Primary radical prostatectomy or ablative radiotherapy as protective factors for patients with mCRPC treated with radium-223 dichloride: an Italian multicenter study

Background. We provide an analysis aiming to investigate, in a real-life setting, the prognostic relevance of previous primary treatment (radical prostatectomy (RP) or external beam radiotherapy (EBRT)) in terms of overall survival, in mCRPC patients treated with 223-Ra. Materials and methods In this multicenter retrospective study we enrolled 275 consecutive patients. Demographics and clinical data, as well as mCRPC characteristics, have been obtained and evaluated at baseline and the end of the treatment or progression. 223-Ra has been administered according to the current label authorization until disease progression or unacceptable toxicity. We divided the whole cohort into 2 groups: men previously treated with primary radical prostatectomy or ablative radiotherapy (RP/EBRT) and patient with no prior primary treatment available (NO). Results 128 out of 275 patients (46.5%) are alive and currently on follow-up; 103 patients (37.4%) dropped treatment out for disease progression or onset of comorbidities, and 147 patients died during the follow-up (53.5%). 93 patients underwent RP, 76 patients performed ablative EBRT. 132 patients enrolled in the RP/EBRT group (48%), 143 patients in the NO group (52%). Data showed a clear advantage for patients subjected to RP or EBRT in respect of those without primary treatment performed, with an estimated median survival of 18 months and 11 respectively (p<0.001). The multivariate analysis corroborated this trending results, returning in an HR of 0.7 (pvalue= 0.0443), confirming the best outcome of the RP/EBRT group.Conclusions Previous radical treatment plays a protective role in mCRPC patients who underwent 223-Ra treatment.