Aggressiveness of colon carcinoma in blacks and whites. National Cancer Institute Black/White Cancer Survival Study Group

Black patients with colon cancer in the Black/White Cancer Survival Study were found to have a poorer survival than white patients. More advanced-stage disease at diagnosis was the primary determinant, accounting for 60% of the excess mortality. After adjusting for stage, factors such as poverty, other socioeconomic conditions, and treatment did not further explain the remaining survival deficit. This study examined the aggressiveness of colon tumors in blacks and whites to explore its role in the racial survival differences. Tumor characteristics of 703 cases of newly diagnosed invasive colon adenocarcinoma were centrally evaluated by a gastrointestinal pathologist, blinded in regard to the age, race, and sex of the patients. Blacks were less likely to have poorly differentiated (grade 3) tumors [odds ratio (OR), 0.44; 95% confidence interval, 0.22-0.88] and lymphoid reaction (OR, 0.49; 95% confidence interval, 0.26-0.90) when compared with whites. These black/white (B/W) differences remained statistically significant after adjusting for age, sex, metropolitan area, summary stage, socioeconomic status, body mass index, and health care access and utilization. In addition, blacks were less likely to have high-grade (grade 3) nuclear atypia, mitotic activity, and tubule formation, although these ORs did not reach a statistical significance level of 0.05. Similar B/W differences were observed for patients with advanced disease but not with early stage. Comparison by anatomical subsite showed that blacks had statistically significantly better differentiated tumors for cancers of the proximal and transverse colon but not for the distal. No racial differences were found for blood vessel and lymphatic invasion, necrosis, fibrosis, and mucinous type of histology. The findings, therefore, are the opposite of those hypothesized. After adjusting for stage, more aggressive tumor characteristics do not explain the adverse survival differential in blacks. This suggests that there may be racial differences in environmental exposure, and that the intensity and mode of delivery of carcinogen insult as well as host susceptibility may differ by race and anatomical subsite. Future studies should explore the B/W differences in tumor biology using molecular markers that precede the conventional histological parameters evaluated here.

Associations of race/ethnicity, education, and dietary intervention with the validity and reliability of a food frequency questionnaire: the Women's Health Trial Feasibility Study in Minority Populations

This report describes the associations of race/ethnicity and years of education with the validity, reliability, and bias of a self-administered food frequency questionnaire (FFQ) designed to be sensitive to low-fat, regional, and ethnic dietary patterns. Data were from the Women's Health Trial Feasibility Study in Minority Populations, a randomized clinical trial conducted between 1992 and 1994 to test the feasibility of a low-fat dietary intervention that targeted low-income, black, and Hispanic women. Of 1,015 participants eligible for these analyses, 28.1% were black, 16.2% were Hispanic, and 12.3% had not completed high school. The analyses focused on percentage of energy obtained from fat, and used 4-day food records as the criterion instrument. Validity at baseline, defined as the correlation between FFQs and food records, was lower among blacks than among whites (0.26 vs. 0.49; p < 0.001), did not differ between Hispanics and whites, and was lower among women with fewer years of education (0.19, 0.35, 0.49, and 0.42 for <12, 12, 13-15, and > or =16 years of education, respectively; for trend, p < 0.05). Six months after randomization, validity increased in most race/ethnicity and education subgroups, and differences across groups became small and statistically nonsignificant. Validity increased significantly among participants receiving the dietary intervention, while increases among control women were somewhat smaller. Reliability, defined as the correlation between baseline and 6-month measures among controls, was similar across racial/ethnic and educational groups. Bias at baseline, defined as the mean value from the FFQ minus the mean from the food record, was 4.6 percentage points of energy from fat; it was lowest among blacks (p < 0.01) and did not differ by years of education. These results suggest that special protocols which address participant training may be necessary when using self-administered FFQs in minority or poorly educated populations.

Dietary relationships with early onset (under age 45) breast cancer in a case-control study in the United States: influence of chemotherapy treatment

Methodologic investigations have addressed selection and recall bias in case-control studies of diet and breast cancer, whereas the effect of disease progression and medical treatment on estimates of dietary intake has been largely overlooked. In a multicenter, population-based case-control study of breast cancer in the United States, 1,588 newly diagnosed cases and 1,451 controls completed a self-administered food-frequency questionnaire. Initial evaluation suggested increased risk related to high intakes of calories, carbohydrates, fat, and protein. All nutrient associations were diminished after adjustment for calories. Evaluation by stage of disease revealed no relation of calories to risk among women with in situ disease, but elevated risks among women with localized (odds ratio [OR] = 1.33, 95 percent confidence interval [CI] = 1.0-1.7 highest cflowest quartile) or regional and distant disease (OR = 1.79, CI = 1.3-2.4). Further evaluation showed that the increased risk associated with calories was restricted to cases who reported having been treated with chemotherapy (OR = 1.66, CI = 1.3-2.1). A gradient of increasing risk with time interval from diagnosis to interview suggested the chemotherapy regimen itself and not necessarily characteristics of tumors requiring this treatment was responsible for the observed increased risk. These results indicate that epidemiologic studies of diet and breast cancer, particularly among young women, should evaluate possible bias related to post-diagnosis influences.

