Organochlorines and breast cancer risk by receptor status, tumor size, and grade (Canada)

OBJECTIVE

We evaluated the association between organochlorines and breast cancer subtype defined by the tumor characteristics: estrogen receptor status, progesterone receptor status, tumor size, and grade.

METHODS

A case-control study was conducted from 1995 to 1997 in Kingston and Toronto, Canada. Breast adipose tissue, taken from 217 cases and 213 biopsy controls frequency-matched on age, was analysed for 14 polychlorinated biphenyl (PCB) congeners and 10 pesticides.

RESULTS

Adjusting for age, geometric means of several organochlorines differed by estrogen receptor status and tumor grade (p < 0.05). Odds ratios (ORs) for each organochlorine relative to the common control group for breast cancers of differing subtype were compared using polytomous logistic regression. Although the ORs did not differ significantly by subtype, the ORs of PCBs and p, p'-1,1-dichloro-2,2-bis(p-chlorophenyl)ethylene (DDE) were higher with risk of estrogen receptor-negative breast cancer than estrogen receptor-positive breast cancer. One of the most extreme differences was with DDE, where the OR for the association with risk of estrogen receptor-negative breast cancer was 2.4 (95% confidence interval (CI) 1.0-5.4) in the uppermost tertile relative to the lowest, whereas the corresponding OR for risk of estrogen receptor-positive breast cancer was 1.1 (95% CI 0.6-1.9). PCBs also tended to be more strongly positively associated with risk of larger and higher-grade tumors.

CONCLUSIONS

The association between organochlorines and breast cancer risk did not significantly differ by subtype, but many PCBs were more strongly associated with tumors of poor prognosis.

The rate of breast-conserving surgery for early breast cancer is not influenced by the surgical strategy of excisional biopsy followed by the definitive procedure

Increased emphasis on breast conservation and the primacy of the patient's preferences has led to the promotion and increased use of a two-step surgical strategy (definitive operation only after a final tissue diagnosis from a biopsy done on a previous visit) in the treatment of early breast cancer, with the assumption being that this is more conducive to the performance of breast-conserving surgery (BCS). We sought to test this by examining the effect of the surgical strategy (one-step versus two-step) on the operation performed (BCS versus mastectomy). A random sample of women with node-negative breast cancer diagnosed in 1991 in Ontario was drawn from the Ontario Cancer Registry database and matched to the Canadian Institute of Health Information and Ontario Health Insurance Plan databases (n = 643). This provided information on the timing and nature of all surgical procedures performed as well as patient, tumor, hospital, and surgeon characteristics. The surgical strategy was defined as either a one-step procedure (biopsy and definitive surgery performed at the same time) or a two-step procedure (surgical biopsy and pathologic diagnosis, followed by definitive surgery at a later date). The axillary lymph node dissection was used to define the definitive procedure. BCS was employed in 68% of patients, and this did not differ significantly between the one-step and two-step groups (66% versus 70%). Patients with palpable lesions had a significantly lower rate of breast conservation than those with nonpalpable lesions. Other variables associated with a lower rate of BCS were larger tumor size, presence of extensive ductal carcinoma in situ (DCIS), and central or multifocal tumors. The use of a one-step procedure was associated with a patient age of more than 50 years, a palpable mass, tumor size larger than 1 cm, previous fine needle aspiration (FNA) biopsy, absence of extensive DCIS, and surgery in an academic setting. Breast conservation was not affected by the surgical strategy used or the timing of the decision, but was associated with several accepted tumor factors. This study shows that, contrary to the opinion of some, there is a group of breast cancer patients in whom treatment in a one-step manner is appropriate.

Factors associated with local breast cancer recurrence after lumpectomy alone: postmenopausal patients

BACKGROUND

We have been following a cohort of patients who underwent a lumpectomy without receiving adjuvant radiotherapy or adjuvant systemic therapy. We now report the experience of a postmenopausal subgroup.

