OCCUPATIONAL CANCER

Dr. Majid Golabadi

Occupational Medicine Specialist Isfahan University of Medical Sciences

What Is Cancer?



Cancer is a large group of diseases (over 200) characterized by uncontrolled growth and spread of abnormal cells.

 The majority of cancers in adults:  Genetic factors  Lifestyle  Environmental and occupational exposure

 Stress  Sleep disturbances ,  Diet: high fat and low in fruits and vegetables  Lack of exercise  Chemicals In Foods  Smoking – 30% of all cancer deaths, 87% of lung cancer deaths  Obesity – 50% higher risk for breast cancer in postmenopausal women, 40% higher risk in colon cancer for men  Viral Factors

 5-10% of all human cancers are thought to be caused by occupational exposure to carcinogens  Carcinogen : Any chemical , physical or biologic agent present at the workplace which increases the risk of cancer among exposed workers

Stages in Tumor Development

1. Initiation  Cancers come from an abnormal cell (mutation in DNA) 2. Promotion  To a benign or preneoplastic tumor 3. Progression  To a malignant tumor

Carcinogens

 Initiator  Promoter  Complete Carcinogens

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Medical surveillance :

 Occupational cancers are completely preventable 

Induction-latency period

 3-5 years for radiation or toxin induced leukemias  40 or more years for some cases of asbestos induced mesothelioma  For Solid tumors usually 10-25 years  There is controversy about the existence of threshold doses for carcinogenic agents

OCCUPATIONAL CANCER

 Avoid the use of chemical in IARC groups 1 and 2A  Use agent in group 2B only with very tight controls when there are no viable alternatives

OCCUPATIONAL HUMAN CARCINOGENS

GROUP 1 (IARC) CLASSIFICATION

Arsenic Asbestos Benzene Beryllium Cadmium Chromium Coal tar Mustard gas Nickel Solar radiation Lung, Skin, Liver Pleura & peritoneum, Lung, Larynx, GI Leukemia Lung Lung Lung Skin, Scrotum, Lung Lung Lung, Nasal sinus Skin Vinyl chloride Liver

Selected industrial processes causally associated with human cancer

Industrial process Aluminum production Shoe manufacture Iron and steel founding Rubber industry Agent PAH Benzene PAH,Silica Cancer site Lung,bladde Leukemia lung r Aromatic amines, solvents Bladder, leukemia

یلغش روآ نایز لماوع

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LUNG

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MESOTHELIOMA

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NASAL CAVITY & SINUSES

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LARYNX

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BLADDER

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LIVER

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SKIN

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HEMATOLOGIC

LUNG CANCER

LUNG CANCER

 The currently accounts for almost 30% of all cancer deaths  The most preventable risk factor: cigarette smoking  In occupations with high prevalence of smoking  There is no one cell type that is pathognomonic of an occupationally related lung cancer

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Asbestos

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Radon

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Chloromethyl ethers

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PAHs

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Chromium

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Nickel

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Arsenic

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Mustard

Asbestos

(Asbestos miners, Textile, Insulation ,filter, Shipyard)

Blue asbestos (Crocidolyte) White asbestos (Chrysotile) Brown asbestos (Amosite)

Asbestos

 The accounting for 20% of all deaths exposed in asbestos  7% of all lung cancer exposure.

is attributable to asbestos  A latency period: 20 years  Synergic effect with Smoking  Cigarette smoke: initiator  Asbestos: promoter  Adenocarcinoma

Radon

(Uranium mining , Domestic exposure)

Excessive lung cancer in uranium miners is independent of cigarette smoking, although exposure to both is synergistic

Polycyclic Aromatic Hydrocarbons (PAHs)

 From the incomplete combustion of coal tar, pitch, oil and coke  The scrotal cancer in chimney sweeps (Dermal exposure to soot)  Coke oven workers, Roofers, Printers, Truckers, Rubber plant workers, Asphalt workers

Chloromethyl Ethers

 Chloromethylmethyl ether (CMME)  Bischloromethyl ether (BCME)  Bactericides, Pesticides, Dispersing agents, Water repellents, Flame-proofing agents  Small cell lung cancer

Arsenic (Organic Arsenic)

