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Thoracic Imaging |
1 From the Department of Radiology (T.A., Y.T., H.W., H.N.), Department of Pathology and Oncology (T.K., H.H.), and Second Department of Surgery (M.K., T.O., K.Y.), University of Occupational and Environmental Health, School of Medicine, 1-1 Iseigaoka, Yahatanishi-ku, Kitakyushu-shi 807-8555, Japan. Received October 24, 2000; revision requested December 6; final revision received March 27, 2001; accepted April 10. Address correspondence to T.A. (e-mail: a-taka@med.uoeh-u.ac.jp)
| ABSTRACT |
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MATERIALS AND METHODS: The subjects were 127 patients with adenocarcinomas smaller than 3 cm in largest diameter who underwent at least a lobectomy with hilar and mediastinal lymphadenectomy. The margin characteristics of nodules and the extent of ground-glass opacity (GGO) within the nodules at preoperative thin-section CT were analyzed retrospectively. Regional lymph node metastasis (LNM) and vessel invasion (VI) were histologically examined in surgical specimens. Survival curves were calculated according to the Kaplan-Meier method.
RESULTS: The frequencies of LNM (4% [1 of 24]) and VI (13% [three of 24]) in adenocarcinomas with GGO components of more than 50% were significantly lower than those with GGO components of less than 10% (LNM, P < .05; VI, P < .01). The patients with GGO components of more than 50% showed a significantly better prognosis than those with GGO components less than 50% (P < .05). All 17 adenocarcinomas smaller than 2 cm with GGO components of more than 50% were free of LNM and VI, and all these patients are alive without recurrence. Coarse spiculation and thickening of bronchovascular bundles around the tumors were observed more frequently in tumors with LNM or VI than in those without LNM or VI (P < .01).
CONCLUSION: Thin-section CT findings of peripheral lung adenocarcinomas correlate well with histologic prognostic factors.
Index terms: Lung neoplasms, CT, 60.12118 Lung neoplasms, diagnosis, 60.3212, 60.3216 Lung neoplasms, staging, 60.3212, 60.3216, 679.3212, 679.3216
| INTRODUCTION |
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The authors of many studies (1317) have documented thin-section CT findings of peripheral lung adenocarcinomas. An adenocarcinoma that appears as a localized ground-glass opacity (GGO) without spiculation is likely to be a bronchioloalveolar carcinoma (BAC) with slow growth (18). However, the correlation of these thin-section CT findings with survival and known histologic prognostic factors, such as regional lymph node metastasis (LNM) and vessel invasion (VI) (19,20), have not been fully clarified, to our knowledge. The purpose of this study was to evaluate the prognostic importance of thin-section CT findings of peripheral lung adenocarcinomas.
| MATERIALS AND METHODS |
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CT was performed with a helical scanner (TCT-900S, Toshiba Medical Systems, Tokyo, Japan; Somatom Plus, Siemens Medical Systems, Erlangen, Germany). Routine scanning of the entire lung (120 kVp, 150 mA) was first performed in the helical mode with a table speed of 10 mm/sec and 10-mm section thickness. Additional thin-section CT with 2.0-mm section thickness (120 kVp, 250 mA, 1.0-second scanning time) to image the tumor was performed for all patients. Thin-section CT images were reconstructed with a high-spatial-frequency algorithm and were printed with fixed window settings (lung center, -700 HU and width, 1,500 HU). The time between CT and surgery ranged from 2 to 48 days.
Between September and November 1999, two chest radiologists (H.W., Y.T.) retrospectively analyzed the findings on thin-section CT scans by consensus. They analyzed the margin characteristics of nodules and the internal characteristics within the nodules at preoperative thin-section CT. The tumor contents were semiquantitatively classified according to the extent occupied by GGO within the whole tumor. GGO was defined as hazy and amorphous increased lung attenuation without obscuration of the underlying vascular markings and bronchial walls. The percentage of GGO component was calculated as follows (Fig 1): ([DGGO - D]/DGGO) x 100, where DGGO is the greatest diameter of the tumor including the GGO area and D is the greatest diameter of the tumor without the GGO area.
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All surgical specimens were fixed in the inflated state by means of transpleural and transbronchial infusion of formalin. The specimens were stained with hematoxylin and eosin. Regional LNM and VI were independently reviewed in the surgical specimens by a lung pathologist (T.K.) who reviewed all lung specimens again for this study. The diagnosis of regional LNM was based on the TNM classification according to the criteria of the International System for Staging Lung Cancer (21). VI was considered to be present if there was tumor invasion of arteries, veins, or lymphatic vessels. On the basis of the histologic growth pattern, the adenocarcinomas were classified into the following three subtypes: BAC, adenocarcinoma with BAC component, and adenocarcinoma without BAC component. The internal characteristics of the tumors seen on thin-section CT scans were compared with those seen at pathologic examination of the specimens. The correlations were decided by consensus between one pathologist (T.K.) and one radiologist (T.A.).
