Comparison of Tc-99m sestamibi, serum neuron-specific enolase and lactate dehydrogenase as predictors of response to chemotherapy in small cell lung cancer

Neuron-specific enolase (NSE) and lactate dehydrogenase (LDH) are tumor mar kers of small cell lung cancer (SCLC) which were reported to predict outcom e of patients with SCLC. We previously reported that dipyridamole-modulated Tc-99m sestamibi (dipyridamole-MIBI) single photon emission computed tomog raphy (SPECT) could predict the response to chemotherapy in SCLC patients. The purpose of this study was to compare dipyridamole-MIBI and pretreatment serum levels of NSE and LDH for the prediction of response to chemotherapy in SCLC. Twenty-eight SCLC patients underwent dipyridamole-MIBI SPECT 3 to 7 days before starting chemotherapy (80 mg/m(2) etoposide and 80 mg/m2 cis platin every 3 or 4 weeks for at lease two cycles). Serum levels of NSE and LDH were also measured at the same day of the imaging. Tomographic images before and after 0.84 mg/kg dipyridamole infusion were acquired 1 hour afte r injection of 370 (10 mCi) and 1,110 (30 mCi) MBq MIBI: respectively. The response to chemotherapy was grouped as specified as complete (CR), partial response (PR), no change (NC), and progressive disease (PD), according to the change in tumor size on chest roentgenography and CI: Patients showing CR and PR were classified as responders, and those who showed NC and PD wer e considered nonresponders. Among the 28 patients, 15 were responders (2 CR 13 PR) and 13 were nonresponders (II NC, 2 PD). The change of tumor-to-nor mal lung ratio (T:NL) after infusion of dipyridamole was significantly high er in responders as compared with nonresponders (0.38+/-0.64 vs. -0.38+/-0. 50, respectively p=0.002). However pretreatment serum NSE and LDH levels di d not correlate with the response to chemotherapy. Increase of T:NL after d ipyridamole infusion was a strong negative predictor of chemotherapeutic re sponse in SCLC patients while NSE and LDH could not predict it.