PubMed Health⌕ Search

Biomedical subjects

M S Simon

Publications and source records attributed to M S Simon.

At least 19 recordsLinked to original sources
PubMed2005

Reproductive factors and subtypes of breast cancer defined by hormone receptor and histology.

Reproductive factors are associated with reduced risk of breast cancer, but less is known about whether there is differential protection against subtypes of breast cancer. Assuming reproductive factors act through hormonal mechanisms they should protect predominantly against cancers expressing oestrogen (ER) and progesterone (PR) receptors. We examined the effect of reproductive factors on subgroups of tumours defined by hormone receptor status as well as histology using data from the NIHCD Women's Contraceptive and Reproductive Experiences (CARE) Study, a multicenter case-control study of breast cancer. We estimated odds ratios (ORs) and 95% confidence intervals (CIs) as measures of relative risk using multivariate unconditional logistic regression methods. Multiparity and early age at first birth were associated with reduced relative risk of ER + PR + tumours (P for trend=0.0001 and 0.01, respectively), but not of ER - PR - tumours (P for trend=0.27 and 0.85), whereas duration of breastfeeding was associated with lower relative risk of both receptor-positive (P for trend=0.0002) and receptor-negative tumours (P=0.0004). Our results were consistent across subgroups of women based on age and ethnicity. We found few significant differences by histologic subtype, although the strongest protective effect of multiparity was seen for mixed ductolobular tumours. Our results indicate that parity and age at first birth are associated with reduced risk of receptor-positive tumours only, while lactation is associated with reduced risk of both receptor-positive and -negative tumours. This suggests that parity and lactation act through different mechanisms. This study also suggests that reproductive factors have similar protective effects on breast tumours of lobular and ductal origin.

Adult↗
PubMed2004

Radial bone density and breast cancer risk in white and African-American women.

A number of different models for assessing individual risk of breast cancer use known risk factors such as age, age at menarche, age at first live birth, previous breast biopsies, and family history. High bone mass in white women is also associated with an increased breast cancer risk; however, bone mass as a risk factor has not been studied in African-American women. We conducted a case-control study to evaluate bone mineral density as a risk factor for breast cancer in white and African-American women. We recruited 221 women with newly diagnosed breast cancer from a comprehensive breast cancer center at a large university hospital, and 197 control women who were frequency matched for ethnicity and age. Odds ratios were based on proximal and distal radial bone density measured by peripheral bone densitometry (Norland pDEXA) and expressed as a standardized "Z-score" (age and ethnicity specific). Logistic regression models were fitted controlling for body mass index, menopausal status, age, and HRT use (ever/never and duration). With proximal bone density Z-score included in the model as a continuous variable, a one-unit increase in radial shaft bone density increased the risk of breast cancer by 25% (p=0.02). When proximal bone density Z-score was analyzed as a dichotomous variable (< or = 0, > 0) the odds ratio was 1.98 (95% CI, 1.32 to 2.97); that is, having an above average proximal bone density (age-specific) doubles the risk of breast cancer. There were no significant interactions with, and no appreciable confounding effects by, other covariates. An above-average radial shaft Z-score is a significant risk factor for breast cancer in both white and African-American women. The present study extends the association between bone mass and breast cancer risk to African-Americans, and suggests another potential application for bone density testing.

Black or African American↗
PubMed2001

The effect of patient reminders on the use of screening mammography in an urban health department primary care setting.

Mammography screening continues to be under-utilized, especially among women from lower socioeconomic groups. In order to determine whether having direct access to health care services has an effect on mammography use among low income women, we conducted a randomized trial of two alternative letter reminders among 1,717 women who were enrolled at two locations of a multi-site inner city health department in Detroit. All participants were 39(1/2) years of age and older and were due for a screening mammogram at randomization. A physician-directed reminder form was placed in each of the participant's medical records at the beginning of the study. In addition participants were randomized to receive either a letter directing them to visit their primary care physician, a letter directing them to contact the clinic directly to schedule a mammogram, or no letter. Study participants were predominantly African-American, two-thirds of whom were over age 50, and who had minimal health insurance coverage. During the intervention year, mammograms were completed by 179 out of 967 study women at site one (18.5%), and 90 out of 750 study women at site two (12%). A multivariate model controlling for the simultaneous effect of age, insurance type, visit history and past mammography use, showed no significant independent effect of either type of letter reminder on mammography completion during the study year. In conclusion, letters targeted at women due for screening mammograms did not have a beneficial effect on mammography utilization above and beyond that of a physician medical record reminder.

