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Background The prognostic value of maximum standardized uptake value (maxSUV) on 18F-fluorodeoxyglucose positron emission tomography (FDG-PET) is known for localized pulmonary adenocarcinoma, which is most commonly non-mucinous adenocarcinoma. We examined the validity of thin-section computed tomography (TS-CT) and FDG-PET findings in mucinous adenocarcinoma. Materials and Methods TS-CT and FDG-PET were performed on 25 patients with mucinous lung adenocarcinoma that was subsequently resected between January 2009 and March 2013. Based on the percentage reduction of maximum tumor diameter on the mediastinal window image compared with the diameter on the lung window image on TS-CT, tumors were classified as air-type (≥50%) or solid-type ( Results Most mucinous adenocarcinomas were located in the lower lobe. All except two were classified as solid-type tumor on TS-CT. Multiple regression analysis revealed the correlation of maxSUV with pathological tumor size and diameter of pathological invasive area; these two parameters showed no significant correlation with each other (r = 0.354, p = 0.083). maxSUV was significantly lower for tumors with invasive area ≤5 mm than for tumors with invasive area >5 mm (1.62 vs. 3.77, p = 0.01), but no statistically significant difference was found in terms of other pathological invasive findings such as the presence of lymphatic or vascular invasion, pleural involvement, or predominant histological subtype. Conclusions Most mucinous adenocarcinomas had appearances of solid-type tumor on TS-CT. maxSUV on FDG-PET indicates the pathological invasive area in mucinous adenocarcinoma as well as non-mucinous adenocarcinoma.

We divided pulmonary adenocarcinoma of ≤ 20 mm into air-containing and solid-density types based on a percentage reduction of the maximum tumor diameter in the mediastinal window image compared to the area in the lung window image on thin-section (TS) CT of ≥ 50% (air-containing type) and50% (solid-density type). No relapse occurred in patients with air-containing type. The prognosis of solid-density type may be poor even when the tumor size is 20mm or smaller. We investigated whether CT findings for these tumors could serve as prognostic factors.The subjects were 105 patients with solid-density type pulmonary adenocarcinoma that was identified on TSCT and found to have a diameter of 20mm or smaller after surgical resection during the period from April 1997 to November 2004. Notches, air bronchogram, pleural retraction, spiculation, venous involvement, and ground glass opacity were examined on TSCT, and their associations with pathological findings (i.e., pleural invasion, lymphatic permeation, vascular invasion, lymph node metastasis, and Noguchi's classification) and relapse were investigated using chi-square test and Cox proportional hazards model.The incidence of relapse was significantly higher in cases with notches. The incidence of notches increased with tumor growth and notches were frequent in Noguchi type D tumors, reflecting poorly differentiated adenocarcinoma. Lymphatic permeation and type D cases were independent factors associated with a poor prognosis using Cox proportional hazards model.TSCT findings may be useful for prediction of the prognosis of solid-density type pulmonary adenocarcinoma.

(18)F-fluorodeoxyglucose positron emission tomography (FDG-PET) is commonly used to distinguish benign from malignant lesion. Recently, maximum standardized uptake value (SUVmax) on FDG-PET has found to have prognostic value. We examined the relationship between SUVmax and proliferative activities as indicated by maximum diameter of tumor opacity on mediastinal-window images (TOM), Ki-67 index, and diameter of the pathological invasive area in lung adenocarcinomasor=30 mm.Thin-section computed tomography (TS-CT) and FDG-PET were performed on 140 patients with resectable lung adenocarcinomasor=30 mm between March 2006 and May 2008. Tumors were classified as air-type or solid-type based on TS-CT findings. In all resected specimens, diameter of the pathological invasive area and Ki-67 index were assessed.SUVmax was significantly lower for air-type than for solid-type tumors (0.97 vs. 3.96, p0.0001). In solid-type tumors, SUVmax correlated with diameter of TOM (r=0.450, p0.0001), Ki-67 index (r=0.567, p0.0001), and diameter of the pathological invasive area (r=0.672, p0.0001). In multiple regression analysis, SUVmax correlated significantly with Ki-67 index and diameter of the pathological invasive area but not with diameter of TOM. The cut-off value of SUVmax for predicting invasive area5mm was determined as 2.15 by ROC analysis, with sensitivity of 88.3% and specificity of 84.6%.SUVmax correlated significantly with Ki-67 index and diameter of the pathological invasive area. The present results suggest the potential role of FDG-PET in predicting adenocarcinomas with invasive characteristics.

