Skeletal Metastases In Apparently Operable Lung Cancer Evaluated With Whole Body Bone Scan – A Pilot Study In South India.

Abstract

Study objectives: The management of patients diagnosed with non-small cell lung cancer is dependant on the stage of disease, which is also crucial for prognosis and selection of an appropriate treatment regimen. Historically a whole body bone scan has been used to identify skeletal metastases. The aim of this study was to investigate the usefulness of whole-body bone scanning (BS) in detecting bone metastases in newly diagnosed and apparently operable cases of lung cancer. Design and patients: Ninety two patients with a diagnosis made between 2008 and 2010 were recruited (squamous cell carcinoma, n =29; adenocarcinoma, n=36 ; non-small cell carcinoma, n= 22; others n=5). None of these patients had clinical factors suggesting bone metastasis (skeletal pain, elevated alkaline phosphatase, hypercalcemia). BS was performed in all patients, and additional imaging or biopsy was ordered in patients where there were doubtful lesions. Measurements and results: Bone metastases were detected in 14.13 % (n =13 ) of 92 clinical factor-negative patients. Of the eighteen abnormal bone scan results (eleven positive and seven probable), thirteen were true-positive and the five remaining were false-positive. In our study, PPV of the BS was 72.2%. Skeletal metastases was found more commonly in adenocarcinoma (46.15%, n=6 ) than other cell types. In 13 patients diagnosed with metastases, 53.8 % (n=7) were patients with non-small cell lung cancer and 38.4% (n=5) with small cell lung cancer. 4 of the 18 patients (22.2%) in T2N0M0 clinical stage had bone metastases. The routine bone scanning prevented thirteen futile thoracotomies (14%) in 92 patients with apparently operable lung cancer. Conclusions: Though clinical factors have a high NPV and the bone scans have less than desired specificity in diagnosing metastases, BS could be considered in those asymptomatic patients as a part of their work up and staging, in whom operative intervention is contemplated.