Thallium-201 SPECT in advanced non-small cell lung cancer: in relation with chemotherapeutic response, survival, distant metastasis and p53 status.

PURPOSE The aim of this study was to evaluate the relationship between 201Tl tumor uptake, chemotherapeutic response, metastasis, p53 status and survival in non-small cell lung cancer (NSCLC). METHODS A total of 23 patients underwent 201Tl SPECT. In 9 patients, 2nd 201Tl SPECT study were performed 1 week after the 3rd cycle of chemotherapy (ChT), and early (ER) and delayed (DR) tumor/normal lung ratios and retention indices (RI) were obtained. In 15 patients p53 status was assayed with immuno-histochemical staining. The patients were divided into subgroups after the 3rd cycle of ChT; responders [R(+) (n = 10)] and non-responders [R(-) (n = 13)], distant metastasis [(M1) n = 11] and [(M0) n = 12], and mutant p53 status [p(+) n = 7, p53(-) n = 8]. RESULTS The differences for ER, DR and RI values between all of the subgroups were not statistically significant. ER and DR of responders decreased significantly after ChT; from to 2.46 to 1.36 (p = 0.04) and 2.29 to 1.53 (p = 0.04), respectively. In the non-responder group, both ER and DR slightly increased after ChT (p > 0.05). CONCLUSION Our results suggest that in NSCLC, there was a weak correlation between higher 201Tl ratios and positive response to chemotherapy, absence of distant metastasis, and p53(-) status. Significant 201Tl uptake decrease after chemotherapy indicates that delayed 201Tl uptake can be used in evaluating the chemotherapeutic response.