Weekly docetaxel monotherapy for metastatic extramammary Paget's disease: Retrospective single-institute analysis

Monthly docetaxel (DTX) monotherapy is the first-line regimen that is preferably used for metastatic extramammary Paget's disease (EMPD). However, the high-dose DTX regimen frequently causes severe hematological adverse events (AE). To overcome such safety concerns, a weekly low-dose DTX monotherapy has been proposed for use in the treatment of various cancer types. In this study, we aimed to evaluate the feasibility and efficacy of weekly DTX (25 mg/m² ) monotherapy for metastatic EMPD by retrospectively analyzing the clinical courses of 14 patients treated with this regimen. Weekly DTX monotherapy was well tolerated and all patients completed the treatment schedule without treatment withdrawal, dose reduction or treatment-related death. While five cases (35.7%) experienced hematological AE, their severity was mild. The response rate was 35.7% (5/14 cases), which included five partial responses. The mean progression-free survival (PFS) and overall survival were 7.1 (95% confidence interval [CI], 5.1-9.1) and 26.4 months (95% CI, 16.7-36.1), respectively. Furthermore, the median PFS was 7.3 months (95% CI, 4.5-10.0) in patients aged 65 years and younger and 7.1 months (95% CI, 4.4-9.9) in patients older than 65 years. These results suggest that weekly DTX monotherapy may be a useful regimen that has a high treatment continuation rate with low levels of hematological toxicity, regardless of the patient's age for metastatic EMPD.