Pre-cancerous breast lesions: implications for breast cancer prevention trials

Benign Breast Diseases: Evaluation and Management

Benign breast disease is a spectrum of common disorders. The majority of patients with a clinical breast lesion will have benign process. Management involves symptom control when present, pathologic-based and imaging-based evaluation to distinguish from a malignant process, and counseling for patients that have an increased breast cancer risk due to the benign disorder.

Comparison of the effects of genetic and environmental risk factors on in situ and invasive ductal breast cancer

Little is known about the etiology of in situ ductal breast cancer (DCIS) or what influences its possible progression to invasive ductal disease. Comparison of risk factors for DCIS and invasive ductal cancer may throw some light on these issues. We estimated relative risks for DCIS and invasive ductal breast cancer according to 12 genetic and eight environmental risk factors among 1.1 million postmenopausal women in a large prospective UK study. There was no strong evidence of a different association with DCIS versus invasive ductal cancer for any of the 12 susceptibility loci examined. We also found similar associations of age at menarche, age at first birth, parity, age at menopause, family history of breast cancer and use of hormone replacement therapy with DCIS and invasive ductal cancer. Only body mass index (BMI) showed a clear difference in association in that it was positively associated with the risk of invasive ductal cancer but not DCIS (RRs per 5 kg/m(2) = 1.20 and 1.01, respectively; p-value for heterogeneity = 0.002). The very similar risk factor profiles observed here for DCIS and invasive ductal cancer suggest that DCIS is a precursor of invasive ductal cancer and most risk factors affect the risk of invasive ductal cancer primarily through their effects on the risk of DCIS. The lack of association between BMI and DCIS suggests a greater influence of BMI on disease progression.

Reproductive and menstrual factors and risk of ductal carcinoma in situ of the breast in a cohort of postmenopausal women

PURPOSE

The contribution of menstrual and reproductive factors to risk of ductal carcinoma (DCIS) of the breast is poorly understood.

METHODS

The association between menstrual and reproductive factors and subsequent DCIS risk was examined in Women's Health Initiative (WHI) clinical trial participants, in which mammography was protocol mandated. The cohort consisted of 64,060 women, among whom 664 cases of DCIS were ascertained over a median follow-up of 12.0 years. Cox proportional hazards models were used to estimate hazard ratios (HR) and 95% confidence intervals (95% CI).

RESULTS

After adjustment for covariates, only older age at menopause (HR ≥ 55 vs. 45-54 : 1.39, 95% CI 1.08-1.79) was significantly associated with risk; however, greater parity (HR ≥ 5 live births vs. 0: 0.70, 95% CI 0.47-1.03), among parous women, and age at first live birth (HR ≥ 30 years relative to <20 years: 1.32, 95% CI 0.92-1.90) were of borderline significance. Age at menarche and months of breast-feeding were not associated with risk. Associations did not differ between high- and low-/moderate-grade DCIS, or by level of body mass index or family history of breast cancer; however, there was a suggestion that the associations of age at menopause, parity, and age at first live birth were limited to women who had ever used hormone therapy.

CONCLUSIONS

Findings from this large cohort of postmenopausal women suggest that age at menopause, and possibly, age at first live birth, and parity are associated with risk of DCIS, whereas age at menarche and duration of breast-feeding are not.

Benign breast diseases: classification, diagnosis, and management

Benign breast diseases constitute a heterogeneous group of lesions including developmental abnormalities, inflammatory lesions, epithelial and stromal proliferations, and neoplasms. In this review, common benign lesions are summarized and their relationship to the development of subsequent breast cancer is emphasized.

Impact of concurrent proliferative high-risk lesions on the risk of ipsilateral breast carcinoma recurrence and contralateral breast carcinoma development in patients with ductal carcinoma in situ treated with breast-conserving therapy

BACKGROUND

The purpose of the study was to determine the risk of ipsilateral breast carcinoma recurrence (IBCR) and contralateral breast carcinoma (CBC) development in patients with a concurrent diagnosis of ductal carcinoma in situ (DCIS) with atypical ductal hyperplasia (ADH), atypical lobular hyperplasia (ALH), or lobular carcinoma in situ (LCIS).

METHODS

Records of all 307 patients with DCIS treated with breast-conserving treatment (BCT) from 1968 to 1998 were analyzed. Initial pathology reports and all slides available were re-reviewed for evidence of ADH, ALH, or LCIS. Actuarial local recurrence rates were calculated.

