A predictive index of axillary nodal involvement in operable breast cancer

Assessment of the axilla in women with early-stage breast cancer undergoing primary surgery: a review

Sentinel node biopsy (SNB) is routinely performed in people with node-negative early breast cancer to assess the axilla. SNB has no proven therapeutic benefit. Nodal status information obtained from SNB helps in prognostication and can influence adjuvant systemic and locoregional treatment choices. However, the redundancy of the nodal status information is becoming increasingly apparent. The accuracy of radiological assessment of the axilla, combined with the strong influence of tumour biology on systemic and locoregional therapy requirements, has prompted many to consider alternative options for SNB. SNB contributes significantly to decreased quality of life in early breast cancer patients. Substantial improvements in workflow and cost could accrue by removing SNB from early breast cancer treatment. We review the current viewpoints and ideas for alternative options for assessing and managing a clinically negative axilla in patients with early breast cancer (EBC). Omitting SNB in selected cases or replacing SNB with a non-invasive predictive model appear to be viable options based on current literature.

Factors Influencing Axillary Node Metastasis in Breast Cancer

Aims and Background

The status of the axillary lymph nodes at the time of diagnosis has been accepted as one of the most important prognostic factors for the overall and disease-free survival of patients with breast cancer. The aim of our study was to determine which factors influence axillary node involvement in invasive breast cancer.

Methods

The data presented here were obtained from 344 patients who were treated for invasive breast cancer at the Department of Radiation Oncology, Uludag University Medical College, Bursa, Turkey. Possible prognostic factors were categorized as patient related and tumor related. The Mann-Whitney U test was used for univariate analysis and logistic regression was used for multivariate analysis.

Results

In univariate analysis, a familial cancer history (P = 0.0042), age <40 years (P = 0.0276), higher T stage (P <0.0000), nipple involvement (P = 0.0345), skin involvement (P = 0.0270), perineural invasion (P = 0.0231), and lymphatic vessel invasion (P <0.0000) were correlated with increased axillary node involvement. A higher incidence of ≥4 involved lymph nodes was associated with higher T stage (P = 0.0004), nipple involvement (P = 0.0292), presence of an extensive intraductal component (P = 0.0023), skin involvement (P = 0.0008), perineural invasion (P = 0.0523), and lymphatic vessel invasion (P <0.0000) in univariate analysis. In multivariate analysis, age <40 years (P = 0.0454), cancer history within the family (P = 0.0024), higher T stage (P = 0.0339), lymphatic vessel invasion (P = 0.0003), and perineural invasion (P = 0.0408) were found to be independent factors for axillary lymph node positivity. Age <40 years (P = 0.0221), perineural invasion (P = 0.0408), and an extensive intraductal component (P = 0.0132) were associated with an increased incidence of ≥4 involved nodes in the logistic regression analysis. In patients with breast cancer, the incidence of axillary lymph node involvement was independently influenced by age <40 years, presence of cancer history within the family, higher T stage, lymphatic vessel invasion, and perineural invasion.

Conclusions

In conclusion, absence of familial cancer history, presence of lymphatic vessel invasion, higher T stage, and age below 40 years independently increased the risk of axillary node involvement. Presence of perineural invasion and lymphatic vessel invasion, age below 40, and an extensive intraductal component of more than 25% independently affected the risk of having ≥4 nodes involved. Patients characterized by these factors may be classified into a higher risk group for nodal involvement, but more data are needed to define factors that can help in the decision-making regarding the omission of axillary treatment.

Questioning the role of axillary node dissection in sentinel node positive early stage breast cancer in the South Eastern Cancer Centre

INTRODUCTION

Axillary node status is a predictor of breast cancer survival. Axillary node dissection (ALND) following positive sentinel node biopsy (SLNB) is challenged by the American College of Surgeons Z0011 trial, where clinically/radiologically node-negative, SLNB positive early stage patients failed to derive therapeutic benefit from ALND at 6 years.

AIMS

To quantify the rates of non-sentinel lymph node positivity after ALND in all breast cancer stages. To assess Z0011 trial result application to an Irish patient population.

