Will postoperative radiation decrease the likelihood of prostate cancer recurrence?

This study examined the safety and efficacy of radiation therapy to the prostate bed and pelvic lymph nodes following surgery for prostate cancer.

Postoperative radiation therapy is a standard treatment for prostate cancer patients who are at an increased risk for recurrence (return of the disease even after surgery to remove the prostate). The radiation is generally focused on the prostate bed, or the area where the prostate was before it was surgically removed. Multiple studies have shown that radiation therapy decreases recurrence rates; however, it is not clear whether radiation therapy to the pelvic lymph nodes is beneficial. The pelvic lymph nodes are one of the early sites of metastasis for prostate cancer.

The PLATIN clinical trials have examined the safety and effectiveness of pelvic lymph node radiation therapy in combination with radiation therapy to extended pelvic areas. The current study analysed results from the PLATIN 3 trial examining radiation therapy to the prostate bed and the pelvic lymph nodes.

This study included 40 high-risk prostate cancer patients undergoing radiation therapy following surgical removal of the prostate. These patients were also undergoing androgen-deprivation therapy, which blocks the production or use of testosterone by the body, the hormone necessary for cancer growth. Prostate-related symptoms and toxicities, such as gastrointestinal symptoms, incontinence, and erectile dysfunction were assessed before, during and after treatment. The study lasted 24 months. 

During the trial only one patient had to discontinue treatment due to toxicity. Therefore, the treatment was associated with a safe treatment application rate of 97.5% (39/40).

67.5% of patients experienced low-grade gastrointestinal toxicity, the most common being diarrhea. 12.8% of patients had symptoms of rectal discomfort or passing of mucus or blood the required medical intervention.

64.8% of patients were experiencing incontinence 12 months following treatment, though 62.5% of patients were already experiencing incontinence prior to treatment.  This percentage had decreased to 33.4% by 24 months post-treatment.

Directly after surgery and before the start of androgen deprivation therapy 85% of patients reported a complete loss of erectile function. This percentage increased during the course of treatment and follow-up to 95%.

10% of patients (4 of the 39 that completed the trial) experienced a biochemical recurrence. This was indicated by three elevated measurements of prostate-specific antigen in a row. Prostate-specific antigen is a protein released by the prostate and found in abnormally high concentrations in men with prostate cancer.

This study concluded that radiation therapy to both the prostate bed and the pelvic lymph nodes is a safe and effective treatment in prostate cancer.

The follow-up period for this trial was only 24 months, therefore further trials should be undertaken to determine if radiation therapy is beneficial in the long-term.