A New Era Begins in Prostate Cancer Treatment

Prostate cancer is the most common male cancer worldwide. Although it accounts for %20 of newly diagnosed male cancers, its mortality rate is very low. Newly developed treatments contribute greatly to this progress.

Prostate cancerarises from uncontrolled growth of cells in the prostate, a male reproductive gland. Cancer cells need male hormones called androgens, meaning testosterone , to grow. Discovering in the 1940s that growth and spread depended on hormonal stimulation, and introducing androgen-suppressing treatments, laid the foundations of metastatic prostate cancer treatment.

Of patients diagnosed with prostate cancer, %80 are at an early stage. At diagnosis, disease has spread through the body in %4. Although hormone suppression helps, resistance develops within an average of 1 year. This results from testosterone and other male hormones continuing to be produced through different pathways in the body and tumor. One drug developed to suppress this pathway too is abiraterone (zytiga). It blocks the enzyme (CYP17) converting other body hormones into male hormones. Discovered in 1990, the drug entered clinical trialsin metastatic prostate cancer in 2004. Zytiga (Abiraterone) received approval in metastatic disease that progressed despite initial classic androgen suppression followed by chemotherapy after nonresponse, in 2011 from the FDA and entered clinical use. It remains used as 3. line treatment in our country.

A major recent question has been whether adding Abireteron to classic hormonal treatment from the beginning benefits locally advanced and metastatic disease. For 2 years, we have used chemotherapy with classic hormonal therapy, particularly in advanced patients with high tumor burden. Could dual hormonal treatment eliminate chemotherapy at this stage? In other words, “Can initial dual hormonal treatment achieve success convincing enough to replace chemotherapy?

Seeking an answer, ASCO 2017featured LATITUDE study results, later published in the world-famous NEJM (New England Journal of Medicine).

The study involved 34 countries and a total of 235 centers. Newly diagnosed high-risk prostate cancer with body-wide metastasis involved 1199 patients, in whom adding to classic

hormone-suppressing treatment abiraterone was evaluated. High-risk factors were defined as; Gleason score 8 or above, metastases in more than three bone sites, and spread to internal organs. Patients were divided into two groups: classic hormone suppression alone, or that treatment plus abiraterone and prednisone (cortisone).

Ultimately, adding abiraterone to standard hormone suppression in high-risk metastatic prostate cancer doubled time to worsening (14.8 versus 33 months) and reduced disease-related death risk by %38. Average overall survival was 34 months with standard treatment, but could not yet be determined with abiraterone because most patients remained alive. The abiraterone arm had a %53 lower risk of cancer worsening and an additional 18-month delay in cancer growth.

Serious side effects occurred at %68 in the abiraterone arm and %48 with placebo. Discontinuation because of side effects did not differ. The most frequent abiraterone effects were high blood pressure in %20 and low potassium in %10, but these were easily managed and did not require stopping the drug.

Earlier studies show that some newly diagnosed prostate cancer patients benefit when standard hormone-suppressing treatment is combined with Docetaxel chemotherapy. This study showed similar benefit with abiraterone.

These results are good news for our prostate cancer patients. New hope has been added to hormonal treatment, following a similar strategy almost since the 1950s. This approach may also eliminate the need for chemotherapy currently used initially.

Prostate cancer innovations have reached dizzying levels over the past 10 years. Each day, new options reduce disease-related deaths and remarkably prolong survival. However, these advances bring financial difficulties for countries. We hope that, based on healthcare equality, these innovations will become equally accessible not only in our country but worldwide.