A nonrandomized confirmatory phase III study of sublobar surgical resection for peripheral ground glass opacity dominant lung cancer defined with thoracic thin-section computed tomography (JCOG0804/WJOG4507L).

Abstract

8561 Background: The optimal mode of surgery for peripheral ground glass opacity (GGO) dominant lung cancer (LC) defined with thoracic thin-section computed tomography (TSCT) remains unknown. Methods: We conducted multi-institutional confirmatory phase III trial to evaluate the efficacy and safety of sublobar resection for peripheral GGO dominant LC. Mode of surgery is basically wedge resection, and segmentectomy is allowed when surgical margin is insufficient ( < 5 mm) or histological invasiveness. LC with maximum tumor diameter (MTD) ≤ 2.0 cm and with consolidation tumor ratio ≤ 0.25 based on TSCT were registered. The primary endpoint was 5-year relapse-free survival (RFS). The planned sample size was 330, with the expected 5-year RFS of 98%, threshold of 95%, one-sided α of 5% and power of 90%. Survival analyses were performed using the Kaplan-Meier method and their confidence intervals were estimated by Greenwood’s formula. Results: Between May 2009 and April 2011, 333 pts were enrolled from 51 institutions. The primary endpoint, RFS was estimated on 314 pts who underwent sublobar resection. Median age was 62 (range 24 - 79) and 104 were smokers. Median MTD on lung window was 1.20 cm (0.53 - 2.00). Median MTD of consolidation was 0 (0.00 - 0.48). Operative modes were 258 wedge resection and 56 segmentectomy. Histological diagnosis were 310 adenocarcinomas, 27 precancerous lesions, and 14 non-neoplastic lesions. Median pathological surgical margin was 15 mm (0 - 55). Grade 2 or higher postoperative complications based on CTCAE v3.0 were observed in 119 (37.9%), and Grade 3 in 17 (5.4%), without any Grade 4 or 5. The 5-year RFS was 99.7% (95% CI, 97.7 - 100.0%), which met the primary endpoint. There was no local relapse. The ratio of FEV1.0 change between preoperative and one year after surgery over preoperative value ranged -37% to +49% with a median of -5%. Conclusions: Sublobar resection, mainly wedge resection, offered sufficient local control and RFS for peripheral GGO dominant LC on TSCT. Sublobar resection should be the first choice of mode of surgery if surgical margin is enough preserved. Clinical trial information: 000002008.