METHODS

Retrospective review of a prospectively maintained database of clinically node-negative patients undergoing breast conserving surgery and ALND for a positive SLNB from January 2011 to January 2012.

RESULTS

Of 174 new breast cancers diagnosed, 144 underwent surgery of which 127 patients were clinically/radiologically node-negative; 46 patients were SLNB positive; 34 (73.9 %) proceeded to ALND. Of 9 T1 tumours, 3 (33.3 %) had further positive nodes on ALND. Of 24 T2 tumours, 11 (45.8 %) had further positive nodes on ALND. All 3 (100 %) T3/T4 tumours had further positive nodes on ALND. Mean numbers of sentinel and axillary nodes harvested were 2.3 and 15.2, respectively. In the SLNB positive, ALND negative group, 12 of 18 (66.7 %) patients were <60 years versus 14 of 17 (82.4 %) in the SLNB positive, ALND positive group. This may be indicative that younger women have a trend toward node positivity following ALND for a positive SLNB.

CONCLUSION

These data suggest that a significant proportion (41.9 %) of T1/T2 tumours undergoing ALND following positive SLNB have further positive nodes. It may be premature to exclude ALND in patients with T1/T2 tumours following a positive SLNB.

Changes in survival during the past two decades for breast cancer at the Kyoto University Hospital

AIMS

To report the changes in survival over 20 years of 775 breast cancer women operated between 1982 and 2003 at the Kyoto University Hospital in Japan, reflecting changes in clinical practice over that period.

RESULTS

Survival curves have significantly improved between the periods 1982-1989 and 1990-2003. The 5- and 10-year survival rates between these periods were 80.3% and 85.1%, and 67.5% and 75.0%, respectively. Moreover, there was a difference in overall survival curves of patients of stages II and III, of 35-54 ages, or of positive estrogen receptor (ER) status between these periods.

CONCLUSION

The present study presented the recent advance of the survival rates might be due to the rational development of breast cancer treatment, and suggested the possibility that the patients of stages II and III, of 35-54 ages, or of positive ER status were received benefits by these treatments.

Significance of lymph vessel invasion identified by the endothelial lymphatic marker D2-40 in node negative breast cancer

Monoclonal antibody D2-40, a marker of lymphatic endothelium, identifies tumor emboli in lymph vessels. The aim of the study was to assess whether D2-40+ lymph vessel invasion (LVI) correlates with clinicopathologic factors including lymphovascular invasion (LVI) as assessed by haematoxylin and eosin-stained sections (H&E+ or H&E-) and to assess the prognostic significance in node-negative breast cancer. The study group consisted of 303 node-negative breast cancer patients that had a median follow-up of 7.6 years. Clinical and pathological data were retrieved from the Henrietta Banting database. Immunohistochemical staining was performed on formalin-fixed, paraffin-embedded tissue sections of the primary invasive carcinoma using D2-40. Immunostaining with CD31 was performed on the discordant cases that were H&E+/D2-40-. D2-40+ lymph vessel invasion was detected in 82/303 (27%) cases. The foci of lymphatic invasion occurred predominantly at the invasive front of the tumor. The absence of D2-40 and CD31 in 13/17 discordant cases was suggestive of retraction artefact. D2-40+ lymph vessel invasion correlated significantly with age (P=0.0003), tumor size (P=0.005), histological grade (P=0.0001), H&E+ (P=<0.0001) and estrogen receptor status (P=0.005) but not with histological type or progesterone receptor status. Multivariate analysis revealed that D2-40+ lymph vessel invasion was the only significant predictor of distant recurrence. There was no significant association between D2-40 status and local recurrence (P=0.752) or regional recurrence (P=0.13). Both D2-40+lymph vessel invasion (P=0.009) and H&E+LVI cases (P=0.02) were associated with overall shorter survival in univariate analysis. These data indicate that D2-40 identifies lymphatic invasion in breast tumors and is a significant predictor of outcome in breast cancer.

Probability of axillary lymph node metastasis when sentinel lymph node biopsy is negative in women with clinically node negative breast cancer: a Bayesian approach

BACKGROUND

Although sentinel lymph node biopsy(SLNB)is highly accurate in predicting axillary nodal status in patients with breast cancer, it has been shown that the procedure is associated with a few false negative results. The risk of leaving metastatic nodes behind in the axillary basin when SLNB is negative should be estimated for an individual patient if SLNB is performed to avoid conventional axillary lymph node dissection(ALND).

