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Background: We aimed to estimate the effects of smoking cessation on survival among people diagnosed with cancer. Methods: We used data from a Comprehensive Community Cancer Program that is part of a large urban safety-net hospital system. Eligible patients were diagnosed with primary invasive solid tumors between 2013 and 2015, and were current smokers at time of diagnosis. Our exposure of interest was initiation of smoking cessation within 6 months of cancer diagnosis. We estimated inverse probability weighted restricted mean survival time (RMST) differences and risk ratio (RR) for all cause 3-year mortality. Results: Our study population comprised 369 patients, of whom 42% were aged < 55 years, 59% were male, 44% were racial/ethnic minorities, and 59% were uninsured. The 3-year RMST was 1.8 (95% CL: − 1.5, 5.1) months longer for individuals who initiated smoking cessation within 6 months of cancer diagnosis. The point estimate for risk of 3-year mortality was lower for initiation of smoking cessation within 6 months of diagnosis compared with no initiation within 6 months (RR = 0.72, 95% CL: 0.37, 1.4). Conclusions: Our point estimates suggest longer 3-year survival, but the results are compatible with 1.5 month shorter or 5.1 longer 3-year overall survival after smoking cessation within 6 months of cancer diagnosis. Future studies with larger sample sizes that test the comparative effectiveness of different smoking cessation strategies are needed for more detailed evidence to inform decision-making about the effect of smoking cessation on survival among cancer patients. Implications for Cancer survivors: The benefits of smoking cessation after cancer diagnosis may include longer survival, but the magnitude of benefit is unclear.

Background Prior studies reported survival benefits from early initiation of adjuvant chemotherapy for stage III colon cancer, but this evidence was derived from studies that may be sensitive to time-related biases. Therefore, we aimed to estimate the effect of initiating adjuvant chemotherapy ≤8 or ≤ 12 weeks on overall and disease-free survival among stage III colon cancer patients using a study design that helps address time-related biases. Methods We used institutional registry data from JPS Oncology and Infusion Center, a Comprehensive Community Cancer Program. Eligible patients were adults aged < 80 years, diagnosed with first primary stage III colon cancer between 2011 and 2017, and received surgical resection with curative intent. We emulated a target trial with sequential eligibility. We subsequently pooled the trials and estimated risk ratios (RRs) along with 95% confidence limits (CL) for all-cause mortality and recurrence or death at 5-years between initiators and non-initiators of adjuvant chemotherapy ≤8 or ≤ 12 weeks using pseudo-observations and a marginal structural model with stabilized inverse probability of treatment weights. Results Our study population comprised 222 (for assessing initiation ≤8 weeks) and 310 (for assessing initiation ≤12 weeks) observations, of whom the majority were racial/ethnic minorities (64–65%), or uninsured with or without enrollment in our hospital-based medical assistance program (68–71%). Initiation of adjuvant chemotherapy ≤8 weeks of surgical resection did not improve overall survival (RR for all-cause mortality = 1.04, 95% CL: 0.57, 1.92) or disease-free survival (RR for recurrence or death = 1.07, 95% CL: 0.61, 1.88). The results were similar for initiation of adjuvant chemotherapy ≤12 weeks of surgical resection. Conclusions Our results suggest that the overall and disease-free survival benefits of initiating adjuvant chemotherapy ≤8 or ≤ 12 weeks of surgical resection may be overestimated in prior studies, which may be attributable to time-related biases. Nevertheless, our estimates were imprecise and differences in population characteristics are an alternate explanation. Additional studies that address time-related biases are needed to clarify our findings.

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Purpose Evidence of cardiotoxicity risk related to anthracycline or trastuzumab exposure is largely derived from breast cancer cohorts that under-represent socioeconomically marginalized women, who may be at increased risk of cardiotoxicity because of high prevalence of cardiovascular disease risk factors. Therefore, we aimed to estimate cardiotoxicity risk among socioeconomically marginalized breast cancer patients treated with anthracyclines or trastuzumab and describe clinical consequences of cardiotoxicity. Methods We linked electronic health records with institutional registry data from a Comprehensive Community Cancer Program within a safety-net health system. Eligible patients were adult females, diagnosed with first primary invasive breast cancer between 2013 and 2017, and initiated anthracyclines or trastuzumab as part of first-line therapy. We estimated cumulative incidence (risk) of cardiotoxicity with corresponding 95% confidence limits (CL) using the Aalen-Johansen estimator with death as competing risk. Results Our study population comprised 169 women with breast cancer (103 initiated anthracyclines and 66 initiated trastuzumab). Cumulative incidence of cardiotoxicity was 21% (95% CL: 12%, 32%) at one year and 25% (95% CL: 15%, 35%) at three years among women who initiated trastuzumab, whereas cumulative incidence was 3.9% (95% CL: 1.3%, 8.9%) at one year and 5.9% (95% CL: 2.4%, 12%) at three years among women who initiated anthracyclines. More than half of patients with cardiotoxicity experienced interruption of cancer treatment. Conclusion Our findings suggest high risk of cardiotoxicity among socioeconomically marginalized breast cancer patients after initiation of anthracyclines or trastuzumab. Strategies are needed for optimizing cancer treatment effectiveness while minimizing cardiotoxicity in this population.