Varying recurrence rates and risk factors associated with different definitions of local recurrence in patients with surgically resected stage I non-small cell lung cancer

Abstract

7583 Background: To examine the effects of different definitions of local recurrence on the reported patterns of failure and associated risk factors in patients undergoing potentially curative resection of Stage I non-small cell lung cancer (NSCLC). Methods: The study included 306 consecutive patients treated from 2000–2005 without radiotherapy. Local recurrence was defined as either: “radiation” (i.e., recurrences confined to the post-operative radiotherapy fields used in the Phase III trial of adjuvant radiotherapy by Trodella et al) (LRR), including the bronchial stump, staple line, the ipsilateral hilum, and ipsilateral mediastinum; or “comprehensive” (LRC), including these sites plus the ipsilateral lung and contralateral mediastinal and hilar nodes. Results: The median follow-up was 33 months. Proportions of LRC and LRR at 2, 3 and 5 years were 14%, 21% and 29%; and 7%, 12%, and 16%, respectively. Significant risk factors for LRC on multivariable analysis were diabetes, lymphatic vascular invasion and tumor size; significant factors for LRR were resection of less than a lobe and lymphatic vascular invasion. Distant (non-local) relapse proportions using these definitions at 2, 3 and 5 years were 10%, 12%, and 18%; and 14%, 19%, and 29%, respectively. Significant risk factors for distant failure were histology when using the LRC definitions and tumor size using the LRR definition. Conclusions: Local recurrence increased nearly two-fold when a broad definition was used, rather than a narrow one. The definition also affected which factors were significantly associated with both local and distant failure on multivariate analysis. Comparable definitions must be used when analyzing different series. No significant financial relationships to disclose.