Smoking may modify the association between neoadjuvant chemotherapy and survival from ovarian cancer

Objective: Tobacco smoking by cancer patients is associated with increased mortality. Less is known of the impact of smoking on recurrence risk and interaction with chemotherapy treatment. We examined these associations in ovarian cancer.

Methods: Patients were identified from the Alberta Cancer Registry between 1978 and 2010 and were oversampled for less-common histologic ovarian tumor types. Medical records were abstracted for 678 eligible patients on lifestyle, medical and cancer treatment, and review of pathology slides was performed for 605 patients. We estimated hazard ratios (HR) and 95% confidence intervals (CI) using Cox proportional hazard models adjusted for age at diagnosis, race, stage and residual disease.

Results: Among patients receiving adjuvant chemotherapy (N=432), current smoking was significantly associated with shorter duration of overall (OS; HR, 8.56; 95% CI, 1.50-48.7) and progression-free (PFS; HR, 5.74; 95% CI, 1.05-31.4) survival from mucinous ovarian cancer only. There was no significant association between neoadjuvant chemotherapy and survival. However, among patients receiving neoadjuvant chemotherapy (N=44), current smokers had shorter PFS (HR, 4.32; 95% CI, 1.36-13.8; N=32 progressed/9 censored events) compared to never smokers, but the HRs were not statistically different across smoking categories (P interaction=0.87).

Conclusions: Adverse associations were observed between smoking status and OS or PFS among patients with mucinous ovarian cancer receiving adjuvant chemotherapy. No significant effect was found from neoadjuvant chemotherapy on PFS overall; however, smoking may modify this association. Although needing replication, these findings suggest that patients may benefit from smoking cessation interventions prior to treatment with chemotherapy.