Breast cancer staging by subtype in the Lower Mississippi Delta region States.

INTRODUCTION: To evaluate disparities in breast cancer stage by subtype (categorizations of breast cancer based upon molecular characteristics) in the Delta Regional Authority (Delta), an impoverished region across eight Lower Mississippi Delta Region (LMDR) states with a high proportion of Black residents and high breast cancer mortality rates. METHODS: We used population-based cancer registry data from seven of the eight LMDR states to explore breast cancer staging (early and late) differences by subtype between the Delta and non-Delta in the LMDR and between White and Black women within the Delta. Age-adjusted incidence rates and rate ratios were calculated to examine regional and racial differences. Multilevel negative binomial regression models were constructed to evaluate how individual-level and area-level factors affect rates of early- and late-stage breast cancers by subtype. RESULTS: For all subtypes combined, there were no Delta/non-Delta differences in early and late stage breast cancers. Delta women had lower rates of hormone-receptor (HR+)/human epidermal growth factor 2 (HER2-) and higher rates of HR-/HER2- (the most aggressive subtype) early and late stage cancers, respectively, but these elevated rates were attenuated in multilevel models. Within the Delta, Black women had higher rates of late-stage breast cancer than White women for most subtypes; elevated late-stage rates of all subtypes combined remained in Black women in multilevel analysis (RR = 1.10; 95% CI = 1.04-1.15). CONCLUSIONS: Black women in the Delta had higher rates of late-stage cancers across subtypes. Culturally competent interventions targeting risk-appropriate screening modalities should be scaled up in the Delta to improve early detection.

Disparities in breast cancer subtypes among women in the lower Mississippi Delta Region states.

PURPOSE: To describe and elucidate rates in breast cancer incidence by subtype in the federally designated Mississippi Delta Region, an impoverished region across eight Southern/Midwest states with a high proportion of Black residents and notable breast cancer mortality disparities. METHODS: Cancer registry data from seven LMDR states (Missouri was not included because of permission issues) were used to explore breast cancer incidence differences by subtype between the LMDR's Delta and non-Delta Regions and between White and Black women within the Delta Region (2012-2014). Overall and subtype-specific age-adjusted incidence rates and rate ratios were calculated. Multilevel negative binomial regression models were used to evaluate how individual-level and area-level factors, like race/ethnicity and poverty level, respectively, affect rates of breast cancers by subtype. RESULTS: Women in the Delta Region had higher rates of triple-negative breast cancer, the most aggressive subtype, than women in the non-Delta (17.0 vs. 14.4 per 100,000), but the elevated rate was attenuated to non-statistical significance in multivariable analysis. Urban Delta women also had higher rates of triple-negative breast cancer than non-Delta urban women, which remained in multivariable analysis. In the Delta Region, Black women had higher overall breast cancer rates than their White counterparts, which remained in multivariable analysis. CONCLUSION: Higher rates of triple-negative breast cancer in the Delta Region may help explain the Region's mortality disparity. Further, an important area of future research is to determine what unaccounted for individual-level or social area-level factors contribute to the elevated breast cancer incidence rate among Black women in the Delta Region.

Spatial Accessibility to Mammography Services in the Lower Mississippi Delta Region States.

PURPOSE: To characterize spatial access to mammography services across 8 Lower Mississippi Delta Region (LMDR) states. These states include the Delta Region, a federally designated, largely rural, and impoverished region with a high proportion of black residents and low mammography utilization rates. METHODS: Using the enhanced 2-step floating catchment area method, we calculated spatial accessibility scores for mammography services across LMDR census tracts. We compared accessibility scores between the Delta and non-Delta Regions of the LMDR. We also performed hotspot analysis and constructed spatial lag models to detect clusters of low spatial access and to identify sociodemographic factors associated with access, respectively. We obtained mammography facility locations data from the Food and Drug Administration and sociodemographic variables from the American Community Survey and the US Department of Agriculture. RESULTS: Overall, there were no differences in spatial accessibility scores between the Delta and non-Delta Regions, though there was some state-to-state variation. Clusters of low spatial access were found in parts of the Arkansas, Mississippi, and Tennessee Delta. Spatial lag models found that poverty was associated with greater spatial access to mammography. CONCLUSIONS: The lack of identified differences in spatial access to mammography in the Delta and non-Delta Regions suggests that psychosocial or financial barriers play a larger role in lower mammography utilization rates. Identifying clusters of low spatial access to mammography services can help inform resource allocation. Further, our study underscores the value of using coverage-based methods rather than travel time or container measures to evaluate spatial access to care.