RESULTS

Fifty-five cases of DCIS were associated with ADH, 11 with ALH or LCIS, and 14 with both ADH and ALH or LCIS. Overall, IBCR occurred in 14% and no significant difference in the IBCR rate was identified for patients with proliferative lesions compared with patients without these lesions (P = 0.38). Development of CBC in patients with concurrent DCIS and ADH was 4.4 times (95% confidence interval [CI], 1.44-13.63) that in patients with DCIS alone (P < 0.01). The 15-year cumulative rate of CBC development was 22.7% in patients with ALH or LCIS compared with 6.5% in patients without these lesions (P = 0.30) and 19% in patients with ADH compared with 4.1% in patients with DCIS alone (P < 0.01).

CONCLUSION

The risk of CBC development is higher with concurrent ADH than in patients with DCIS alone, and these patients may therefore be appropriate candidates for additional chemoprevention strategies. Concurrent ADH, ALH, or LCIS with DCIS is not a contraindication to BCT.

Acceptance of tamoxifen chemoprevention by physicians and women at risk

BACKGROUND

In the National Surgical Adjuvant Breast and Bowel Project (NSABP) P-1 trial, tamoxifen was shown to reduce breast carcinoma risk by 49% in high-risk women. The purpose of the current study was to identify factors associated with being offered, and accepting, tamoxifen chemoprevention.

METHODS

The records of 219 women who sought risk evaluation after the publication of the NSABP P-1 trial between September 1998 and October 2002 were reviewed. Risk was calculated using the model of either Gail et al. or Claus et al. The impact of individual risk factors on the offering and acceptance of tamoxifen was compared using the Fisher exact test and logistic regression analysis.

RESULTS

Tamoxifen was offered to 137 women (63%) in the current study. The magnitude of Gail risk, age, menopausal status, hysterectomy, and history of lobular carcinoma in situ (LCIS) or atypical hyperplasia (AH) were all found to be significant predictors of a patient being offered tamoxifen. On multivariate analysis, only a history of AH or LCIS and hysterectomy were found to be significant, with odds ratios of 20.3 and 3.4, respectively. Fifty-seven of the women who were offered tamoxifen (42%) took the drug. Only a history of LCIS or AH and older age were found to be predictive of tamoxifen acceptance.

CONCLUSIONS

In the current study, risk due to AH or LCIS was found to be the main predictor of being offered and accepting tamoxifen chemoprevention.

Identification of the woman at risk for breast cancer: problem solved?

The clinical availability of antiestrogens to reduce breast cancer incidence has focused increased attention on the ability to identify women at increased risk for breast cancer development. Multiple risk factors, which can be grouped under the headings of genetic and familial factors, hormonal factors, benign breast disease, and environmental factors have been described. However, of these risk factors, only genetic mutations and atypical hyperplasia, lobular carcinoma in situ, and ductal carcinoma in situ have a relative risk of four or more. Many of the other risk factors, although associated with statistically significant increases in risk in large populations, are of little practical significance for the individual woman. Lack of knowledge of the interactions among various positive and negative risk factors also complicates the evaluation of risk. In addition, the impact of some risk factors may not be constant over time, and the majority of data on risk come from studies of white women, and little is known about the impact of ethnic diversity on these factors. Finally, there is no consensus about what level of increase in risk is necessary for a women to be labeled "high risk." It is important to recognize that only 50% of breast cancers occur in women with identifiable risk factors other than age. Thus, an improved ability to define risk status is needed if prevention studies directed at high-risk women are to have a major impact on breast cancer incidence and mortality.

The presence of proliferative breast disease with atypia does not significantly influence outcome in early-stage invasive breast cancer treated with conservative surgery and radiation

PURPOSE

To evaluate the influence of the benign background breast-tissue change of atypical hyperplasia (AH) on outcome in patients with early-stage invasive breast cancer treated with conservative surgery and radiation.

