Background Worldwide, prostate cancer is the second most commonly diagnosed cancer in men. In Europe and Spain, for many years it was the number one cancer diagnosis (436 500 in Europe in 2012 and 32 641 in Spain in 2014).¹ The use of oral therapies in metastatic patients instead of intravenous chemotherapy improves treatment comfort but the costs are much higher. According to the guidelines and protocols for chemotherapy, after failure with oral therapy, intravenous therapies must be started.

Purpose To evaluate control of the disease with oral therapies in prostate cancer patients and to determine if their treatments were switched to intravenous therapy in the event of failure of oral therapies.

Material and methods Patients treated with abiraterone or enzalutamide during the first half of 2016 in Complejo Hospitalario Universitario in Granada were included in the study. Those treatments that decreased prostate specific antigen (PSA) levels were classified as ‘effective’, while those that maintained PSA levels with variations of 5% were classified as ‘stable’. If there was an increase in PSA levels, these patients were classified as ‘non- effective’.

Results 22 patients were treated: 19 with abiraterone and 3 with enzalutamide. 63.63% (14 patients) had received 6 months or less of treatment at the time of the study. Regarding abiraterone, 9 were classified as ‘effective’ treatment, 4 were ‘stable’ and 5 had disease progression in spite of treatment with abiraterone. One patient was withdrawn due to medication toxicity. 2 patients treated with enzalutamide had disease progression and 1 had ‘effective’ treatment. 3 of 7 patients with progression (42.85%) continued treatment despite the poor results and did not switch to intravenous therapy. Abiraterone and enzalutamide accounted for 92.24% (€296 203.32 of €321 094.84) of the total expenditure of patients treated for prostate cancer.

Conclusion There was a high percentage of patients who failed oral therapies and continued with them without switching to intravenous therapy. This constitutes serious detriment to the patient and a marked increase in drug spending.

References and/or acknowledgements 1. Prostate cancer 2016. AECC (online). Available at https://www.aecc.es/SobreElCancer/CancerPorLocalizacion/cancerdeprostata/Paginas/incidencia.aspx (accessed 05/09/16).

No conflict of interest