Effect of variations in operational definitions on performance estimates for screening mammography.

RATIONALE AND OBJECTIVES: The Mammography Quality Standards Act requires practices to measure limited aspects of their performance. The authors conducted this study to calculate the differences in measurements of sensitivity and specificity due only to differences in the definitions used in the analysis. This included definitions for case inclusion. MATERIALS AND METHODS: Data from the New Mexico Mammography Project for January 1991 to December 1995 on 136,540 women who underwent screening mammography were analyzed. A starting definition was created for each performance measure. The components of the definition were varied, and estimates of sensitivity and specificity for the different definitions were calculated. RESULTS: Sensitivity was lower and specificity was higher when assessed on the basis of the results of all imaging performed in the screening work-up rather than on the initial screening examination alone. Sensitivity was higher and specificity was lower in women who did not undergo rather than in women who did recently undergo a previous examination. When the definition of a positive examination included cases that were recommended for short-term follow-up, the work-up sensitivity was slightly higher and the work-up specificity was considerably lower. Longer follow-up times for determining the diagnosis of cancer were associated with decreasing sensitivity, particularly when the follow-up period extended beyond 12 months. CONCLUSION: Variations in the operational definitions for measures of mammographic performance affect these estimates. To facilitate valid comparisons, reports need to be explicit regarding the definitions and methods used.

Current medicolegal and confidentiality issues in large, multicenter research programs.

The convenience of fast computers and the Internet have encouraged large collaborative research efforts by allowing transfers of data from multiple sites to a single data repository; however, standards for managing data security are needed to protect the confidentiality of participants. Through Dartmouth Medical School, in 1996-1998, the authors conducted a medicolegal analysis of federal laws, state statutes, and institutional policies in eight states and three different types of health care settings, which are part of a breast cancer surveillance consortium contributing data electronically to a centralized data repository. They learned that a variety of state and federal laws are available to protect confidentiality of professional and lay research participants. The strongest protection available is the Federal Certificate of Confidentiality, which supersedes state statutory protection, has been tested in court, and extends protection from forced disclosure (in litigation) to health care providers as well as patients. This paper describes the careful planning necessary to ensure adequate legal protection and data security, which must include a comprehensive understanding of state and federal protections applicable to medical research. Researchers must also develop rules or guidelines to ensure appropriate collection, use, and sharing of data. Finally, systems for the storage of both paper and electronic records must be as secure as possible.

Spit (smokeless) tobacco use by high school baseball athletes in California.

OBJECTIVE: To describe the prevalence, patterns, and correlates of spit (smokeless) tobacco (ST) use in a sample of high school baseball athletes in California. DESIGN: This cross sectional study was a survey of 1226 baseball athletes attending 39 California high schools that were randomly selected from a list of all publicly supported high schools with baseball teams. At a baseball team meeting, athletes who agreed to participate and had parental consent completed the study questionnaire. To enhance the accuracy of self reported ST use status, a saliva sample was collected from each subject. The questionnaires and saliva samples were coded and salivary cotinine assay was performed on a random subsample of 5% of non-users who also were non-smokers. Biochemical assay indicated that 2% tested positive for cotinine inconsistent with self reported ST non-use. RESULTS: Overall, 46% had ever used ST and 15% were current users. Odds ratios and 95% confidence intervals (CI) suggested that, among high school baseball athletes, age, living in a rural area, being white, smoking cigarettes, drinking alcohol, not knowing about the adverse effects of ST, perceiving little personal risk associated with ST use, and believing that friends, role models, teammates, and same age baseball athletes in general used ST, increased the likelihood of being an ST user. CONCLUSION: The findings indicate that considerable experimentation with ST products occurs among high school baseball athletes in California, and many are current users. ST interventions targeting this population are needed to stop the transition from experimental ST use to tobacco dependence. Correlates of ST use for consideration in future intervention studies are identified.

Mortality among women with ductal carcinoma in situ of the breast in the population-based surveillance, epidemiology and end results program.

BACKGROUND: Over 14% of breast cancers diagnosed in the United States annually are ductal carcinomas in situ (DCIS). There are no published population-based reports of the likelihood of breast cancer death among US women with DCIS. METHODS: We used data from the Surveillance, Epidemiology and End Results program to determine the likelihood of breast cancer death at 5 and 10 years among US women aged 40 and older diagnosed with DCIS from 1978 to 1983 (before screening mammography was common; n = 1525) and from 1984 to 1989 (when screening mammography became common; n = 5547). We also calculated standardized mortality ratios (SMRs) to compare observed deaths from breast cancer, cardiovascular disease, and all causes combined among women with DCIS with deaths expected based on general population mortality rates. RESULTS: Among women diagnosed with DCIS from 1978 to 1983, 1.5% died of breast cancer within 5 years and 3.4% within 10 years. Among women diagnosed from 1984 to 1989, 0.7% died of breast cancer within 5 years and 1.9% within 10 years. Relative to the general population, risk of breast cancer death was greater for women diagnosed from 1978 to 1983 (SMR, 3.4; 95% confidence interval [CI], 2.5-4.5) than for women diagnosed from 1984 to 1989 (10-year SMR, 1.9; 95% CI, 1.5-2.3). Women diagnosed from 1984 to 1989 were significantly less likely than women in the general population to have died of cardiovascular diseases (10-year SMR, 0.6; 95% CI, 0.5-0.7) or of all causes combined (SMR, 0.8; 95% CI, 0.7-0.8). CONCLUSIONS: Among women diagnosed with DCIS, risk of death from breast cancer was low, at least within the 10 years following diagnosis. This may reflect the effectiveness of treatment for DCIS, the "benign" nature of DCIS, or both. At 10 years, women diagnosed from 1984 to 1989 were less likely than women diagnosed from 1978 to 1983 to have died of breast cancer, and their risk of dying of all causes combined was lower than that in the general population.

