Controversy about Small Peripheral Lung Adenocarcinomas: How Should We Manage Them?

Using frozen section to identify histological patterns in stage I lung adenocarcinoma of ≤ 3 cm: accuracy and interobserver agreement

AIMS

The IASLC/ATS/ERS classification of lung adenocarcinoma provides a prognostically significant histological subclassification. The aim of this study was to investigate the accuracy, limitations and interobserver agreement of frozen sections for predicting histological subtype.

METHODS AND RESULTS

Frozen section and permanent section slides from 361 resected stage I lung adenocarcinomas ≤ 3 cm in size were reviewed for predominant histological subtype and the presence or absence of lepidic, acinar, papillary, micropapillary and solid patterns. Fifty cases were additionally reviewed by three pathologists to determine interobserver agreement. To test the accuracy of frozen section in judging degree of invasion, five pathologists reviewed frozen section slides from 35 cases with a predominantly lepidic pattern. There was moderate agreement on predominant histological subtype between frozen sections and final diagnosis (κ = 0.565). Frozen sections had high specificity for micropapillary and solid patterns (94% and 96%, respectively), but sensitivity was low (37% and 69%, respectively). The interobserver agreement was satisfactory (κ > 0.6, except for the acinar pattern).

CONCLUSIONS

Frozen section can provide information on the presence of aggressive histological patterns-micropapillary and solid-with high specificity but low sensitivity. It was difficult to predict the predominant pattern on the basis of frozen sections, mostly because of sampling issues.

Clinical model to estimate the pretest probability of malignancy in patients with pulmonary focal Ground-glass Opacity

BACKGROUND

Effective strategies for managing patients with pulmonary focal Ground-glass Opacity (fGGO) depend on the pretest probability of malignancy. Estimating a clinical probability of malignancy in patients with fGGOs can facilitate the selection and interpretation of subsequent diagnostic tests. METHODS : Data from patients with pulmonary fGGO lesions, who were diagnosed at Sun Yat-sen University Cancer Center, was retrospectively collected. Multiple logistic regression analysis was used to identify independent clinical predictors for malignancy and to develop a clinical predictive model to estimate the pretest probability of malignancy in patients with fGGOs.

RESULTS

 One hundred and sixty-five pulmonary fGGO nodules were detected in 128 patients. Independent predictors for malignant fGGOs included a history of other cancers (odds ratio [OR], 0.264; 95% confidence interval [CI], 0.072 to 0.970), pleural indentation (OR, 8.766; 95% CI, 3.033-25.390), vessel-convergence sign (OR, 23.626; 95% CI, 6.200 to 90.027) and air bronchogram (OR, 7.41; 95% CI, 2.037 to 26.961). Model accuracy was satisfactory (area under the curve of the receiver operating characteristic, 0.934; 95% CI, 0.894 to 0.975), and there was excellent agreement between the predicted probability and the observed frequency of malignant fGGOs.

CONCLUSIONS

We have developed a predictive model, which could be used to generate pretest probabilities of malignant fGGOs, and the equation could be incorporated into a formal decision analysis.

Small peripheral lung adenocarcinoma: CT and histopathologic characteristics and prognostic implications

Since the introduction of computed tomography (CT), detection of small lung cancer, especially small peripheral adenocarcinoma, is common. Recently, the morphological characteristics, including thin-section CT and pathologic findings, and prognosis of small peripheral lung adenocarcinomas have been studied extensively. The radiologic and microscopic findings correlate well with each other and are closely associated with tumour prognosis. Most importantly, some subtypes of small lung adenocarcinomas with specific CT or pathologic features are curable. Therefore, all defining characteristics (CT, pathologic and prognostic) of this kind of tumour should be integrated to improve our understanding, provide guidelines for management and accurately assess its prognosis.

How to deal with incidentally detected pulmonary nodules less than 10mm in size on CT in a healthy person

The high frequency of non-calcified pulmonary nodules (NCN) <10mm incidentally detected on a multi-detector CT (MDCT) of the chest raises the question of how clinicians and radiologists should deal with these nodules. Management algorithms for solitary pulmonary nodules >10mm do not carry across to sub-centimeter lesions. Purpose of this review is to provide a 10-step approach for routinely detected sub-centimeter NCN on a MDCT in healthy persons in order to be able to make an optimal discrimination between benign and malignant NCNs. Recommendations are primarily based on individual cancer risk, the presence or absence of calcifications and nodule size. In nodules >4-5mm nodule consistency, margin and shape should be taken into account. Next steps in the nodule evaluation are the assessment of localization, nodule number, presence or absence of growth and volume doubling time. Growth is defined as a volume doubling time of 400 days or less, based on volumetry. For nodules <4mm, a follow-up CT at 12 months is recommended in high risk persons, whilst for low-risk persons no follow-up is needed. If no growth is observed at 12 months, no further follow-up is required. For solid, smooth or attached indeterminate NCN between 5 and 10mm we recommend an annual repeat scan, whilst for purely intra-parenchymal nodules a 3-month repeat scan should be made to assess growth. Growing lesions with a volume doubling time <400 days require further work-up and diagnosis, otherwise an annual repeat scan to assess growth is recommended.