METHODS

A retrospective analysis of 512 women with T1-3N0M0 breast cancer was conducted to derive a prevalence of nodal metastasis by T category as a pre-test(i.e., before SLNB)probability and to examine potential confounders on the relationship between T category and axillary nodal involvement. Probability of nodal metastasis when SLNB was negative was estimated by means of Bayes' theorem which incorporated the pre-test probability and sensitivity and specificity of SLNB.

RESULTS

Axillary nodal metastasis was observed in 6.1% of T1a-b, 25.1% of T1c, 28.7% of T2, 35.0% of T3 tumors. Point estimates for the probability of nodal involvement when SLNB was negative ranged from 0.3-1.3% for T1a-b, 1.6-6.3% for T1c, 2.0-7.5% for T2, and 2.6-9.7% for T3 tumors with representative sensitivities of 80%, 85%, 90% and 95%, respectively. The risk may be higher when the tumor involves the upper outer quadrant of the breast, while it may be lower for an underweight woman.

CONCLUSIONS

The probability of axillary lymph node metastasis when SLNB is negative can be estimated using a Bayesian approach. Presenting the probability to the patient may guide the decision of surgery without conventional ALND.

A randomized trial comparing axillary dissection to no axillary dissection in older patients with T1N0 breast cancer: results after 5 years of follow-up

SUMMARY BACKGROUND DATA

Axillary dissection, an invasive procedure that may adversely affect quality of life, used to obtain prognostic information in breast cancer, is being supplanted by sentinel node biopsy. In older women with early breast cancer and no palpable axillary nodes, it may be safe to give no axillary treatment. We addressed this issue in a randomized trial comparing axillary dissection with no axillary dissection in older patients with T1N0 breast cancer.

METHODS

From 1996 to 2000, 219 women, 65 to 80 years of age, with early breast cancer and clinically negative axillary nodes were randomized to conservative breast surgery with or without axillary dissection. Tamoxifen was prescribed to all patients for 5 years. The primary endpoints were axillary events in the no axillary dissection arm, comparison of overall mortality (by log rank test), breast cancer mortality, and breast events (by Gray test).

RESULTS

Considering a follow-up of 60 months, there were no significant differences in overall or breast cancer mortality, or crude cumulative incidence of breast events, between the 2 groups. Only 2 patients in the no axillary dissection arm (8 and 40 months after surgery) developed overt axillary involvement during follow-up.

CONCLUSIONS

Older patients with T1N0 breast cancer can be treated by conservative breast surgery and no axillary dissection without adversely affecting breast cancer mortality or overall survival. The very low cumulative incidence of axillary events suggests that even sentinel node biopsy is unnecessary in these patients. Axillary dissection should be reserved for the small proportion of patients who later develop overt axillary disease.

Prognostic value of the 2002 TNM classification for breast carcinoma with regard to the number of metastatic axillary lymph nodes

BACKGROUND

The American Joint Committee on Cancer (AJCC) TNM classification for breast carcinoma had not been changed for 15 years, since the publication of the third edition in 1987. However, in the sixth edition, published in 2002, significant modifications were made with regard to the number of metastatic axillary lymph nodes. The authors investigated whether the sixth edition of the TNM classification provided more reliable prognostic information compared with the third edition.

METHODS

The records of 1230 patients who underwent surgery for invasive breast carcinoma between 1993 and 1999 were reviewed. Each patient was assigned to axillary lymph node and disease stage groups according to the 1987 and 2002 AJCC TNM classifications. Disease-free survival (DFS) curves were calculated and plotted using the Kaplan-Meier method and the two-sided log-rank test was used to compare the survival curves of the patient groups.