Knowledge, beliefs, attitudes, and cancer screening among inner-city African-American women

Three hundred twenty-one inner-city African-American women were interviewed to determine their knowledge, attitudes, and beliefs regarding cancer and cancer screening, and their cancer screening histories. The women were recruited from a variety of sources in Atlanta and were interviewed in their homes by trained lay health workers. Half of the subjects had an annual household income of < $15,000. About half had received a Pap smear and clinical breast examination within the year preceding the interviews. For women > 35 years old, 35% had received a mammogram within the recommended interval. Younger women and women with higher incomes were more likely than older women and those with lower incomes to have received a Pap test and clinical breast examination within the preceding year, but income was not significantly associated with mammography histories. In general, women who were more knowledgeable about cancer and its prevention were more likely to have been appropriately screened. However, various attitudes and beliefs regarding cancer generally were not associated with screening histories. We conclude that cancer screening programs for inner-city minority women should focus on improving knowledge levels among older women rather than attempting to alter attitudes and beliefs.

Alcohol consumption and breast cancer risk among women under age 45 years

In a population-based case-control study of women younger than 45 years of age, we obtained a detailed lifetime history of alcohol use to evaluate the effects of drinking during different periods of life in relation to breast cancer risk. This analysis focused on interviews obtained from 1,645 cases and 1,497 controls. Breast cancer risk was not influenced by drinking during the teenage years or early adulthood. Contemporary drinking (that is, average intake during the recent 5-year interval) was directly associated with risk, but the adverse effect of recent drinking was restricted to women who consumed > or = 14 drinks per week [relative risk (RR) = 1.7; 95% confidence interval (CI) = 1.2-2.5]. The effect of alcohol was most pronounced among women with advanced disease. Compared with nondrinkers, the risk estimate associated with recent consumption of > or = 14 drinks per week was 2.4 (95% CI = 1.6-3.8) for women with regional/distant disease. Our data add support to the accumulating evidence that alcohol consumption is associated with increased risk of breast cancer and further indicate that alcohol acts at a late stage in breast carcinogenesis.

Modification of oral contraceptive relationships on breast cancer risk by selected factors among younger women

In a case-control study of 1647 breast cancer cases and 1501 population controls under 45 years of age, potential modifying effects of other risk factors on the relationship of oral contraceptives to breast cancer were examined. Among the total series of study subjects, the relationship of extended pill usage was greater in non-white than white women. Oral contraceptive associations, however, did not appear to be substantially modified by other risk factors, including parity, body size, or family history of breast cancer (apart from a somewhat enhanced relationship among subjects who reported a sister with breast cancer. Further, oral contraceptive relationships did not vary by a history of benign breast disease, although the majority of subjects began pill usage prior to the development of benign breast disease. Among the women under the age of 35, in whom oral contraceptive relationships were heightened (over a twofold excess risk for use of 5 years or longer), pill relationships were less modified by race than in the total series. Although among these younger subjects there was no effect of pill usage in heavy women, and an enhanced relationship among heavier consumers of alcoholic beverages, these interactive effects were not statistically significant. The findings of this study generally support no substantial variation in oral contraceptive relationships by other breast cancer risk factors, although some further attention might be warranted regarding possible modifying effects of race, body size, type of relative with breast cancer, and alcohol consumption.

Assessments of food-frequency questionnaires in minority populations

To assess the performance of food-frequency questionnaires in minority populations, we reviewed published studies of such questionnaires with respect to reports of reliability, bias in mean intake estimates, validity, and factors that might affect these characteristics, including the method by which a questionnaire was developed. Because of the small number of studies and the variation in their methods, the results of the review are not easily summarized and cannot be generalized. Most reliability correlation coefficients were in the range usually reported in evaluations of the performance of questionnaires in nonminority populations (0.5-0.8). Mean intakes derived from questionnaires were generally higher than those estimated with use of referent methods, although this varied according to the population, questionnaire, and nutrient being assessed; moreover, the accuracy of the referent method was questioned by some investigators. Validation correlation coefficients were variable, with some indicating that the questionnaires performed less well in certain populations. Additional research is needed on the performance of food-frequency questionnaires in minority and multicultural populations and on determining how best to develop such questionnaires.

