A novel approach to assessing the effects of smoking on treatment response rate in muscle-invasive bladder cancer.

• DOI: 10.1200/jco.2022.40.16_suppl.e16554
• Publication Date: 2022-06-06T16:23:41Z
• Authors: Jeromy Gotschall; C. Kendall Major; Linda A. Jacobs; Donna A. Pucci; Abigail Blauch; Steven C. Palmer; Ronac Mamtani
• Keywords: 03 medical and health sciences; 0302 clinical medicine; 3. Good health

e16554 Background: Cigarette smoking is the strongest modifiable risk factor for bladder cancer and has been implicated in mechanisms of chemotherapy resistance. Prior studies examining tobacco exposure on chemotherapy response were limited by use of retrospective design and self-report assessment of smoking status, potentially under-estimating the association and risking bias towards the null. Cotinine is the central metabolite of nicotine and can be detected in saliva for up to 4 days after tobacco use. In this prospective cohort study, we tested the association between salivary cotinine level and pathologic response to neoadjuvant chemotherapy, assessed post-chemotherapy at the time of cystectomy, among patients with muscle-invasive bladder cancer (MIBC). Methods: Thirty-one patients with MIBC were prospectively recruited and surveyed on their smoking habits. Salivary cotinine was measured during chemotherapy using NicAlert test strips with cotinine concentration > 10ng/mL indicating active smoking (cotinine = 1) and cotinine concentration < 10ng/mL indicating no evidence of active tobacco use (cotinine = 0). Primary outcome was pathologic response at cystectomy, defined as complete response (pT0) or residual disease (pT1-4 or node+). For patients with prior history of tobacco use, the association between pre-chemotherapy cotinine level and post-chemotherapy response at cystectomy was assessed using a chi-squared test and an odds ratio with a 95% confidence interval (CI) using the Baptista-Pike method. Results: Thirty-one patients had cotinine levels measured during chemotherapy and 25 reported prior history of smoking. Of these 25 patients, 17 patients denied active smoking, 2 of whom had cotinine levels = 1 during chemotherapy. Response to chemotherapy by cotinine level among patients with prior history of tobacco use are shown in table 1. One patient declined cystectomy and was excluded from the analysis. The odds ratio of a complete response at cystectomy for patients with cotinine = 0 vs. cotinine = 1 was 3.86 (95% CI: 0.54-22.05) (p = 0.148). The odds ratio of residual disease with cotinine = 0 vs. cotinine = 1 was 0.26 (95% CI: 0.045-1.86) (p = 0.148). Conclusions: Prior smokers with no evidence of active tobacco use during curative chemotherapy were more than three-times as likely to demonstrate a complete response at the time of cystectomy compared to those with evidence of current tobacco use based on salivary cotinine levels. While this study was limited by a small sample size, it highlights a novel approach to tobacco use monitoring and the importance of continued smoking cessation counseling in patients with bladder cancer even after the diagnosis of cancer is made.[Table: see text]