RESULTS

Of the 1067 patients who were classified as having Stages II and III disease according to the 1987 classification, 411 (38.5%) were shifted to higher disease stages using the 2002 classification. Among the 1987 Stage IIA, Stage IIB, and Stage IIIA patients, the DFS rates of the patients who were shifted to higher stages of disease were significantly worse than those of the patients for whom the stage of disease was not changed. Among those patients classified as having T4anyNM0 (Stage IIIB) disease according to the 1987 classification, there was no survival difference noted between those patients with T4N0,1,2M0 disease (who formed the Stage IIIB group) and those with T4N3M0 disease (who formed the Stage IIIC group) according to the new staging system. Of the 221 patients who formed the new Stage IIIC group, 12.2% were classified as having Stage IIA disease, 42.1% as having Stage IIB disease, 38.9% as having Stage IIIA disease, and 6.8% as having Stage IIIB disease according to the 1987 classification. The survival rates of these Stage IIA, Stage IIB, and Stage IIIA patients were not found to be significantly different; however, the survival of patients in the Stage IIIB group was found to be significantly worse than the survival of the patients in the other disease stage groupings, and the patients in the Stage IIIC group were not a prognostically homogeneous group. On the basis of these results, the authors placed patients with T4anyNM0 disease in the same group (Stage IIIB). When the 2002 classification was rearranged in this manner, patients with Stage IIIC disease formed a homogeneous group; the 5-year DFS rate of patients with Stage IIIB disease was found to be significantly worse than that for patients with Stage IIIC disease (P = 0.0011).

CONCLUSIONS

In the 2002 TNM classification for breast carcinoma, patients with T4anyNM0 disease should form a distinct stage grouping and this stage grouping (Stage IIIC) should be placed before Stage IV, and Stage IIIB disease groupings should include patients with T1,2,3N3M0 disease. In this way, the authors hope that the 2002 AJCC TNM classification, which provides more reliable prognostic information than the 1987 classification, will become more refined.

Importance of the retro-mammary space as a route of breast cancer metastasis

BACKGROUND

There are many cases of breast cancer with axillary lymph node metastases without lymphatic invasion. We hypothesized that in these cases cancer cells may pass through the retro-mammary space (RS) into lymph nodes and that axillary lymph node metastases may correlate with the tumor invasion of the RS.

METHODS

A total of 127 patients who had undergone radical operation between April 1997 and April 2001 were studied. Whether or not the tumor had invaded the RS was histologically examined with hematoxylin and eosin staining of sections made at the point where the distance between the tumor and the fascia of the major pectoral muscle was the shortest.

RESULTS

Eighty-five cases did not have lymphatic invasion. Twenty-nine of these 85 cases had RS invasion and 56 cases did not. Among the 29 cases with RS invasion, 14 cases had lymph node metastases. In contrast, of 56 cases without RS invasion only 3 cases had lymph node involvement. Of the 85 cases without lymphatic invasion, the relationship between RS invasion and lymph node invasion was statistically significant (RS(+) vs. RS(-), p<0.0001, chi-square test). For all 127 cases, if cases showing either lymphatic invasion or RS invasion were diagnosed with lymph node involvement, the sensitivity, specificity, accuracy, and negative predictive value were 93.5%, 65.4%, 75.6% and 94.6%, respectively.

CONCLUSION

These data suggest that lymph node metastases may occur via the tumor cell migration through lymphatic vessels and the RS.

Is axillary lymph node dissection necessary in elderly patients with breast carcinoma who have a clinically uninvolved axilla?

BACKGROUND

Axillary dissection in elderly patients with early-stage breast carcinoma who do not have palpable axillary lymph nodes is controversial because of the associated morbidity of the surgery, reduced life expectancy of the patients, and efficacy of hormone therapy in preventing recurrences and axillary events.

METHODS

The authors performed a retrospective analysis of 671 consecutive patients with breast carcinoma who were age >or= 70 years and who underwent conservative breast surgery with axillary dissection (172 patients) or without axillary dissection (499 patients). Tamoxifen always was given. The effects of axillary dissection compared with no axillary dissection on breast carcinoma mortality and distant metastasis were analyzed using multiple proportional-hazards regression models. Because the assignment to axillary treatment was nonrandom, covariate adjustments were made for baseline variables that influenced the decision to perform axillary dissection and for prognostic factors.