MATERIALS AND METHODS

Four hundred and sixty women with Stage I--II breast cancer treated with conservative surgery and radiation from 1982-1994 had pathologic assessment of their background adjacent benign breast tissue. The median follow-up was 5.6 years (range 0.1-15). The median age was 55 years (range 24-88). Of these, 23% had positive axillary nodes; 25% received adjuvant chemotherapy (CMF or CAF) with (9%) or without (17%) tamoxifen. Of the total, 24% received adjuvant tamoxifen alone. The patients were divided into 2 groups: 131 patients with atypical hyperplasia (ductal, 99 patients; lobular, 20 pts; and type not specified, 12 pts), and 329 patients with no proliferative changes or proliferative changes without atypia.

RESULT

A statistically significant difference was observed between the 2 groups for method of detection, primary tumor size, presence of lobular carcinoma in situ (LCIS), pathologic nodal status, region(s) treated with radiation, and type of adjuvant therapy. Patients with atypical hyperplasia (AH) had smaller primary tumors (T1 80% vs. 70%) more often detected solely by mammography (51% vs. 36%) with negative axillary nodes (87% vs. 73%) and radiation treatment to the breast only (93% vs. 78%). LCIS was observed in 9% of the patients with AH and 3% of those without AH. Patients with AH more often received tamoxifen alone (32% vs. 21%), rather than chemotherapy (15% vs. 29%). There were no statistically significant differences between the 2 groups for race, age, menopausal status, family history, histology, histologic subtype DCIS when present, the presence or absence of an extensive intraductal component, final margin status, estrogen or progesterone receptor status, use of re-excision, or total radiation dose to the primary. The 5- and 10-year actuarial ipsilateral breast tumor recurrence rates were 2% and 12% for patients with AH and 4% and 8% for those without AH (p=0.44). Younger women or those with a positive family history of breast cancer with AH did not have an increased rate of breast failure when compared to similar patients without AH. There were no significant differences in the 5- and 10-year actuarial rates of distant metastases (AH 5- and 10-year 7% and 7%, no AH 5- and 10-year 8% and 16%,p=0.31), regional node recurrence (AH 1% and 1%, no AH 1% and 1%,p=0.71), contralateral breast cancer (AH 3% and 3%, no AH 3% and 8%,p=0.71), overall survival (AH 95% and 86%, no AH 95% and 89%, p=0.79), or cause-specific survival (AH 98% and 95%, no AH 96% and 91%,p=0.27). Subset analysis for ipsilateral breast tumor recurrence, distant metastases, overall, and cause-specific survival for T1 vs. T2 tumors and path node-negative vs. path node-positive patients revealed no significant differences between the 2 groups.

CONCLUSION

AH was not associated with an increased risk of ipsilateral breast tumor recurrence or contralateral breast cancer in this study of patients with invasive breast cancer treated with conservative surgery and radiation. Therefore, the presence of proliferative changes with atypia in background benign breast tissue should not be a contraindication to breast-conservation therapy.

Parity, age at first birth and the risk of carcinoma in situ of the breast

Epidemiological studies of in situ breast cancer are sparse, and the role of reproductive history, an established risk modifier for invasive breast cancer, remains incompletely investigated. To examine possible associations with parity and age at first birth, we undertook a case-control study nested in a nationwide cohort of Swedish women. The reproductive history of 1,368 women aged 65 or younger with a diagnosis of carcinoma in situ of the breast were compared with that of 6,837 age-matched controls drawn randomly from a population-based Fertility Registry. Statistical analyses were performed by conditional logistic regression. Compared to nulliparous women, ever-parous women were at a reduced risk of carcinoma in situ of the breast. The risk decreased with number of live births, with the estimated risk reduction in the highest parity group (5+), being of the same magnitude as that reported for invasive breast cancer. By contrast, a positive association with increasing age at first birth was somewhat less pronounced than that observed previously in the same data set with respect to invasive breast cancer. Our findings indicate that parity affects the risk of invasive breast cancer and carcinoma in situ similarly, whereas the effect of age at first birth appears to be weaker for the risk of carcinoma in situ.

Lobular carcinoma in situ as a component of breast cancer: the long-term outcome in patients treated with breast-conservation therapy

PURPOSE

The purpose of this study is to assess the long-term outcome of breast cancer patients with a component of lobular carcinoma in situ (LCIS) treated with conservative surgery and radiation therapy.