Prenatal and perinatal risk factors for breast cancer in young women

There is increasing interest in the role of early life exposures in breast carcinogenesis, especially estrogen exposure in utero. Estrogen levels during pregnancy may be higher in twin pregnancies and among older women and slightly lower among smokers. We analyzed early life risk factors in a population-based case-control study in the United States of 2,202 breast cancer cases and 2,009 controls under age 55 years. Twins were at an increased risk of breast cancer compared with singletons (relative risk = 1.62; 95% confidence interval = 1.0-2.7), particularly women with a twin brother (relative risk = 2.06), a finding consistent with the observation of high estrogen levels in dizygotic twin pregnancies. Little association was seen between maternal age at birth and breast cancer risk. We carried out further analyses for 534 cases and 497 controls under age 45 years, using data from a questionnaire completed by their mothers relating to the daughters' early life exposures. There was no evidence of an effect of smoking or diethylstilbestrol exposure during pregnancy on daughters' breast cancer risk. A reduced breast cancer risk was seen among women who had been breastfed (relative risk = 0.74; 95% confidence interval = 0.6-1.0). These findings indicate some effect of early life exposures on breast cancer risk, although the role of estrogen exposure may be less central than previously suggested.

Effect of a cancer screening intervention conducted by lay health workers among inner-city women

INTRODUCTION

We conducted a randomized controlled trial to determine if an in-home educational intervention conducted by lay health workers (LHWs) could increase adherence among low-income, inner-city, African-American women to breast and cervical cancer screening schedules.

METHODS

We recruited 321 African-American women from diverse inner-city sources. After baseline interviews, they were randomly assigned to either the intervention (n = 163) or the control (n = 158) group. Those in the intervention group were visited in their homes up to three times by LHWs who provided a culturally sensitive educational program that emphasized the need for screening.

RESULTS

Ninety-three (93) women in the intervention group and 102 in the control group completed the postintervention interview. For Pap smears, the increase in screening was similar in both groups. For clinical breast exams (CBEs), however, there was a modest increase in the intervention group. The improvement was greatest for mammography, for which there was a 10% to 12% increase. Among women who were not on recommended schedules at baseline, the improvement was substantial and greater in the intervention group.

CONCLUSIONS

LHWs' intervention appeared to improve the rate at which inner-city women obtained CBEs and mammograms, but had no effect on Pap smears. A high attrition rate weakened our ability to make conclusive statements about the exact impact of the intervention.

Breast cancer and hormonal contraceptives: further results. Collaborative Group on Hormonal Factors in Breast Cancer

The Collaborative Group on Hormonal Factors in Breast Cancer has brought together and reanalysed the worldwide epidemiological evidence on breast cancer risk and use of hormonal contraceptives. Original data from 54 studies, representing about 90% of the information available on the topic, were collected, checked and analysed centrally. The 54 studies were performed in 26 countries and include a total of 53,297 women with breast cancer and 100,239 women without breast cancer. The studies were varied in their design, setting and timing. Most information came from case-control studies with controls chosen from the general population; most women resided in Europe or North America and most cancers were diagnosed during the 1980s. Overall 41% of the women with breast cancer and 40% of the women without breast cancer had used oral contraceptives at some time; the median age at first use was 26 years, the median duration of use was 3 years, the median year of first use was 1968, the median time since first use was 16 years, and the median time since last use was 9 years. The main findings, summarised elsewhere, are that there is a small increase in the risk of having breast cancer diagnosed in current users of combined oral contraceptives and in women who had stopped use in the past 10 years but that there is no evidence of an increase in the risk more than 10 years after stopping use. In addition, the cancers diagnosed in women who had used oral contraceptives tended to be less advanced clinically than the cancers diagnosed in women who had not used them. Despite the large number of possibilities investigated, few factors appeared to modify the main findings either in recent or in past users. For recent users who began use before age 20 the relative risks are higher than for recent users who began at older ages. For women whose use of oral contraceptives ceased more than 10 years before there was some suggestion of a reduction in breast cancer risk in certain subgroups, with a deficit of tumors that had spread beyond the breast, especially among women who had used preparations containing the highest doses of oestrogen and progestogen. These findings are unexpected and need to be confirmed. Although these data represent most of the epidemiological evidence on the topic to date, there is still insufficient information to comment reliably about the effects of specific types of oestrogen or of progestogen. What evidence there is suggests, however, no major differences in the effects for specific types of oestrogen or of progestogen and that the pattern of risk associated with use of hormonal contraceptives containing progestogens alone may be similar to that observed for preparations containing both oestrogens and progestogens. On the basis of these results, there is little difference between women who have and have not used combined oral contraceptives in terms of the estimated cumulative number of breast cancers diagnosed during the period from starting use up to 20 years after stopping. The cancers diagnosed in women who have used oral contraceptives are, however, less advanced clinically than the cancers diagnosed in never users. Further research is needed to establish whether the associations described here are due to earlier diagnosis of breast cancer in women who have used oral contraceptives, to the biological effects of the hormonal contraceptives or to a combination of both. Little information is as yet available about the effects on breast cancer risk of oral contraceptive use that ceased more than 20 years before and as such data accumulate it will be necessary to re-examine the worldwide evidence.

