Prospective evaluation of unilateral adrenal masses in patients with operable non-small-cell lung cancer. Impact of magnetic resonance imaging.

UNLABELLED

We designed a prospective study to evaluate the accuracy of magnetic resonance imaging in distinguishing a benign from a malignant adrenal mass in patients with otherwise operable non-small-cell lung cancer.

METHODS

Potentially operable non-small-cell lung cancer was prospectively staged. If a unilateral adrenal mass was found by computed tomographic scanning, respiratory compensated and cardiac gated thin section magnetic resonance imaging of the adrenal glands was done. One radiologist interpreted the magnetic resonance imaging scan blinded and, on the basis of the relative signal strengths of the T1- and T2-weighted images, judged whether the adrenal mass was benign or malignant. The patients then underwent a percutaneous needle biopsy of the adrenal mass, if technically feasible. If the result of the needle biopsy was nondiagnostic or if the biopsy was not feasible, an adrenalectomy through a posterior approach was performed.

RESULTS

Twenty-seven patients with a unilateral adrenal mass entered the study-11 men and 16 women whose ages ranged from 42 to 75 years (median 58 years). Four patients had epidermoid and 23 adenocarcinoma of the lung. The clinical locoregional stage was I in 9, II in 1, IIIA in 16, and IIIB in 1. Twenty-five completed the magnetic resonance imaging procedure. Five adrenal masses (19%) were metastatic non-small-cell lung cancer (adenocarcinoma = 4, epidermoid = 1); 22 masses (81%) were benign (adenoma = 20, hyperplasia = 2). There were no significant differences in age, sex, histologic type, or locoregional stage between those with a benign versus a malignant mass. However, the malignant masses were significantly larger (3.8 +/- 1.9 cm; range 2.5 to 7.1; median 3.1) than the benign masses (2.0 +/- 0.4 cm, range 1.2 to 2.8; median 2.0) (p < 0.001). Among those having magnetic resonance imaging (n = 25), the technique correctly predicted a malignant mass in the four patients with a histologically confirmed metastasis from non-small-cell lung cancer. However, among the 21 histologically benign masses, the magnetic resonance imaging was interpreted as benign in 5, malignant in 14, and indeterminate in 2. Therefore, although the false-negative rate was 0%, the false-positive rate was 67%.

CONCLUSION

Most adrenal masses in patients with otherwise operable non-small-cell lung cancer are benign. Currently available magnetic resonance imaging methods cannot replace biopsy.