Smoking cessation reduces risk for kidney cancer progression, mortality
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Key takeaways:
- Patients who quit smoking had a 50% lower risk for death and a 56% lower risk for disease progression.
- Researchers observed the beneficial effects of quitting smoking across all patient subgroups.
Patients with primary renal cell carcinoma who quit smoking after diagnosis had a 50% lower risk for death than those who continued to smoke, according to study results published in Journal of Clinical Oncology.
Quitting smoking resulted in a 56% lower risk for disease progression compared with continuing smoking, researchers noted.
Rationale and methodology
Smoking is a well-known risk factor for kidney cancer, and current evidence suggests that quitting smoking can significantly reduce an individual’s risk for developing the disease, Mahdi Sheikh, MD, PhD, researcher in the genomic epidemiology branch of the International Agency for Research on Cancer in Lyon, France, told Healio.
“However, limited evidence was available on whether quitting smoking after a kidney cancer diagnosis can still be beneficial,” Sheikh said. “With more than 400,000 people diagnosed with kidney cancer annually, of whom 15% to 20% still smoke at the time of diagnosis, it is concerning that many patients do not receive any support, assistance or encouragement to quit smoking. Therefore, we believed it was crucial to investigate the effects of quitting smoking among these patients and evaluate whether quitting smoking could affect the risk for death and cancer progression among patients with kidney cancer who smoke.”
Sheikh and colleagues recruited 212 current smokers diagnosed with primary renal cell carcinoma between 2007 and 2016 from the urological department at N.N. Blokhin National Medical Research Center of Oncology in Moscow.
They administered structured questionnaires upon enrollment and followed patients annually through 2020 to repeatedly assess smoking status and disease progression.
Researchers used Kaplan-Meier method, time-dependent Cox proportional hazards regression and Fine-Gray competing-risk models to assess survival probabilities and hazards for all-cause and cancer-specific mortality and disease progression.
Median follow-up was 8.2 years.
Findings
Approximately 40% of patients quit smoking after diagnosis, and 56% of them quit before receiving their first treatment.
Researchers observed 110 cases of disease progression, 100 total deaths and 77 cancer-specific deaths within the cohort.
The total person-years at risk were 748.2 for the continuing smoking period vs. 611.2 for the quitting smoking period. Researchers reported higher rates of both OS (85% vs. 61%; P < .001) and PFS (80% vs. 57%; P < .001) at 5-year follow-up during the quitting smoking vs. continuing smoking period.
Results of multivariable time-dependent models showed associations of quitting smoking with lower risk for all-cause mortality (HR = 0.51; 95% CI, 0.31-0.85), disease progression (HR = 0.45; 95% CI, 0.29-0.71) and cancer-specific mortality (HR = 0.54; 95% CI, 0.31-0.93).
Researchers observed the benefits of quitting smoking across all subgroups, including light vs. moderate-heavy smokers and those with early-stage vs. late-stage tumors.
Implications
Patients with cancer who smoke should be encouraged to quit smoking at any time and at each visit after diagnosis, regardless of their tumor stage, treatment status or smoking intensity, Sheikh told Healio.
“The study’s results underscore the need for collaborative efforts at various policymaking and health care levels to promote and implement smoking cessation programs in cancer care settings,” he said. “We hope that these findings will encourage clinicians to discuss the benefits of smoking cessation with their patients, provide support to patients in their efforts to quit smoking and motivate patients to quit smoking after a cancer diagnosis.”
Future research should examine the effects of implementing smoking treatment as a component of cancer care and management of patients with cancer who smoke, Sheikh added.
“We did not intervene in the routine management, monitoring or treatment process for these patients,” he said. “We need interventional studies to compare the survival and disease progression of patients who receive usual cancer care vs. patients who receive smoking treatment and cessation support in addition to usual cancer care. Additionally, we need studies to assess whether there are differences in the effects of available options for treating smoking cessation on patient survival and tumor progression. Finally, we need to understand the biological mechanisms by which quitting smoking affects the survival of patients with cancer through molecular, genomic and experimental studies. Further research is also necessary to gain a better understanding of the benefits of smoking cessation among patients with kidney cancer who smoke.”
For more information:
Mahdi Sheikh, MD, PhD, can be reached at sheikhm@iarc.who.int.
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