Risk of breast cancer among white women following induced abortion

Some studies (but not all) have suggested that there may be an increase in the risk of breast cancer associated with a prior induced abortion. The risk, if present, may vary according to the duration of the pregnancy in which the abortion occurred, or to a woman's age or parity at that time. The authors conducted a case-control study of breast cancer in white women under age 45 years to address the question of breast cancer risk in relation to induced abortion, with the intention of identifying subgroups of women who might be at particularly increased risk. White women who were diagnosed with breast cancer (n = 1,302) from May 1, 1990, through December 31, 1992, in three geographic regions of the United States (Atlanta, Georgia; Seattle/Puget Sound, Washington; and five counties in central New Jersey) were interviewed about their reproductive histories, including the occurrence of induced abortion. Similar information was obtained from control women identified through random digit dialing. Logistic regression analysis was used to estimate the relative risk of breast cancer associated with a history of induced abortion, controlling for the potentially confounding influence of other breast cancer risk factors. Among women who had been pregnant at least once, the risk of breast cancer in those with a prior induced abortion was 20% higher than that in women with no history of abortion (95% confidence interval 1.0-1.5). This small increase in risk varied little according to number of abortions or a woman's current age. The association was present primarily among nulliparous women whose abortions occurred prior to 9 weeks' gestation (estimated relative risk = 2.0, 95% confidence interval 1.2-3.3). There was no excess risk of breast cancer associated with induced abortion among parous women. These data support the hypothesis that there may be a small increase in the risk of breast cancer related to a history of induced abortion among young women of reproductive age. However, the data from this study and others do not permit a causal interpretation at this time; neither do the collective results of the studies suggest that there is a subgroup of women in whom the relative risk associated with induced abortion is unusually high.

Low-fat diet practices of older women: prevalence and implications for dietary assessment

OBJECTIVE

To evaluate the importance of information on low-fat diet practices and consumption of reduced-fat foods for accurate assessment of energy and fat intakes using a semiquantitative food frequency questionnaire (FFQ).

SUBJECTS

Subjects were 7,419 women, aged 50 to 79 years, who filled out an FFQ as part of eligibility screening for a diet modification component and/or a hormone replacement trial in a multicenter study of chronic disease prevention in postmenopausal women (Women's Health Initiative).

STATISTICAL ANALYSIS

For 26 FFQ questions, we recoded the low-fat diet choices of participants to a high-fat counterpart and recalculated energy and fat intakes. We then determined the decrease in energy and nutrient estimates attributable to adding low-fat options to the FFQ.

RESULTS

Low-fat diet practices were widespread in this population. For example, 69% of respondents rarely or never ate skin on chicken, 76% rarely or never ate fat on meat, 36% usually drank nonfat milk, 52% usually ate low-fat or fat-free mayonnaise, 59% ate low-fat chips/snacks, and 42% ate nonfat cheese. These low-fat choices had substantial effects on energy and nutrient estimates. Absolute decreases (and mean percentage decreases) for energy and nutrient measures attributable to adding low-fat diet options to the FFQ were 196 kcal (11.4%) energy, 9 percentage points in percentage energy from fat (22.3%), 23.2 g fat (29.0%), and 9.6 g saturated fat (32.5%). Black and Hispanic women and women of lower socioeconomic status reported significantly fewer low-fat diet practices than white women and women of higher socioeconomic status.

CONCLUSION

Failure to collect information on low-fat diet practices with an FFQ will result in an upward bias in estimates of energy and fat intake, and the amount of error will vary by the personal characteristics of respondents.

