Impact of tumor size on survival in stage IB (T2N0M0) non-small cell lung cancer (NSCLC)

Abstract

7557 Background: Patients with stage IB NSCLC have a relatively poor survival of ∼60% despite adequate surgical resection. The role of adjuvant chemotherapy in this disease remains controversial since the results of the IALT, JBR.10, ANITA and CALGB 9633 trials. It is important to risk stratify patients with Stage IB NSCLC and to offer adjuvant therapies to those at greatest risk for recurrence. Methods: We conducted a retrospective review of 216 consecutive, surgically treated patients with stage IB NSCLC. None of the patients received adjuvant chemotherapy. We studied the association of various clinical factors as well as tumor size and visceral pleural invasion upon tumor recurrence, disease free survival (DFS) and overall survival (OS) at 5 years. Results: Of 216 patients, 135 (62%) were male, 97 (45%) had adenocarcinoma, 115 (53%) had poorly differentiated tumors and the majority (88%) were treated with lobectomy. Visceral pleural invasion was noted in 37 (17%) patients. The 5 year OS and DFS rates were 59% and 54% respectively. Tumor size was = 4cm in 120 (56%) patients, 4.1–5 cm and >5cm in 48 (22%) patients each. The 5 year DFS was 40% and 58% for tumors > 5cm and = 5 cm respectively (p < 0.01). The 5 year OS was 49% and 61% respectively for tumors > 5cm and = 5cm. Pleural invasion was a predictor for DFS in the univariate analysis (p < 0.01) but not for OS. In the multivariable analysis, tumor size = 5cm was the only independent predictor of improved DFS (HR 0.46, C.I. 0.25–.84) and OS (HR=0.43, C.I. 0.23–0.80). Age, gender, histology, differentiation and visceral pleural invasion did not impact upon survival. Conclusions: In stage IB NSCLC, tumors > 5cm in diameter have a significantly worse prognosis. These findings if confirmed in other large series, make a case for subdividing Stage IB NSCLC. Tumor size appears to be the most important factor in risk stratification for patients with stage IB NSCLC. Hence patients with large tumors should be offered adjuvant therapy. No significant financial relationships to disclose.