The importance of timing of radiotherapy after radical prostatectomy in patients with prostate cancer

The study compared outcomes of adjuvant radiotherapy (AR) versus observation with salvage radiotherapy (SR) in patients with prostate cancer (PCa) after radical prostatectomy (RP). The authors found that careful observation with SR is a safer treatment after RP for preventing cancer progression.

RP surgically removes the prostate and surrounding tissues in patients whose cancer is confined to the prostate gland. Radiotherapy is performed after RP to prevent PCa from returning. AR is given early after RP to patients without evidence of cancer. Alternatively, patients can be carefully observed with SR given only after an increase in prostate-specific antigen (PSA). PSA is a protein found in the blood used to monitor PCa recurrnce. Higher levels of PSA mean the return of PCa.

The optimal timing of radiotherapy after RP is unclear.

The study included 1396 patients with PCa who had a RP. After undergoing RP, 697 patients were assigned to receive AR and 699 patients were put on observation. SR was given to the observation group in case of biochemical progression (BP; an increase in PSA levels). The average follow-up was 4.9 years after RP.

93% of patients from the AR group underwent radiotherapy within 6 months of RP. 33% of patients from the SR group reported radiotherapy within 5 years after RP. There was no difference between the AR and SR group in terms of BP. 85% of patients from the AR group and 88% from the SR group survived for 5 years without BP.

Toxicity due to radiotherapy was more common in the AR group compared to the SR group. Severe haematuria (blood in urine) occurred in 3% patients in the AR group and less than 1% patients in the SR group, within 2 years. After 2 years, 4% of AR and less than 1% of SR group experienced severe haematuria. Serious narrowing of urethra (the tube that passes urine) was reported in 6% patients from the AR group and 4% patients from the SR group, within 2 years.

The study concluded that AR is not recommended after RP since it increased urinary complications. The authors suggest that careful observation with SR should be considered for preventing BP after RP.

The follow up period in this study was not sufficient enough to evaluate long-term survival. Also, some patients in the study received hormonal treatment after RP. This might have affected the results.