Positron emission tomography scans can detect radiographically occult lung cancer in the central airways

Endosonographic features predictive of malignancy in mediastinal lymph nodes in patients with lung cancer

BACKGROUND

EUS is useful in determining mediastinal lymph node (LN) metastases in patients undergoing staging for lung cancer. However, FNA of LNs is often performed only if suspicious features are present. The utility of individual LN features in predicting malignant cytology remains unclear.

OBJECTIVE

To evaluate the utility of EUS-determined LN features for predicting malignant cytology.

DESIGN

Prospective observational study.

SETTING

Two U.S. tertiary-care centers.

PATIENTS

This study involved 425 patients with primary lung cancer who underwent EUS.

INTERVENTION

All mediastinal LNs were described according to size, shape, echogenicity, and margin characteristics. FNA was performed on LNs with any features suggestive of malignancy. EUS-guided FNA cytology was classified as benign or abnormal (suspicious/malignant). The utility of LN features in predicting malignant cytology was determined and further analyzed by logistic regression, and a predictive model was established.

MAIN OUTCOME MEASUREMENTS

Accuracy of individual LN features for predicting malignancy.

RESULTS

EUS detected 836 LNs in 425 patients, and FNA was obtained in 698 patients. On multivariable analysis, only round shape, a short axis of >8.3 mm, and sharp margins were predictive of malignant cytology. According to the predictive model, the calculated probability of having malignancy is less than 4% (95% confidence interval [CI], 0.022-0.064) when none of the LN features are present and 63% (95% CI, 51%-72.2%) when all features were seen.

LIMITATIONS

No surgical histology as the criterion standard.

CONCLUSION

Among patients with lung cancer, EUS features of round shape, sharp margins, and short axis of >8.3 mm are significant predictors of malignancy. The probability of malignancy is low when none of the features are present.

Detection and Staging of Preinvasive Lesions and Occult Lung Cancer in the Central Airways with 18F-Fluorodeoxyglucose Positron Emission Tomography: A Pilot Study

PURPOSE

To evaluate the role of (18)F-fluorodeoxyglucose positron emission tomography (FDG-PET) in radiologically occult preinvasive lesions and lung cancer in the central airways.

EXPERIMENTAL DESIGN

Twenty-two patients with 24 preinvasive lesions and early squamous cell cancer (SCC) being occult on high-resolution computed tomography were studied. All lesions were diagnosed based on histology sampled using autofluorescence bronchoscopy. FDG-PET findings were correlated with WHO histologic classification. FDG-PET was considered true-positive when the final diagnosis was SCC and true-negative when the lesions were classified as severe dysplasia or less.

RESULTS

FDG-PET was true-positive in 8 of 11 and true-negative in 11 of 13 cases corresponding with a sensitivity of 73% [95% confidence interval (CI), 0.43-0.91] and specificity of 85% (95% CI, 0.57-0.97). Positive and negative predictive values were 80% (95% CI, 0.48-0.96) and 79% (95% CI, 0.52-0.93), respectively.

CONCLUSIONS

Our very preliminary data suggest that FDG-PET might be useful for the evaluation of early central airway lesions, being positive in most SCC and negative in cases of severe dysplasia. Validation in a larger multicenter study is needed.

What is early lung cancer? A review of the literature

The dismal cure rate of patients with lung cancer and the stage shift hypothesis have propelled the interest to perform screening at large, despite that previous randomized clinical trials failed to show any mortality benefit and the controversial issue of overdiagnosis. Due to early detection programs, a larger number of individuals at risk will be found to harbor small and potentially malignant early stage lesions. The application of non- and minimal invasive techniques for early detection, staging and treatment will become increasingly important. This review deals with the available clinical, surgical and pathological data focusing on early lung cancer lesions < or =1 cm. Literature data from both centrally located and parenchymal lesions < or =3 cm. have been analyzed. For all sub-centimeter lesions, minimal invasive staging and treatment approaches must still be considered inappropriate. Less invasive and less extensive treatment methods may be considered in high risk individuals with < or =1 cm. peripheral lesion showing > or =50 ground glass opacity on high resolution CT scan and those with superficial lesion in their central airways without deeper tumor invasion in the bronchial wall. Caution is necessary, however, as clinical staging remains inferior to pathological staging which is based on tissue samples collected after complete tumor removal and mediastinal lymph nodes dissection have been performed.

Innovative molecular and imaging approaches for the detection of lung cancer and its precursor lesions

Current approaches for the therapy of lung cancer, the majority of which being advanced cancers, have failed to impact on long term survival. The key to improvement lies in the combination of early diagnosis and the introduction of novel targeted therapies. In this article we review some of the innovative approaches, both imaging and molecular, that are currently under investigation for early detection. Because lung cancers may arise in the central or peripheral compartments of the lung, newer approaches must target tumours arising in both of these compartments. Specimens available for analysis include sputa and blood. Detection of genetic changes in peripheral blood is a promising avenue being explored by several groups. Molecular techniques discussed include gene mutations, detection of nuclear riboprotein, methylation related silencing of genes and malignancy associated changes. Newer imaging technologies include autofluorescence bronchoscopy, virtual bronchoscopy, optical coherent tomography and confocal microscopy. Although the impact of these new technologies on survival has not been determined, they offer a wide range of exciting new approaches. In time they may completely revamp the present highly conservative and unsuccessful approaches to early diagnosis.