Radiation Therapy in the Management of Locally Advanced Prostate Cancer

Abstract

With the advent of PSA-screening, locally advanced prostate cancer, defined as intermediate- and high-risk prostate cancer, has significantly declined from 30 to 40 % of newly diagnosed cases of prostate cancer to approximately 15–20 % of new cases. In absolute terms, however, this category is still numerous and is the most challenging and important in terms of therapy as these are men who, without effective treatment, will go on to die of their disease. A series of randomized clinical trials show that radiation therapy for locally advanced prostate cancer provides good local control and when delivered to high dose or in combination with androgen deprivation therapy (ADT), reduces the subsequent rate of development of metastatic disease. An overall survival advantage has also been seen with the addition of ADT to radiation therapy. Similarly, an overall survival advantage has also been seen when adding radiation therapy to ADT. The optimal duration of ADT in combination with radiation therapy for locally advanced prostate cancer is still subject to debate but the evidence points to an advantage to long-term ADT (≥2 years and 4 months) for the highest risk prostate cancer patients. Weighing the risks of ADT, especially cardiovascular morbidity and mortality, with the benefit may help guide management decisions. The rationale for the use and safety of radiation in combination with ADT for locally advanced prostate cancer is strong and founded on class one evidence from a series of randomized clinical trials. Though other methods of treating this category of prostate cancer exist, a radiation-based approach must remain the yardstick against which all others are measured.