Background and importance Addition of docetaxel to hormonal treatment in low and high burden metastatic hormone sensitive prostate cancer (mHSPC) has raised important issues. There are studies suggesting increased overall survival (OS) in high burden disease and lack of benefit for low volume of metastases.

Aim and objectives To perform a systematic search and methodological evaluation of subgroup analyses about the use of docetaxel in mHSPC according to volume of metastatic disease (VMD).

Material and methods A systematic search in Pubmed was conducted up to 25 September 2020. The following search strategy was used in the ‘Clinical Queries/Narrow’ tool: (Therapy/Narrow[filter]) AND (docetaxel AND prostate cancer AND hormone sensitive). Randomised clinical trials (RCTs) with subgroup analysis regarding VMD for OS were included. The rest of the review results were excluded. Two methodologies were used. One evaluated the heterogeneity of the subgroups (p<0.1), prespecification, biological support and consistency among subset analysis of similar RCTs.¹ The second methodology was a validated tool made up of preliminary questions to discard subgroup analyses without minimal relevance and a checklist.² This checklist provided recommendations of applicability for subgroup results.

Results There were 31 results in the search and the following were excluded: 9 were not RCTs, 13 did not evaluate the effect of docetaxel, 4 had no subset analysis for VMD and 1 did not assess OS. Therefore, four RCTs were included. According to the first methodology, heterogeneity among subgroups was observed in one RCT. Subset analysis was prespecified in two RCTs. Biological support was found in the subgroup analyses of all RCTs. No consistency among results of these subgroup analyses were observed. Preliminary questions of the second methodology discarded applicability of subset analysis in three RCTs. In the remaining RCT, a ‘null’ recommendation was obtained for applicability of subgroup results because of inconsistency.

Conclusion and relevance Regarding the use of docetaxel in mHSPC, no consistent differences for OS were found in subset analysis according to VMD. Patients with low and high burden mHSPC benefited from docetaxel therapy. This is the first study with a systematic review and methodology of subgroup analyses in mHSPC according to VMD.

References and/or acknowledgements

1. Sun X, et al. How to use a subgroup analysis: users’ guide to the medical literature. JAMA 2014;311:405–11.

2. Gil-Sierra MD, et al. Checklist for clinical applicability of subgroup analysis. J Clin Pharm Ther 2020;45:530–8.

Conflict of interest No conflict of interest