Adjuvant radiotherapy may be beneficial in treating locally advanced prostate cancer
Some 5,400 men are diagnosed with prostate cancer in Finland every year. Although in most cases prostate cancer can be cured, approximately 900 men every year die of it. Treatment recommendations for prostate cancer are largely based on the cancer's stage (TNM classification), the cancer's aggressiveness determined from a prostate biopsy (the Gleason score), and prostate-specific antigen (PSA) obtained from a blood test, as well as the risk categorisation determined on the basis of these.
The treatment options for a local, low-risk prostate cancer are established and the prognosis is good. On the other hand, the prognosis for a higher-risk, locally spread or metastasised cancer is poorer, and there is no consensus on the treatments due to a lack of sufficient research data.
In connection to the surgical removal of the prostate, the cancer may be found to have extended to the surface of the removed prostate or to have already spread through the capsule surrounding the prostate. In such cases, the risk of recurrence is higher than in situations in which the cancer cells are confined within the prostate.
The Finnish FinnProstataX study investigated whether radiotherapy administered after the removal of the prostate benefited patients whose cancer had spread to the surface of the prostate or beyond the capsule that surrounds the prostate. At the moment, treatment practices in these situations vary.
The randomised study carried out in 2004-2012 included 250 patients. Of these 250 patients, 126 received adjuvant radiotherapy after the removal of the prostate, while the treatment of 124 patients consisted of the mere removal of the prostate.
Over the roughly nine-year follow-up, only two patients—one from each group—died of prostate cancer. Based on PSA measurements, 82 per cent of the members of the adjuvant treatment group were disease-free at the end of the follow-up period; the equivalent percentage in the control group was 61. An increase in the PSA value usually precedes the recurrence of prostate cancer, and in the study, the patients with a maximum PSA of 0.4 mg/l were determined to be disease-free.
No metastases were detected in 98 per cent of those in the adjuvant treatment group and 96 per cent of those in the control group during the follow-up period.
"Tolerance for the adjuvant treatment was good, and it prolonged the disease-free period measured from the PSA compared to the mere surgical removal of the prostate. Even so, the adjuvant treatment did not extend patients' survival," says professor Akseli Hemminki, summing up the results of the study.
"Prostate cancer may generate metastases and, in the worst case, result in death more than 10 years after the recurrence of the disease, detected from a PSA increase. Given that the patients in this study were monitored for less than 10 years on average, it's only natural that the treatment we studied did not have a significant impact on survival. In even longer follow-up, a difference in PSA increases could also lead to a difference in mortality," says the article's lead author, Greetta Hackman (Lic.Med.).
Hackman stresses that when making treatment decisions, it is important to discuss the available options openly with the patient.
"More treatment also means more side effects. However, at the same time, we can likely influence the disease's prognosis in a situation in which the cancerous tissue already extends to the prostate's surface or has penetrated through the prostate's capsule, but has not yet metastasised."
The parties involved in the study, published in the respected journal European Urology, were the universities of Helsinki and Tampere and the university hospitals of Helsinki and Tampere; the university hospitals of Oulu, Kuopio and Turku; the central hospitals of Päijät-Häme, Mikkeli and Joensuu; Docrates Cancer Center and the Finnish Cancer Registry.
"This study is a great example of cooperation between Finnish hospitals and universities to perform an important research-driven academic clinical trial. There are not many studies of this kind these days," says Hemminki.