METHODS

The postmenopausal subgroup included 244 patients accrued between 1977 and 1986 and followed up. The end point was ipsilateral local breast cancer recurrence. The factors studied were the patient's age in years; tumor size (in mm); nodal status (N-, Nx, N+); estrogen and progesterone receptor status (< 10, - 10 fmol/mg protein); presence or absence of lymphovascular/perineural invasion; presence or absence, and type, of DCIS (none, non-comedo, comedo); percentage of DCIS; histological grade (1,2,3); and nuclear grade (1,2,3). Univariate analyses consisted of Kaplan-Meier plots and the Wilcoxon (Peto-Prentice) test statistic; the multivariate analyses were step-wise Cox and log-normal regressions.

RESULTS

The median follow-up of those patients still alive was 9.1 years, and the overall relapse rate was 24% (59/244). The univariate results indicated that the characteristics of smaller tumor size, negative nodes, positive ER status, and no lymphovascular or perineural invasion were associated with significantly (P <.05) lower relapse. From the multivariate analyses, the factors lymphovascular or perineural invasion, age, and amount of DCIS were all significantly associated with local relapse with both Cox and log-normal regressions. Additionally, there was weak evidence of an association between ER (P = .08 in the Cox regression and in the log-normal) and nodal status (P = .09 in the log-normal regression) with local relapse. We also are able to define a low-risk subgroup (N-, age -65, no comedo, ER positive, no emboli) with a crude 10-year local recurrence rate of 9%.

CONCLUSION

With longer follow-up, and for postmenopausal patients, there continues to be support for the theory that local relapse is affected by the factors lymphovascular or perineural invasion, age, amount of DCIS, ER, and nodal status. A low risk subgroup has been identified.

Factors affecting distant disease-free survival for primary invasive breast cancer: use of a log-normal survival model

BACKGROUND

Invasive breast cancer is a frequently diagnosed disease that now comes with an ever expanding array of therapeutic management options. We assessed the effects of 20 prognostic factors in a multivariate context.

METHODS

We accrued clinical data for 156 consecutive patients with stage 1-3 primary invasive breast cancer who were diagnosed in 1989-1990 at the Henrietta Banting Breast Center, and followed to 1995. There is complete follow-up for 91% of patients (median follow-up of 4.9 years). The event of interest was distant recurrence (for distant disease-free survival, DFS). We used Cox and log-normal step-wise regression to assess the multivariate effects of the following factors on DFS: age, tumor size, nodal status, histology, tumor and nuclear grade, lymphovascular and perineural invasion (LVPI), ductal carcinoma-in-situ (DCIS) type, DCIS extent, DCIS at edge of tumor, ER and PgR, ERICA, adjuvant systemic therapy, ki67, S-phase, DNA index, neu oncogene, and pRb.

RESULTS

There was strong evidence against the Cox assumption of proportional hazards for nodal status, and nodal status was not in the Cox step-wise model. With step-wise log-normal regression, a large tumor size (P < .001), positive nodes (P = .002), high nuclear grade (P = .01), presence of LVPI (P = .03), and infiltrating duct carcinoma not otherwise specified (P = .05) were associated with a reduction in DFS.

CONCLUSIONS

For nodal status, there was strong evidence against the Cox assumption of proportional hazards, and it was not included in the Cox model although it was in the log-normal model. Only traditional factors were included in the step-wise models. Thus, this statistical management of prognostic markers in breast cancer appears to be very important.

RT-PCR amplification of CK19 mRNA in the blood of breast cancer patients: correlation with established prognostic parameters

We optimized the assay for detection of cytokeratin 19 (CK19) mRNA by the reverse transcriptase-polymerase chain reaction (RT-PCR) in blood as an index of circulating tumor cells in breast cancer patients. The limit of detection of < 1 MCF7 tumor cells per 10(6) peripheral blood leukocytes (PBL) was achieved in mixing experiments. We did not detect CK19 mRNA in control bloods (0/30) or in the blood of patients with benign breast disease (0/15). In blood samples from 109 patients with invasive breast cancer, CK19 mRNA was detected in 7/23 patients with node-negative disease, in 21/58 with node-positive disease, and in 20/28 with distant metastases. There was a significant association (P < 0.01) of CK19 positivity with distant metastatic versus both node-negative and node-positive disease, but not with any other histopathological parameter examined. In a small number of patients with distant metastases, increased intensity of the CK19 RT-PCR signal was associated with a reduced survival.