METHODS AND MATERIALS

The pathology reports of all patients treated with conservative surgery and radiation therapy at our institution prior to 1992 were reviewed to identify patients who had LCIS as a histologic component. A total of 51 patients were identified. Primary histology of the 51 patients was as follows: 53% infiltrating lobular, 20% invasive and intraductal, 18% invasive ductal, 10% intraductal. There were no patients treated who had LCIS only. One thousand forty-five patients treated conservatively during the same time interval without LCIS served as a control group. All patient characteristics, staging, treatment and outcome variables were entered into a computer database.

RESULTS

As of 3/96, the median follow-up for the LCIS-containing group and control group was 10.6 and 11.4 years, respectively. There were no significant differences in age of presentation, clinical stage, nodal status, estrogen receptor status, or adjuvant therapy received between the two groups. Twenty-two patients (43%) in the LCIS group underwent reexcision. Of those, 69% had residual LCIS in the reexcision specimen. LCIS was characterized as focal in 29%, diffuse in 25%, and not specified in all other cases. The primary histology of the two populations differed significantly with a larger percentage of infiltrating lobular primaries in the LCIS group (53 vs. 5%, p < 0.001). The LCIS group also differed from the control group with respect to the percentage of patients with bilateral disease (17 vs. 8%, p = 0.05), and the percentage of patients with "false negative" mammograms (20 vs. 10%, p = 0.02). There was no statistically significant difference between the LCIS group and control group in the 10-year overall survival (67 vs. 72%), distant disease-free survival (62 vs. 79%), or ipsilateral breast tumor recurrence-free survival (77% LCIS vs. 84% control).

CONCLUSION

Patients with LCIS as a histologic component of breast cancer do not carry a worse prognosis than breast cancer patients without an LCIS component. Furthermore, the comparable local control rates between conservatively treated patients with or without LCIS suggests that patients with a histologic component of LCIS are suitable candidates for conservative surgery and radiation therapy.

Variation of bcl-2 expression in breast ducts and lobules in relation to plasma progesterone levels: overexpression and absence of variation in fibroadenomas

Some women with benign breast disease eventually develop breast cancer. The mammary gland undergoes tissue remodelling according to hormonal influences, involving a balance between quiescence, proliferation, and mechanisms of cell death. Proliferation and/or apoptotic events could therefore be investigated to help understand the mechanisms of benign lesion formation and identify mastopathies with a poor prognosis. bcl-2 expression was analysed by immunohistochemistry in 75 benign mastopathies. Protein levels were quantitated with an image analyser in various epithelial structures on frozen sections, including adenoses, fibroadenomas, ductal epithelial hyperplasias, cysts, and apparently normal surrounding lobules and ducts. bcl-2 levels were equivalent in apparently normal lobules and ducts, as well as in cysts and ductal hyperplasias. bcl-2 staining was significantly higher in fibroadenomas, known to be of lobular origin [mean = 10.1, quantitative immunochemistry score (QIC) arbitrary units (AU), n = 19], than in normal lobules (mean = 5.1 AU, n = 43, P = 7 x 10(-5). bcl-2 levels in normal lobules and ducts varied according to the menstrual cycle, being higher during the follicular than the luteal phase (P = 1.8 x 10(-2) and P = 1.7 x 10(-2), respectively). This was further supported by a statistical link (P = 5 x 10(-3) between high levels of circulating progesterone and weak bcl-2 staining in lobules and ducts. This progesterone-dependent variation was absent in fibroadenomas. No statistical correlation was found between bcl-2 expression and circulating levels of oestradiol, and follicle-stimulating or luteotrophic hormones. Although these are only preliminary results, they suggest an influence of progesterone on bcl-2 expression which might be lost in fibroadenomas. A hypothesis is proposed concerning the potential involvement of altered regulation of the apoptotic process in the formation of such benign lesions.

The woman at high risk for breast cancer. Importance of hyperplasia

In summary, some histopathologically identifiable lesions within the human breast indicate later development of invasive breast cancer at an increased incidence over that of the general population. Many of these may be regarded as markers of increased risk because they are indicative of cancers presenting anywhere in either breast, whereas the noncomedo DCIS lesions are unique in indicating a high likelihood of invasive disease at the same site of detection of the initial high-risk lesion (Table 2).