Case-control study of cervical cancer and gynecologic screening: A SEER-Medicare analysis.

OBJECTIVE: To determine the association between Pap smear and pelvic examination screenings and the development of invasive cervical cancer in a Medicare population using a matched case-control design. METHODS: Matched case-control data sets were constructed from the SEER-Medicare database that links the Surveillance Epidemiology End Results (SEER) cancer registry data and Medicare enrollment and claims data of subjects who received care between the years 1991 and 1999 aged 65years or older. The study identified 1267 cervical cancer cases. Controls (N=10.137) were matched to cases representing up to eight matched controls (on age and registry geographic location) for a single case. The association between gynecologic screenings and the development of invasive cervical cancer was ascertained using conditional logistic regression analysis. RESULTS: Having had a Pap smear during the PIDP (pre-invasive detectable phase - 2 to 7years prior to diagnosis) was significantly negatively associated with the development of invasive cervical cancer (OR=0.64, 95% CI=0.53-0.78) which was reduced after taking into account the estimated prevalence of hysterectomy among controls (OR=0.38, 95% CI=0.32-0.46). The negative association between Pap smear screenings and cervical cancer was strongest for squamous tumors (OR=0.48, 95% CI=0.37-0.61). Restricting the subjects to those 72 and over did not affect risk. CONCLUSIONS: There is a reduction in risk for invasive cervical cancer when women over age 65 are screened. This suggests that cervical cancer screening in the aged population may be beneficial.

Breast cancer among women in Michigan following exposure to brominated flame retardants.

In this updated follow-up, we investigated the breast cancer experience among women in Michigan exposed to brominated flame retardants, some 30 years following exposure. Michigan residents were enrolled in a study cohort after exposure to polybrominated biphenyls (PBBs) through the consumption of contaminated food products. PBB concentrations were measured in serum at the time of enrolment. Cancer experience was determined by linkage to the Michigan Cancer Registry. We conducted a nested case-control study that included 51 women diagnosed with breast cancer during 1974-2004 and 202 age-matched controls. While the data suggest an increase in breast cancer risk with higher PBB exposure, this did not reach statistical significance. The OR of having breast cancer among women with PBB concentrations ≥10 ng/mL compared to women with PBB concentrations at or below the limit of detection of 1 ng/mL was 2.60, 95% CI 0.93 to 7.27, (p=0.07), when adjusted for age and family history of cancer in a first-degree female relative. It remains important to examine exposure to brominated chemicals and possible health effects, and to continue following the cancer experience of participants in this study.

Reproductive factors and risk of lung cancer in female textile workers in Shanghai, China.

PURPOSE: Hormonal factors may play a role in the development of lung cancer in women. This study examined the relationship between lung cancer and reproductive factors in a large cohort of women, most of whom never smoked (97%). METHODS: A cohort of 267,400 female textile workers in Shanghai, China, enrolled in a trial of breast self-examination provided information on reproductive history, demographical factors, and cigarette smoking at enrollment in 1989-91. The cohort was followed until July of 2000 for incidence of lung cancer; 824 cases were identified. Hazard ratios (HR) and 95% confidence intervals (CI) associated with selected reproductive factors were calculated using Cox proportional hazards modeling, adjusting for smoking, age, and also parity when relevant. RESULTS: Nulliparous women were at increased risk compared to parous women (HR = 1.33, 95% CI 1.00-1.77). Women who had gone through menopause at baseline were at increased risk compared to women of the same age who were still menstruating. Risk was higher in women with a surgical menopause (HR = 1.64, 95% CI 0.96-2.79) than in those with a natural menopause (HR = 1.35, 95% CI 0.84-2.18), and risk was highest in those postmenopausal women with a hysterectomy and bilateral oophorectomy at baseline (HR = 1.39, 95% CI 0.96-2.00), although the risk estimates were not statistically significant. CONCLUSIONS: These results support experimental data that demonstrate a biological role for hormones in lung carcinogenesis.

Genital powder exposure and the risk of epithelial ovarian cancer.

