High Risk of Neutropenia for Hormone-naive Prostate Cancer Patients Receiving STAMPEDE-style Upfront Docetaxel Chemotherapy in Usual Clinical Practice

treatment. Our observed rates of grade 3 and 4 neutropeniawere 14/ 39 (36%) and rates of grade 3 and 4 neutropenic sepsis were 8/39 (20%). Both of these are significantly higher than that observed in the STAMPEDE trial: 12% for both. It has previously been observed that clearance of docetaxel increases by about 100% in castrate patients compared with those who are hormone naive (with a two-fold reduction in the area under the curve) [2]. This may explain the higher toxicity observed in our cohort when compared with those receiving docetaxel in the castrateresistant setting, but not the difference when compared with those published in the STAMPEDE trial (the median time from initiation of hormones to starting docetaxel in our cohort was 9 weeks versus 8.6 weeks in the STAMPEDE trial). We draw a number of conclusions from these findings. First, early docetaxel is not a risk-free strategy, despite the impressive survival benefits observed in the published data. This is of particular relevance when discussing treatment options with the non-metastatic high risk locally advanced patient where there is no proven overall survival advantage. Second, consideration might be given to the role of growth factor prophylaxis during treatment, especially if the true rate of haematological toxicity is similar to that observed in our study. Third, clinical trial results do not always directly translate into real life clinical practice. We recommend that other centres prospectively audit their rates of neutropenia in the initial stages of implementation of the STAMPEDE results.