Adult↗
PubMed2001

Comparison of dietary assessment methods in a low-fat dietary intervention program.

The food frequency questionnaire (FFQ) is commonly utilized for assessment of dietary fat intake, but its validity among individuals following a low-fat diet is unclear. We evaluated the agreement of nutrient estimates derived from FFQ, 24-h recall, and 3-day food records obtained from 104 participants in a randomized trial of a low-fat dietary intervention for women at elevated breast cancer risk. Comparisons were made for total calories, percent calories from fat, and total fat after 1 yr. Correlation was assessed using standard methods based on a null hypothesis of no agreement between instruments as well as by a methodology based on a null hypothesis that the instruments should be in agreement. With the use of standard methods, FFQ estimates for women on the low-fat diet were significantly correlated to records only for percent calories from fat (r = 0.39), whereas recall and record estimates were significantly correlated for all three dietary variables. Using the new method, we found no significant correlation between FFQ and either recalls or records for women following a low-fat diet but significant correlation between recall and record estimates for total calories (r = 0.67). Traditional correlation testing may overestimate the extent of agreement in dietary instruments among women on a low-fat diet. We found empirical support for the nontraditional method.

Adult↗
PubMed2001

Levels of 5-hydroxymethyl-2'-deoxyuridine in DNA from blood of women scheduled for breast biopsy.

Systemic oxidative stress is thought to contribute to risk of various cancers, including breast cancer. DNA repair ability also has been associated with breast cancer risk. In this work, we examined levels of oxidative DNA damage as an indication of breast cancer risk in women because oxidative DNA damage levels should reflect the net balance of oxidative stress and DNA repair ability. Levels of 5-hydroxymethyl-2'-deoxyuridine, one form of oxidative DNA damage, were measured in DNA from blood of women scheduled for breast biopsy. The blood samples analyzed included women whose biopsy results indicated invasive breast cancer, high-risk lesions (atypical hyperplasia or carcinoma in situ), or benign lesions. Mean levels of 5-hydroxymethyl-2'-deoxyuridine were significantly higher in blood of women who had high risk or invasive breast lesions versus women with benign lesions. If atypical hyperplasia or carcinoma in situ are precursor lesions for breast cancer, then these results suggest that oxidative DNA damage may be involved in the cancer process before invasive cancer develops.

Biomarkers, Tumor↗
PubMed2000

Recruitment for a pilot case control study of oxidative DNA damage and breast cancer risk.

Oxidative DNA damage (ODD) can result from numerous endogenous metabolic processes as well as from exposure to environmental and dietary oxidants. One important type of ODD that may have a role in carcinogenesis is the formation of hydroxylated DNA bases. Our major purpose was to determine the potential for subject accrual for a multisite case-control study of ODD and breast cancer risk within a large urban university medical center. We examined the levels of a hydroxylated thymine residue, 5-hydroxymethyl-2'-deoxyuridine in DNA obtained from the peripheral blood of 26 women with breast cancer and an age-matched group of 29 control women without breast cancer. The isolated DNA was analyzed for levels of 5-hydroxymethyl-2'-deoxyuridine by gas chromatography with mass spectral detection. Our recruitment methods resulted in a relatively high yield of eligible cases (72%) and a lower yield of controls (46%). We evaluated the dose-response relationship of ODD level to breast cancer risk, using quartiles of ODD. The covariate-adjusted odds ratio of breast cancer exceeded 2.0 for women in the highest quartile of ODD (compared with the lowest quartile), although this result was not statistically significant. ODD levels were significantly more variable among African-American controls (SD = 224.1) than among white controls (SD = 57.5), p < 0.001. Overall, these results suggest a possible slight increase in breast cancer risk among women in the highest ODD quartile, after adjusting for race, menopausal status, and family history of breast cancer.

Antineoplastic Agents↗
PubMed2000

Follow-up among women with an abnormal mammogram in an HMO: is it complete, timely, and efficient?

