Background: The purpose of this preliminary study was to evaluate retrospectively the relation between chemotherapy response and survival time, using technetium-99m methoxyisobutylisonitrile (Tc-99m MIBI) uptake in small cell lung carcinoma (SCLC) to detect the expression of multidrug resistance (mdr)-mediated 170-kDa P-glycoprotein (PgP).
Methods: Before the administration of chemotherapy (which consisted of cisplatin 25 mg and etoposide 125 mg every day per 3-day course), 15 male patients (ages 54-64 years) with SCLC were enrolled in this study to undergo Tc-99m MIBI chest imaging, including single photon emission computed tomography (SPECT) and planar imaging, for qualitative and quantitative assessments of PgP in their SCLC.
Results: In 12 of 15 cases (80%), SCLC could be detected by visual interpretation of the Tc-99m MIBI chest SPECT images. In 13 of 15 cases (87%), Tc-99m MIBI chest SPECT images (either positive SPECT with good response or negative SPECT with poor response) correctly predicted chemotherapy response. The correlation between tumor uptake ratios obtained by planar images (total counts in the region of interest [ROI] of the tumor divided by total counts in the same size ROI of the contralateral normal lung) and survival days (from the time of SCLC diagnosis to the time of the patient's death) was both positive and good (correlation coefficient=0.83).
Conclusions: Tc-99m MIBI chest images have the potential to demonstrate mdr-PgP expression in SCLC and to predict patient prognosis and chemotherapy response.