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Abstract
Introduction/Background To analyze the relationship of 18F-FDG-PET/CT biomarkers and clinical, surgical and pathological variables with the response to neoadjuvant chemotherapy(NACT) in startup inoperable patients (FIGO III/IV) high-grade serous ovarian cancer(HGSC).
Methodology Retrospective review of HGSC patients who underwent 18F-FDG-PET/CT before(PETpre) and after NACT(PETpost). NACT response was assessed by CA-125 levels, pathological chemotherapy response score(CRS 3-complete vs CRS1&2-partial and no response), and cytoreduction(R0-complete vs. R1-incomplete). 18F-FDG-PET/CT parameters were obtained by means of the segmentation of the supra and infradiaphragmatic disease using Syngo.via, with automatic thresholding at 30% of SUVmax. Metabolic parameters studied: metabolic active tumor volume(MTV) and total lesion glycolysis(TLG). The values for all these parameters at PETpre, as well as the presence of ascites with pathological 18F-FDG uptake(SUVmax ascites >SUVmean blood pool) and the modeled CA-125 elimination rate constant(KELIM, favourable if ≥ 1) were assessed in relation to NACT response. Variables were described by mean(SD) or median(IQR). Paired relationship among variables was assessed by McNemar and Wilcoxon test.
Results Seventeen patients were included, mean age of 63.6 years(range: 37–78); all patients displayed CA-125>35 and 76.5% showed pathological uptake in ascites in PETpre. After NACT(94.1% of patients received three cycles), values of CA-125<35 were observed in 35.3%, all patients normalized pathological uptake in ascites in PETpost and metabolic parameters studied decreased very significantly after NACT. Almost half patients(47.1%) presented complete CRS and 88.2% complete cytoreduction(R0); KELIM was favourable in 42.9%.
Despite these changes, only reduction of CA-125 was moderately correlated to reduction of some metabolic parameters: total TLG(rho:0.535; p=0,027), total infradiaphragmatic disease MTV(rho:0.577; p=0,015) and TLG(rho:0.597; p=0,011), and total peritoneal disease MTV(rho:0.609; p=0,012) and TLG(rho:0.609; p=0,014). Studied variables did not relate to cytoreduction and CRS.
18F-FDG-PET/CT maximum intensity projections (MIP) for staging (A1 and A2) and for response assessment after NACT (B1 and B2). A1) The MIP image shows a bilateral high-grade serous ovarian cancer process with lymph node involvement (supra and infradiaphragmatic) and peritoneal carcinomatosis. A2) Segmentation of the supradiaphragmatic (segmented lymph nodes in orange) and infradiaphragmatic disease (segmented primary tumor in green, segmented peritoneal carcinomatosis in pink, and segmented infradiaphragmatic lymph nodes in yellow). B1) The MIP image shows a good partial morphometabolic response after NACT of the entire disease, both supra and infradiaphragmatic. B2) Segmentation of residual supra and infradiaphragmatic disease after NACT.
Conclusion NACT in HGSC patients with FIGO III-IV is related to big changes in most variables studied. Nevertheless, relationships to CRS and cytoreduction were impaired by the small sample size.
Disclosures Nothing to disclose.