Case Study: Treating Asymptomatic mCRPC

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Following the initial presentation, a 62 year-old Caucasian man with Gleason score 4+3 prostate cancer was treated with a robotically assisted radical retropubic prostatectomy. Postoperative indicators suggested the presence of residual disease, resulting in the administration of adjuvant radiotherapy. Eventually, the PSA began to rise with a doubling time of approximately 7 months. As a result, continuous androgen deprivation therapy (ADT) with depot leuprolide along with bone-targeted agents and calcium/vitamin D supplements were administered. At this point, the patient's PSA declined to 0.4 ng/mL and follow-up monitoring was conducted every 4 months, notes Raoul S. Concepcion, MD.

At age 69, the patient's PSA rose to 1.4 ng/mL and doubled to 2.8 ng/mL after 8 months. As a result, the treating urologist chose to restage the patient using CT imaging and bone scans. The CT demonstrated a 1.5 cm enlarged pelvic lymph node and the bone scan showed three areas on the thoracic and lumbar spine. However, the patient did not have any symptoms, remarks Concepcion.

At this point, given the lack of symptoms, notes Lawrence I. Karsh, MD, it is too early to begin treatment with chemotherapy, making this patient an ideal candidate for treatment with sipuleucel-T (Provenge). Moreover, Karsh notes, immunotherapy is more effective when the PSA and tumor volume are low. The treatment for patients with newly diagnosed metastatic castration-resistant prostate cancer (CRPC) is divided by the presence of symptoms, notes Concepcion. For those who are asymptomatic, the current category 1 evidence suggests sipuleucel-T or abiraterone acetate.

In this situation, most physicians assume the patient is castration-resistant given the increasing PSA level; however, testosterone levels should also be checked to ensure the diagnosis, stresses Leonard G. Gomella, MD. At this point, if you are going to use sipuleucel-T, this is the best opportunity to administer the treatment. According to an exploratory analysis that divided PSA levels in the IMPACT trial into quartiles, the survival advantage with sipuleucel-T when the PSA was below 22 was 13 months compared to only 2.8 months with a PSA above 134.

An interesting aspect of this case study, points out Mark C. Scholz, MD, is that a bone scan was conducted when the PSA was 2.8 ng/mL Traditionally, when treatments were not available, bone scans were reserved until the PSA was higher. However, now that treatments are approved, bone scans should be conducted much earlier to detect early metastases so that an immune treatment can be administered when it is likely to be more effective.