P2.17-23 the Role Adjuvant Chemotherapy in Resected Stage 1 NSCLC with High Risk Factors: A Turkish Oncology Group Study

Adjuvant chemotherapy is accepted as a standard treatment for suitable patients who have undergone surgery for T2N0 non-small cell lung cancer with tumors larger than 4 cm. Despite similar relapse rates, the benefit of adjuvant chemotherapy for smaller tumors with high risk features is not clear. In this retrospective analysis our aim was to evaluate the prognostic impact of adjuvant platin-based chemotherapy in high-risk stage 1 NSCLC patients. This cooperative group study included 250 NSCLC patients who underwent curative surgery for stage 1 NSCLC with tumor size 2-4 cm and adverse prognostic factors consisting of visceral pleural invasion (VPI), lympho-vascular invasion (LVI), high grade, presence of solid-micropapillary(SMP) components or STAS. Records of patients were analyzed to investigate the prognostic impact of adjuvant chemotherapy in this cohort. DFS was defined as the time from surgery to the last follow-up, until relapse or death, CSS; time from surgery to death related to cancer or last known contact, OS; time from diagnosis to death or last known contact. Statistical analysis was performed using SPSS 20.0 software (SPSS Inc, Chicago, USA). Median age at presentation was 63 years (range 18-90). The mean tumor size was 29.4 ± 7.4 mm. The frequency of patients with specified risk factors were: VPI: n: 92 (36.8%); LVI: n: 91 (36.4%); Grade 3:n: 49 (19,6%); SMP:n: 76 (30.4%); STAS:n: 15 (6%). A total of 51 patients had received adjuvant platin-based chemotherapy. There were significantly more patients who received chemotherapy in the younger age group (<65 years old, ≥65 years old) and those with larger tumors (2 – 3 cm, 3 – 4 cm). During a median follow-up period of 91.8 months; 79 patients (31.6%) experienced recurrence, 62 patients (24.8%) have died, 144 patients (57.6%) were alive without disease and 24 patients (9.6%) were alive with disease. 5-year and 10-year OS rates were 72.7% (± 3,5) and 46.8%(± 8), respectively. There was a significant improvement in DFS with adjuvant chemotherapy, especially in groups with VPI (93.3% vs 53.6%, p:0.016) and SMP (92.3% vs 57.3%, p:0.03). There was also a non-significant trend for improved CSS and OS among patients who received CT.Table 1Effects of chemothrapy on survivalChemotherapy Group Events/N Median 5-years DFSNon - treatment Group Events/N Median 5-years DFSP ValueDFS12/51 NE % 74.9 ± 6.381/190 71.1 months % 54 ± 4.20,032*CSS4/49 NE % 89 ± 541/179 91.8 months % 76.9 ± 3.80,078OS10/49 NE %77.4 ± 6.451/179 88.9 months % 72.1 ± 40,541*All values are stratified, respecting to significant confounding factors such as age, gender and tumor size. Open table in a new tab *All values are stratified, respecting to significant confounding factors such as age, gender and tumor size. Adjuvant platin-based chemotherapy should be considered for this subset of patients having high grade tumors, or those with VPI, LVI or solid-micropapillary components. Prospective, randomized trials incorporating clinical and molecular risk factors are required to clarify the role of adjuvant chemotherapy for stage 1 NSCLC patients.