OBJECTIVE: To describe the extent to which women with seriously abnormal mammograms complete indicated follow-up, the timeliness of this follow-up, and variations in the pattern of use of diagnostic procedures. STUDY DESIGN: Retrospective chart review. PATIENTS AND METHODS: Ninety-two women enrolled in a single urban health maintenance organization (HMO) with an abnormal index mammogram (mass or suspicious calcifications) during 1995 or 1996 were identified by review of all HMO mammography reports. Data were abstracted from medical records concerning all clinical services received over the 11 months after the date of the abnormal mammogram. Procedure costs were estimated based on 1997 Medicare relative-value units. Logistic regression and a multivariate accelerated failure-time model were used to evaluate the association between predictor variables and the occurrence and timing of completion of follow-up. RESULTS: Follow-up was not completed by 31 (34%) of the 92 study women and was delayed beyond 60 days for another 32 (35%). In adjusted analysis, factors associated with completion within 60 days included age less than 50 years and inclusion of a specific follow-up recommendation in the mammogram report. Completion by the end of the study (a minimum of 11 months after the index mammogram) was associated only with the presence of a specific follow-up recommendation. The follow-up process (i.e., the diagnostic procedures used) was highly variable but almost always included surgical evaluation. The average cost among those completing follow-up was about $1900 (in 1997 dollars). CONCLUSIONS: Incomplete follow-up after a potentially seriously abnormal mammogram constitutes an important barrier to breast cancer control efforts in the study HMO, but its explanation remains incompletely understood. The follow-up process itself is highly variable, and improvement in its efficiency and timely completion will require a better understanding of its determinants.

Adult↗
PubMed1999

Accrual to breast cancer clinical trials at a university-affiliated hospital in metropolitan Detroit.

Despite the large number of available studies, most women with breast cancer do not participate in clinical trials, and this is especially true among lower income and minority women. In this study the authors surveyed the practice patterns of four medical oncologists who comprised the clinical breast service at a large urban university hospital to develop a better understanding of the clinical trials enrollment process for women with breast cancer. Of 136 new female breast cancer patients seen by the four physicians over a 7-month period, there were 47 women (34%) offered participation in a clinical trial, and 16 women (12%) were eventually enrolled. Women who were offered participation were more likely to be younger (p = 0.068) and to have earlier stage disease then were women not offered participation (p = 0.008). Women enrolled into a trial were also more likely to be younger, although this difference was not statistically significant (p = 0.114). Patient race was not associated with the accrual or enrollment process. Over half of the women were not offered participation in clinical trials because of the lack of available studies. Further work evaluating the process of patient enrollment and physician and patient barriers is necessary to develop effective strategies for recruitment into breast cancer clinical trials.

Breast Neoplasms↗
PubMed1998

How reminders given to patients and physicians affected pap smear use in a health maintenance organization: results of a randomized controlled trial.

BACKGROUND: Despite its effectiveness as a method of controlling cervical carcinoma, the use of Pap smear testing remains incomplete, and its promotion in the primary care setting provides an important opportunity for intervention. METHODS: The authors conducted a randomized controlled trial that involved three sites of a health maintenance organization (HMO) serving an urban minority population. Their aim was to evaluate the impact of reminders given to patients and physicians on site visitation by patients and Pap smear use. Eligible women (n=5801) were randomly assigned to 1 of 4 intervention combinations (in which reminders were given to either the patient or the physician, to both, or to neither). If they were ineligible for patient reminder intervention, patients were randomized only to physician reminder intervention (the presence or absence of it). The letter of reminder mailed to the patient invited women due for Pap smears to visit the HMO site, and the reminder for physicians was a medical record notice that a Pap smear was due. Logistic and survival analyses were used to investigate the correlation of intervention status with visitation, interval of time to a visit, and Pap smear use. RESULTS: In the primary intent-to-treat analysis, there was no significant effect of either patient or physician reminder interventions on rates of visitation or Pap smear completion. The secondary efficacy analyses demonstrated no overall effect of either patient or physician reminders, but effects among subgroups of women at individual HMO sites were noted. At Site 3, there was an apparent increase in time to the next visit among the subgroup of women with a chronic illness (16 weeks with intervention vs. 9 weeks without). With the physician reminder, the odds that a Pap smear would be given during the study year were increased among women without a previous Pap smear at Site 1 (adjusted odds ratio=1.39) and those with a chronic illness at Site 2 (adjusted odds ratio=3.38). CONCLUSIONS: Reminders given to patients and physicians had a limited impact on visitation by patients to the HMO sites or Pap smear completion. Although some subgroups of women may benefit, the authors also observed a possibly unfavorable impact among other subgroups. These results emphasize the importance of identifying more effective interventions, targeting them to women most likely to benefit, and not overlooking the possibility that preventive intervention will have an unanticipated adverse effect.

