Factors related to enrollment in the breast cancer prevention trial at a comprehensive cancer center during the first year of recruitment

BACKGROUND

Using an a priori theoretic model of behavior change, factors predicting enrollment in a randomized chemoprevention trial during the first year of recruitment were assessed prospectively.

METHODS

Eligible participants were asked to complete a 90-item semistructured questionnaire after attendance at an informational meeting. Components of the Health Belief Model (including perceived susceptibility, perceived severity, perceived benefits and barriers, cues to action, and health motivation), health status, preventive health behaviors, and social influence were assessed in relation to enrollment.

RESULTS

Overall, 331 women attended one of the meetings, and 73% completed a questionnaire; 45% enrolled on the trial and 55% did not. In bivariate analyses, all but one of the perceived barriers were associated negatively with enrollment; however, items assessing perceived susceptibility, perceived severity, and perceived benefits were not. Nonparticipants also were more likely to be over 49 years of age, to be currently or to have been on estrogen replacement therapy, and to have had hot flashes. In logistic regression analysis, not being able to take estrogen replacement therapy was the strongest predictor of nonparticipation (odds ratio [OR], 12.13, 95% confidence interval [CI], 3.63, 40.60). Other factors associated with nonparticipation were concern about side effects of tamoxifen (OR, 5.06; CI, 2.37, 10.80); the possibility of getting a placebo (OR, 7.75; CI, 1.51, 39.67); the costs associated with the trial (OR, 3.21; CI, 1.12, 9.24); and absence of concern that significant others would be reassured if the respondent was taking tamoxifen (OR, 2.58; CI, 1.04, 6.41).

CONCLUSIONS

These findings support the view that recruitment efforts for chemoprevention trials should address barriers specific to their circumstances. In addition, increasing the support available from personal social networks may enhance recruitment to chemoprevention trials for breast cancer.

Validation of a breast cancer risk assessment model in women with a positive family history

BACKGROUND

Gail et al. developed a statistical model for estimating the risk of developing breast cancer in white women screened annually with mammography. This model is used for counseling and for admission to clinical trials.

PURPOSE

We evaluated the model prospectively in a cohort of women with a family history of breast cancer.

METHODS

We followed women who participated in the American Cancer Society 1987 Texas Breast Screening Project. The model was evaluated by comparing the observed (O) and expected (E) numbers of breast cancers using composite background rates from both the Breast Cancer Detection and Demonstration Project and the Surveillance, Epidemiology, and End Results program of the National Cancer Institute. Data were partitioned by adherence to American Cancer Society screening guidelines.

RESULTS

The Gail et al. model predicted the risk well among women who adhered to the American Cancer Society guidelines (O/E = 1.12; 95% confidence interval = 0.75-1.61) but overpredicted risk for women who did not adhere to the guidelines. There was an indication that the model overpredicted risk for women younger than 60 years old and underpredicted risk in women aged 60 years and older.

CONCLUSIONS

Overall, the Gail et al. model accurately predicts risk in women with a family history of breast cancer and who adhere to American Cancer Society screening guidelines. Thus, the model should be used as it was intended, for women who receive annual mammograms.

Factors associated with perceived risk of breast cancer among women attending a screening program

A person's perception of the risk of, or susceptibility to, developing a disease is believed to be an important determinant of health-related behavior, yet little is known about the determinants of perceived risk. Knowledge of these correlates may be useful in identifying and addressing barriers to performance of health behaviors such as mammography screening. Data collected from over 36,000 women participating in a breast cancer screening program in Texas were used to examine the associations between perceived risk of ever getting breast cancer and a number of demographic factors, health-related behaviors, and risk factors for breast cancer. There was a strong positive association between family history of breast cancer and risk perception (OR = 11.3, CI = 10.34-12.35). Women who reported other risk factors for breast cancer also reported higher perceived risk, but those associations were of lesser magnitude. Age was inversely associated with perceived risk, and black, but not Hispanic, women were more likely to perceive their risk as high compared with white women. Of the health-related behaviors for the early detection of breast cancer, only having had a prior mammogram was associated with perceived risk. Educational interventions to heighten women's awareness of breast cancer risk factors may increase perceived risk in high risk women and influence their decision to undergo screening mammography.