The prognostic value of maximum standardized uptake value (maxSUV) on (18)F-fluorodeoxyglucose positron emission tomography (FDG-PET) is known for localized pulmonary adenocarcinoma, which is most commonly non-mucinous adenocarcinoma. We examined the validity of thin-section computed tomography (TS-CT) and FDG-PET findings in mucinous adenocarcinoma.TS-CT and FDG-PET were performed on 25 patients with mucinous lung adenocarcinoma that was subsequently resected between January 2009 and March 2013. Based on the percentage reduction of maximum tumor diameter on the mediastinal window image compared with the diameter on the lung window image on TS-CT, tumors were classified as air-type (≥50%) or solid-type (50%). All resected specimens were pathologically diagnosed according to the International Association for the Study of Lung Cancer (IASLC) classification, and the diameter of the pathological invasive area was assessed.Most mucinous adenocarcinomas were located in the lower lobe. All except two were classified as solid-type tumor on TS-CT. Multiple regression analysis revealed the correlation of maxSUV with pathological tumor size and diameter of pathological invasive area; these two parameters showed no significant correlation with each other (r=0.354, p=0.083). maxSUV was significantly lower for tumors with invasive area ≤5 mm than for tumors with invasive area5mm (1.62 vs. 3.77, p=0.01), but no statistically significant difference was found in terms of other pathological invasive findings such as the presence of lymphatic or vascular invasion, pleural involvement, or predominant histological subtype.Most mucinous adenocarcinomas had appearances of solid-type tumor on TS-CT. maxSUV on FDG-PET indicates the pathological invasive area in mucinous adenocarcinoma as well as non-mucinous adenocarcinoma.

Background Maximum standardized uptake value (SUVmax) of 18F-fluorodeoxyglucose positron emission tomography (FDG-PET) has been found to have prognostic value. We previously reported the correlation between SUVmax and pathological invasive area, and determined an SUVmax cut-off value of 2.15 for predicting the recurrence potential of an invasive area of diameter 5 mm. Here, we evaluate the validity of FDG-PET for prediction of recurrence in pathological stage IA lung adenocarcinoma. Methods From February 2006 to May 2008, 100 patients with pathological stage IA lung adenocarcinoma underwent complete resection at our hospital. Tumors were classified as air-type or solid-type based on thin-section computed tomography (TS-CT) findings and the influence of TS-CT classification, SUVmax, and clinicopathologic features were evaluated in terms of the incidence of recurrence. Results Unlike air-type adenocarcinomas, recurrent disease was detected in 8 of 62 solid-type adenocarcinomas. SUVmax and diameter of invasive area were significantly correlated with recurrence and a shorter time to recurrence. All 8 recurrent cases had pathological invasive area >5 mm. All except one case of recurrence were solid-type adenocarcinomas with SUVmax ≥ 2.15. Three-year disease-free survival rates were 100% in air-type adenocarcinomas, 97.1% in solid-type adenocarcinomas with SUVmax Conclusion Combined evaluation of TS-CT classification and SUVmax had significant value in predicting recurrence in stage IA lung adenocarcinoma, reflecting the aggressiveness of primary lung adenocarcinoma. Prediction of tumor aggressiveness could contribute to decision-making regarding the choice of surgical procedure and treatment after surgery.