PURPOSE: Primary lung cancer patients who underwent preoperative induction therapy were examined, and the relationships among pre- and postoperative trends in the maximal standardized uptake value (SUVmax) on 18F-fluorodeoxyglucose positron emission tomography (FDG-PET), treatment success rate, and histopathological findings were investigated.
METHODS: Seven hundreds and eighty six patients underwent surgery for primary lung cancer at our center between January 2005 and October 2009. Of these patients, 53 (6.7%) received preoperative induction therapy. Following preoperative induction therapy, 25 cases underwent FDG-PET. The pathological stage before induction therapy was IIB/IIIA/IIIB = 8/12/5. Twenty patients received radiotherapy+chemotherapy (CRT), and five received chemotherapy only. In the CRT group, radiotherapy was done concurrently in all cases. The SUVmax of the tumor and lymph nodes on FDG-PET was measured before and after induction, and the decrease rate in SUVmax (SDR) was calculated as 1 − (pretreatment SUVmax) / (posttreatment SUVmax).
RESULTS: The SDR was 13-85% in tumors and 4-100% in lymph nodes. No difference was seen in the SDR between the CRT and chemotherapy groups (p=0.957). Downstaging after induction therapy was seen in 19 cases (76%), and the treatment effect was Complete Response/Partial Response/Stable Disease/Progressive Disease = 0/22/3/0. A correlation of r=0.420 was seen between the shrinkage rate of the target lesions and the SDR. The SDR was significantly higher in the group with the higher histological treatment effects (64%) than in the group with the lower effects (39%; p=0.001). The SDR was significantly higher in the downstage group (59%) than in the non-downstage group (37%; p=0.031).
CONCLUSION: No difference in the SDR was seen by treatment method. A correlation was shown between the treatment success rate of the target lesions and the SDR, and the SDR were higher in cases with higher histopathological treatment effects and greater downstaging.
CLINICAL IMPLICATIONS: The SDR is thought to reflect the treatment effect and to be useful for preoperative evaluation following induction therapy.
DISCLOSURE: Makoto Takahama, No Financial Disclosure Information; No Product/Research Disclosure Information