Clinical management of women at increased risk for breast cancer

A large number of women in the population are at risk for the development of breast cancer. Methods now exist to accurately assess risk and to provide quantitative estimates of the chance of a woman developing breast cancer in her lifetime. Histologic assessment of premalignant breast pathology aids in the evaluation of risk. The availability of primary chemoprevention clinical trials reduces the number of indications for prophylactic mastectomy. Women at risk for breast cancer and women who have had a malignant lesion at another anatomic site have an increased risk for new cancers at multiple sites. We propose screening strategies based on epidemiologic information about the risks of these diseases and on the predictive value of the available screening tests. The merits and inadequacies of specific management strategies are considered. We review the risks and benefits of estrogen replacement therapy for women at increased risk for breast cancer and consider the ethical implications of both risk assessment and the various interventions.

The Texas Breast Screening Project: Part II. Demographics, risk profiles, and health practices of participants

More than 36,000 of the 64,459 women who had $50 mammograms after a media campaign in 1987 completed a demographic and risk factor questionnaire. The screened women were young and well educated with high annual incomes. Only 32% had had mammograms before 1987. Most women reported that high cost and lack of referral for mammography by their physicians were their reasons for not being screened previously. Publicity promoting the project and the lower cost for mammography were the features of the project that attracted participants. Population-based telephone surveys before and after the project showed a change in attitudes about breast cancer screening. The model used for recruitment in this project can improve compliance with recommendations for regular mammographic screening if charges for screening are reduced. Additional efforts are needed to attract minorities and poor or elderly women to regular breast screening.

The Texas Breast Screening Project: Part I. Mammographic and clinical results

The 1987 Texas Breast Screening Project was designed to educate women about the benefits and safety of mammographic screening. During the 2-week promotion, 109,339 women called toll-free telephone numbers to inquire about the program, and 64,459 (65%) of 99,650 eligible callers had $50 mammograms at 306 participating community radiology centers. Biopsies were obtained for 1,122 women (1.7% of those screened), and the ratio of benign to malignant biopsy results was 4.2:1. Among the women having biopsies, 214 cancers were found (3.3 cancers per 1,000 women screened). Forty-seven percent of the tumors were not palpable, 80% were smaller than 2 cm, and 72% were clinicopathologic stage 0 or I. These results show that women will respond to an invitation to attend mammographic screening, and that community radiology centers can detect large numbers of early, curable breast cancers.

Epidemiology and etiology of leukemia

New clinical and epidemiologic studies provide information about the possible causes of human leukemia. Evidence for a viral etiology continues to appear, and the relationship between myelodysplastic syndrome and the leukemias is now linked through molecular genetic studies. Molecular mechanisms of leukemogenesis are being understood through evaluation of preleukemic conditions and predisposing medical illnesses. Epipodophyllotoxins and, to a lesser extent, cisplatin are being linked causally to secondary leukemia. Potential environmental causes of leukemia are being intensively investigated with both positive and negative results. The literature on the epidemiology of leukemia is growing rapidly, and important leads toward a more complete understanding of its etiology are emerging.

Early detection, epidemiology, and prevention of breast cancer

Control of breast cancer will ultimately be achieved through a better understanding of the epidemiology of the disease and application of primary prevention. Until then, use of screening mammography offers the promise of a 30% reduction in breast cancer mortality, which continues to be shown by screening studies with prolonged follow-up. Biologic markers of cancer risk, including nipple aspirates and cyst fluid, suggest that a complete risk profile can be developed using fluid and tissue obtained from the normal breast. Epidemiologic studies of dietary factors and geographic differences in breast cancer risk continue to provide promising leads relating to the etiology of the disease. Increasing evidence suggests that circulating androgens and estrogens affect breast cancer risk, whereas exogenous estrogen therapy does not increase risk except for small subgroups of women at risk. Increasing understanding of the genetics of breast cancer will have an impact on the disease in the near future. The greatest impact in the short term will come from the use of tamoxifen for primary prevention of breast cancer. The retinoids, particularly N-(4-hydroxyphenyl)retinamide, hold great promise as agents for primary prevention.