Breast adipose tissue concentrations of polychlorinated biphenyls and other organochlorines and breast cancer risk

Numerous studies have examined the relationship between organochlorines and breast cancer, but the results are not consistent. In most studies, organochlorines were measured in serum, but levels in breast adipose tissue are higher and represent cumulative internal exposure at the target site for breast cancer. Therefore, a hospital-based case-control study was conducted in Ontario, Canada to evaluate the association between breast cancer risk and breast adipose tissue concentrations of several organochlorines. Women scheduled for excision biopsy of the breast were enrolled and completed a questionnaire. The biopsy tissue of 217 cases and 213 benign controls frequency matched by study site and age in 5-year groups was analyzed for 14 polychlorinated biphenyl (PCB) congeners, total PCBs, and 10 other organochlorines, including p,p'-1,1-dichloro-2,2-bis(p-chlorophenyl)ethylene. Multiple logistic regression was used to assess the magnitude of risk. While adjusting for age, menopausal status, and other factors, odds ratios (ORs) were above 1.0 for almost all organochlorines except five pesticide residues. The ORs were above two in the highest concentration categories of PCB congeners 105 and 118, and the ORs for these PCBs increased linearly across categories (Ps for trend < or =0.01). Differences by menopausal status are noted especially for PCBs 105 and 118, with risks higher among premenopausal women, and for PCBs 170 and 180, with risks higher among postmenopausal women. Clear associations with breast cancer risk were demonstrated in this study for some PCBs measured in breast adipose tissue.

Hereditary breast cancer. Psychosocial issues and family physicians' role

OBJECTIVES

To outline the psychosocial issues in hereditary breast cancer (HBC) assessment and discuss the role of family physicians.

QUALITY OF EVIDENCE

A literature search using MEDLINE, CINAHL, CancerLit, and HealthStar databases was conducted from January 1990 to April 1998, using the key words breast cancer or neoplasm and familial or hereditary, genetic testing or screening, primary care or family physician or counseling, genetic counseling, psychosocial or psychological. We found only a few studies focusing on a small number of well-studied "research families."

MAIN FINDINGS

Women with a family history of breast cancer were likely to be highly interested in genetic testing for cancer risk. The benefit of testing for those with negative results is reassurance. Those found to be carriers of genetic mutations might benefit from increased surveillance and prophylactic therapy. Risks of testing include anxiety, depression, guilt, altered self-image, and insurance and employment discrimination. A family physician's role is to assess risk, to provide information and support so women can make informed choices about referral to familial cancer clinics, to offer cancer surveillance, and to provide support once genetic test results are available.

CONCLUSION

Genetic testing is rapidly moving from research to clinical applications. Family physicians play an integral role in educating and managing women at risk for HBC. Physicians must prepare themselves with knowledge and counseling skills to meet the challenges of this new technology.

Hereditary breast cancer. Risk assessment of patients with a family history of breast cancer

OBJECTIVES

To assist family physicians in stratifying women with a family history of breast cancer as being at low, moderate, or high risk of hereditary breast cancer (HBC). To present guidelines for managing each of these risk groups.

QUALITY OF EVIDENCE

A MEDLINE search was conducted from January 1976 to December 1997 using key words related to breast cancer risk factors, risk assessment, prevention, and screening. Risk stratification criteria were derived empirically and assessed using retrospective chart review.

