patients in the observation arm had required salvage radiotherapy. Data from the primary endpoint of freedom from distant metastases were not yet mature. The 5-year progression-free survival (PFS) rate was similar in the two groups, at 85% for radiotherapy and 88% for observation (HR 1.10, P = .56). Furthermore, patients who did not receive radiotherapy had lower rates of associated adverse events (AEs) compared to those who received adjuvant radiotherapy, including self-reported urinary incontinence (2.7% vs 5.3%; P = .008) and grade 3/4 urethral stricture (5% vs 8%; P = .03).

In support of this study, the prospective ARTISTIC meta-analysis combined results from a total of 2,151 patients from the RADICALS trial as well as two similar studies, RAVES and GETUG-AFU17. Claire Vale, PhD (University College London, United Kingdom), presented this analysis during the Presidential Session. In this analysis, approximately half of patients had received adjuvant radiotherapy following surgery while the other half underwent observation followed by salvage radiotherapy if necessary. At the time of the presentation, 37% of patients in the observation arm had received salvage radiotherapy due to early signs of biochemical recurrence. While data from this analysis are not yet mature, early results indicated no difference in event-free survival (EFS) between the two arms (HR 1.09, P = .47).

The investigators of these two studies concluded that adjuvant radiotherapy is no more effective than salvage radiotherapy in preventing recurrence in men with early-stage prostate cancer. Delaying radiotherapy avoids unnecessary side effects by limiting radiation treatment to patients who develop disease recurrence, rather than giving toxic treatment to all patients. Dr Parker indicated that delayed radiotherapy is now the standard approach in his institution and suggests this be the standard of care for early-stage prostate cancer moving forward. The discussant of these studies, Xavier Maldonado, MD (Hospital Universitari Vall d’Hebron, Barcelona, Spain), agreed that these data are likely to change practice but cautioned that long-term follow-up of the RADICALS trial will be needed. Furthermore, Dr Maldonado indicated that some patients will still require adjuvant radiotherapy and those who opt for delayed radiotherapy will need very careful observation in order to detect recurrence in early stages.

Read more about these studies on Medscape Medical News.
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