Adolescent↗
PubMed1998

Factors affecting participation in a mammography screening program among members of an urban Detroit health maintenance organization.

Breast cancer mortality rates remain disproportionately high among black women despite recent improvements in mammography screening utilization. We conducted a telephone survey among a sample of women (N = 202) participating in a randomized controlled trial investigating the effectiveness of a mammography reminder letter that was one component of a breast cancer control intervention strategy. The objectives of the survey were to ascertain the extent to which the letter reminder was received and acted upon, and to determine attitudes and breast cancer control practices in the target population. The study was conducted among members of a large health maintenance organization serving predominantly black women in Detroit, Michigan. Forty-eight percent of the participants completed a mammogram during the year after the letter was sent. While 72% of the women remembered receiving the letter reminder, only 5% responded to the recommendations in the letter. Important predictors of mammography completion included past mammogram utilization (OR: 2.49; 95% CI: 1.05-5.93), a prior physician recommendation for a mammogram (OR: 1.99; 95% CI: 1.00-3.95) and subject's knowledge of her primary physician's name (OR: 2.05; 95% CI: 0.91-4.60). Letter reminders promoting primary care visits were relatively ineffective since few women reported being prompted by the letter recommendation. Strategies which target physician mammography referral behavior may have an important impact on mammography utilization among inner-city women.

Adult↗
PubMed1997

Trends in primary surgical and radiation therapy for localized breast cancer in the Detroit Metropolitan area 1973-1992.

PURPOSE: The purpose of this report is to describe trends in primary surgical and radiation therapy for localized breast cancer from 1973 through 1992 among residents of the Detroit Metropolitan area. METHODS AND MATERIALS: Data on surgical and radiation therapy procedures for women with local stage breast cancer were obtained from the population-based Metropolitan Detroit Cancer Surveillance System (MDCSS). RESULTS: Women age 75 years and older were treated less aggressively than younger women (< age 75) as evidenced by higher rates of simple mastectomy or no treatment among older women. Younger women (< age 75) were more likely to have had optimal breast conservation therapy which consisted of partial mastectomy, axillary lymph node dissection (ALND), and radiation therapy, than were women who were older than 75. Partial mastectomy has increased proportionally from 4% of all breast cancer surgeries in the time period 1973 to 1977, to 39% of all surgeries from 1988 through 1992. CONCLUSION: A marked difference in surgical treatment of breast cancer exists for younger vs. older women. Despite changes in surgical treatment trends for breast cancer, a large proportion of women who are candidates for conservative therapy continue to undergo mastectomy.

Age Factors↗
PubMed1997

Racial differences in breast cancer survival: the interaction of socioeconomic status and tumor biology.

OBJECTIVE: Our purpose was to evaluate the effect of sociodemographic and clinical variables on survival rates of African-American and white women with breast cancer. STUDY DESIGN: Between 1988 and 1992 the Metropolitan Detroit Cancer Surveillance System Identified 10,502 women (82% white and 18% African-American) in whom invasive breast cancer was diagnosed. Cox proportional hazards regression was used to estimate the relative risk of death for African-Americans compared with whites after controlling for variables believed to influence survival. RESULTS: African-American women were more likely than white women to have tumors that were of a more advanced stage, a higher grade, and hormone receptor-negative. After controlling for age, tumor size, stage, histologic grade, census-derived socioeconomic status, and the presence of a residency training program at the treatment hospital, the relative risk of dying for African-Americans compared with whites was 1.68 (95% confidence interval, 1.27-2.23) for women less than 50 years of age, and 1.33 (95% confidence interval, 1.13-1.56) for women older than 50 years of age. CONCLUSIONS: Known factors that predict survival differences between African-Americans and whites are more prevalent among women less than 50 years of age, emphasizing the need to focus more attention on public health efforts directed toward younger women.

Adolescent↗
PubMed1997

A randomized trial of a low-fat dietary intervention in women at high risk for breast cancer.

