Age‐Specific Gonadotoxic Alkylating‐Agent Exposure in Pediatric and Reproductive‐Age Females: A Claims‐Based Study Using Cyclophosphamide Equivalent Dose
Kentaro Taniguchi, Mizuki Ohashi, Yuji Tanaka, Tetsuro Hanada, Akie Takebayashi, Akimasa Takahashi, Tsukuru Amano, Shunichiro TsujiABSTRACT
Purpose
To describe age‐specific patterns of gonadotoxic alkylating‐agent exposure and evaluate how the cyclophosphamide equivalent dose (CED) framework captures real‐world exposure relevant to fertility preservation in females aged 0–43 years.
Methods
This descriptive study used a Japanese claims database. Patients were classified as pediatric (< 15 years) or reproductive‐age (15–43 years). Twelve alkylating agents were evaluated, and six CED‐calculable agents were converted to CED.
Results
Among approximately 3.86 million females, 0.04% of the pediatric cohort and 0.16% of the reproductive‐age cohort were exposed to at least one alkylating agent. Total CED identified at least intermediate‐risk exposure in 33% of exposed pediatric and 14% of exposed reproductive‐age patients. Compared with single‐agent assessment, summed total CED identified additional patients mainly in the pediatric group, corresponding to relative increases of 20.2% and 0.3%, respectively. Agents not included in the current CED formula accounted for 8.7% of all alkylating‐agent prescription records, approximately 90% of which were observed in reproductive‐age patients.
Conclusions
CED captured alkylating‐agent exposure differently by age group: summed CED added exposure information mainly in pediatric patients, whereas agents lacking conversion coefficients limited exposure capture in reproductive‐age females. These findings support refinement of CED‐based assessment while emphasizing exposure capture, not outcome prediction.