Differences between black and white patients with cancer of the uterine corpus in interval from symptom recognition to initial medical consultation (United States)

To determine whether Black women with symptoms of uterine corpus cancer had longer times from symptom recognition to initial medical consultation than did White women in the United States, 331 newly diagnosed patients living in Atlanta (GA), New Orleans (LA), and San Francisco/Oakland (CA) during 1985-87 were interviewed to collect information on symptoms, dates of recognition and consultation, and other factors that might affect the interval. Data were analyzed to estimate medical consultation rates and rate ratios following symptom recognition. Median recalled times between symptom recognition and consultation were 16 days for Black women and 14 days for White women. Although poverty, having no usual source of healthcare, and other factors were associated with lower consultation rates, the adjusted rate among Black women was only somewhat lower (0.87) than among White women, and the 95 percent confidence interval (CI = 0.58-1.31) was consistent with no true difference between the races. In addition, the median time to consultation for women with stage IV cancer was only 15 days longer than the time (14 days) for the women with stage I cancer. These results suggest that time from symptom recognition to initial medical consultation does not contribute importantly to the more advanced stage cancer of the uterine corpus commonly found among Black women.

Epidemiology of in situ and invasive breast cancer in women aged under 45

The incidence of in situ breast cancer in the USA has increased rapidly in recent years, even among young women. A population-based case-control study of 1616 breast cancer cases aged under 45 in the USA was used to examine risk factors for in situ, local and regional/distant tumours. Almost 60% of in situ tumours were detected by routine mammograms compared with 18% of local tumours and 8% of regional/distant tumours. After adjustment for screening history and established risk factors, family history of breast cancer in a first-degree relative and African-American race were associated with an increased risk of all stages of breast cancer. The associations with nulliparity, a previous breast biopsy and body mass index were significantly stronger for in situ tumours than for local or regional/distant disease. Alcohol consumption was associated with an increasing trend in risk of regional/distant tumours but not of earlier stage tumours, indicating that alcohol may be involved in late-stage events. Analyses by histological type of in situ tumours suggested that both ductal and lobular carcinoma in situ were associated with most established breast cancer risk factors, and the magnitude of association tended to be greater for the ductal form.

Body size and breast cancer risk among women under age 45 years

In a multicenter population-based case-control study that included 1,588 cases and 1,394 controls less than age 45 years, the authors examined the relation of adult body size and breast cancer risk among young women. Breast cancer patients and healthy controls were identified in Atlanta, Georgia; Seattle/Puget Sound, Washington; and central New Jersey. Cases were newly diagnosed with in situ or invasive breast cancer during the period of May 1, 1990, through December 31, 1992. Anthropometric variables thought to reflect early environmental factors (e.g., height, sitting height, frame size), obesity, and body fat distribution were measured directly. Height, but not sitting height or frame size, was a breast cancer risk factor. Risk of the disease was increased 46 percent among women in the fourth quartile of height (> 167 cm) compared with women in the first quartile (< 159 cm). Body weight, but not body fat distribution, was related to breast cancer risk. Risk of the disease was 35 percent lower among women in the highest quartile of Quetelet index (> 28.8 kg/m2) compared with women in the lowest quartile (< 22.0 kg/m2). Risk of the disease was increased about 2.1-fold (95 percent confidence interval 1.2-3.8) among women who were thin and tall compared with women who were heavy and short. Thus, breast cancer risk was increased substantially among younger women with a linear body type.

The association between fruit and vegetable intake and chronic disease risk factors

Understanding the associations between fruit and vegetable intake and other health behaviors is important for properly interpreting the rapidly growing number of studies that link low intakes of fruits and vegetables to the risk of cancer and cardiovascular disease. To examine the association between fruit and vegetable intake and behavioral risk factors for chronic diseases, we analyzed data from a population-based behavioral risk factor survey. Data were collected in 1990 from 21,892 adults in 16 states by a random-digit-dial telephone survey. Respondents answered questions about behaviors related to chronic disease risk, including their frequency of intake of fruits and vegetables, using a six-item questionnaire. Consumption of fruits and vegetables was lowest among those who also reported that they were sedentary, heavy smokers, heavy drinkers, or had never had their blood cholesterol checked. Because fruit and vegetable intake covaries with several other chronic disease risk factors, it is important to account for possible confounding between fruit and vegetable intake and other behaviors in etiologic studies of the risk of cancer and cardiovascular disease.

