Predictive ability of [18]F-fluorodeoxyglucose positron emission tomography/computed tomography for pathological complete response and prognosis after neoadjuvant chemotherapy in triple-negative breast cancer patients

Objective The mortality of patients with locally advanced triple-negative breast cancer [TNBC] is high, and pathological complete response [pCR] to neoadjuvant chemotherapy [NAC] is associated with improved prognosis. This retrospective study was designed and powered to investigate the ability of [18]F-fluorodeoxyglucose positron emission tomography/computed tomography [[18]F-FDG-PET/CT] to predict pathological response to NAC and prognosis after NAC

Methods The data of 32 consecutive women with clinical stage II or III TNBC from January 2006 to December 2013 in our institution who underwent FDG-PET/CT at baseline and after NAC were retrospectively analyzed. The maximum standardized uptake value [SUV[max]] in the primary tumor at each examination and the change in SUV[max] [delta SUV[max]] between the two scans were measured. Correlations between PET parameters and pathological response, and correlations between PET parameters and disease-free survival [DFS] were examined

Results At the completion of NAC, surgery showed pCR in 7 patients, while 25 had residual tumor, so-called non-pCR. Median follow-up was 39.0 months. Of the non-pCR patients, 9 relapsed at 3 years. Of all assessed clinical, biological, and PET parameters, N-stage, clinical stage, and delta SUV[max] were predictors of pathological response [p=0.0288, 0.0068, 0.0068; Fischer's exact test]. The cut-off value of delta SUV[max] to differentiate pCR evaluated by the receiver operating characteristic [ROC] curve analysis was 81.3%. Three-year disease-free survival [DFS] was lower in patients with non-pCR than in patients with pCR [p=0.328, log-rank test]. The cut-off value of delta SUV[max] to differentiate 3-year DFS evaluated by the ROC analysis was 15.9%. In all cases, 3-year DFS was lower in patients with delta SUV[max] <15.9% than in patients with delta SUV[max] >/=15.9% [p=0.0078, log-rank test]. In non-pCR patients, 3-year DFS was lower in patients with delta SUV[max] <15.9% than in patients with delta SUV[max] >/=15.9% [p=0.0238, log-rank test]

Conclusions FDG-PET/CT at baseline and after NAC could predict pathological response to NAC before surgery and the clinical outcome after surgery in locally advanced TNBC patients

Dual radioisotopes simultaneous SPECT of [99m]Tc-tetrofosmin and [123]I-BMIPP using a semiconductor detector

Objective[s]: the energy resolution of a cadmium-zinc-telluride [CZT] solid-state semiconductor detector is about 5%, and is superior to the resolution of the conventional Anger type detector which is 10%. Also, the window width of the high-energy part and of the low-energy part of a photo peak window can be changed separately. In this study, we used a semiconductor detector and examined the effects of changing energy window widths for [99m]Tc and [123] I simultaneous SPECT

Methods: the energy "centerline" for [99m]Tc was set at 140.5 keV and that for [123]I at 159.0 keV. For [99m]Tc, the "low-energy-window width" was set to values that varied from 3% to 10% of 140.5 keV and the "high-energy-window width" were independently set to values that varied from 3% to 6% of 140.5 keV. For [123]I, the "low energy-window-width" varied from 3% to 6% of 159.0 keV and the high-energy-window width from 3% to 10% of 159 keV. In this study we imaged the cardiac phantom, using single or dual radionuclide, changing energy window width, and comparing SPECT counts as well as crosstalk ratio

Results: the contamination to the [123]I window from [99m]Tc [the crosstalk] was only 1% or less with cutoffs of 4% at lower part and 6% at upper part of 159KeV. On the other hand, the crosstalk from [123]I photons into the [99m]Tc window mostly exceeded 20%. Therefore, in order to suppress the rate of contamination to 20% or less, [99m]Tc window cutoffs were set at 3% in upper part and 7% at lower part of 140.5 KeV. The semiconductor detector improves separation accuracy of the acquisition inherently at dual radionuclide imaging. In, this phantom study we simulated dual radionuclide simultaneous SPECT by [99m]Tc-tetrofosmin and [123] I-BMIPP

Conclusion: we suggest that dual radionuclide simultaneous SPECT of [99m]Tc and [123]I using a CZT semiconductor detector is possible employing the recommended windows