MAIN FINDINGS

Although up to 20% of women in the general population have a family history of breast cancer, less than 5% are at high risk for HBC. Certain features in a family history suggest increased risk. Women with none of these features are at low risk for HBC and should have annual clinical breast examinations and mammography at least every 2 years starting at age 50. Women with one or more features of increased risk who do not meet criteria for referral to a familial cancer clinic are at moderate risk for HBC and should begin annual mammography and clinical breast examination at age 40. Women who meet referral criteria are at high risk for HBC and should be counseled regarding referral to a familial cancer clinic for more detailed risk assessment and consideration for genetic testing. All women should be taught proper breast self-examination technique and encouraged but not pressured to practise it monthly for life.

CONCLUSION

A simple algorithm can assist physicians in stratifying women into low, moderate, and high HBC risk groups. Management strategies for each group are given in this article and the two following (Heisey et al page 114 and Carroll et al page 126).

Hereditary breast cancer. Identifying and managing BRCA1 and BRCA2 carriers

OBJECTIVES

To present a strategy for identifying candidates for consideration of BRCA1 and BRCA2 mutation testing. To discuss the implications of identifying patients as BRCA1 or BRCA2 mutation carriers, and to provide recommendations for managing them.

QUALITY OF EVIDENCE

A MEDLINE search from January 1990 to May 1998 was performed using the terms genetic breast screening, BRCA1, and BRCA2. The bibliographies of articles found were searched for further relevant titles. There are no published, randomized controlled clinical trials of management strategies for known BRCA carriers. Many recommendations for management are based on expert opinion only.

MAIN FINDINGS

About 5% of women with breast cancer are carriers of genetic mutations. An accurate and detailed family history is the most important tool for identifying potential BRCA1 and BRCA2 mutation carriers. Women identified as carriers have a substantially increased risk of breast and ovarian cancer. Male carriers have a moderately increased risk of prostate cancer. Management strategies for carriers are not well studied but include increased surveillance, preventive surgery, chemoprevention, and lifestyle modification.

CONCLUSION

Family physicians must be able to identify people at risk, to discuss management strategies, and when appropriate, to offer referral for consideration of genetic testing. There is an urgent need for research to determine the effectiveness of surveillance strategies, preventive surgery, chemoprevention, and lifestyle modification for BRCA1 and BRCA2 mutation carriers.

Assessment of treatment for patients with primary ductal carcinoma in situ in the breast

BACKGROUND

Current mammographic technology has resulted in increased detection of ductal carcinoma in situ (DCIS). It is necessary to assess which patients presenting with DCIS are good candidates for breast conservation and which of these patients should receive adjuvant radiation.

METHODS

We accrued clinical data for 124 patients with a primary diagnosis of DCIS from 1979 through 1994. Primary therapy was a mastectomy for 18 patients, and a lumpectomy for 106 patients. Only 18 of the latter group of patients received adjuvant radiotherapy. For the 88 lumpectomy-alone patients (median follow-up, 5.2 years), we evaluated the effects of clinical (age and initial presentation) and pathologic (nuclear grade, architecture, parenchymal involvement, calcifications, and measured margins) factors on recurrence of DCIS or the development of invasive breast cancer.

RESULTS

Patients who underwent lumpectomy with or without adjuvant radiotherapy (median follow-up, 5.0 years) were significantly more likely to have recurrence of DCIS (P=.05) than those who underwent mastectomy (median follow-up, 6.7 years): 18% (19/106) versus 0% (0/18), respectively; lumpectomy-alone patients experienced a 19% (17/88) rate of DCIS recurrence. All recurrent DCIS was ipsilateral. For lumpectomy-alone patients, the factors associated with ipsilateral recurrence of DCIS were extent of involvement of the parenchyma (P=.01, for univariate; P=.07, for multivariate) and initial presentation (P=.05, for univariate; P=.07, for multivariate). Eleven lumpectomy-alone patients developed invasive breast cancer (6 ipsilateral, 5 contralateral); none of the 18 lumpectomy patients who received adjuvant radiation developed invasive disease. None of the factors investigated, including primary surgery and adjuvant radiotherapy, were associated with a significant effect on the development of invasive disease.