Low incidence of familial breast cancer among Hispanic women

There is a paucity of data on familial patterns of breast cancer among minority populations. This study compared the frequency of cancer in 1,095 first-degree relatives of 50 White, 46 Black, and 49 Hispanic breast-cancer patients referred to The University of Texas M.D. Anderson Cancer Center (United States). Family histories of cancer were derived from a self-administered questionnaire on risk factors. Expected numbers of cancers were calculated from the Connecticut Tumor Registry for White and Black relatives and from the New Mexico Tumor Registry for Hispanic relatives. Family history of a first-degree relative with breast cancer was the most important risk factor for both Black and White patients. Significantly elevated standardized incidence ratios (SIR) for breast cancer were noted among White (SIR = 4.5, 95 percent confidence interval [CI] = 1.2-11.4) and Black (SIR = 4.1, CI = 1.1-10.4) relatives younger than age 45. Despite the small number of Black patients, the combined effect of family history of breast cancer and the relative's age at diagnosis (under 45 years) was associated with an SIR of 7.1 (CI = 1.9-18.1). A deficit of cancer was noted in Hispanic women; only one patient reported having a first-degree relative with breast cancer. These findings, although based on small numbers, suggest that Hispanics have a lower rate of familial breast cancer than Whites and Blacks, and that they may possess protective factors that reduce their risk for breast cancer.

Design and conduct of a low-cost mammography screening project: experience of the American Cancer Society, Texas Division

To improve compliance with recommendations for screening mammography, the American Cancer Society (ACS) Texas Division designed and conducted a media-promoted screening project in 1987. The project was planned during a 2-year period by a task force made up of physicians and lay members of ACS division committees. Radiology centers desiring to participate in the project were asked to submit information about the number of patients they could screen and their equipment, along with physics data, to a review committee. Of 306 facilities that responded, 266 (87%) passed the initial review. Thirteen facilities (4%) submitted images from two examinations using a dedicated mammography phantom, and 27 sites (9%) entered the project by agreeing to adhere to the project standards and guidelines without undergoing formal review. All facilities agreed to provide mammograms for $50 to women scheduling appointments during a 2-week media campaign in February 1987. The project generated 64,459 mammographic screening examinations. Our experience indicates that a media campaign can encourage women to have screening mammograms and that screening facilities will agree to screen a large number of women at reduced cost. This strategy, if widely applied, can improve compliance with mammographic screening recommendations and reduce breast cancer mortality.

Identification of women at increased risk for breast cancer in a population-based screening program

A multivariate model to assess breast cancer risk was developed by Gail et al. (M. H. Gail, L. A. Brinton, D. B. Byar, D. K. Corle, S. B. Green, C. Schairer, and J. J. Mulvihill, J. Natl. Cancer Inst., 81: 1879-1886, 1989) based on data analysis of the Breast Cancer Detection and Demonstration Project. We evaluated the model's usefulness for assigning women to risk groups for counseling and follow-up by applying it to the 1987 Texas Breast Screening Project data. We identified 3165 women with one or more first-degree relatives affected with breast cancer. The mean risk score for the group was 3.3 (range, 2.7-11.8), indicating a greater than 3-fold elevated risk. The mean risk score for the remaining 27,439 women without affected first-degree relatives was 1.5 (range, 1.24-3.2). Risk perception was found to be a motivator for participation. Women with a risk score greater than 5 perceived themselves to be at high risk for breast cancer. The perception of risk was related to the type of affected first-degree relatives: 80.0% of the women with three affected first-degree relatives and 71.5% of women whose mother and sister were both affected with breast cancer perceived themselves to be at high risk. The Gail model is potentially useful in the clinical setting because women at high risk for breast cancer can be entered into etiological studies, enrolled in primary prevention trials, or referred to programs seeking to improve compliance with screening mammography. The Gail model needs validation, but it is useful for estimating the risk of breast cancer in large populations.

Breast cancer screening behaviors and attitudes in three racial/ethnic groups

Data from a multiethnic sample of women participating in the American Cancer Society 1987 Texas Breast Screening Project was used to compare attitudes and behaviors related to breast cancer screening for whites, blacks, and Hispanics. In general, similar patterns of association were observed across racial/ethnic groups between a number of demographic and risk factors and prior mammography and recent clinical breast examination (CBE), although the magnitude of the associations varied somewhat across groups. Reasons for not having had prior mammography also were similar across groups, with lack of physician referral and cost cited as the two most important reasons. However, Hispanics were less likely than blacks or whites to report prior breast cancer screening, including mammography, CBE, and breast self-examination (BSE). This study demonstrated that women of different racial/ethnic backgrounds can be successfully recruited to participate in a patient-initiated, community-based program. However, this programmatic approach requires augmentation with other intervention strategies designed to reach low-income women because women with more years of education and higher family income were overrepresented in all three groups.