Statistical analysis of the relationship between thin-section CT findings and pathologic findings of LNM or VI was performed by using the Fisher exact test. Survival was calculated from the date of the surgery to the date of death or last contact with the patient. Survival outcomes were obtained from the patients medical records or from those of their primary care physicians. After surgery, 19 (15%) of the 127 patients were treated with chemotherapy or radiation therapy, and seven of the 19 patients were alive as of September 2000 (group 1, four patients; group 2, three patients). Survival curves were calculated according to the Kaplan-Meier method, and statistical evaluation of the factors was performed with the log-rank test by using software (SAS; SAS Institute, Cary, NC). These analyses were performed for all cases with tumors at least 2 cm in largest diameter and also for cases with tumors smaller than 2 cm. We also performed multivariate analyses by using the stepwise Cox proportional hazards model to assess the effects on survival of thin-section CT findings, histologic prognostic factors, sex, and age.
| RESULTS |
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2 test and unpaired t test, respectively). The frequencies of LNM (4% [1 of 24]) and VI (13% [3 of 24]) in adenocarcinomas in group 3 were significantly lower than those in group 1 (LNM, P < .05; VI, P < .01). Pathologically, GGO was associated with a growth pattern involving replacement of alveolar lining cells with a relative lack of acinar filling. Coarse spiculation (Fig 5) and thickening of bronchovascular bundles around tumors (Fig 6) occurred with a significantly higher frequency among adenocarcinomas with LNM or VI than among those without LNM or VI (P < .05). The desmoplastic response resulted in fibrotic strands, which show direct infiltration of the tumor into adjacent bronchovascular sheaths, and lymphangitic extension corresponded to the coarse spiculation and thickening of the bronchovascular bundles around the tumors. Direct infiltration of the tumor into adjacent bronchovascular sheaths and lymphangitic extension were identified in seven (47%) of 15 adenocarcinomas with coarse spiculation.
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| DISCUSSION |
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Although a tumor with a larger GGO component is likely to be BAC (17,18, 26,27) and therefore to have low propensity for distant spread, it is not possible to differentiate various subtypes of adenocarcinoma distinctively at CT. According to recent reports (18,27) of analysis of serial changes in the appearance of BAC at CT, localized GGO can change into mixed areas of GGO and solid attenuation, and the solid component can increase during the interval. These results prompted us to suspect that an adenocarcinoma with a larger GGO area is at an early and curable stage and that thin-section CT findings may provide a clue to predict the prognostic outcome for patients with lung adenocarcinomas.
Several authors (16,17) have reported that the GGO at thin-section CT in pathologically proved lung adenocarcinomas corresponds to a growth pattern involving alveolar septa with a relative lack of acinar filling. Our results showed the GGO component was well correlated with histologic prognostic factors, such as LNM, VI, and survival. The frequencies of LNM and VI in adenocarcinomas with a GGO component of more than 50% were significantly lower than those with a GGO component of less than 10%. Although distinction between pure BAC and adenocarcinoma with BAC component could not be made at thin-section CT, the patients with a GGO component of more than 50% had a significantly better prognosis. When tumors with GGO components of more than 50% were limited to a diameter smaller than 2 cm, no LNM or VI was seen, and the outcome was excellent. Therefore, the GGO component of tumors can be an excellent predictor of the histologic prognostic factors and survival in small peripheral lung adenocarcinoma, and it may allow differentiation of adenocarcinomas with various biologic behaviors.
Zwirewich et al (16) showed that coarse spiculation occurred with a significantly higher frequency among malignant lung nodules than among benign lung nodules. They reported that the spiculation pathologically correlated with a desmoplastic response in the nodule, which resulted in fibrotic strands radiating into the surrounding lung parenchyma, or with direct infiltration of the tumor into adjacent bronchovascular sheaths or localized lymphangitic extension. These findings were not distinguishable on thin-section CT images. In this study, coarse spiculation and thickening of bronchovascular bundles around tumors occurred with a significantly higher frequency among adenocarcinomas with LNM or VI than among those without LNM or VI, and they were significantly related to survival.
Although several conditions resulting in chronic interstitial fibrosis of the lungs are associated with the later development of cancer, most of the so-called scars in adenocarcinomas are currently considered a desmoplastic reaction to the tumor and are formed during tumor growth (22,28). Shimosato et al (22) demonstrated that central fibrosis occurs as a result of alveolar collapse secondary to degeneration and death of tumor cells lining the alveoli and that a high degree of collagenization is correlated with a poor outcome. Although not all the coarse spiculation corresponded to direct infiltration of the tumor into adjacent bronchovascular sheaths or localized lymphangitic extension, the desmoplastic response resulting in coarse fibrotic strands radiating from the nodule may suggest an advanced adenocarcinoma with a high degree of collagenization of surrounding lung parenchyma.
Since small adenocarcinomas of the lung have been increasingly detected in elderly patients with recent advances in diagnostic modalities, a suitable surgical approach that achieves the most benefit for these patients must be considered. Several studies (11,29) dealt with the risk of limited surgery in patients with lung cancer. However, limited surgical resection has the benefit of preserving the postoperative quality of life without impairment of respiratory function (30). Although such a surgical approach for lung cancer tumors smaller than 3 cm has not shown the same effectiveness as standard surgery, including lobectomy (11), limited surgical resection in properly selected cases could offer the same therapeutic effect. CT calculation software could not be used in this retrospective study, because the GGO component had been calculated by using a semiquantitative method.
The results of our study show that a lung adenocarcinoma smaller than 2 cm with a GGO component of more than 50% at thin-section CT has a high likelihood of being free of LNM or VI. In clinical settings in which limited surgical resection is desirable, preoperative quantification of GGO at thin-section CT may be a helpful tool in determining eligibility of patients.
| ACKNOWLEDGMENTS |
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| FOOTNOTES |
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Author contributions: Guarantor of integrity of entire study, T.A., H.N.; study concepts, T.A., H.N.; study design, T.A.; literature research, T.A., Y.T.; clinical studies, Y.T., T.A., H.W., T.K.; data acquisition, T.A., T.K., M.K.; data analysis/interpretation, T.A., Y.T.; statistical analysis, T.A.; manuscript preparation, T.A., H.N.; manuscript definition of intellectual content, H.N., H.H., K.Y., T.O.; manuscript editing, T.A., H.N.; manuscript revision/review, all authors; manuscript final version approval, T.A., H.N.
| REFERENCES |
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