BACKGROUND: We conducted a population-based, case-control study to examine the association between the use of genital powder and ovarian cancer risk, including measures of extent and timing of exposure. We also assessed the relationship of powder use with risk of disease subtypes according to histology and degree of malignancy. METHODS: Information was collected during in-person interviews with 812 women with epithelial ovarian cancer diagnosed in western Washington State from 2002 to 2005 and 1,313 controls. Logistic regression was used to calculate odds ratios (ORs) and 95% confidence intervals (CIs). RESULTS: Overall, the perineal use of powder after bathing was associated with a slightly increased ovarian cancer risk (OR = 1.27, 95% CI: 0.97-1.66), which was most evident among women with borderline tumors (OR = 1.55, 95% CI: 1.02-2.37). We noted no clear pattern of risk increase on the basis of the extent of use, assessed as years in which powder was used, or as lifetime number of applications for invasive or borderline tumors, or their histologic subtypes. There was no alteration in the risk of ovarian cancer associated with other types of powder exposure (e.g., on sanitary napkins or diaphragms). CONCLUSIONS: The International Agency for Research on Cancer has designated perineal exposure to talc (via the application of genital powders) as a possible carcinogen in women. A modest association of ovarian cancer with this exposure was seen in our study and in some previous ones, but that association generally has not been consistent within or among studies. Therefore, no stronger adjective than "possible" appears warranted at this time.

Oral contraceptives and the risk of all cancers combined and site-specific cancers in Shanghai.

From 1998 to 1991, an in-person baseline interview was administered to approximately 267,400 female textile workers in Shanghai, China. The cohort was followed until July 2000 for incident cancer cases. Incidence rate ratios (RR) for 12 types of cancers in users of oral contraceptives (OCs) were calculated using Cox Proportional Hazards analysis. There was a reduced risk of uterine corpus cancer for women who had ever used OCs (RR = 0.68, 95% CI = 0.45-1.04) and a trend of decreasing risk with increasing duration of use (p = 0.015). There was an increased risk of colon cancer in women who had used OCs for 10 years or more (RR = 1.56, 95% CI = 1.01-2.40) and an increased risk of rectal cancer in women who had ever used OCs (RR = 1.31, 95% CI = 0.98-1.75), with a trend of increasing risk with increasing duration of use (p = 0.017), but these associations may have been due to uncontrolled confounding by physical activity or other non-causal factors. No associations were observed between OCs and the risk of all cancers combined or for any of the nine other cancers. It is unlikely that the use of OCs has contributed to the temporal trends in cancer incidence in China in recent decades.

Monthly injectable contraceptives and the risk of all cancers combined and site-specific cancers in Shanghai.

PURPOSE: The risk of 12 types of cancer in relation to use of monthly injectable contraceptives was assessed in a prospective study in Shanghai, China. METHODS: From 1989 to 1991, an in-person interview was administered to 267,400 female textile workers to ascertain information on risk factors for breast cancer, contraceptive use and induced abortions. The cohort was followed until July 2000 for incident cancer cases. Cox proportional hazards analysis was used to calculate incidence rate ratios for specific types of cancer in women who ever had used monthly injectable contraceptives and by length of use. RESULTS: There was a reduced risk of uterine corpus cancer for women who had ever used monthly injectable contraceptives. No association was observed between the use of monthly injectable contraceptives and the risk of all cancers combined and for any of the 11 other cancers considered. CONCLUSION: There appears to be no evidence of an increased risk of cancer after exposure to monthly injectable contraceptives in our study.

Induced abortions and the risk of all cancers combined and site-specific cancers in Shanghai.

Although some previous case-control studies found an increased risk of breast cancer in women who had an induced abortion, the evidence from prospective studies suggests that induced abortions do not cause breast cancer. We have assessed risks of 12 types of cancer in women who have had induced abortions in a prospective study in China. Female textile workers (n = 267,400) completed a baseline questionnaire (1989-1991) that ascertained information on the major risk factors for breast cancer, contraceptive use, and induced abortions and were actively followed until July 2000. Cox Proportional Hazards analysis was used to calculate incidence rate ratios for specific types of cancer in women who ever had an induced abortion and by number of induced abortions. Women who had had an abortion were not at increased risk of cancer. There was a significant reduction in risk of uterine corpus cancer in women who had ever had an induced abortion, and a significant decreasing trend in risk with increasing number of induced abortions. No convincing associations with other cancers were observed. Women who have induced abortions after a live birth are not at increased risk of cancer and induced abortions may reduce risk of cancer of the corpus uteri.