High-risk populations as targets for breast cancer prevention trials

Breast cancer risk factors include age; a family history of the disease in first-degree relatives (particularly if premenopausal with bilateral disease); proliferative benign breast disease with or without atypia; mammographic parenchymal pattern showing glandular, dense, dysplastic, or Wolfe P2 changes; and obesity. Women in these risk groups have annual breast cancer incidence rates 2 to 10 times higher than baseline. Using data from the National Cancer Institute SEER Program, the U.S. 1987 census estimates, and published prevalence and incidence estimates for breast cancer risk factors, estimates were made for the number of women in the white female population who are at increased risk for breast cancer and who might serve as suitable subjects for an antiestrogen chemoprevention intervention trial. More than 30 million white women are older than 50 years. Two million women older than 50 years have at least one first-degree relative with breast cancer. Six million women over age 50 have undergone breast biopsy for benign disease; one-fourth of these women have proliferative changes, and 11% also have a family history of breast cancer. More than 8 million women older than 50 years are obese, and at least a million older women have high-risk mammographic parenchymal patterns. Thus, there are at least 12 million women at increased risk for breast cancer in the United States, and each year 200,000 additional women enter the high-risk pool. These data indicate that sufficient numbers of women at increased risk for breast cancer are present in the population to justify a chemoprevention trial. The optimal recruitment strategy is yet to be identified.

Mammographic screening of women with increased risk of breast cancer

Five hundred one women from Dallas County, Texas who participated in the American Cancer Society 1987 Texas Breast Screening Project were selected because of a self-reported family history of breast cancer (cases). They were matched with 501 randomly selected women from the same county with no family history (controls). Although there was a statistically significant trend with age for an increasing proportion of women to report having undergone mammography, there was no significant difference when comparing mammographic histories of cases with controls after controlling for age (31.5% versus 35.1%, P = 0.33). Significantly more cases (79%) perceived their risk for breast cancer to be moderate or greater compared with controls (54%, P less than 0.0001), but mammographic histories were not different when controlling for perceived risk. Both cases and controls cited lack of physician referral and cost as their reasons for not having undergone mammography. Women at increased risk for breast cancer (because of their family history) are not undergoing regular mammographic screening despite their self-awareness of the increase in their risk.

Inhibition of protein kinase C by the 12-O-tetradecanoylphorbol-13-acetate antagonist glycyrrhetic acid

Glycyrrhetic acid is an anti-inflammatory agent isolated from licorice root that inhibits 12-O-tetradecanoylphorbol-13-acetate (TPA)-mediated tumor promotion in mouse skin. Although it has been established that glycyrrhetic acid inhibits a number of events induced by the phorbol ester tumor promoter TPA in cultured cells, its mechanisms of action has remained obscure. In this report, we demonstrate that glycyrrhetic acid inhibits the Ca2+-and phospholipid-dependent phosphotransferase activity of protein kinase C (PKC), the phorbol ester tumor promoter receptor. Therefore, inhibition of PKC may play a role in the anti-promoting activity of glycyrrhetic acid.

Elevated protein kinase C expression in human breast tumor biopsies relative to normal breast tissue

The Ca2+- and phospholipid-dependent protein kinase, protein kinase C (PKC), is a critical enzyme in the regulation of cell growth. In this report, we demonstrate elevated expression of PKC activity in surgical specimens of eight of nine spontaneous human breast tumors, as compared with the expression of PKC activity in normal breast tissue obtained from the same patients. The mean PKC specific activity in histologically normal breast tissue was 166 +/- 63 pmol 32P/min/mg, whereas the mean PKC specific activity in the breast tumors was 460 +/- 182 pmol 32P/min/mg (P = 0.0003; Student's t test). The low interpatient variability among the PKC levels observed in the histologically normal breast tissue specimens and the significant elevation of PKC levels observed in the tumors indicate that elevated expression of PKC activity in breast tissue is a potential marker for malignant disease in the breast.