Smokeless tobacco cessation intervention for college athletes: results after 1 year.

OBJECTIVES: The purpose of this study was to determine the efficacy of a college-based smokeless tobacco cessation intervention targeting college athletes. METHODS: Sixteen colleges were matched for prevalence of smokeless tobacco use in their combined baseball and football teams and randomly assigned within college pairs to the intervention or the control group. One-year prevalence of cessation among smokeless tobacco users was determined by self-report of abstinence for the previous 30 days. Differences between groups were analyzed in a weighted version of the Fisher 1-sided permutation test for paired samples after adjustment for significant predictors of quitting other than the intervention (i.e., smokeless tobacco uses per week and most frequently used brand). RESULTS: Cessation prevalences were 35% in the intervention colleges and 16% in the control colleges when subjects with unknown quit status were defined as nonquitters. After adjustment for other significant predictors of quitting, the difference of 19% increased to 21%. The intervention effect increased with level of smokeless tobacco use. CONCLUSIONS: This intervention was effective in promoting smokeless tobacco cessation, especially among those who were more frequent users.

Birthplace and yield of nipple aspirate fluid in Chinese women.

The different rates of breast cancer found between Chinese women in Asia compared with Chinese-born women in the United States suggest that dietary and environmental factors may be of etiological significance. We evaluated the proportion of 480 premenopausal Chinese women who yielded nipple aspirate fluid (NAF) by birthplace in Asia versus the United States and by reproductive and other risk factors. Birthplace was used as a surrogate for presumed differences in exposures during gestation, childhood, and adolescence that might influence yield of NAF in premenopausal women. In United States-born Chinese women compared with Asia-born Chinese women, the proportion yielding NAF was 44 of 95 (46.3%) versus 120 of 385 (31.2%), respectively. The relative risk of yield of NAF in United States-born women compared with Asia-born women was odds ratio = 2.37 (95% confidence interval, 1.26-4.47). Independent positive associations of NAF yield were also found with history of parity and breast feeding, cerumen phenotype, and a negative association with ever use of oral contraceptives. These findings support the hypothesis that early environmental exposures may have long-lasting physiological effects discernible in the breast glands of adult women.

Occurrence of other cancers among patients with prior basal cell and squamous cell skin cancer.

Epidemiological studies suggest that individuals with basal cell carcinoma (BCC) and squamous cell carcinoma (SCC) of the skin are more likely to develop other malignancies; however, the factors responsible for this are unknown. To clarify the risk of other cancers following the occurrence of BCC and SCC, we followed participants in a multicenter skin cancer prevention trial for subsequent malignancies. The study group consisted of 1805 BCC and SCC patients who had enrolled in a trial testing the efficacy of oral beta-carotene. Medical confirmation was sought for all cancers (other than BCC or SCC), which were reported by participants or their next-of-kin over a follow-up period of 10 years. We computed the rate ratio (RR) and 95% confidence interval (CI) of time to first new, primary cancer in relation to history of BCC and SCC, using a proportional hazards model. A total of 235 participants had a new primary invasive cancer during 13,887 person-years of follow up. The risk of other cancers was modestly elevated in patients with one or more previous SCCs compared with those who only had a history of BCC (adjusted RR, 1.37; 95% CI, 0.91-2.07). Risk of other cancers also appeared to be increased among those who had multiple prior BCCs relative to those who had only one prior BCC (adjusted RR, 1.21; 95% CI, 0.91-1.61). Further adjustment for smoking history, Quetelet index, radiotherapy, extent of actinic skin damage, treatment assignment, or baseline beta-carotene concentrations did not appreciably alter the results. Cancer of the respiratory system was most strongly related to previous SCC or multiple BCC [RRs (95% CI), 2.20 (1.05-4.62) and 2.34 (1.14-4.83), respectively]. Our data suggest that unidentified exposures or inherited risk factors may play a common etiological role in the pathogenesis of nonmelanoma skin cancer and other cancers, especially respiratory cancers, although larger studies would be necessary to exclude the role of chance in these findings.

A comparison of two methods to teach smoking-cessation techniques to medical students.

