Use of endocrine therapy for estrogen receptor-positive breast cancer among American Indians and Alaska natives

BACKGROUND

American Indian/Alaska Native (AI/AN) women with estrogen receptor-positive (ER +) breast cancer have higher mortality compared to non-Hispanic whites (NHW). The purpose of this study is to compare rates of initiation of endocrine therapy (ET) between AI/AN and NHW and further determine survival outcomes for ER + breast cancer.

METHODS

We used the National Cancer Database to identify patients diagnosed with ER + breast cancer, stage I-III, between 2004 and 2017. Multivariable logistic regression was performed to determine factors associated with initiation of adjuvant ET. Overall survival was estimated using the Kaplan-Meier analysis and Cox proportional hazards modeling.

RESULTS

We identified a total of 771,619 patients (AI/AN, n = 2473; NHW, n = 769,146). Compared to NHW, AI/AN patients were more likely to live in rural areas, be younger, and have tumors that were higher grade, node positive, and larger. Initiation of adjuvant ET was high in both groups and not significantly different between AI/AN and NHW. Independent predictors of ET initiation included rural location, age, higher tumor grade, node-positive disease, larger tumor size, and progesterone receptor-positive status. Initiation of ET was significantly associated with improved overall survival among all patients. Overall survival was significantly worse among the AI/AN population.

CONCLUSION

AI/AN race was significantly and independently associated with worse overall survival after diagnosis of ER + breast cancer. We did not find a significant difference in the initiation of adjuvant ET between AI/AN and NHW. Exact reasons why AI/AN women with ER + breast cancer have higher mortality rates remain elusive but are probably multifactorial.

Impact of Low-dose Chest CT Screening on the Association Between Rurality and Lung Cancer Outcomes

INTRODUCTION

Lung cancer mortality is higher among rural United States populations compared with nonrural ones. Little is known about screening low-dose chest computed tomography (LDCT) outcomes in rural settings.

MATERIALS AND METHODS

This retrospective cohort study examined all patients (n=1805) who underwent screening LDCT in a prospective registry from March 1, 2015, through December 31, 2019, in a majority-rural health care system. We assessed the proportion of early-stage lung cancers (American Joint Committee on Cancer stage I-II) diagnosed among LDCT-screened patients, and analyzed overall survival after early-stage lung cancer diagnosis according to residency location.

RESULTS

The screening cohort had a median age of 63 and median 40-pack-year smoking history; 62.4% had a rural residence, 51.2% were female, and 62.7% completed only 1 LDCT scan. Thirty-eight patients were diagnosed with lung cancer (2.1% of the cohort), of which 65.8% were early-stage. On multivariable analysis, rural (vs nonrural) residency was not associated with a lung cancer diagnosis (adjusted hazard ratio 1.59; 95% CI, 0.74-3.40; P =0.24). At a median follow-up of 37.1 months (range, 3.3 to 67.2 months), 88.2% of rural versus 87.5% of nonrural patients with screen-diagnosed early-stage lung cancer were alive ( P =0.93).

CONCLUSIONS

In a majority-rural United States population undergoing LDCT, most screen-detected lung cancers were early-stage. There were no significant differences observed between rural and nonrural patients in lung cancer diagnosis rate or early-stage lung cancer survival. Increased implementation of LDCT might blunt the historical association between rural United States populations and worse lung cancer outcomes.