A randomized intervention trial of dietary fat reduction to 15% of total calories was initiated in 1987 for women at high risk for breast cancer to determine the feasibility of recruiting and maintaining them on a low-fat diet. The study has enrolled 194 women between the ages of 18 and 67 years who met at least one of three eligibility criteria: 1) a first-degree relative with breast cancer, 2) a P2 or DY Wolfe mammographic pattern, and 3) a prior breast biopsy demonstrating epithelial hyperplasia with or without atypia. Eligible women must also have had diets that contained > or = 30% of calories from fat at entry. Women were randomized to a nonintervention usual diet vs. a 15% low-fat diet. Recruitment was sought through physicians, personal mailings, breast cancer patients, and the news media. Two study sites participated: a large urban hospital affiliated with a university medical center and a community oncology private practice. The results from both institutions were similar and demonstrated that a low-fat dietary plan could be effectively conducted in private as well as academic settings with recruitment tailored to the community where the trial is being conducted. Reduction in dietary fat intake was maximal during the first three months of the dietary intervention and remained stable throughout 12 months of follow-up. Reductions in total calories, weight loss, and percent body fat were minimal. The nonintervention group experienced no major change in their diet. We conclude that it is feasible to recruit women who are at high risk for breast cancer into a dietary intervention trial and with sufficient dietary counseling and motivation on the part of participants, reduction in dietary fat intake can be achieved and maintained. More in-depth analyses of these data will be presented in subsequent reports.

Adolescent↗
PubMed1996

The effect of patient and physician reminders on use of screening mammography in a health maintenance organization. Results of a randomized controlled trial.

BACKGROUND: Despite its demonstrated efficacy in reducing breast carcinoma mortality, screening mammography remains underutilized and its promotion in the primary care setting provides an important opportunity for intervention. METHODS: A randomized controlled trial was conducted in two sites of a health maintenance organization (HMO) serving an urban, minority population to evaluate the impact of patient and physician reminders on site visitation and mammography use. Eligible women (n = 2368) were randomly assigned to 1 of 4 intervention combinations (patient and physician reminders individually, together, or neither). The patient reminder letter invited mammography-due women to visit. The physician reminder was a notice placed in the medical record of mammography-due women. Logistic analysis and survival analysis were used to investigate the relationship of intervention status to visitation, time to a visit, and mammography use. RESULTS: The patient reminder intervention had no effect upon rates of study year visitation or mammography at either site. However, among HMO Site 2 enrollees with entitlement insurance, the median time to the next visit was reduced from 12 to 9 weeks in association with assignment to patient reminder intervention. The physician reminder intervention was also effective in increasing the rate of completed mammography at Site 2 among all assignees (36% vs. 22% for those with vs. those without physician reminders) and among assignees who visited (59% vs. 43%). CONCLUSIONS: Patient reminder letters had limited impact on visitation in this setting. Physician reminders are more effective but sites vary in their responsiveness. Further improvement in mammography utilization will require a better understanding of the determinants of patient and physician behavior.

Adult↗
PubMed1996

Levels of 5-hydroxymethyl-2'-deoxyuridine in DNA from blood as a marker of breast cancer.

BACKGROUND: Oxidative DNA damage can result from numerous endogenous metabolic processes as well as from exposure to environmental and dietary oxidants. One important type of oxidative DNA damage is the formation of hydroxylated DNA bases. This type of DNA damage may have a role in carcinogenesis. METHODS: We examined the levels of a hydroxylated thymine residue, 5-hydroxy-methyl-2'-deoxyuridine, in DNA obtained from the peripheral blood of breast cancer patients and control women. The isolated DNA was analyzed for levels of 5-hydroxymethyl-2'-deoxyuridine by gas chromatography with mass spectral detection. RESULTS: The levels of this modified base were significantly higher in 25 breast cancer patients compared with 38 controls, with levels of 0.112 +/- 0.046 in the cancer patients versus 0.083 - 0.025 in the controls, given as pg 5-hydroxymethyl-2'-deoxyuridine/ng thymidine, mean +/- standard deviation (P = 0.019). After controlling for various covariates, the adjusted mean levels of oxidative DNA damage were still significantly higher in women with breast cancer relative to controls. CONCLUSIONS: These results indicate that the levels of 5-hydroxymethyl-2'-deoxyuridine in DNA from peripheral nucleated blood may be potentially useful as a marker of breast cancer.

Biomarkers, Tumor↗
PubMed1996

Racial differences in survival of female breast cancer in the Detroit metropolitan area.