PURPOSE: To evaluate two smoking-cessation practice exercises, one using standardized patients (SPs), the other using role playing by medical students. METHOD: In the spring of 1994 all 120 first-year University of California, San Francisco, School of Medicine Students were given lectures on the health effects of smoking and how physicians can help patients quit. Afterward some of the students were randomly assigned to two groups in which to practice counseling patients: Group 1 (n = 35) used SPs, Group 2 (n = 37) used role playing. Each of the Group 1 students practiced smoking-cessation techniques with an SP; the SP evaluated the student on cognitive and communication skills, assigned an overall rating, and provide feedback using a standardized form. The Group 2 students (as well as the 48 students not assigned to a group) role-played in pairs and used the same form to provide feedback. All the students evaluated their respective practice practices. Two weeks later 24 Group 1 and 31 Group 2 students participated in a clinic-skills-assessment exercise using SPs. As in the Group 1 practice exercise, each student was evaluated by an SP on cognitive and communication skills and assigned an overall rating. Data were analyzed through a number of statistical methods. The cost of the SP program was determined. RESULTS: The Group 1 students rated their practice exercise much more favorably than did the Group 2 students. However, there was no significant difference between the groups in their ratings by the SPs on the clinical-skills-assessment exercise. The use of SPs cost a great deal more than did the use of role playing. CONCLUSION: Although the students rated the SPs higher than they did the role playing, the two tools produced similar levels of skills attainment. The data suggest that having students practice smoking-cessation techniques through role playing may be as effective as using the more extensive SPs.

Increases in ductal carcinoma in situ (DCIS) of the breast in relation to mammography: a dilemma.

The increased use of screening mammography has resulted in a marked increase in detected cases of ductal carcinoma in situ (DCIS) of the breast since the early 1980s. In 1993, there were an estimated 23,275 newly diagnosed cases of DCIS in the United States, of which 4,676 were in women aged 40-49. DCIS accounted for 14.7% of all newly diagnosed breast cancers in women aged 40-49 in 1993, and perhaps 40% of all mammographically detected breast cancers in this age group are DCIS. Among women aged 40-49, an estimated 1,890 mastectomies and 2,707 lumpectomies (with or without radiation) were performed for DCIS in 1993. There is an urgent need to better understand the relationship of mammographically detected DCIS to invasive and potentially life-threatening breast cancer. Better information about the appropriate treatment of DCIS is also needed to reduce the confusion and uncertainty many women and their physicians currently experience in the face of a DCIS diagnosis. For the present, women considering screening mammography should be told the likelihood of being diagnosed with DCIS and that only some DCIS cases may be clinically significant but almost all will be treated surgically.

Incidence of and treatment for ductal carcinoma in situ of the breast.

OBJECTIVE: To describe trends in incidence and treatment for ductal carcinoma in situ (DCIS) of the breast in the United States between 1973 and 1992 and to estimate total numbers of in situ cases diagnosed and numbers treated by mastectomy since 1983, when screening mammography for breast cancer began to become widespread. DESIGN: Analysis of population-based breast cancer incidence data collected by the National Cancer Institute's Surveillance, Epidemiology, and End Results (SEER) program since 1973 and treatment data collected by the SEER program since 1983. STUDY POPULATION: All women in the geographic areas af the United States included in the SEER program. MAIN OUTCOME MEASURES: Annual age-adjusted and age-specific incidence rates for DCIS; time trends in distribution of cases by type of treatment; percentage of cases treated by mastectomy by geographic area; and estimated numbers for the entire United States of DCIS cases, mastectomies for DCIS, and cases attributable to mammography. RESULTS: There was a marked increase in DCIS incidence beginning in the early 1980s. Average annual increases in rates between 1973 and 1983 and between 1983 and 1992 changed from 0.3% to 12.0% among women aged 30 to 39 years, from 0.4% to 17.4% among women aged 40 to 49, and from 5.2% to 18.1% among women aged 50 years or older. The total estimated number of DCIS cases in the United States in 1992 (23,368) was 200% higher than expected based on 1983 rates and trends between 1973 and 1983. Between 1983 and 1992, there was a marked decline in the proportion of DCIS cases treated by mastectomy (from 71% to 43.8%) and an increase in those treated by lumpectomy (from 25.6% to 53.3%). In 1992, 23.3% of cases were treated by lumpectomy and radiation, 30.2% by lumpectomy alone, and 2.6% with no surgery. Treatment patterns varied substantially by geographic area, with 57.7% of cases in New Mexico treated by mastectomy in 1992 compared with 28.8% in Connecticut. Despite the decline in the proportion of cases treated by mastectomy, the increased DCIS incidence rates resulted in an increase in the absolute number of cases treated by mastectomy until 1990 (n=10,657); in 1992, there were an estimated 10,242 DCIS cases treated by mastectomy. CONCLUSIONS: Incidence rates of DCIS of the breast have increased dramatically since 1983. This increase correlates with the widespread adoption of modern mammographic screening. While early detection of invasive breast cancer is beneficial, the value of DCIS detection is currently unknown. There is cause for concern about the large number of DCIS cases that are being diagnosed as a consequence of screening mammography, most of which are treated by some form of surgery. In addition, the proportion of cases treated by mastectomy may be inappropriately high, particularly in some areas of the United States.