Comparing the effectiveness and safety of prostate-only versus pelvic radiotherapy for patients with prostate cancer spread to nearby lymph nodes.

This study compared the safety and effectiveness of whole-pelvis radiotherapy (WPRT) and prostate-only radiotherapy (PORT) in patients with node-positive prostate cancer (PC) (PC that has spread to nearby lymph nodes). The study found that WPRT improves survival without relapse in these patients, with more short-term gastrointestinal side effects.

Current treatment for PC involves radical prostatectomy (removal of the prostate gland), radiotherapy, and or hormonal therapy such as androgen deprivation therapy (ADT). Many patients receive a combination of these treatments to improve their outcomes. During surgery, nearby lymph nodes are also removed and checked for cancer spread. If at the pathology exam one or more lymph nodes have signs of cancer, this is called pathological node-positive cancer (pN1). In pN1 PC the risk of cancer relapse and mortality is higher.

Currently, the best therapy for pN1 is unknown. In patients with clinical node-positive (cN1; affected nodes are seen on imaging before surgery) PC, combined therapies have shown good results. However, with pN1 there is a lack of scientific evidence on the best treatment using adjuvant therapies.

Some studies suggested that radiotherapy (RT) can improve the outcomes of patients with pN1 PC. RT can be given to the prostate bed only (the place where the prostate gland used to be before surgery; PORT) or to the whole pelvic area (WPRT). WPRT may be associated with greater side effects. Therefore, it is important to evaluate how PORT compared to WPRT in terms of outcomes and safety in patients with pN1 PC. 

This study included 64 patients with pN1 PC. All patients had previously undergone prostate surgery or radiotherapy, lymph node removal surgery, and 2 years of ADT. Patients were randomly assigned to receive either PORT (33 patients) or WPRT (31 patients). The average follow-up was 30 months for the POR group and 36 months for the WPRT group. 

After 3 years, 92% of patients in the PORT group were alive compared to 93% in the WPRT group. No patient died from prostate cancer.

Biochemical recurrence (BCR) means a rise in prostate-specific antigen (PSA) levels after treatment. PSA is a protein made by the prostate gland that rises in PC. After 3 years, 79% of patients in the PORT group were alive without BCR compared to 92% in the WPRT group. 88% of patients in the PORT group were alive at 3 years without clinical relapse compared to 92% in the WPRT group. 

Short-term gastrointestinal side effects were experienced by 15% of patients in the PORT group compared to 45% in the WPRT group. Genitourinary toxicity was reported in 27% of the PORT group compared to 39% in the WPRT group.

The study concluded that WPRT had better relapse-free survival compared to PORT with a higher risk of gastrointestinal and genitourinary toxicity.

This study had a small number of participants and a short follow-up period. RT tends to act long-term, therefore longer-term studies are needed to evaluate the full effects of these therapies.