Occupational chronic myeloid leukaemia in a radiology technician: a quantitative Probability of Causation assessment

Chronic myeloid leukaemia (CML) is a clonal myeloproliferative neoplasm associated with the Philadelphia chromosome, and ionizing radiation is a well-established leukemogenic factor. Despite regulated dose limits, occupationally related CML remains rare and under-recognized. We present the case of a 53-year-old male radiology technician diagnosed with CML following the detection of leukocytosis during routine periodic fitness-for-work surveillance. The patient had 29 years of documented occupational exposure with a cumulative effective dose of 150 mSv, without acute incidents. While International Commission on Radiological Protection recommendations primarily focus on fitness-for-work rather than malignancy screening, this case-the first officially recognized and institutionally attributed occupational CML in our country-demonstrates how systematic surveillance can facilitate the identification of serious haematological conditions in high-exposure (Class A) workers. It provides a structured Probability of Causation assessment to support occupational attribution and statutory recognition within a regulated low-dose environment on a probabilistic basis.