Limited Impact of Distinguishing between Bronchioloalveolar Carcinoma and Early Invasive Adenocarcinoma of the Lung in Frozen Sections.
Ann E Walts, Robert J McKenna, Alberto M Marchevsky. Cedars-Sinai Medical Center, Los Angeles, CA
Background: Pathologists at our hospital are asked to distinguish between bronchioloalveolar carcinoma (BAC), early invasive adenocarcinoma (BAC with <5mm invasion;EIA) and mixed adenocarcinoma (MAC) of the lung at intraoperative frozen section (FS), information that is considered important to determine the extent of resection.
Design: 224 consecutive pulmonary resections diagnosed at FS as MAC (160), EIA (22), BAC (19), deferred benign vs. malignant (12), benign (9), and deferred BAC vs. EIA (2) were retrieved from our pathology files. Operations performed at FS were classified as wedge/segmental resection (WS) or more extensive resection (trisegmentectomy, lobectomy, bilobectomy) and correlated with FS diagnoses using the chi-square test. Our files were also searched for re-operations performed within 3 months of the FS and reasons for re-operation were investigated.
Results: 13 (68.4%) patients with FS diagnosis of BAC, 11 (50%) with FS diagnosis of EIA, and 36 (22.5%) with FS diagnosis of MAC underwent WS. Each of the 164 others underwent a more extensive resection. Comparisons of the proportions of WS showed a significant difference in operation performed following FS diagnoses of benign, BAC, or EIA and MAC (p<0.01). No significant difference (p>0.05) was observed in the proportions of WS that followed FS diagnoses of BAC, EIA, benign, deferred benign vs. malignant, or deferred BAC vs. EIA suggesting that tumor size and location, respiratory function, and/or other factors were considered in determining the extent of resection in some cases. In 4 cases (3 benign vs. malignant deferrals and 1 EIA read as benign at FS), re-operation with completion lobectomy was performed 1-90 days after FS for underdiagnosis of BAC (1), of EIA (2), and of MAC (1). The prior wedge resection margins had been clear in 3 of the 4 cases. The completion lobectomies showed no residual tumor, a 1.7 cm MAC and a 7 cm MAC each apparently separate from the previously excised FS tumors, and a 0.9 cm residual MAC, respectively.
Conclusions: -Distinction between BAC and EIA in FS appears to have limited influence on the extent of lung resection in this case cohort. -Distinction of mixed adenocarcinoma (MAC) from the other diagnostic categories remains the most important decision to be made by pathologists at FS. -Deferrals or false negative diagnoses of malignancy at FS pose infrequent problems in surgical management as evidenced by the 4 (1.8%) patients who required re-operation.
Tuesday, March 1, 2011 1:00 PM
Poster Session IV # 277, Tuesday Afternoon