OA15.01 Limited Resection Trial for Pulmonary Sub-solid Nodules: Case Selection Based on High Resolution CT: Outcome at Median Follow-up of 105 Months

Abstract

The objective of this study is to confirm limited resection efficacy as radical surgery in patients with minimally invasive lung cancer as indicated by high-resolution (HR) computed tomography (CT), and to confirm intraoperative cytology as a negative margin indicator and reliable margin non-recurrence predictor. Enrollment required patients with a tumor ≤2 cm in diameter, diagnosed or suspected as a clinical T1N0M0 carcinoma in the lung periphery based on a CT scan. They had to have a HRCT scan indicating a sub-solid nodule with tumor disappearance ratio; TDR ≥ 0.5. (TDR = 1- DM/DL; DM: maximum tumor diameter on mediastinal settings, DL: maximum tumor diameter on lung settings). Patients unfit for lobectomy and systematic lymph node dissection were excluded. We performed a wedge or segmental resection. The used stapling cartridges were washed with saline, which was cytologically evaluated. If cytology was cancer positive, additional margin was resected, and cytologic examination repeated. If the second exam was positive, a routine lobectomy and systematic lymph node dissection was performed. We aimed at enrolling 100 patients. The primary endpoint is 10-year local recurrence free survival rate. This prospective study started in November 2003, and 101 patients were enrolled in 6 years. Of them, 99 were eligible for analysis. The mean age was 62 years (range: 30-75), and 60 were women. There were 11 Noguchi type A tumors, 54 type B tumors, 26 type C tumors, one type D tumor, one malignant lymphoma, 3 hyperplastic lesions, and 3 inflammatory fibroses. None of the 93 malignant nodules showed any vessel invasion. Although no positive cytology results were obtained, pathologically positive margin was reported after surgery in one type C patient. He later underwent a routine lobectomy and systematic lymph node dissection. There was no clear correlation between tumor size, TDR, and Noguchi subtype. No mortality occurred, but one patient developed postoperative pneumothorax and pneumonia, and another hemorrhagic gastric ulcer. With a median follow-up period of 105 months (range: 72−129) as of June 2016, there have been no recurrences, but one patient died for unspecified cause. We have repeatedly warned that delayed cut-end recurrence is possible following limited resection even for small sub-solid lung cancers. So far, however, HRCT scans appear to predict non- or minimally invasive sub-solid lung cancers with high reliability, warranting limited resection as curative surgery in this cohort. Intraoperative cytology reliably indicated negative margins and seems to predict freedom from local recurrence.