99mTC-tetrofosmin scintigraphy in lung carcinoma staging and follow-up evaluations

99mTC-tetrofosmin recently has emerged as a new radiopharmaceutical for cancer visualization. In this study, the authors have investigated, for the first time in a comprehensive way, its ability to assess lung carcinoma dissemination and progression.

A 99mTC-tetrofosmin scan was incorporated into the pretreatment and posttreatment diagnostic workup of all lung carcinoma patients seen in a second referral institution for a province of 500,000 inhabitants during the years 1998 and 1999. Sixty-one patients, strongly suspected of lung carcinoma were photon-scanned; 21 of them were rescanned after completion of their front-line treatment. Eleven patients eventually underwent surgery, and 3 others underwent mediastinoscopy. Both planar and single photoemission computed tomography thoracic views were obtained. Images for the whole body also were acquired.

All 57 patients whose lung carcinoma was pathologically confirmed showed accumulation of the radiotracer (100% sensitivity). However, three of the four nonmalignant lesions were also 99mTC-tetrofosmin positive. 99mTC-tetrofosmin scan was highly sensitive for the detection of the T0-T2 disease (97% sensitivity) and highly specific for the N0-N1 disease (83% specificity). In the 16 pathologically staged mediastina, sensitivity, specificity, and accuracy rates were 73%, 100%, and 81%, respectively. 99mTC-tetrofosmin scan correctly detected most skeleton (9 of 10) and brain (5 of 7) metastases. The treatment response evaluation made with 99mTC-tetrofosmin corresponded to the clinical estimate in almost half of the sample.

This study shows that 99mTC-tetrofosmin scan is a relatively accurate method for lung carcinoma evaluation. The authors' preliminary data exclude, however, that noninvasive diagnostic efficiency might be substantially increased by a scintigraphy with 99mTC-tetrofosmin. More studies are needed for a better understanding of the real value of this technique.