CONCLUSIONS

Longer follow-up is required to determine if the benefits of either mastectomy or radiotherapy following lumpectomy persist. There is a suggestion that patients under 40 years of age or women who present with nipple discharge might be considered for either adjuvant radiotherapy following lumpectomy or a simple mastectomy.

Surgical management of early stage invasive breast cancer (stage I and II). Provincial Breast Disease Site Group

GUIDELINE QUESTION

What is the optimal surgical management of early stage invasive breast cancer (stage I and II)? More specifically, what is the relative efficacy (and safety) of breast conservation therapy (lumpectomy with axillary dissection) compared with modified radical mastectomy?

OBJECTIVE

To make recommendations about surgical management and techniques in the treatment of early stage invasive breast disease (stage I and II).

OUTCOMES

Survival, local recurrence (for lumpectomy patients) and quality of life are the primary outcomes of interest.

PERSPECTIVE (VALUES)

Evidence was selected and reviewed by 6 members of the Ontario Cancer Treatment Practice Guidelines Initiative, Disease Site Group for Breast Cancer (Breast DSG). Earlier drafts of this evidence-based recommendation have been reviewed, discussed and approved by the Breast DSG, which comprises surgeons, medical oncologists, radiation oncologists, epidemiologists, a pathologist and a medical sociologist. There was no consumer participation in the development of this guideline.

QUALITY OF EVIDENCE

There are 7 randomized controlled trials (RCTs) comparing breast conservation therapy with mastectomy in women with early stage breast cancer.

BENEFITS

In 6 RCTs, no statistically significant differences were detected in survival rate between the mastectomy and conservative therapy (lumpectomy) groups. In 1 RCT, a statistically significant differences was detected in favour of the mastectomy arm; however, this was an early trial with substantial methodologic weaknesses.

HARMS

None.

PRACTICE GUIDELINE

Women with early stage invasive breast cancer (stage I and II) who are candidates for breast conservation therapy (see discussion of technical factors) should be offered the choice of either breast conservation therapy (excision of tumour with clear margins and axillary dissection) or modified radical mastectomy. The choice is an individual one for the patient, and thus she should be fully informed of the options, including the risks and benefits of each procedure. She should be informed that breast irradiation is part of the procedure for breast conservation therapy. In addition, she should be aware of the potential need for further surgery if the margins are positive. For further information about the use of radiotherapy in the management of early stage breast cancer, please refer to the Ontario Cancer Treatment Practice Guidelines Initiative's practice guideline Breast Irradiation in Women with Early Stage Invasive Breast Cancer Following Breast Conserving Surgery.

Breast cancer and organochlorines: a marker for susceptibility?

The incidence of breast cancer is increasing and despite extensive research efforts, the etiology of this disease is largely unknown. Most women exhibit no known risk factors except for their age and sex. It has recently been postulated that the increased breast cancer incidence might be attributed to exposure to environmental carcinogens such as the organochlorine compounds. In this article, the scientific literature with respect to this possibility is reviewed and alternative hypotheses, which may in part explain the possible role of organochlorine compounds in the etiology of breast cancer, are presented.

The surgical and oncologic significance of the axillary arch during axillary lymphadenectomy

An uncommon and often-overlooked anatomic variation of the latissimus dorsi muscle is the axillary arch. It is formed by an anomalous slip of the muscle that arises from the body of the latissimus dorsi but then inserts along with the pectoralis major muscle anterior to the axillary vein and neurovascular bundle. If an axillary arch is encountered during axillary lymphadenectomy, the lymph nodes posterior and lateral to the arch should be excised. Experience with a number of cases is used to consider local therapeutic and staging factors.

An improved statistical approach: can it clarify the role of new prognostic factors for breast cancer?

