Conditioned overconsumption is dependent on reinforcer type in lean, but not obese, mice

Associative learning can drive many different types of behaviors, including food consumption. Previous studies have shown that cues paired with food delivery while mice are hungry will lead to increased consumption in the presence of those cues at later times. We previously showed that overconsumption can be driven in male mice by contextual cues, using chow pellets. Here we extended our findings by examining other parameters that may influence the outcome of context-conditioned overconsumption training. We found that the task worked equally well in males and females, and that palatable substances such as high-fat diet and Ensure chocolate milkshake supported learning and induced overconsumption. Surprisingly, mice did not overconsume when sucrose was used as the reinforcer during training, suggesting that nutritional content is a critical factor. Interestingly, we also observed that diet-induced obese mice did not learn the task. Overall, we find that context-conditioned overconsumption can be studied in lean male and female mice, and with multiple reinforcer types.

Conditioned overconsumption is dependent on reinforcer type in lean, but not obese, mice

Associative learning can drive many different types of behaviors, including food consumption. Previous studies have shown that cues paired with food delivery while mice are hungry will lead increased consumption in the presence of those cues at later times. We previously showed that overconsumption can be driven in male mice by contextual cues, using chow pellets. Here we extended our findings by examining other parameters that may influence the outcome of context-conditioned overconsumption training. We found that the task worked equally well in males and females, and that palatable substances such as high-fat diet and Ensure chocolate milkshake supported learning and induced overconsumption. Surprisingly, mice did not overconsume when sucrose was used as the reinforcer during training, suggesting that nutritional content is a critical factor. Interestingly, we also observed that diet-induced obese mice did not learn the task. Overall, we find that context-conditioned overconsumption can be studied in lean males and female mice, and with multiple reinforcer types.

A Large National Study on Racial Disparities among Asian American, Native Hawaiian, and Other Pacific Islander Cancer Patients Who Refuse Radiation Therapy and Surgery

PURPOSE/OBJECTIVE(S)

Asian Americans (AAs) are the only race for whom cancer is the leading cause of death in the US. Despite radiation therapy (RT) and surgery being curative treatments, prior work demonstrated AAs refuse RT/surgery at a higher rate than other races. Given AAs are often aggregated with Native Hawaiians and other Pacific Islanders (NHPIs), rates of RT/surgery refusal within this community are poorly understood. We aimed to 1) assess RT/surgery refusal on overall survival (OS) using propensity-score (PS) matched groups, 2) identify AA and NHPI populations that refuse RT/surgery and 3) determine predictors of refusing RT/surgery.

MATERIALS/METHODS

A US hospital-based retrospective cohort study of the National Cancer Database was conducted. Patients included were ≥18 years old, AA by ethnogeographic region (South AA, East AA, and Southeast AA) or NHPI race, with a confirmed diagnosis of 1 of the 10 most common US cancers during 2004-2017 who were recommended for RT/surgery. Cox proportional hazard models with adjusted Hazard Ratios (aHR) assessed propensity-score matched groups (1:10) based on age, race, cancer stage, comorbidity index, rurality, facility type, facility location, and year of diagnosis. Adjusted odds ratios (aOR) were calculated and 95% confidence intervals (95% CI) for treatment refusal using logistic regression. Population heterogeneity for treatment refusal by race was assessed with likelihood ratio tests (p-heterogeneity).

RESULTS

The cohort of 147,685 patients who met the inclusion criteria were predominantly East AA (43%), diagnosed with breast cancer (42%), and had a <2 comorbidity index (99%). Median age was 61 years. Median follow-up was 58 months. Overall, 2,888 (5%) patients refused RT, and 1,073 (1%) refused surgery. RT refusal by race was 5.7% (East AA), 7.9% (NHPI), 4.6% (South AA), and 4.6% (Southeast AA). Surgery refusal rates were 1.5% (East AA), 1.9% (NHPI), 1.1% (South AA) and 1.2% (Southeast AA). RT refusal significantly predicted poorer OS (aHR = 1.15, 95% CI = 1.06-1.25) whereas surgery refusal did not. Compared to East AA, NHPIs had a higher risk of RT refusal (aOR = 1.44, 95% CI = 1.27-1.62), whereas South AA (aOR = 0.85, 95% CI = 0.75-0.95) and Southeast AA (aOR = 0.82, 95% CI = 0.75-0.90) had a significantly lower risk (p-heterogeneity<.0001). Predictors of RT refusal were older patient age, high comorbidity index, oral cavity cancer, urban-rural residence, Midwest or West US region, and diagnosis 2011-2017.

