ABSTRACT
AIM: In therapy response monitoring by [18F]2-fluoro-2-deoxy-D-glucose positron emission tomography (FDG-PET), different tumor delineations are used, resulting in different values for change in glucose metabolic rate (DMRglu). We propose a technique to compare metabolic rates in a region of interest (ROI) based on fixed volumes rather than on fixed thresholds. This method involves change in lesion size. METHODS: In 49 patients with colorectal carcinoma (CRC) and 50 patients with non-small cell lung carcinoma (NSCLC) scheduled for chemotherapy, FDG-PET was performed at baseline and during chemotherapy. A ROIfixed thresholds was determined by using a 50% threshold on both baseline and follow-up FDG-PET. A ROIfixed volumes was determined by using a 50% threshold, determined on the series with the largest tumor volume. This ROIfixed volumes is used on consecutive scans. Predictive effects of both methods were investigated by survival analysis for overall and progression free survival. RESULTS: In CRC, only ROIfixed volumes based DMRglu showed significant predictive ability. In NSCLC, both techniques showed significant predictive ability. During multivariate analysis, ROIfixed volumes determined DMRglu was an independent predictor for both overall and progression free survival in NSCLC whereas ROIfixed thresholds determined MRglu was not. After dichotomization at the median DMRglu, median survival ratio was higher in ROIfixed volumes than ROIfixed thresholds for CRC (overall survival: 1.78 vs 1.25, progression free survival: 1.57 vs 1.21) and NSCLC (overall survival: 2.01 vs 2.01, progression free survival: 2.93 vs 2.13). CONCLUSION: ROIfixed volumes based DMRglu shows better correlation with survival than DMRglu determined from a ROIfixed thresholds.
ABSTRACT
AIM: In therapy response monitoring by [¹8F]2-fluoro-2-deoxy-D-glucose positron emission tomography (FDG-PET), different tumor delineations are used, resulting in different values for change in glucose metabolic rate (ΔMR(glu)). We propose a technique to compare metabolic rates in a region of interest (ROI) based on fixed volumes rather than on fixed thresholds. This method involves change in lesion size. METHODS: In 49 patients with colorectal carcinoma (CRC) and 50 patients with non-small cell lung carcinoma (NSCLC) scheduled for chemotherapy, FDG-PET was performed at baseline and during chemotherapy. A ROI(fixed thresholds) was determined by using a 50% threshold on both baseline and follow-up FDG-PET. A ROI(fixed volumes) was determined by using a 50% threshold, determined on the series with the largest tumor volume. This ROI(fixed volumes) is used on consecutive scans. Predictive effects of both methods were investigated by survival analysis for overall and progression free survival. RESULTS: In CRC, only ROI(fixed volumes) based ΔMR(glu) showed significant predictive ability. In NSCLC, both techniques showed significant predictive ability. During multivariate analysis, ROI(fixed volumes) determined ΔMR(glu) was an independent predictor for both overall and progression free survival in NSCLC whereas ROI(fixed thresholds) determined MRglu was not. After dichotomization at the median ΔMR(glu), median survival ratio was higher in ROI(fixed volumes) than ROI(fixed thresholds) for CRC (overall survival: 1.78 vs 1.25, progression free survival: 1.57 vs 1.21) and NSCLC (overall survival: 2.01 vs 2.01, progression free survival: 2.93 vs 2.13). CONCLUSION: ROI(fixed volumes) based ΔMR(glu) shows better correlation with survival than ΔMR(glu) determined from a ROI(fixed thresholds).
Subject(s)
Fluorodeoxyglucose F18/metabolism , Image Interpretation, Computer-Assisted/methods , Neoplasms/metabolism , Neoplasms/mortality , Positron-Emission Tomography/statistics & numerical data , Proportional Hazards Models , Radiopharmaceuticals/metabolism , Adult , Aged , Antineoplastic Agents/therapeutic use , Computer Simulation , Female , Humans , Middle Aged , Models, Biological , Neoplasms/drug therapy , Netherlands/epidemiology , Prevalence , Prognosis , Reproducibility of Results , Risk Assessment , Risk Factors , Sensitivity and Specificity , Survival Analysis , Survival Rate , Treatment OutcomeABSTRACT
BACKGROUND: The aim of this prospective study was to evaluate the value of F-18-fluorodeoxyglucose-positron emission tomography (FDG-PET) for early assessment of chemotherapy response in patients with advanced colorectal cancer. METHODS: Dynamic FDG-PET was carried out before and at 2 (n = 50) and 6 months (n = 19) after the start of treatment. Quantitative Patlak analysis [metabolic rate of glucose (MRGlu)] and a simplified method to measure glucose metabolism [standardized uptake value (SUV)] were evaluated. The predictive value of changes in glucose metabolism was assessed with Cox proportional regression analysis. Overall survival (OS) and progression-free survival (PFS) were calculated using Kaplan-Meier estimates. RESULTS: There was an increase in the rates of death (P = 0.049 for DeltaMRGlu PET1-2; P = 0.017 for DeltaSUV PET1-2; P = 0.032 for DeltaMRGlu PET1-3; P = 0.048 for DeltaSUV PET1-3) and progression (P = 0.026 for DeltaMRGlu PET1-2; P = 0.035 for DeltaSUV PET1-2; P = 0.041 for DeltaMRGlu PET1-3; P = 0.081 for DeltaSUV PET1-3) associated with worse response as assessed by PET on Cox proportional regression analysis. The OS and PFS analysis showed a significant predictive value at broad ranges of DeltaMRGlu and DeltaSUV cut-off levels. CONCLUSION: The degree of chemotherapy-induced changes in tumor glucose metabolism is highly predictive for patient outcome. The use of FDG-PET for therapy monitoring seems clinically feasible since simplified methods (SUV) are sufficiently reliable.
Subject(s)
Colorectal Neoplasms/diagnostic imaging , Colorectal Neoplasms/mortality , Fluorodeoxyglucose F18 , Neoplasm Invasiveness/pathology , Positron-Emission Tomography , Aged , Antineoplastic Combined Chemotherapy Protocols/administration & dosage , Antineoplastic Combined Chemotherapy Protocols/adverse effects , Chemotherapy, Adjuvant , Colorectal Neoplasms/pathology , Colorectal Neoplasms/therapy , Combined Modality Therapy , Disease-Free Survival , Evaluation Studies as Topic , Female , Follow-Up Studies , Humans , Kaplan-Meier Estimate , Male , Middle Aged , Neoplasm Staging , Predictive Value of Tests , Probability , Prospective Studies , Risk Assessment , Sensitivity and Specificity , Survival Analysis , Treatment OutcomeABSTRACT
The cranial sensory nerve supply in three skeletal populations, two distinct prehistoric Polynesian groups from New Zealand, the Moriori and Maori, and one contemporary Indian group, are investigated. This paper assesses an aspect of the hypothesis that Polynesian groups have anatomical adaptations that enabled them to survive in a cool and wet environment. To this end the relationship between sensory nerve dimensions were examined, based on the area of cranial nerve foramina, and external environmental temperature. Statistical comparisons between the Polynesians and Indians showed significantly reduced cranial cutaneous sensory nerve foramina size, and therefore diminished facial cutaneous sensory nerve supply in the Polynesians. On this basis it is inferred that sensory supply to the skin of the infracranial body was also lessened. This paper proposes that reduced skin sensory nerve supply was selected as an adaptation to a cool and wet environment, where it acted as a body energy conserving mechanism by delaying the onset of body warming mechanisms.
