Field Effect of Cancer

Abstract

INTRODUCTION: Field cancerization (FC) refers to constellation of locoregional changes triggered by long-term exposure of a field of tissue to a carcinogen. FC occurs in any embryologic tissue eg, colorectal, breast ducts, bladder, bronchial, laryngeal epithelia, and digestive tract. CASE PRESENTATION: We present a case of FC in a 58 year old female. Patient presented to ER with chest pain and ruled out for ischemia. A CT angiogram showed 3 mm nodule in right upper lobe. Being an active smoker for 45 years patient was referred for outpatient pulmonology surveillance. A nine month follow up CT scan revealed a new 5 mm left lower lobe nodule that increased in size over 6 months to 16 × 9 mm. Right upper lobe nodule remained stable. CT guided biopsy of left lower lobe nodule was negative for malignancy. Subsequent PET scan showed left perihilar pulmonary nodule with increased FDG avidity. Patient became symptomatic with cough, intermittent hemoptysis, and lost almost nine pounds. Patient underwent FOB that showed unanticipated appearance of multiple endobronchial lesions in the right upper lobe, right lower lobe, left main stem and the left lower lobe. Endobronchial biopsy results from all the lesions were consistent with squamous cell carcinoma in situ. Bronchial brushing and washings showed the same results. Left lower lobe transbronchial biopsy was positive for squamous cell carcinoma. On further imaging there were no distant metastases. Cardiothoracic surgery deemed patient inappropriate surgical candidate because of extensive involvement. Patient was considered as stage IV squamous cell carcinoma and referred for chemotherapy. DISCUSSION: Exact pathogenesis of FC is not clear. The presence of a field with genetically altered cells is a risk factor. Historically it has been described by Slaughter and his colleagues as the existence of generalized carcinogen induced early genetic changes in the epithelium from which multiple independent lesions occur, leading to the development of multifocal cancers. CONCLUSIONS: This extensive tumor involvement that was out of the proportion to what expected is clearly the example of FC.