Relation between geographic variability in kidney stones prevalence and risk factors for stones

To determine whether geographic variability in rates of kidney stones in the United States was attributable to differences in personal and environmental exposures, the authors examined cross-sectional data that included information on self-reported, physician-diagnosed kidney stones collected from 1,167,009 men and women, aged > or = 30 years, recruited nationally in 1982. Information on risk factors for stones including age, race, education, body mass, hypertension, and diuretic and vitamin C supplement use was obtained by self administered questionnaire. Consumption of milk, coffee, tea, soft drinks, and alcohol was based on food frequency data. Indices of ambient temperature and sunlight level were assigned to subjects based on state of residence. Stones were nearly twice as prevalent in the Southeast as in the Northwest among men and women. Ambient temperature and sunlight indices were independently associated with stones prevalence after controlling for other risk factors for stones. Regional variation was eliminated for men and greatly reduced for women after adjustment for temperature, sunlight, and beverage consumption. Other factors appeared to not contribute to regional variation. These results provide evidence that ambient temperature and sunlight levels are important risk factors for stones and that differences in exposure to temperature and sunlight and beverages may contribute to geographic variability.

Prolactin response to suckling and maintenance of postpartum amenorrhea among intensively breastfeeding Nepali women

The aim of the study was to determine the association between PRL responses to suckling and maintenance of postpartum amenorrhea among breastfeeding mothers. Three blood spot samples (5, 30, and 50 min following a timed nursing bout) were collected from 71 intensively breastfeeding Nepali women for PRL determination. Maternal age, BMI (weight/height2), menstrual status, caste, infant age, nursing bout length, and duration of supplementation were recorded at time of sample collection. Independent and paired t tests, linear regression analyses, and general linear models were used to evaluate differences between cycling (n = 36) and amenorrheic (n = 35) women and associations among variables. Logistic regression analyses were used to relate PRL measures to the odds of maintaining lactational amenorrhea. Amenorrheic breastfeeding mothers had higher (P < .001) PRL levels at all 3 collection times than cycling breastfeeding mothers, and PRL levels declined with time since birth (P < 0.05). The odds (OR) of having ceased lactational amenorrhea was significantly higher (OR = 5.0, 95% Cl = 1.3-19.9) among mothers with lower PRL levels (< or = 10 ng/mL) at 50 min post-sucking, and PRL at 50 min showed a significant dose response relationship with menstrual status. The association between 50 min PRL levels and lactational amenorrhea appears to be independent of time postpartum, maternal age, BMI, nursing bout length, and duration of supplementation. Among intensively nursing women, maintenance of elevated PRL levels across the interbout interval increases the odds of maintaining lactational amenorrhea.

Breast enlargement and reduction: results from a breast cancer case-control study

In a population-based case-control study of breast cancer that included 2174 cases and 2009 population controls under 55 years of age, prior breast implants were reported by 36 cases versus 44 controls. After adjustment for the matching factors as well as variables associated with both breast cancer risk and breast enlargement (race, family history of breast cancer, body size, screening history), the relative risk of breast cancer associated with a prior implant was 0.6 (95% CI 0.4-1.0). The reduced risk persisted with increasing interval since surgery, arguing against selection bias as an explanation. Further, although a deficit of in situ tumors was seen among women with implants (RR = 0.2), the risk associated with implants remained reduced for both localized and distant tumors (RR = 0.8 for both stages). In a smaller group of women who had prior breast reduction surgery (10 cases, 13 controls), a reduced risk of breast cancer also was observed (RR = 0.7, 95% CI 0.3-1.6). The results of this study must be interpreted cautiously because of the small number of women involved and reliance on patient reports of prior operations. In not showing any elevation in breast cancer risk following a breast implant, our results confirm several record linkage studies but contradict some clinical studies that suggest an adverse effect. Additional investigations are needed in relation to specific types of breast implants, including the polyurethane-coated implants, which have been linked to high cancer rates in laboratory animals.

Determinants of black/white differences in colon cancer survival

BACKGROUND

Blacks have lower survival rates for colon cancer than whites, possibly related to more advanced stages of disease at diagnosis and to socioeconomic differences between blacks and whites. While the black/white difference in colon cancer survival is well documented, the few studies that have investigated this difference have been limited by the modest number and type of explanatory factors that were considered.

PURPOSE

We analyzed data from the National Cancer Institute Black/White Cancer Survival Study to determine 1) what characteristics might contribute to the racial difference in colon cancer survival and 2) if a survival disparity remained between black and white patients after adjustment was made for these characteristics.

METHODS

This prospective study included 454 blacks and a stratified random sample of 521 whites, aged 20-79 years, with cancer of the colon diagnosed from January 1, 1985, through December 31, 1986, and who were residents of the metropolitan areas of Atlanta, New Orleans, and San Francisco/Oakland. Follow-up was truncated on December 31, 1990. Cox proportional hazards regression was used to estimate the death rate among blacks relative to that among whites after adjustment for potential explanatory factors, including sociodemographic factors, concurrent (comorbid) medical conditions, stage at diagnosis, tumor characteristics, and treatment. All P values were calculated from two-tailed tests of statistical significance.