Dietary epidemiology of colon cancer

Epidemiologic studies of the relationship of diet to cancer etiology are hampered by methodologic difficulties which can be overcome by careful trial design. The use of appropriate dietary assessment instruments is necessary to minimize bias and improve accuracy of diet assessment. Population studies implicate dietary fat intake in the etiology of colorectal carcinogenesis, and the incidence of colorectal malignancies around the world is positively correlated with meat and fat consumption and total calorie intake. Retrospective studies of fat intake yield equivocal results, whereas prospective studies have failed to show a relationship between fat intake and colon cancer risk. An inverse relationship exists between fiber consumption and colorectal cancer incidence and mortality rates. The positive observational studies are supported by laboratory studies of experimental carcinogenesis which show a greater number of tumors in animals fed high-fat or high-calorie diets. Increased fiber intake appears to offer some protection against colorectal cancer. Plausible mechanisms have been proposed in animals for the role of fat and fiber in colorectal carcinogenesis; the mechanisms in human populations await further description. The interrelationships between fat consumption and consumption of dietary fiber and micronutrients have made it difficult to assess the roles of these substances in the etiology of colorectal cancer. Calcium offers protection in animal systems, and the data in humans are suggestive but not yet conclusive. Data on the role of alcohol in colorectal carcinogenesis remain inconclusive. Little evidence exists for a protective effect of retinoids and carotenoids; the evidence for selenium and vitamin C is limited and evolving.

Personal risk factors. What do they mean?

Epidemiologic studies have identified myriad factors related to cancer risk. Risk can be quantified on the basis of demographic factors, genetics, occupation, medical conditions, and lifestyle. Existing evidence suggests that: (1) individuals at risk often are unaware of their risk; (2) physicians may not know well those factors associated with the highest cancer risk; and (3) methods to reduce risk have been under-applied because of lack of knowledge, lack of funds, or lack of motivation among both patients and physicians. Methods to reduce risk do not follow the usual medical model in that those groups requiring risk-modification intervention usually are symptom free. Evidence indicates that elimination of tobacco use would reduce lung cancer deaths by 83% and substantially reduce the incidence of head and neck malignancies. Broad application of mammographic screening would effect a 30% reduction in breast cancer mortality. Dietary modification could potentially reduce cancer mortality by 30%. An effective program to reduce cancer risk will accomplish the following: (1) develop new and refine existing risk factor measurements to improve identification of individuals at risk; (2) apply risk factor identification and modification more completely to populations known to be at risk; (3) use combinations of risk factors to identify subpopulations at the highest risk; (4) apply existing prevention and screening modalities more broadly and uniformly; (5) identify new screening strategies with improved test performance and cost effectiveness to maximize screening efficiency; and (6) provide accurate and rapid means of risk assessment and quantification using the best available multivariate estimates of risk. An emphasis on education of primary care physicians to practice cancer prevention programs focused on personal risk profiles is reasonable since the populations these physicians serve express risk factors which represent 50% of the attributable risk for cancer in the US. A summary of site-specific risk factors which are amenable to intervention by primary care physicians is provided.

Venoocclusive disease of the liver following bone marrow transplantation

Review of 235 consecutive patients undergoing bone marrow transplantation was performed in order to define the clinical syndrome of venoocclusive disease of the liver (VOD) in these patients. Analysis of all patients with histologically proven VOD revealed a consistent clinical syndrome of liver dysfunction occurring within the first 3 weeks after marrow infusion. This was characterized by hyperbilirubinemia peaking at greater than or equal to 2 mg/dl with at least 2 of 3 other findings: hepatomegaly, ascites, and 5% or greater weight gain. VOD developed in 22% (52 of 235). A persistently elevated aspartate aminotransferase (SGOT) prior to transplant was associated with an increased risk of developing VOD by multivariate analysis (P = 0.0003), and acute leukemia in first remission was associated with a decreased risk (P = 0.02). Neither the preparative regimen (busulfan and cyclophosphamide versus cyclophosphamide and total body irradiation) nor the type of graft (allogeneic versus autologous) influenced the occurrence. Twenty-four of these 52 patients (47%) died with VOD (10% of the entire group). This makes VOD the third leading cause of death in our allogeneic graft recipients, and the second leading cause in our patients receiving autologous transplants. VOD is a common complication of bone marrow transplantation and has a specific clinical presentation, which usually allows diagnosis without the need of liver biopsy.