Legacy Exposure and Regulatory Gaps: Advanced Lung Adenocarcinoma in a Lifelong Non-Smoker following Prolonged Occupational Asbestos Exposure

Asbestos exposure remains a significant occupational health hazard, particularly in developing countries where its use persists in industrial applications. This case report describes a 61-year-old lifelong non-smoker diagnosed with advanced lung adenocarcinoma (T2N3M1a, Stage IV) with a substantial history of occupational etiology. The patient presented with persistent hoarseness initially misdiagnosed as upper respiratory tract infection, leading to delayed definitive evaluation. A detailed occupational history revealed approximately four decades of cumulative exposure to asbestos during roles involving boiler maintenance and insulation handling in a palm oil mill. Notably, early employment years lacked essential safety measures, including personal protective equipment, engineering controls, and exposure monitoring. Radiological investigations, including contrast-enhanced computed tomography and PET-CT, confirmed metastatic disease, while histopathology established lung adenocarcinoma. Despite advanced malignancy, carcinoembryonic antigen (CEA) levels were not elevated, highlighting the recognized limitations of CEA as a standalone biomarker. Potential mechanisms reported in the literature include tumor heterogeneity and variation in CEACAM5 expression; however, these mechanisms were not evaluated in this patient and therefore remain speculative in the context of this case. Critically, this case illustrates systemic gaps in occupational health governance. The patient’s exposure began prior to the implementation of Malaysia’s Occupational Safety and Health Act 1994 and continued under suboptimal enforcement conditions, reflecting limitations in regulatory oversight and the absence of retrospective protection for legacy-exposed workers. The lack of structured medical surveillance further contributed to delayed detection of malignancy. This case emphasizes the need for strengthened enforcement, establishment of exposure registries, and implementation of long-term surveillance programs for high-risk occupational cohorts. It also highlights the importance of integrating occupational history into routine clinical assessment. Aligning with Sustainable Development Goals 3, 8, and 12, this report advocates for a shift towards preventive occupational health strategies to reduce the burden of asbestos-related diseases and improve worker safety globally.