Abstract 1158P
Background
While clinical trials have demonstrated survival benefits with adjuvant chemotherapy treatment (Tx) in early non-small cell lung cancer (eNSCLC), a high proportion of patients subsequently relapse. This study evaluated real-world Tx patterns, time from surgery to adjuvant Tx initiation and associated overall survival (OS) among eNSCLC resected patients.
Methods
Patients newly diagnosed with NSCLC stages IA to IIIB (AJCC 7th edition) between 2010 and 2015 who underwent surgery were identified from the SEER Medicare database. Patients were continuously enrolled in Medicare Part A and B for ≥7 months prior to and ≥12 months after diagnosis, and ≥6 months after surgery. Unadjusted 5-year OS rates were calculated for patients receiving adjuvant Tx, which included chemotherapy, radiation, or other systemic Tx. The association between OS and time from surgery to adjuvant Tx was evaluated using an extended Cox model adjusting for patient characteristics and adjuvant Tx regimen.
Results
Among 7172 eNSCLC patients who had resection, 1941 (27%) received adjuvant Tx. The most common regimen was carboplatin + paclitaxel (30%). Median Tx duration was 2.1 months. The unadjusted 5-year OS rate was 55.9% and varied from 68.3% for stage IA to 40.3% for IIIB. Median time from surgery to adjuvant Tx was 6.3 weeks. The adjusted risk of death within the first 30 months after adjuvant Tx initiation was significantly higher among those initiating Tx outside the 6-8 week window after surgery (Table). Subgroup analysis by stage showed results remain significant for stages I-II but were no longer significant for stage III. Table: 1158P
Impact of time from surgery to adjuvant Tx on OS
| Time from surgery to adjuvant Tx | N | HR* | 95% CI | |
| Survival during first 12 months after adjuvant Tx | ||||
| 6 to <8weeks (ref) | 432 | – | – | – |
| <3 weeks | 294 | 2.59 | 1.86 | 3.60 |
| 3 to <6 weeks | 570 | 1.55 | 1.12 | 2.14 |
| 8 to <16 weeks | 488 | 1.48 | 1.06 | 2.07 |
| ≥16 weeks | 157 | 2.53 | 1.72 | 3.74 |
| Survival between 12 and 30 months after adjuvant Tx | ||||
| 6 to <8 weeks (ref) | 374 | – | – | – |
| <3 weeks | 182 | 1.16 | 0.74 | 1.84 |
| 3 to <6 weeks | 448 | 0.99 | 0.67 | 1.47 |
| 8 to <16 weeks | 392 | 1.62 | 1.12 | 2.33 |
| ≥16 weeks | 98 | 1.83 | 1.09 | 3.09 |
| Survival >30 months after adjuvant Tx | ||||
| 6 to <8 weeks (ref) | 265 | – | – | – |
| <3 weeks | 128 | 0.81 | 0.43 | 1.51 |
| 3 to <6 weeks | 303 | 0.88 | 0.54 | 1.41 |
| 8 to <16 weeks | 230 | 0.91 | 0.55 | 1.51 |
| ≥16 weeks | 55 | 0.12 | 0.02 | 0.91 |
*HR in bold are statistically significant at p<0.05
Conclusions
A substantial proportion of eNSCLC patients did not receive adjuvant Tx despite standard of care guidelines and real-world OS remains poor, suggesting an unmet need for improved systemic Tx in the adjuvant setting. Survival outcomes might be impacted by defining an optimal time window for adjuvant Tx initiation for each individual patient.
Clinical trial identification
Editorial acknowledgement
Legal entity responsible for the study
Genentech, Inc.
Funding
Genentech, Inc.
Disclosure
J.M. Lee: Financial Interests, Personal, Advisory Board: Bristol Myers Squibb; Financial Interests, Personal, Advisory Board: AstraZeneca; Financial Interests, Personal, Advisory Board: Novartis; Financial Interests, Personal, Advisory Board: Genentech; Financial Interests, Personal, Leadership Role: Genentech; Financial Interests, Personal, Leadership Role: Novartis. R. Wang: Financial Interests, Institutional, Full or part-time Employment: Genentech; Financial Interests, Institutional, Stocks/Shares: Genentech. A. Johnson: Financial Interests, Personal, Full or part-time Employment: Genentech. S. Ogale: Financial Interests, Personal, Full or part-time Employment: Genentech; Financial Interests, Personal, Stocks/Shares: Genentech. M. Kent: Financial Interests, Personal, Full or part-time Employment: Genentech. J. Lee: Financial Interests, Institutional, Full or part-time Employment: Genentech; Financial Interests, Institutional, Stocks/Shares: Genentech.