Recently, there has been a proliferation of new biomarkers, some of which may lead to an improved prognostic index or may influence treatment selection. However, there are methodological and statistical issues that require attention in assessing the role and use of these prognostic factors. Between 1977 and 1986, 1097 primary breast cancer patients were accrued for multidisciplinary research at the Henrietta Banting Breast Centre, Women's College Hospital; follow-up to 1990 is complete for 96% of the patients. Data for these patients are used here to illustrate strategies: (1) for the comparison of results from diverse assessments of biomarkers; (2) for the improved comparability of inter-laboratory results; (3) for the examination of the results from monoclonal or polyclonal antibody assays for possible clinically relevant bimodality; (4) for good statistical resolution of overlapping distributions; (5) that involve the use of quantitative values for prognostic factors whenever possible; and (6) for improved multivariate analyses. Good data handling and analyses may enable more accurate and rapid assessment of new prognostic factors, thereby expediting and improving their clinical application.

Alternative multivariate modelling for time to local recurrence for breast cancer patients receiving a lumpectomy alone

Certain prognostic factors (patient and/or tumour characteristics) may be associated with low (or high) risk for local recurrence. Patients with these characteristics could be candidates for less (or more) adjuvant therapy or a less (or more) aggressive surgical approach. However, the assessment of many factors can be problematic with the standard multivariate technique-a Cox proportional hazards model and step-wise regression. We compared the results obtained when using a Cox model with those from four alternative models (exponential, Weibull, log logistic and log Normal) in step-wise and all subset regressions. Between 1977 and 1986, 293 primary invasive breast cancer patients were treated at the Henrietta Banting Breast Centre with a lumpectomy with or without an axillary dissection, and with no postoperative adjuvant therapy. The variables considered were age, lymph node status, tumour size, estrogen receptor (ER), progesterone receptor (PgR), histologic grade, nuclear grade, carcinoma in situ (CIS), amount of CIS, and presence of tumour emboli. With follow-up to 1991, nodal status was not found to be included in the step-wise Cox model, although it was in the step-wise exponential, Weibull and log Normal models, and in the best all subset models for all model types. The variables tumour emboli, ER, age, CIS and nodal status were consistently included in the best all subset regressions, regardless of model type. In the 1993 follow-up, the variables in the step-wise Cox model were tumour emboli, ER, age, CIS and nodal status. The multivariate consideration of all possible subsets of regression variables led to an earlier indication of the importance of nodal status, while the data strongly supported accelerated failure time models over the Cox model.

Combined fine-needle aspiration, physical examination and mammography in the diagnosis of palpable breast masses: their relation to outcome for women with primary breast cancer

OBJECTIVE

To examine the combined and individual predictive values of fine-needle aspiration (FNA), physical examination (PE) of the breast and mammography (the "triple test") in diagnosing breast cancer in relation to the results of open surgical biopsy.

DESIGN

A study of the records of patients who received both FNA and open surgical biopsy for the same palpable breast lump. The results of diagnostic assessment and open surgical biopsy were categorized as positive or negative. Concordance (percentage of tests found to be correct at biopsy), sensitivity, specificity (percentage of patients without breast cancer for whom the diagnostic test was negative) and positive predictive value (percentage of patients with a positive test found to have breast cancer) were determined for the triple test for each diagnostic modality. In addition, prognostic variables (tumour size, node positivity, estrogen and progesterone receptor status) and outcomes were assessed in patients with a diagnosis of breast cancer.

SETTING

A university-affiliated general hospital with a special focus on women's health.

PATIENTS

Of 290 patients who had both FNA and open surgical biopsy, 191 underwent all three diagnostic procedures.

MAIN OUTCOME MEASURES

The diagnostic accuracy of FNA, PE and mammography to permit preoperative definitive therapy or to allow observation without mandating open surgical biopsy.