CONCLUSION

Among AA and NHPI patients with cancers in the US, RT refusal predicted poorer OS. NHPI had the highest risk of RT refusal. Given AA and NHPI are not monolithic groups, data disaggregation is necessary to understand racial/ethnic disparities for treatment refusal. Sociocultural and historical contexts of AA and NHPI populations on treatment refusal are necessary to improve cancer outcomes among these populations.

Racial Disparities in Brachytherapy Treatment among Women with Cervical and Endometrial Cancers: A United States Cohort Study between 2004 and 2017

PURPOSE/OBJECTIVE(S)

Brachytherapy (BT) improves clinical outcomes among women with cervical and endometrial cancers. Recent trends found decreasing BT rates in the United States; however, racial/ethnic differences have not been investigated completely. Here we aim to analyze 1) variations in BT practice patterns, 2) racial differences of BT, and 3) predictors of BT by race among women with cervical and endometrial cancers in the United States.

MATERIALS/METHODS

A retrospective cohort of women with endometrial and cervical cancers in the US was evaluated using the National Cancer Database, between 2004 and 2017. Primary endpoint was treatment with BT. Women ≥18 years of age were included for FIGO Stage IA-IVA, non-surgically treated cervical cancers and high intermediate risk (PORTEC-2 and GOG-99 definition) or FIGO Stage II-IVA endometrial cancers. Racial groups were in accordance with federal guidelines including Asian, American Indian and Alaska Native (AIAN), Black, Native Hawaiian and other Pacific Islander (NHPI), and White. BT practice patterns and trends over time were evaluated by race. To identify predictors of BT by race, logistic regression calculated adjusted odds ratios (aOR) and 95% confidence intervals (95% CI) after assessing for multicollinearity.

RESULTS

A total of 13,857 women with cervical cancer and 140,942 women with endometrial cancer were included. Median follow-up was 69 months. Median (IQR) age was 53 (43-63) years for cervical cancer and 64 (57-72) years for endometrial cancer. Most cervical cancers were Stage III (44%), squamous cell carcinoma (88%), and lymphovascular space invasion (LVSI) positive (49%). Most endometrial cancers were Stage IB (45%), endometrioid histology (82%), and LVSI-positive (50%). Between 2004 and 2017, endometrial cancer BT increased (34% to 57%). BT rates for cervical cancer ranged from 65% NHPI, 63% Asian, 62% White, 59% AIAN, and 57% Black. BT rates for endometrial cancer ranged from 26% Black, 25% White, 25% Asian, 21% AIAN, and 20% NHPI. By race, only Black women with cervical cancer were significantly less likely to receive BT (aOR = 0.8; 95% CI = 0.7-0.9), compared to White women. Only NHPI women with endometrial cancer were less likely to receive BT (aOR = 0.7; 95% CI = 0.5-1.0), compared to White women. Community cancer center treatment was the only factor associated with a decreased odds of BT for both Black women with cervical cancer (aOR = 0.7; 95% CI = 0.6-0.9) and NHPI women with endometrial cancer (aOR = 0.3; 95% CI = 0.1-0.8), compared to academic centers.

CONCLUSION

In this study of women diagnosed with endometrial and cervical cancers with stages known to benefit from BT, NHPI women with endometrial cancer and Black women with cervical cancer were less likely to receive brachytherapy compared to White women. Community engagement is needed to increase BT access for patients treated at community cancer centers to ensure equitable gynecologic cancer care.