 Lead, Copper and Zinc smelting  Pesticides

Chromium

 Chromate production

Nickel

 Soluble forms

Probably Carcinogenic for lung cancer

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Acrilonitryl

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Beryllium

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Cadmium

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Vinyl chloride

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Formaldehyde

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Acid Sulfuric

Medical monitoring in the workplace

(

Screening

)  Periodic examination:  History , Physical exam, smoke, training  Symptoms : persistent cough, blood-streaked sputum, chest pain, Voice change  Environmental monitoring  Serial Chest Radiography and Sputum cytology (OSHA,NIOSH)  CT Scan (spiral,…..), HRCT

Prevention

 Primary prevention :  The most effective methods  Complete avoidance of exposure to the carcinogen  Identification of etiologic agents in the workplace  Worker education

Asbestos

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Asbestos miners

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Textile manufacturing

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Insulation and filter production

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Construction workers

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Welders, Plumbers, electricians

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Roofers

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Shipyard workers

MESOTHELIOMA

30 years or more increase the risk of MM Symptoms

: Persistent gnawing chest pain , dyspnea, dry cough, weight loss Pleural effusion , pleural thickening or nodularity, interstitial pulmonary fibrosis, pleural plaques, pleural calcification

CXRay:

Unilateral pleural effusion

CT_Scan:

Most sensitive test for pleural surface Sputum cytology Thoracentesis Thorachotomy and thoracoscopy

MESOTHELIOMA

 Treatment :  Surgical  Radiotherapy   Chemotherapy Prognosis:  75% of patients die within 1 year after diagnosis  Pleura, peritoneal

 More frequent in men than women (2:1)  Usually squamous cell histology (50%),  The disease is very uncommon in workers under 50 years of age, and rates increase with age

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Wood and other dusts ( Furniture, Textile, boot and shoe manufacturing, bakes )

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Chromium ( Nasal septum ulcer and perforation ) (Chromate pigment production , metal plating )

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Nickel (Nickel refinery workers)

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Isopropyl alcohol, Formaldehyde (laboratory workers , other industries )

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Owen workers, foundry workers, Radium, Radon, mustard

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Symptoms

:

Unilateral nasal obstruction Non-healing ulcer Occasional bleeding A low-grade chronic infection, associated with discharge, obstruction ,and minor intermittent bleeding

 Chronic hypertrophic rhinitis  Dry atrophic nasal mucosa  Nasal polyps  Almost Adenocarcinomas

Prevention



Primary prevention:

 Complete avoidance of exposure to the carcinogen is the ultimate goal, but this is not always possible  Identification of etiologic agents in the workplace  Worker education

 Laryngeal cancer is primarily a disease of older workers.

 Cancer of the larynx is much more common than sinonasal cancer  Cigarette smoking and alcohol abuse are the primary etiologic factors  Much more frequent in men than women (4.5:1) ,usually middle aged or older

Asbestos

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Asbestos miners

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Textile manufacturing

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Insulation and filter production

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Shipyard workers

 Hoarseness is an early presenting symptom  Usually squamous cell histology  At the time of diagnosis: 60% localized 30% regional spread 10% distance metastases  40% supra-glottic, 59% glottic, 1% sub-glottic

Prevention

 Primary prevention:  Complete avoidance of exposure to the carcinogen is the ultimate goal, but this is not always possible   Identification of etiologic agents in the workplace Worker education 

Periodic examination:

 History , Physical exam, smoke, training  Environmental monitoring (limits)

BLADDER CANCER

 5% of all malignant tumors  M/F = 2/1  Cigarette smoking is the most important etiologic factor (60%)  Water infected to pesticides and other chemicals  The latency period: mean of 20 years  Presenting complaints of hematuria and vesical irritability  Diagnosis by urine cytologic examination and cystoscopy

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Naphtylamine (Textile workers, Dye & pigment manufacture, Rubber manufacture)

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4-Aminobiphenyl (Tire & Rubber manufacture)

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Benzidine (Dye & pigment manufacture)

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Chlornaphazine (leather worker)

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O-toluidine (Painters, Textile workers , Bootblacks)

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Phenastin (Petroleum workers, Hairdressers)

