Active smoking and survival following breast cancer among African American and non-African American women in the Carolina Breast Cancer Study

Abstract

Purpose To examine racial differences in smoking rates at the time of breast cancer diagnosis and subsequent survival among African-American and non-African-American women in the Carolina Breast Cancer Study (Phases I/II), a large population-based North Carolina study. Methods We interviewed 788 African-American and 1,020 Caucasian/non-African-American women diagnosed with invasive breast cancer from 1993–2000, to assess smoking history. After a median follow-up of 13.56 years, we identified 717 deaths using the National Death Index; 427 were breast cancer-related. We used Cox regression to examine associations between self-reported measures of smoking and breast cancer-specific survival within 5 years and up to 18 years after diagnosis conditional on 5-year survival. We examined race and estrogen receptor status as potential modifiers. Results Current (vs never) smoking was not associated with 5-year survival; however, risk of 13-year conditional breast cancer-specific mortality was elevated among women who were current smokers at diagnosis (HR=1.54, 95% CI=1.06–2.25), compared to never smokers. Although smoking rates were similar among African-American (22.0%) and non-African-American (22.1%) women, risk of breast cancer-specific mortality was elevated among African-American (HR=1.69, 95% CI=1.00–2.85), but only weakly elevated among non-African-American (HR=1.22, 95% CI=0.70–2.14) current (vs never) smokers (PInteraction=0.30). Risk of breast cancer-specific mortality was also elevated among current (vs never) smokers diagnosed with ER− (HR=2.58, 95% CI=1.35–4.93), but not ER+ (HR=1.11, 95% CI=0.69–1.78) tumors (PInteraction=0.17). Conclusions Smoking may negatively impact long-term survival following breast cancer. Racial differences in long-term survival, as related to smoking, may be driven by ER status, rather than by differences in smoking patterns.

Alcohol and Tobacco Use in an Ethnically Diverse Sample of Breast Cancer Patients, Including Sea Island African Americans: Implications for Survivorship

“…In our study, 14% of EAs, 14% of non-SIs and 7% of SIs (no significant differences) reported current smoking (occasionally or daily). This is somewhat lower than reported for women in North Carolina with recently diagnosed breast cancer (22% of EAs and AAs), but consistent with their finding of no racial difference in current smoking ( 25 ). In our study sample, EA's were almost twice as likely to have ever smoked compared to the AA groups, suggesting a greater degree of experimentation earlier in life or that many women had quit.…”

“…However, we do not know whether prior smokers had quit smoking earlier in life, or subsequent to their breast cancer diagnosis. Current smoking was more prevalent among younger women and those with less education, consistent with the Carolina Breast Cancer Study ( 25 ). One third to one half of current smokers also consumed alcohol, a double exposure that was nonetheless rare and reported by only seven participants (3–6% by ethnicity), too infrequent to investigate racial/ethnic differences.…”

“…Cigarette smoking may also increase breast cancer mortality among patients who smoke following breast cancer diagnosis and treatment ( 24 ). In North Carolina, Parada et al ( 25 ) reported a 54% elevated hazard rate of 13 year smoking-related conditional breast cancer-specific mortality in the Carolina Breast Cancer Study, particularly among AAs. This mortality may be due to increased metastatic potential of breast cancer cells leading to later disease stage diagnoses ( 26 – 29 ).…”

Relationship between Cigarette Smoking and Cancer Characteristics and Survival among Breast Cancer Patients

“…Additional studies that found an association between BCSS and current smoking had larger sample sizes and follow-up times of >10 years [ 29 , 30 , 31 ]. Data from the Carolina Breast Cancer Study evaluated BCSS in 1808 women and did not detect an association between smoking and BCSS at five years, however, 13-year conditional BCSS was elevated amongst current smokers [ 32 ]. Meta-analysis found that while all-cause mortality was significantly associated with smoking across all time periods, smoking was associated with BCSS only for those with follow-up >10 years [ 26 ].…”

Association of Cigarette Smoking and Alcohol Consumption With Subsequent Mortality Among Black Breast Cancer Survivors in New Jersey

“…On the other hand, 2 studies reported an association of elevated risk of all-cause mortality among current smokers, but only for non-African American women. 8,9 Parada et al 9 reported an association of current smoking and all-cause mortality for current smokers, but only for women who survived at least 5 years after diagnosis; however, when stratified by race, this association was not observed among African American women. This study reported a 69% increased risk of breast cancer-specific mortality for African American women who survived at least 5 years after diagnosis, but not for non-African American women.…”