Purpose: Advances in CT scanning have presented physicians with the challenge of diagnosing small (< 10 mm) or deep (> 5 mm) pulmonary nodules (SmPNs) in patients with known malignancies during workup or follow-up. Wedge excision of SmPNs is difficult with video-assisted thoracoscopic surgery (VATS) and often requires the performance of a thoracotomy. The value of the early detection of metastatic disease must be weighed against the morbidity (ie, thoracotomy) that is necessarily involved in obtaining the information. Little is known about the incidence of metastases in this subset of patients. We describe a VATS technique that allows the reliable excisional biopsy of SmPNs and present our findings in this patient population.
Methods: Using CT scan localization, 150 micro Ci technetium sulfur colloid is injected into the area of the pulmonary nodule. Additional blue dye is injected at the lung surface. During VATS, a sterile gamma probe is used to identify the area of radioactivity and plan placement of staple lines performed by an endostapling instrument. Palpation and the presence of radioactivity in the specimen supported the resection of the correct nodule, and CT scan findings confirmed the procedure. Between March 2000 and January 2001, 17 patients with known malignancies and SmPNs underwent VATS excisional biopsies. Six patients received a new diagnosis of malignancy, and 11 patients were in follow-up of a previously treated malignancy. The malignancies included the following: breast (four patients), head and neck (four patients), pancreas (two patients), lymphoma (two patients), lung (one patient), prostate (one patient), rectal (one patient), seminoma (one patient), and urethral (one patient).
Results: All lesions were successfully resected on the first try. Nodules were removed from 10 segments and all lobes. The mean (+/-/SD) nodule size was 9.2 +/- 3.6 mm, and the mean depth was 9.4 +/- 5.2 mm. Fourteen of 17 nodules (82.4%) could be neither seen nor felt using standard VATS techniques. Diagnoses included metastatic (four patients), new primary lung cancer (one patient), acid-fast bacillus (one patient), granuloma (seven patients), carcinoid (two patients), and inflammatory pseudotumor (two patients). Among these lesions, 29.4% were malignant, and 35.3% of patients received a diagnosis that altered their therapy. Five of 12 SmPNs (41.7%) < 10 mm in size were malignant. The median length of hospital stay was 2 days. Patients returned to full activity within 1 week.
Conclusion: VATS excision of SmPNs after CT scan localization with radiolabeled technetium is reliable, reproducible, and associated with minimal morbidity. The technique prevented thoracotomies in 82.4% of patients. Despite the small size of these lesions, malignancy was found 29.4% of the time. This technique allows the early diagnosis of SmPNs, with low morbidity, in patients with known malignancies.
Clinical implications: The reliability of this technique, the high incidence of malignancy, and the reduction in morbidity from undergoing excisional biopsy procedures will encourage the clinician to strive for earlier and more aggressive diagnoses of SmPNs.