High exposed workers

 Textile workers,  Dye & pigment manufacture,  Tire & Rubber manufacture  leather worker  Painters,  Bootblacks  Petroleum workers,  Hairdressers

4- Aminobiphenyl

Chlornaphazine

Benzidine

Pathogenesis & Pathology

 Body exposure via GI, Dermal or Respiratory  Caused by contact of the bladder epithelium carcinogens in the urine with  The bladder is exposed to higher concentration of these materials than other body tissues  Urothelial tumors:  90% transitional cell type  6-8 % squamous cell  2% adenocarcinoma

Clinical findings



The most common:

 Hematuria 80%  Painless, gross, and intermittent  20%:

the vesical irritability

dysuria, urgency and nocturia alone, with increased frequency,   U/A: RBC, Blood Anemia, Uremia

Prognosis

 Prognosis varies with the stage of the disease  Superficial:  The excellent 5-year survival  Muscle invasion:  40-50% of patients 5-year survival  Local spread of disease in the pelvis:  10-17% of patients survive 5 years

Screening

 Urine cytology and U/A:  Screening tool  Sensitivity (75%),specifity (99.9%)  Used to screen only certain at risk occupations  The screening of high-risk patients may result in a significant reduction of the stage of disease at diagnose, with improved long-term survival

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Vinyl chloride (PVC production)

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Arsenic (Pesticide , Copper ,Lead , Zinc smelting , Wine maker, Fowler)

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Thorotrast

Hepatic Angiosarcoma

 Angiosarcoma of the liver is a rare tumor  M/F: 4/1  Major exposure to vinyl chloride

Sign & symptoms

 RUQ abdominal pain, weight loss  Hepatomegaly on physical examination  Diagonisis by hepatic arterogram and liver biopsy

Clinical Findings

 Non-specific:  Fatigue, weakness, and weight loss are seen in 25-50% of patients  The some patients may be asymptomatic  Abdominal pain is the most common usually in the RUQ symptom,  Phx:    Hepatomegaly with ascites Jaundice Splenomegaly , abdominal mass, tenderness

Laboratory findings

 A mild anemia , target cells and schistocytes  Leukocytosis and thrombocytopenia (1/2 patients)  Prolonged PT  Almost all patients: abnormality of liver function testing  ALT, AST and ALP

Screening tests

 Periodic testing:  History and physical examination  CBC, LFT (SGOT, SGPT, ALP)

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UV radiation (Outdoor workers, welding arc)

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PAHs (coal tar workers , Electrode production , Pigment Industry , Roofers , Shale oil worker)

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Ionizing radiation (Uranium miners, Health care workers, Military personnel)

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Arsenic (Pesticide , Copper ,Lead , Zinc smelting)

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Chronic inflamation

UV Radiation

 Major risk is ultraviolet radiation  There are 4.8 million outdoor workers in the USA (agriculture,…)  The estimated 300000 workers are exposed to industrial radiation sources ( welding arc, germicides and printing processors)

PAHs

Ionizing radiation & skin cancer

 High risk: more than 1000 cGy  Early radiation workers with heavy exposure :  Predominantly SCC  The hands and feet and occasionally on the face  More recently, basal cell cancers have been described following repeated occupational exposures

Arsenic

 Punctate keratoses of the palms and soles and hyperpigmentation are frequently seen

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Ionizing radiation

(Nuclear power plant worker, Health care worker, Military personnel)

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Benzene

(Petrochemical and refinery worker , Rubber worker)

Ionizing radiation & aplastic anemia

 

Dose dependent

Large dose & long term (small amount) 

Risk:

  Increased until 3-5 years after exposure After which there is a marked decline in incidence 

Treatment:

 Bone marrow transplantation,hematopoietic growth factors

Benzene & leukemia

 Benzene is a cyclic hydrocarbon obtained in distillation of petroleum and coal tar  It is used widely in chemical synthesis in many industries  Explosives,soap,perfums, Drugs,dyes,rubber,shoes

Benzene & leukemia

 Workers exposed for 5 years or more risk of death from leukemia had a 21-fold increased  Aplastic or hypoplastic anemia  Acute , chronic (30 years after exposure)  Exposure to 100 ppm cause cytopenia