Radiotherapy Did Not Improve Survival in All Patients With Metastatic Prostate Cancer

Adding radiotherapy to standard-of-care androgen deprivation therapy (ADT) did not improve survival in men with newly diagnosed metastatic prostate cancer, according to the results of the STAMPEDE trial.¹

Compared with standard of care, radiotherapy improved failure-free survival (hazard ratio [HR] = 0.76; 95% confidence interval [CI], 0.68-0.84; P < .0001), but did not improve overall survival (HR = 0.92; 95% CI, 0.80-1.06; P = .266).

However, a subgroup analysis showed that overall survival was improved in those patients with a low metastatic burden at baseline assigned to radiotherapy (HR = 0.68; 95% CI, 0.52-0.90; P = .007). Three-year survival in these men was 81% with radiotherapy compared with 73% in the standard-of-care group. These results support findings from a previous study that showed that survival might be improved in patients with a low metastatic burden following radiotherapy.²

“Evidence suggests that prostate radiotherapy improves overall survival for men with metastatic prostate cancer who have a low metastatic burden, but not for unselected patients,” the researchers wrote. “Prostate radiotherapy should be a standard treatment option for men with newly diagnosed disease with a low metastatic burden.”

In the phase 3 study, men with newly diagnosed metastatic prostate cancer were randomly assigned to standard of care with ADT and upfront docetaxel with (1032 individuals) or without radiotherapy (1029 individuals). The primary outcome of the study was overall survival.

Overall, radiotherapy was well tolerated, with 5% of patients reporting adverse events during radiotherapy and 4% reporting events after radiotherapy. The proportion of patients reporting at least 1 serious adverse event was similar between the 2 groups.

References

1. Park CC, James ND, Brawley CD, et al. Radiotherapy to the primary tumour for newly diagnosed metastatic prostate cancer (STAMPEDE): a randomized controlled phase 3 trial [published online October 21, 2018.  Lancet Oncol. doi: 10.1016/S0140-6736(18)32486-3

2. Boevé LMS, Hulshof MCCM, Vis AN, et al. Effect on survival of androgen deprivation therapy alone compared to androgen deprivation therapy combined with concurrent radiation therapy to the prostate in patients with primary bone metastatic prostate cancer in a prospective randomised clinical trial: data from the HORRAD trial [published online Sept 25]. Eur Urol. doi: 10.1016/j.eururo.2018.09.008