RESULTS

In 81 patients all three diagnostic modalities were in agreement for a diagnosis of either benign or malignant disease; the concordance for the triple test was 98.8% specificity was 100% and sensitivity was 95.5%. Nodal status, tumour size and outcome were similar whether or not the triple test was positive, but, interestingly, when the triple-test results were positive, estrogen (p < 0.05) and progesterone (p < 0.03) receptor values were more likely to be negative.

CONCLUSIONS

When all three diagnostic modalities were in agreement for a diagnosis of malignant disease, the combination of FNA, PE and mammography had excellent concordance with the results of open surgical biopsy, and in this situation definitive treatment may be carried out. If all three modalities are in agreement for a diagnosis of benign disease, a period of close observation with repetition of FNA may be safely entertained. Lack of concordance of the three diagnostic modalities mandates biopsy. Triple-test positively does not predict a worse outcome.

Factors associated with local breast cancer recurrence after lumpectomy alone

BACKGROUND

The purpose was to determine the rate of local breast relapse in patients with breast cancer uniformly treated with partial mastectomy but without postoperative radiotherapy and without systemic adjuvant therapy. We also systematically examined the factors associated with local recurrence to determine whether a low-risk subgroup existed.

METHODS

A retrospective review of a prospectively followed (median, 8 years) cohort of 293 patients was performed. The end-point was ipsilateral local breast cancer recurrence. The patient's age, tumor size, nodal status, estrogen and progesterone receptor status, histology, and tumor and nuclear grade were studied, as were the presence and amount of carcinoma in situ and the presence of tumor emboli using univariate Kaplan-Meier and Cox step-wise multivariate analyses.

RESULTS

The overall local relapse rate was 26% (77 recurrences). Univariate factors significantly associated with decreased local relapse included older age, negative nodes, small tumor size, positive estrogen receptor status, and absence of tumor emboli. Significant multivariate variables were age, nodal status, estrogen receptor status, absence of comedo carcinoma in situ, and tumor emboli. A low-risk subgroup of 66 patients was defined with a 6% 10-year local recurrence rate.

CONCLUSION

Important patient and tumor variables associated with local breast cancer relapse after breast-conserving surgery can define a low-risk subgroup.

An investigation of cut-points for primary breast cancer oestrogen and progesterone receptor assays

Oestrogen and progesterone receptor (ER and PgR) assay values are frequently used in medical decision-making for breast cancer patients. We have proposed statistical standardization of receptor assay values to improve inter-laboratory comparability, and now report the use of standardized log units (SLU) to investigate the effects of ER and PgR cut-points on time to first recurrence outside the breast (DFS). Between 1980 and 1986, there were 678 primary breast cancer patients treated at the Henrietta Banting Breast Centre (HBBC). The effects of ER and PgR cut-points were examined with multivariate analyses considering the variables: age, tumour size, nodal status, weight and adjuvant treatment. We considered receptor assay cut-points ranging from - 1.0 to + 1.0 SLU (ER between 7 and 166 fmol/mg protein; PgR between 7 and 181 fmol/mg protein). PgR was included in the multivariate prognostic models more often than ER, although patients had a better prognosis with both larger ER and PgR values. There was no best cut-point for ER or PgR, and there was strong evidence that ER and PgR should be considered as continuous rather than dichotomous (negative, positive) variables. Patient prognosis should also be more comparable with SLU.

Genetic counselling and testing for susceptibility to breast, ovarian and colon cancer: where are we today?

Recent advances in our understanding of the genetic characteristics of cancer will change approaches to genetic screening and counselling. Cancer results from multiple, cumulative mutations in genes that regulate cell replication and differentiation. In familial cancer a germ-line mutation is passed on in an autosomal dominant pattern, but cancer will develop in people who inherit the defect only if other mutations also occur in susceptible somatic cells. The tumour-suppressor gene known as BRCA1 is thought to affect half of those families who have an inherited breast cancer syndrome and most families with a breast and ovarian cancer syndrome. Another gene, BRCA2, is thought to affect most of the remaining families with a breast-cancer-only syndrome. Hereditary nonpolyposis colon cancer (HNPCC) is caused by mutations in surveillance genes that protect DNA from the spontaneous errors that occur during cell division. Because there are no outcome data on which to base practice guidelines for genetic screening or management of asymptomatic carriers in families at risk, testing should be restricted to research settings.

