Why is radiotherapy used in prostate cancer?

SHORT VERSION

In France, prostate cancer is diagnosed in approximately 70,000 men per year. Prostate cancer is often detected early due to screening by Prostate-Specific Antigen (PSA) quantification in blood and digital rectal examination. This improves its prognosis.. This improves its prognosis. At the localized stage, prostate cancer can be treated by surgery (total prostatectomy), external radiotherapy, or brachytherapy. Its management depends on the disease stage and on patient-specific parameters, such as age and comorbidities.

Each year, approximately 50,000 men receive a diagnosis of prostate cancer in France. The prognosis of this cancer has improved over the years due to the better management and earlier diagnosis by Prostate-Specific Antigen (PSA) testing and digital rectal examination.

 

At the localized stage, prostate cancer can be treated by surgery (total prostatectomy), external radiotherapy, or brachytherapy. All three modalities give excellent and equivalent results. All these treatments have a curative objective (i.e. to cure the cancer). The choice depends on the cancer type (especially its aggressiveness), the patient’s age, comorbidities, and expectations.

 

Radiotherapy and brachytherapy are used to kill the tumor cells without the need of surgically removing the prostate. However,  the whole prostate gland will be irradiated because often there are multiple cancer sites within the prostate, and part of the seminal vesicles may also be invaded. The pelvic lymph nodes also may be irradiated (at a lower dose than that delivered to the prostate), if the risk of lymph node involvement is considered high by the radiation oncologist.

 

Radiation therapy may also be used after surgery in case of cancer recurrence (i.e. increase in PSA concentration). In this case, the radiation treatment will be targeted to the prostatectomy site (i.e. the area where the prostate was located) because it is often a preferred recurrence site after surgery.