RESULTS

After adjustment for age, sex, and geographic area, the black-to-white mortality hazard ratio (HR) was 1.5 (95% confidence interval [CI] = 1.2-1.9), indicating that the risk of death among black patients was 50% higher than that among white patients. Further adjustment for stage reduced the excess cancer mortality to 20% (HR = 1.2; 95% CI = 1.0-1.5), decreasing the overall racial difference in excess mortality from 50% to 20% or to a 60% reduction in excess mortality. Although adjustment for poverty reduced the excess mortality by 20%, adjusting for both stage and poverty did not further reduce the racial difference. Among patients with stages II and III disease, blacks had lower survival rates than whites (HR = 1.8; 95% CI = 1.0-3.1 and HR - 1.5; 95% CI = 1.0-2.3, respectively). Among those patients with metastatic disease (stage IV), survival was similar for whites and blacks.

CONCLUSIONS

Stage at diagnosis accounted for more than half of the excess colon cancer mortality observed among blacks. Poverty and other socioeconomic conditions, general health status, tumor characteristics, and general patterns of treatment did not further explain the remaining survival disadvantage among blacks.

IMPLICATIONS

Because the racial disparity was confined to earlier stages, future studies should investigate whether blacks have more advanced disease at diagnosis and whether less aggressive treatment is provided because of understanding.

System delay in breast cancer in whites and blacks

Survival differences have been noted between black women and white women with breast cancer. It is hypothesized that a prolonged interval between initial medical consultation and establishment of a diagnosis (system delay), resulting in a more advanced stage of disease at diagnosis, might explain part of this survival difference. This study was performed to determine whether system delay differs between black and white breast cancer patients, and to examine predictors of delay in blacks and whites. The study population consisted of 996 female breast cancer patients from the National Cancer Institute's Black/White Cancer Survival Study, a cohort study carried out in 1985-1986 in the metropolitan areas of Atlanta, Georgia, New Orleans, Louisiana, and San Francisco/Oakland, California. The median system delay was slightly longer for blacks than for whites--2.7 weeks versus 2.1 weeks--but this difference was not statistically significant. Having a palpable lump at diagnosis was associated with reduced system delay in both races, while use of a public clinic increased system delay for blacks. Older women were less likely to be subject to longer system delay than younger women, and this effect was somewhat more pronounced in whites. Survival differences between blacks and whites are probably not due to differences in system delay. However, many women had delays of at least 3 months. Given that younger age and the absence of a palpable lump were the factors most predictive of significant system delay, interventions should be targeted specifically toward reducing system delay in younger women who present without the classical painless lump.

Epidemiologic studies of antioxidants and cancer in humans

To assess whether antioxidants may reduce the risk of cancer, we reviewed the epidemiologic literature from 1985 through 1993. We assessed the separate relationships of three antioxidants (carotenoids, vitamin C, and vitamin E) with six sites of cancer (lung, upper aerodigestive tract, uterine cervix, colon, breast, prostate). This review was limited to dietary intake or serum nutrient studies that met a predefined set of methodologic standards. We judged the evidence in support of causal relationships based upon consistency of results across studies, strength of association, and evidence of a dose-response relationship. The data concerning carotenoids and lung cancer risk were most consistent (protection found in 4 of 8 diet studies and 5 of 6 serum studies), with strong associations that tended to follow a dose-response pattern. For lung cancer, there was weaker evidence of protection from vitamin C (2 of 6 diet studies) and vitamin E (3 of 4 serum studies). For upper aerodigestive tract cancers (oral cavity, pharynx, or larynx), there was evidence of a protective effect of carotenoids (3 of 4 diet studies) and vitamin C (4 of 5 diet studies). For cancer of the uterine cervix, we found suggestive evidence of protection from vitamin C (4 of 5 diet studies) and perhaps carotenoids (2 of 5 diet studies). For cancers of the colon, breast, and prostate, the current data do not support a protective effect of antioxidants. More definite conclusions about the benefits of antioxidants in cancer prevention will be derived from on-going intervention trials.

Oral contraceptives and breast cancer risk among younger women

BACKGROUND

Several studies have suggested a link between oral contraceptive use and breast cancer in younger women, but it is possible that chance or bias, including selective screening of contraceptive users, contributed to the putative association.