Characteristics of local recurrence following lumpectomy for breast cancer

We report the clinical characteristics and treatment of local breast relapse in our breast cancer patients who were initially managed with breast conservation surgery (lumpectomy) alone. A retrospective study was conducted of 366 patients who were treated since 1977. The clinical, pathological, and treatment data regarding the primary tumor and the recurrences (91) were reviewed. The actuarial rate of local breast relapse in this group was 31% at 10 years. Breast relapse was significantly less in those patients 65 years old or greater. Acceptable treatment of the breast relapse included total mastectomy or repeat lumpectomy plus radiotherapy. Most relapses were small and occurred in the same area as the original tumor and had similar histology and estrogen and progesterone receptor values. About one-third of patients will have isolated relapses after conservation surgery alone, but in the older age group, isolated breast relapse occurs less frequently. The recurrences are usually surgically resectable, and acceptable results can be achieved with salvage surgery.

A comparison of all-subset Cox and accelerated failure time models with Cox step-wise regression for node-positive breast cancer

Clinical studies usually employ Cox step-wise regression for multivariate investigations of prognostic factors. However, commercial packages now allow the consideration of accelerated failure time models (exponential, Weibull, log logistic, and log normal), if the underlying Cox assumption of proportional hazards is inappropriate. All-subset regressions are feasible for all these models. We studied a group of 378 node positive primary breast cancer patients accrued at the Henrietta Banting Breast Centre of Women's College Hospital, University of Toronto, between January 1, 1977, and December 31, 1986. 85% of these patients had complete prognostic factor data for multivariate analysis, and 96% of the patients were followed to 1990. There was evidence of marked departures from the proportional hazards assumption with two prognostic factors, number of positive nodes and adjuvant systemic therapy. The data strongly supported the log normal model. The all-subset regressions indicated that three models were similarly good. The variables 1) number of positive nodes, 2) tumour size, and 3) adjuvant systemic therapy were included in all three models along with one of three biochemical receptor variables 1) ER, 2) combined receptor (ER- PgR-; ER+PgR-; ER- PgR+; ER+PgR+; or 3) PgR. Better multivariate modeling was achieved by using quantitative prognostic factors, a check for appropriate underlying model-type, and all-subset variable selection. All-subset regressions should be considered for routine use with the many new prognostic factors currently under evaluation; it is very possible that there may not be a single model that is substantially better than others with the same number of variables.

Total mastectomy is not always mandatory for the treatment of recurrent breast cancer after lumpectomy alone

To determine the treatment that offered the best local control for isolated local recurrences of breast cancer after lumpectomy without radiotherapy, the authors reviewed 355 patients initially treated by lumpectomy (with or without axillary dissection) without radiotherapy. Local breast cancer recurred in 79 patients. They underwent either repeat partial mastectomy (PM) or completion total mastectomy (TM). Twenty-four patients (5 TM, 19 PM) received radiotherapy. Local control was defined as the absence of further recurrence of breast or chest-wall cancer. The 19 patients treated with repeat PM and radiotherapy had an actuarial local control rate of 82% at 5 years. Those treated with TM (28 patients) [corrected] or TM plus radiation (5 patients) had rates of local control of 60% and 52% respectively. Although there were no significant differences between the TM and PM plus radiotherapy groups, the 27 patients who had a repeat PM without radiotherapy had a significantly lower rate of local control (32%, p < 0.005). Treatment of recurrent breast cancer with PM and radiotherapy is a viable alternative to TM for enhancing local control. Repeat PM alone gave much poorer results. The authors conclude that local cancer recurrences after lumpectomy alone do not necessarily require TM and can often be treated with repeat excision and radiotherapy.