Identification and management of the woman at increased risk for breast cancer development

Multiple factors which increase a women's breast cancer risk have been identified. These range from conditions such as lobular carcinoma in situ which increase risk to relatively high levels, to reproductive factors such as nulliparity which are associated with only a small increase in risk. When determining an individual's risk, all her potential breast cancer risk factors must be considered. In order for risk information to be meaningful to a woman, risk must be expressed as absolute risk over a defined time interval since there is no uniform agreement on what risk level is high enough to require intervention. At present, careful follow-up or prophylactic mastectomy are the management options available for the woman at increased risk. The efficacy of follow-up including breast self exam, physician exams, and screening mammography for early detection of cancer in a high risk population is unknown. Prophylactic mastectomy, while highly effective, does not provide complete protection from breast cancer and is more radical than the surgery done for established cancer in many cases. Which of these options is chosen by an individual woman is dependent on how much risk she is willing to assume.

Fourteenth Gaddum Memorial Lecture. A current view of tamoxifen for the treatment and prevention of breast cancer

Tamoxifen has been found to be a safe and effective treatment for all stages of breast cancer. Long term tamoxifen therapy is associated with some rare, but potentially serious, side effects so patients should be carefully monitored. However, long term tamoxifen therapy is also associated with a number of physiological benefits over and above its tumouristatic action. These benefits include a decrease in the development of contralateral breast cancer, the maintenance of bone density in postmenopausal women and a decrease in cardiovascular disease. The successful application of tamoxifen to treat breast cancer has increased enthusiasm to test its worth to prevent breast cancer. Although there are individual requests by patients for tamoxifen to prevent breast cancer, individual treatment is inappropriate. Tamoxifen can only be adequately evaluated as a preventive in randomized, double-blind clinical trials. These trials are in place and physicians should encourage women to participate and establish a new therapeutic option as rapidly as possible.

An appraisal of strategies to reduce the incidence of breast cancer

The current focus of breast cancer research is to develop a novel strategy to prevent the disease. In this review a potential model of breast cancer development is proposed based upon the results of laboratory models of the induction of mammary carcinogenesis. It is clear that susceptibility to initiation occurs in young female animals, and a preventive strategy is more effective the sooner it is started after initiation occurs. In humans we do not know the timing or the nature of the carcinogenic insult, but epidemiologic studies suggest that the process is long and initiation is most likely to occur in young adults. Hormones are the key to promotion of the carcinogenic process and it would appear that strategically the earlier an intervention is applied after initiation the better will be the general effect on the population. Hormonal contraception could prevent breast cancer if the appropriate formulation was chosen and used by all young women. This inhibitory strategy might protect women without the need to preselect based on risk factors. Breast cancer prevention would be a side effect of the contraceptive method. Alternatively, tamoxifen, an antiestrogen, is known to prevent mammary carcinogenesis in animals and prevent the appearance of second primary breast cancers in women. This well tested therapeutic agent is currently being evaluated in clinical trials of selected high-risk women aged 35 and above. Finally, retinoids have shown promise as agents in the laboratory to prevent cell replication and inhibit mammary tumorigenesis. A trial of retinoids to prevent second primary tumors in node negative breast cancer patients is currently underway in Italy. The review discusses the relative merits and concerns about these prevention strategies and proposes additional studies to be undertaken.

Strategies for the application of biomarkers for risk assessment and efficacy in breast cancer chemoprevention trials

Current chemoprevention trial designs based on epidemiological risk assessment and occurrence of cancer as an endpoint are inefficient and expensive. Novel biomarkers are needed to facilitate the development of chemopreventive interventions. The following four categories of biomarkers may be useful in prevention trials: histologic and morphometric markers; phenotypic markers of dysregulated proliferation, differentiation, and cell loss; specific oncogenes and growth regulators which are qualitatively or quantitatively altered in breast cancers; and markers of genetic and epigenetic instability. Some of these markers will be generally useful regardless of the chemopreventive approach used, whereas others may be uniquely useful in trials of specific chemopreventive agents [e.g., upregulation of progesterone receptor (PR) expression in response to tamoxifen]. The development of these markers requires three phases of study: "Phase I": assessing the prevalence of the putative marker in malignant and premalignant tissue from individuals who have developed breast cancer; "Phase II": assessing in vivo modulation of the biomarker by the proposed chemopreventive agent; and "Phase III": applying the proposed biomarker in larger-scale trials of chemopreventive agent in high-risk populations, either before or after the development of a primary breast malignancy. The use of these biomarkers may also allow identification of novel targets for chemoprevention.