Technetium-99m methoxyisobutylisonitrile chest imaging for small-cell lungcancer

Aims: This is a retrospective and adaptive randomization study. The purpose of this study was to evaluate the relationship between technetium-99m meth oxyisobutylisonitrile (Tc-99m MIBI) chest-imaging results, chemotherapy res ponse and P-glycoprotein (Pgp) or multidrug resistance related protein (MRP ) expression in small-cell lung cancer (SCLC). Patients and methods: Before chemotherapy, 30 patients (11 females, 19 male s, ages: 52-69 years) with SCLC, including 14 extensive diseases without lo calized problems and 16 limited diseases in excess of solitary pulmonary no dule, underwent early chest imaging, including visual interpretation and qu antitative analyses of tumor uptake ratio (TUR), 10 minutes after intraveno us injection of Tc-99m MIBI. Immunohistochemical analyses were performed, u sing multiple nonconsecutive sections of the biopsy specimens, to detect Pg p and MRP expressions. Chemotherapy response was evaluated in the third mon th after completion of treatment by clinical and radiological methods. Results: All 15 (100%) of the SCLC patients with complete or partial respon se had positive Tc-99m MIBI chest SPECT results, but negative ones for both Pgp and MRP expression. Twelve of the 15 (80%) SCLC patients with no respo nse or progressive disease had negative Tc-99m MIBI chest SPECT results and were positive for either Pgp or MRP expression (P < 0.05). Negative Tc-99m MIBI chest SPECT results predicted complete or partial response. The TUR o f patients with complete or partial response (1.91 +/- 0.29 with a 95% conf idence interval (95% CI): 1.75-2.07) was significantly higher than that of patients with no response or progressive disease (1.19 +/- 0.28 with a 95% CI: 1.04-1.35). Conclusion: Tc-99m MIBI chest images are a potential tool for understanding Pgp and MRP expressions in SCLC and for predicting patient chemotherapy re sponse.