BACKGROUND: In the United States, breast cancer survival is worse among African-American women compared with white women. This difference in survival is likely due to several factors, including tumor biology and/or access to care. In this analysis, we evaluated the effects of sociodemographic and clinical variables on differences in breast cancer survival among African-American and white women. METHODS: The study population included 10,502 women (82% white, 18% African-American), diagnosed between 1988 and 1992 and identified through the Metropolitan Detroit Cancer Surveillance System, a member of the Surveillance, Epidemiology and End-Results (SEER) Program. Cox proportional hazards regression was used to estimate the relative risk of death comparing African-American women with white women after controlling for variables believed to influence survival. RESULTS: The mean age at diagnosis was 61 years and average length of follow-up was 34 months (range, 1-78 months). African-American women were more likely to present with regional or distant disease (45%) than were white women (37%). Although white women had better survival than African-American women during the first 4 years postdiagnosis (P < 0.0001), there were no significant differences in survival by race for women who lived longer than 4 years (P = 0.64). There was a significant interaction between age and race. The unadjusted relative risk of dying for African-American women compared with white women was 2.35 (95% confidence interval [CI], 1.88-2.93) for women younger than 50 years of age, and was 1.66 (95% CI, 1.46-1.88) for women age 50 years or older. After controlling for age, tumor size, stage, histologic grade, census-derived socioeconomic status, and residency training status, the relative risk was 1.68 (95% CI, 1.27-2.24) for women younger than 50 years of age and 1.33 (95% CI, 1.13-1.56) for women age 50 years and older. Adjustment for marital status, hospital size, and the proportion of Medicaid or Medicare discharges had no further effect on the relative risk. CONCLUSIONS: Known factors that predict survival differences between African-American and white women are more prevalent among women younger than age 50.

Aged↗
PubMed1996

Clinical surveillance for early stage breast cancer: an analysis of claims data.

This study estimates the costs of clinical follow-up for women with early stage breast cancer and evaluates the effects of patient and provider characteristics on follow-up intensity. Claims data were cumulated from 1/1/89 through 4/30/93 for a comprehensive set of follow-up tests (office visits, radiologic, and laboratory) ordered for 222 women diagnosed at a university hospital between 1/1/89 and 12/31/91. Aggregated measures of the volume and costs of follow-up over 6 month intervals were expressed in terms of Medicare's 1993 relative value units (RVUs) and their 1993 cost equivalents. Excluding the first 6 months, women received on average, 11.7 RVUs of follow-up in the first year (equivalent to a cost of $362), and 9.5 RVUs in the second year ($297). In the first year, chest x-rays, clinical chemistry tests, automated hemograms, and bone scans, accounted for 36% of the cost of follow-up, while computerized tomographic scans and magnetic resonance imaging studies accounted for 30%. Multiple regression analysis of the first year data showed that women who received radiation and/or were followed by oncology, were more likely to receive intensive follow-up. Age, race, socioeconomic status, insurance, stage, and treatment did not impact follow-up. Costs of follow-up for breast cancer are substantial, though much lower than suggested by others. Additionally, wide variations in practice are largely unexplained by patient and/or provider characteristics. In light of recent evidence questioning the benefit of intensive surveillance, this study supports the need for an accepted set of follow-up guidelines for breast cancer.

Breast Neoplasms↗
PubMed1996

An analysis of the cost of clinical surveillance after primary therapy for women with early stage invasive breast cancer.

Routine surveillance for distant metastases in women with early stage breast cancer has limited clinical utility and can result in large medical care costs. In order to estimate breast cancer surveillance costs, we used the results of a survey administered to a random sample of physician members of the American Society of Clinical Oncology. The survey measured the frequency in which radiographic and laboratory tests are ordered for postmenopausal women with stage I or II breast cancer after the completion of surgery and radiation or adjuvant chemotherapy if indicated. There were 209 completed surveys representing a response rate of 48%. The volume of tests ordered was expressed in terms of Medicare's relative value units (RVUs) and 1993 cost equivalents. The mean total RVUs over 5 years post-diagnosis was 43.8 (interquartile range 30.1-54.2) which represents a cost of $1369 using the 1993 Medicare conversion factor of $31.249. A cumulative logistic regression model categorized RVUs according to intensity of care (minimal, average, and intensive). While medical oncologists compared to surgeons and radiation oncologists, and physicians practicing in the Northeast and Midwest, compared to those practicing in the South and West, were more likely to adopt an intensive practice style, these differences were not statistically significant (p = 0.1). None of the other provider characteristics evaluated, including gender, prior experience, and practice type, had a significant effect on physician practice in a multivariate model. The data showed a wide variation among providers in surveillance practice patterns that was largely unexplained by physician demographics. These results are consistent with the physician practice style hypothesis which suggests that wide variations in treatment patterns result from uncertainty regarding effectiveness of care.

Breast Neoplasms↗