Adjuvant chemotherapy for non-small-cell lung cancer in the elderly: a population-based study in Ontario, Canada

Purpose — Non-small-cell lung cancer (NSCLC) is predominantly a disease of the elderly. Retrospective analyses of the National Cancer Institute of Canada Clinical Trials Group JBR.10 trial and the Lung Adjuvant Cisplatin Evaluation (LACE) meta-analysis suggest that the elderly benefit from adjuvant chemotherapy. However, the elderly were under-represented in these studies, raising concerns regarding the reproducibility of the study results in clinical practice.

Patients and Methods — By using the Ontario Cancer Registry, we identified 6,304 patients with NSCLC who were treated with surgical resection from 2001 to 2006. Registry data were linked to electronic treatment records. Uptake of chemotherapy was compared across age groups: younger than 70, 70 to 74, 75 to 79, and ≥ 80 years. As a proxy of survival benefit from chemotherapy, we compared survival of patients diagnosed from 2004 to 2006 with survival of those diagnosed from 2001 to 2003. Hospitalization rates within 6 to 24 weeks of surgery served as a proxy of severe chemotherapy-related toxicity.

Results — In all, 2,763 (43.8%) of 6,304 surgical patients were elderly (age ≥ 70 years). Uptake of adjuvant chemotherapy in the elderly increased from 3.3% (2001 to 2003) to 16.2% (2004 to 2006). Among evaluable elderly patients, 70% received cisplatin and 28% received carboplatin-based regimens. Requirements for dose adjustments or drug substitutions were similar across age groups. Hospitalization rates within 6 to 24 weeks of surgery were similar across age groups (28.0% for patients age < 70 years; 27.8% for patients age ≥ 70 years; P = .54). Four-year survival of elderly patients increased significantly (47.1% for patients diagnosed from 2001 to 2003; 49.9% for patients diagnosed from 2004 to 2006; P = .01). Survival improved in all subgroups except patients age ≥ 80 years.

Conclusion — Uptake of adjuvant chemotherapy for NSCLC increased in patients age 70 years or older following reporting of pivotal adjuvant chemotherapy trials, but it remained below that for patients younger than age 70 years. Adoption of adjuvant chemotherapy appears to be associated with significant survival benefit in the elderly (age ≥ 70 years), with tolerability apparently similar to that of patients who are younger than age 70 years.