Targeted local therapy in oligometastatic prostate cancer: a promising potential opportunity after failed primary treatment.

Abstract

Prostate cancer is a complex heterogeneous disease. Its tumour biology and mechanisms of metastasis evolution are incompletely understood. In some men there appears to exist an intermediate metastatic state where the number and site of metastatic tumours are limited. Hellman and Weichselbaum labelled this clinical state of limited tumour metastatic burden ‘oligometastases’ in 1995. Two distinct groups of patients have been described; those with true oligometastases, which ‘are present because of limited metastatic competence’ or induced oligometastases ‘following otherwise successful systemic treatment’. In men who have progressed after primary radiotherapy (RT), those with the appearance of less than five metastases from the time of diagnosis enjoyed a longer metastasis-free survival compared with those who developed more than five metastatic sites. However, in this 2004 study overall survival from date of metastasis to death did not differ. There may be a window of opportunity for meaningful intervention early in the metastatic cascade. Where once the only therapeutic option for metastatic disease was hormone therapy an emerging paradigm in cancer care is that the oligometastatic state may be amenable to targeted local therapy.