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.