Marijuana use and risk of oral squamous cell carcinoma.

Previous laboratory investigations, case reports, and a hospital-based case-control study have suggested that marijuana use may be a risk factor for squamous cell head and neck cancer. We conducted a population-based case-control study to determine whether marijuana use is associated with the development of oral squamous cell carcinoma (OSCC). Case subjects (n = 407) were 18-65-year-old residents of three counties in western Washington State who were newly diagnosed with OSCC from 1985 through 1995. Control subjects (n = 615), who were similar to the cases with respect to age and sex, were selected from the general population using random-digit telephone dialing. Lifetime histories of marijuana use and exposure to known OSCC risk factors were ascertained using a structured questionnaire. Information on genetic polymorphisms in glutathione S-transferase enzymes was obtained from assays on participant DNA. Odds ratios for associations with features of marijuana use were adjusted for sex, education, birth year, alcohol consumption, and cigarette smoking. A similar proportion of case subjects (25.6%) and control subjects (24.4%) reported ever use of marijuana (adjusted odds ratio, 0.9; 95% confidence interval, 0.6-1.3). There were no trends in risk observed with increasing duration or average frequency of use or time since first or last use. No subgroup defined by known or suspected OSCC risk factors (age, cigarette smoking, alcohol consumption, and genetic polymorphisms) showed an increased risk. Marijuana use was not associated with OSCC risk in this large, population-based study.

Serologic evidence of human papillomavirus 16 and 18 infections and risk of prostate cancer.

Human papillomavirus (HPV) subtypes 16 and 18 are sexually transmitted and have been associated with an increased incidence of several anogenital tumors. Although previous epidemiological studies have suggested that sexual behaviors such as an early age at first intercourse and larger numbers of sexual partners are also related to an increased risk of prostate cancer, seroepidemiological studies of these infectious agents in relation to prostate cancer have produced differing results. To further evaluate this potential relationship, we completed a population-based control study in King County, Washington. Middle-aged (40-64 years) men diagnosed with prostate cancer (n = 642) were ascertained through the Seattle-Puget Sound Surveillance, Epidemiology, and End Results cancer registry between January 1993 and December 1996. Controls (n = 570) of similar age were selected from the same population as the cases by random digit dialing. Overall, there was no association between serological evidence of prior HPV-16 (adjusted odds ratio, 1.06; 95% confidence interval, 0.71-1.57) or HPV-18 (adjusted odds ratio, 1.36; 95% confidence interval, 0.69-2.69) infection and the risk of prostate cancer. Analyses of clinical features demonstrated no relationship between HPV infection status and Gleason score, stage of disease, or a combined measure of disease aggressiveness. Our findings indicate that HPV-16 and HPV-18 are not associated with prostate cancer risk.

Endometrial cancer in Asian migrants to the United States and their descendants.

OBJECTIVE: The purpose of this study was to determine the extent to which the incidence of endometrial cancer in Chinese, Japanese, and Filipino residents of the United States varies according to country of birth. METHODS: Women 35-74 years diagnosed with endometrial cancer between 1973 and 1986 among residents of the San Francisco/Oakland (CA) metropolitan area, 13 counties of western Washington, and the state of Hawaii were identified by cancer registries serving these populations. From a special tabulation of the 1980 US census, we estimated the size of the population at risk in each of these three areas according to age, race, and country of birth. RESULTS: The annual incidence of primary endometrial cancer was lower among Chinese-American (42.6/100,000) and Japanese-American (25.3/100,000) women born in Asia than among their counterparts who were born in the United States (57.2/100,000 and 51.2/100,000, respectively). No difference in incidence was observed between Filipino women born in Asia (27.4/100,000) and those born in the United States (25.4/100,000). The rate of endometrial cancer among US-born white women (77.0/100,000 women years) exceeded that in any of these Asian-American subgroups. CONCLUSIONS: These findings suggest that some clues to the aetiologies of endometrial cancer may be found in exposures whose prevalence differs between generations of Chinese and Japanese Americans.