Occult Micrometastasis to Bone Marrow in Early Lung Cancer:A Clinicopathologic Study from West Bengal, India

Although bone marrow micrometastasis may remain silent, its detection changes the staging and managementof lung cancer. In the present study conducted in West Bengal, India, 74 diagnosed bronchogenic carcinomacases (28 squamous cell carcinomas, 20 adenocarcinomas, 9 small cell carcinomas, 4 large cell carcinomas, 13unclassified) in early stages (stage I, II and IIIA) were included. Complete hemograms, bone marrow aspirationand cell blocks of aspirated material, trephine biopsy were done for detection of micrometastasis. Overallmicrometastases in bone marrow were noted in 17 cases (23.0%). We detected marrow metastasis in 44.4% casesof small cell carcinomas and 21.2% cases of non small cell lung cancer (50% of large cell carcinomas, 20% ofadenocarcinomas, 17.9% of squamous cell carcinomas) and 15.4% cases of unclassified carcinoma. We found astatistically significant correlation between marrow metastasis and low platelet count (P=0.0001) and high ESR(P=0.0003), but no significant correlation with hemoglobin percentage (P=0.36), total leukocyte count (P=0.58)and eosinophil count (P=0.44). A definite correlation noted between micrometastasis with the clinical stage (nocase in Stage I, 12.5% in Stage II, 30.4% in Stage IIIA patients). We emphasize that detection of micrometastasisis essential particularly in non small cell cancers, where treatment with curative intent is planned, which can besuitably done by morphological study of bone marrow aspirate and biopsy in countries like India.