RESUMO
BACKGROUND: Research on the relationship between neuron-specific enolase (NSE) levels and normal organs, particularly the central nervous system, in small cell lung cancer is limited. Therefore, this study aimed to investigate the relationship between positron emission tomography-computed tomography (PET-CT) accumulation at hypothalamic/pituitary regions, tumor activity, and NSE level in limited-stage small cell lung cancer. We retrospectively analyzed patients who were diagnosed with limited-stage small cell lung cancer at Tokyo Medical University Hospital between July 1, 2019, and May 31, 2023, and were treated with chemoradiotherapy or radiotherapy. Leukocytes, erythrocytes, hemoglobin, platelets, total protein, albumin, NSE, and carcinoembryonic antigen were measured in blood samples obtained before treatment initiation. The maximum standardized uptake value (SUVmax), volume, and total lesion glycolysis (TLG) of each hypothalamic /pituitary region, primary tumor, and lymph node metastases were extracted from PET-CT images. The total tumor volume (primary tumor volume plus lymph node metastases volume) and total TLG (primary tumor TLG plus lymph node metastases TLG) were calculated. RESULTS: This study included 19 patients (mean age, 70.1 ± 8.8 years; 13 men and 6 women); the pathology in all patients was small cell lung cancer. Patients were classified into two groups according to the NSE reference value (16.3 ng/mL): six patients having NSE level below the reference value and 13 having NSE level above the reference value. The SUVmax in the hypothalamic/pituitary region was 2.95 in the NSE < 16.3 ng/mL group and 4.10 in the NSE > 16.3 ng/mL group, with a statistically significant difference (p = 0.03). The total tumor volume was 17.8 mL in the NSE < 16.3 ng/mL group and 98.9 mL in the NSE > 16.3 ng/mL group, with a statistically significant difference (p < 0.01). A correlation coefficient of r = 0.458 (p = 0.0486) was observed between SUVmax in the hypothalamus/pituitary and NSE level. A correlation coefficient of r = 0.647 (p < 0.01) was also observed between total tumor volume and NSE level. Finally, a correlation coefficient of r = 0.53 (p = 0.01) was observed between hypothalamic/pituitary TLG and primary tumor TLG. CONCLUSIONS: The findings demonstrated a correlation between hypothalamic/pituitary activity and tumor activity, suggesting the prognostic significance of NSE.
RESUMO
OBJECTIVE: To investigate the positron emission tomography/computed tomography (PET/CT) findings of T1/T2N0M0 glottic cancer (hereafter referred to as T1/T2) and dose distribution in radiotherapy. SUBJECTS AND METHODS: We retrospectively collected data from patients diagnosed with T1/T2N0M0 glottic cancer who received radiotherapy. The extent of fluorine-18-fluorodeoxyglucose (18F-FDG) accumulation in primary tumors, maximum standardized uptake value (SUVmax), total lesion glycolysis (TLG), tumor volume of primary tumors on PET/CT were compared. Furthermore, the tumor identified on PET/CT was incorporated into the radiotherapy plans. A dummy plan (radiation field 6x6cm, prescription point facing the vertebral body, maximum dose ≤107%, T1/T2 66Gy/33 fractions) was developed for three-dimensional conformal radiotherapy, and the dose distribution of primary tumors was calculated. RESULTS: Twenty-nine patients (27 men and two women) were included; their mean age was 67.2±15.0 years. Increased 18F-FDG accumulation in primary tumors was observed on PET/CT in 22/29 (78.5%; T1: 14/21 [67%], T2: 8/8 [100%]) patients. The median SUVmax, TLG, and primary tumor volume were significantly different between T1 and T2 (SUVmax, T1: 4.56 vs. T2: 8.43, P=0.035; TLG, T1: 1.01 vs. T2: 3.71 SUVxmL, P<0.01; primary tumor volume, T1: 0.38mL vs. T2: 0.80mL, P=0.01). At a TLG cut-off value of 3.470, the area under the curve was 0.875, sensitivity was 0.875, and specificity was 0.929 for T1-T2 differentiation. In 20 patients with 18F-FDG accumulation, the minimum radiation dose was significantly different between T1 and T2 (66Gy vs. 64Gy, P<0.01) at the same 66Gy prescription. The minimum radiation dose and primary tumor volume show the correlation value (r=-0.516, P=0.02). CONCLUSION: In glottic cancer, T1 and T2 can be differentiated by the extent of 18F-FDG accumulation in primary tumors on PET/CT. The minimum radiation dose rate decreases as volume increases.
