Occupational cancer A. H. Mehrparvar, MD Occupational Medicine department Yazd University of Medical Sciences

Importance One in every 2 or 3 individuals develop cancer 5-10% of all cancers are occupational Most occupational cancers are preventable

Carcinogenesis Carcinogens: 2 types Initiator: Promoter: Carcinogenic alone Covalently bind to DNA (irreversible alterations) No threshold dose Single exposure may be sufficient Promoter: Active after initiator exposure Act by induction of cellular proliferation Threshold exist Repeated exposures required

Carcinogens IARC groups: Group 1: carcinogenic to humans (benzene) Group 2A: probably carcinogenic to humans (acrylonitrile) Group 2B: possibly carcinogenic to humans (chloroform) Group 3: not classifiable Group 4: probably not carcinogenic

Important industrial processes associated with human cancer Al production Boot and shoe manufacturing Coke production Furniture manufacture Nickel refining Rubber industry Mining Petroleum refining

Important occupational carcinogens Asbestos Benzene Beryllium Cadmium Ionizing radiation Nickel Radon Strong inorganic acids Vinyl chloride PAH Silica (?)

Occupational cancers Lung Mesothelioma Skin Nasal cavity Larynx Bladder Hepatic angiosarcoma Hematologic

Lung cancer Four major types: Clinical findings: Paraclinic: SCC, adenocarcinoma, large-cell carcinoma, small-cell carcinoma Clinical findings: Cough, hemoptysis, dyspnea, weight loss Findings of tumor spread Tracheal obstruction, esophageal compression Paraclinic: CXray: mass lesion, pulmonary infiltrate, adenopathy CT Sputum cytology Bronchoscopy and biopsy Transthoracic FNA Biopsy Open biopsy Surveillance: Serial CXray (?) Serial sputum cytology (?)

Lung cancer Occupational exposures: Asbestos: Radon: PAH: Ni: Cr: As: Mining Insulation textile Radon: Uranium mining Indoor pollution PAH: Al reduction Rubber work Petrochemical plants, petroleum refinery Ni: Ni mining, refining Cr: Chromate production As: As pesticide Copper, lead, zinc smelting

Mesothelioma Tumor of the pleura or peritoneum Clinical findings: Persistent gnawing chest pain radiating to shoulder or arm Dyspnea on exertion Dry cough Weight loss Paraclinic: Pleural thickening, pleural effusion in chest CX-ray or CT Pleural fluid cytologic examination Thoracotomy with multiple biopsies

Mesothelioma has an important differential diagnosis Occupational exposures: Asbestos: Mining Construction work Insulation Roofing Textile Note: Mesothelioma has an important differential diagnosis metastatic tumors

Skin cancer Two types: Melanoma Nonmelanomatous SCC BCC Bowen disease Premalignant entities (solar keratoses)

BCC Nodular or nodular-ulcerative lesion on the skin of head and neck and 10% on trunk Smooth, shiny, translucent with telangiectatic vessles Local invasion, rare metastasis 40% of tumors in shaded areas

SCC Usually a pre-malignant stage: In-situ carcinoma: Areas: Rough, reddened placque on sun-exposed areas In-situ carcinoma: Well-demarcated slightly raised erythematous placque with scaling Areas: Almost always on sun-exposed areas: tip of nose, forehead, lower lip, back of the hands

Occupational exposures: UV: Outdoor workers Arsenic: As pesticide production and use Cu, Zn, Pb smelting PAHs: Al reduction Rubber work Ionizing radiation: HCWs Uranium miners

Nasal cavity and sinuses Occupational exposures: Wood dust Boot and shoe manufacturing Furniture workers Textile workers Ni: Nickel refinery workers Cr: Chromate manufacturing Metal plating Isopropyl alcohol: Laboratory workers

Clinical findings: Paraclinic: Unilateral nasal obstruction Non-healing nasal ulcer Occasional nasal bleeding Paraclinic: Flexible nasoscope CT scan

Larynx Occupational exposures: Asbestos: Clinical findings: Mining Construction work Insulation Roofing Textile Clinical findings: Hoarseness, difficulty in swallowing, lump in the throat Paraclinic: Lateral neck X-ray, CT scan

Bladder Occupational exposures: Naphthylamine Benzidine (azo dyes) Textile workers (dye/pigment) Benzidine (azo dyes) Dye/pigment manufacturing Toluidine: Painters Rubber manufacturing Phenacetin: Hairdressers Petroleum workers

Clinical and paraclinical findings: Hematuria Vesical irritability Diagnosis: urine cytology cystoscopy

Hepatic angiosarcoma Occupational exposures: Clinical findings: Vinyl chloride: PVC production Arsenic: As pesticide production and use Cu, Zn, Pb smelting Clinical findings: RUQ abdominal pain Weight loss hepatomegaly

Paraclinic: Diagnosis: Anemia Prolonged PT Elevated ALP Elevated ALT, AST Diagnosis: Hepatic angiography Open liver biopsy

Hematologic cancers Occupational exposures: Clinical findings: Benzene: Rubber workers Petrochemical workers Refinery workers Ionizing radiation: HCWs Uranium miners Nuclear power plant workers Clinical findings: Weakness, malaise, anorexia, fever, easy bruisabilirty Pallor, hepatosplenomegaly, lymphadenopathy, anemia, thrombocytopenia, leukocytosis or leukopenia