Consequences of additional use of contrast-enhanced (18)F-FDG PET/CT in target volume delineation and dose distribution for pancreatic cancer.

OBJECTIVE: To compare the differences between contrast-enhanced (CE) fluorine-18 fludeoxyglucose ((18)F-FDG) positron emission tomography (PET)/CT and CECT in target volume delineation and radiotherapy (RT) dose distribution, and to evaluate the sparing of organs at risk (OARs) in the treatment plan of locally advanced pancreatic cancer (LAPC). METHODS: 21 consecutive patients with LAPC with histologically or cytologically confirmed adenocarcinoma underwent both non-CECT and (18)F-FDG scans; 11 of whom also underwent CECT scans. Intensity-modulated RT plans (prescribed dose, 54 Gy) were constructed to cover the corresponding gross tumour volume (GTV). The differences among GTVCT, GTVPET, GTVPET-CT and OARs in these different image sets as well as the uniformity of target dose were analysed. RESULTS: The mean non-CE GTVCT, GTVPET and GTVPET-CT were 76.9 ± 47.8, 47.0 ± 40.2 and 44.5 ± 34.7 cm(3) (mean ± standard deviation), respectively. The non-CE GTVPET-CT was significantly smaller than the non-CE GTVCT (p < 0.001). The CE GTVPET-CT was significantly smaller than the CE GTVCT (p = 0.033). For both the non-CE GTVCT and the CE GTVCT, the intestine V40 (the percentage of the intestine volume irradiated by 40 Gy), intestine V50, intestine Dmax (the mean maximum dose), cord Dmax, left kidney V30, right kidney V30, left kidney Dmean (the mean dose), right kidney Dmean and liver V30 were 5.90%, 2.52%, 5500 cGy, 2194 cGy, 3.40%, 0.68%, 747 cGy, 550 cGy and 5.37%, respectively. There are significant differences between the non-CE CT and the non-CE PET-CT in intestine Dmax (p = 0.023) and right kidney Dmean (p = 0.029). CONCLUSION: Co-registration of (18)F-FDG PET with CECT may improve the accuracy of GTV delineation in LAPC and might reduce the adverse effect of irradiation. ADVANCES IN KNOWLEDGE: Individual adaptation of RT based on functional CE (18)F-FDG PET/CT imaging is possible and highly promising in LAPC.

Increased circulating immunosuppressive CD14(+)HLA-DR(-/low) cells correlate with clinical cancer stage and pathological grade in patients with bladder carcinoma.

This study investigated CD14(+)HLA-DR(-/low) cells in peripheral blood mononuclear cells (PBMCs) from 64 patients with bladder carcinoma (BC) and 14 healthy controls. Cell phenotypes were determined and CD14(+)HLA-DR(-/low) cells, CD14(+)HLA-DR(+) cells and PBMCs depleted of CD14(+)HLA-DR(-/low) cells were isolated. Proliferation of stimulated PBMCs and interferon-γ (IFN-γ) production after addition of CD14(+)HLA-DR(-/low) and CD14(+)HLA-DR(+) cells at different ratios were measured. IFN-γ production was also measured after addition of L-arginine and/or antitransforming growth factor-ß (TGF-ß) neutralizing monoclonal antibody, and in PBMCs depleted of CD14(+)HLA-DR(-/low) cells. The proportion of CD14(+)HLA-DR(-/low) cells in BC patients was significantly higher than in controls. CD14(+)HLA-DR(-/low) cells significantly decreased T-cell proliferation and IFN-γ production in a dose-dependent manner. This suppressive activity was partially reversed by L-arginine or anti-TGF-ß. Enhanced IFN-γ secretion was also seen in PBMCs depleted of CD14(+)HLA-DR(-/low) cells. The level of CD14(+)HLA-DR(-/low) cells was associated with gender, tumour size, number of tumours, cancer pathological grade and clinical stage. CD14(+)HLA-DR(-/low) cells may represent a subpopulation of myeloid-derived suppressor cells in BC patients.