Experience with de-intensification of intensified treatment in metastatic castration-sensitive prostate cancer in Venezuela: A pilot study.

e17080 Background: Novel therapeutic approaches in recent years have changed the management of metastatic castration-sensitive prostate cancer (mCSPC). Traditionally, an antiandrogenic agent was used for androgen deprivation (AD); currently, the approach is to do treatment intensification with AD plus an additional medication (such as abiraterone, enzalutamide, docetaxel, among others). Historically, intermittent versus sustained AD have been considered as equally effective therapeutic measures. In developing countries, treatment adherence has been limited by access to some of these medications, as well as financial toxicity. Recently a new therapeutic approach has been proposed, one which entails treatment de-intensification in patients with a negative PSA after 1 year of treatment, aiming to decrease adverse events and improve treatment adherence. Methods: We included patients with mCSPC that received treatment intensification with AD plus either abiraterone or enzalutamide. Concurrent use of docetaxel was allowed. After at least twelve months of treatment and with a PSA level under 0.2 ng/mL, we proceeded to suspend intensified therapy, maintaining AD alone (de-intensification). These patients were followed up every 12 weeks, with a clinical evaluation plus PSA measurement. Patients that were deemed to have biochemical progression were excluded from the study, and underwent full imaging evaluation as well as a change in their current therapy on a case-by-case basis. Results: A total of 28 patients with mCSPC are included, with a mean age of 71.71 years. Thirteen patients have synchronic disease (46.42%), and fifteen patients have metachronic disease (53.58%). Of the original 28 patients, 16 patients have low volume disease (57.14%) and 12 have high volume (42.85%). Concurrently, 26 out of the 28 included patients had a negative PSA after six months of follow up (92.85%). To this date, 18 patients have completed twelve months of follow up, out of which 15 patients have maintained a negative PSA (83.3% of total sample). Out of the other 3 that developed biochemical progression, 2 of them had high volume disease and all 3 had a Gleason 8 score. Conclusions: Treatment de-intensification appears to be an acceptable therapeutic approach. This strategy could prove most beneficial in developing countries, where access to some medications is limited, and could improve treatment adherence in the long run. Adverse events associated to medications is also minimized with this approach. It’s also possible that this new therapeutic approach is most beneficial in lower risk patients (Gleason score < 8, low volume metastatic disease). In order to make these results more robust, a larger population sample and longer follow up is required.