PURPOSE

Given that oral contraceptives were first marketed in the United States in the early 1960s, we conducted a population-based case-control study to examine the relationship between use of oral contraceptives and breast cancer among women in a recently assembled cohort, focusing on women younger than 45 years of age who had the opportunity for exposure throughout their entire reproductive years.

METHODS

Breast cancer patients and healthy control subjects were identified, the latter group by random-digit dialing, in Atlanta, Ga., Seattle/Puget Sound, Wash., and central New Jersey. In Seattle and New Jersey, the study was confined to women 20 through 44 years of age; in Atlanta the age range was extended through 54 years. Patients included women with in situ or invasive breast cancer newly diagnosed during the period of May 1, 1990, through December 31, 1992. In-person interviews were completed by 2203 (86.4%) of 2551 eligible patients and 2009 (78.1%) of 2571 eligible control subjects. Analyses focused on women younger than 45 years of age (1648 patients and 1505 control subjects) to maximize opportunities for extended exposure. Logistic regression analyses were used to obtain maximum likelihood estimates of relative risks (RRs) and their 95% confidence intervals (CIs).

RESULTS

Among women younger than 45 years, oral contraceptive use for 6 months or longer was associated with an RR for breast cancer of 1.3 (95% CI = 1.1-1.5). Risks were enhanced for breast cancers occurring prior to age 35 years (RR = 1.7; 95% CI = 1.2-2.6), with the RR rising to 2.2 (95% CI = 1.2-4.1) for users of 10 or more years. The RR for breast cancer for those whose oral contraceptive use began early (before age 18 years) and continued long-term (> 10 years) was even higher (RR = 3.1; 95% CI = 1.4-6.7). The RRs observed for those who used oral contraceptives within 5 years of cancer diagnosis were higher than for those who had not, with the effect most marked for women younger than age 35 years (RR = 2.0; 95% CI = 1.3-3.1). Oral contraceptive associations were also strongest for cancers diagnosed at advanced stages. Evaluation of screening histories and methods of diagnosis failed to support the speculation that associations could be due to selective screening. Among women 45 years of age and older, no associations of risk with use of oral contraceptives were noted.

CONCLUSIONS

The relationship between oral contraceptives and breast cancer in young women appears to have a biologic basis rather than to be an artifact or the result of bias.

A brief, telephone-administered food frequency questionnaire can be useful for surveillance of dietary fat intakes

A 13-item questionnaire designed for quick telephone administration was evaluated for use in surveillance of fat intake in the United States. Study populations included 560 middle-aged and older adults from Beaver Dam, WI, 252 middle-aged and older women from Wisconsin, 73 young, low income Hispanic women from Chicago, IL, 52 older adults from Arizona and 135 younger adults from Augusta, GA. Correlations between fat scores and fat intakes measured by multiple food records or recalls or by more extensive food frequency questionnaires ranged from 0.33 to 0.60, similar to results from other published questionnaire validation studies. Correlations with percentage of energy from fat were lower (0.26 to 0.42), except for the Chicago population, for which there was no correlation (-0.02). There was no systematic variation in correlations among other subgroups defined by demographic and health-related characteristics, including race (black vs. white). Most, but not all, of the substantial differences in fat intakes among subgroups were identified by the questionnaire. The questionnaire will not capture small differences in intakes among groups and is inappropriate when the sample size is limited or for populations with diets substantially different from the typical U.S. diets, such as the Chicago population. However, with attention to its limitations, the questionnaire is useful for surveillance.

Estrogen replacement therapy and fatal ovarian cancer

The authors examined the relation between use of estrogen replacement therapy and ovarian cancer mortality in a large prospective mortality study of 240,073 peri- and postmenopausal women, none of whom had a prior history of cancer, hysterectomy, or ovarian surgery at enrollment in 1982. During 7 years of follow-up, 436 deaths from ovarian cancer occurred. Cox proportional hazard regression was used to adjust for other risk factors. Ever use of estrogen replacement therapy was associated with a rate ratio for fatal ovarian cancer of 1.15 (95% confidence interval (CI) 0.94-1.42). The mortality rate ratio increased with duration of use prior to entry to this study to 1.40 (95 CI% 0.92-2.11) with 6-10 years of use and 1.71 (95% CI 1.06-2.77) with > or = 11 years of use. The increase in mortality associated with > or = 6 years of use was observed in both current users (rate ratio (RR) = 1.72, 95% CI 1.01-2.90) and former users at study entry (RR = 1.48, 95% CI 0.99-2.22), relative to never users. Risk associated with use was not modified by any of the other risk factors. These data suggest that long-term use of estrogen replacement therapy may increase the risk of fatal ovarian cancer.