RESULTS

The crude cumulative incidence curves for breast carcinoma mortality and distant metastasis did not appear to differ significantly between the two groups (P = 0.530 and P = 0.840, respectively). The crude cumulative incidences of axillary lymph node occurrence at 5 years and 10 years were 4.4% and 5.9%, respectively (3.1% and 4.1%, respectively, for patients with pT1 tumors).

CONCLUSIONS

Elderly patients with breast carcinoma who have no evidence of axillary lymph node involvement may be treated effectively with conservative surgery and tamoxifen. Immediate axillary dissection is not necessary but should be performed in the small percentage of patients who later develop overt axillary lymph node involvement.

A prospective validated model for predicting axillary node metastases based on 2,000 sentinel node procedures: the role of tumour location [corrected]

AIMS

The purpose was to identify the independent predictive factors of axillary lymph-node metastases (ALNM) in infiltrating ductal carcinoma (IFDC) and to create a prospective, validated statistical model to predict the likelihood of ALNM in patients in the present era of sentinel lymph-node (SLN) biopsy and enhanced histopathology.

METHODS

Univariate and multivariate analyses of 13 clinicopathological variables (including tumour location) were performed to determine predictors of ALNM in 1659 eligible SLN biopsy procedures. A logistic regression model was developed and then prospectively validated on a second population of 187 subsequent consecutive procedures.

RESULTS

Age, pathological tumour size, palpability, lymphovascular invasion (LVI), histological grade, nuclear grade, ductal histological subtype, tumour location (quadrant) and multifocality were associated with ALNM in univariate analyses (P < 0.001). Of these, only palpability and histological grade were not statistically associated with ALNM in the multivariate analysis (P> 0.05). The frequency of ALNM in upper-inner-quadrant (UIQ) tumours was 20.6%, compared with 33.2% for all other quadrants (P<0.0005). There was no statistical difference between UIQ and other-quadrant tumours in any clinicopathological variables analysed. The logistic regression model, developed based on the population of 1659, had the same accuracy, sensitivity, specificity, positive predictive value and negative predictive value when applied prospectively to the second population.

CONCLUSION

Tumour size, LVI, age, nuclear grade, histological subtype, multifocality and location in the breast were independent predictive factors for ALNM in IFDC. ALNM is less frequent in UIQ tumours than in other-quadrant tumours. Our prospectively validated predictive model could be valuable in pre-operative patient discussions, although staging of the axilla in the individual patient remains necessary.

Basal cell carcinoma of the nipple: a case report and review of the literature

BACKGROUND

The nipple is an extremely unusual location for basal cell carcinoma (BCC).

OBJECTIVE

To report a case of BCC originating on the areola and nipple region in a 47-year-old Dominican woman treated with Mohs micrographic surgery (MMS).

METHODS

We discuss a case of BCC originating on the areola and nipple region treated with MMS and review the literature regarding treatment of BCC of the nipple.

RESULTS

BCCs of the nipple occur rarely, with a total of 19 cases reported in the literature, 6 of which occurred in females. While many of the reported cases were treated with simple excision, several of these required postoperative radiation therapy and/or mastectomy due to their large size and aggressive nature.

CONCLUSION

MMS should be considered for treating BCCs at this site as a tissue-sparing measure to minimize deformity of this important anatomic area and to minimize the risk of recurrence.

Predicting axillary lymph node metastases in patients with T1infiltrating ductal carcinoma of the breast

Factors which can predict an increased risk of axillary metastases in cases of T1 breast cancer could help to identify those patients most likely to benefit from axillary surgery. This pragmatic study aimed to examine the ability of commonly reported tumour pathological features to predict axillary metastases. All cases of T1 infiltrating ductal carcinoma excised with ipsilateral axillary nodes over a 7 year period were reviewed retrospectively. Of the 639 cases, 197 (30.8%) had positive nodes. Axillary metastases were found with 66.3% of tumours showing vascular invasion but only 16.0% of those without vascular invasion. Following multivariate analysis, vascular invasion and tumour size were found to be independent predictors of positive nodes but tumour grade was not. The decision to perform axillary dissection in T1 breast cancer could be based on the presence of vascular invasion and the size of the primary tumour.

Assessment of axillary lymph node involvement in small breast cancer: analysis of 893 cases

Axillary nodal involvement (ANI) remains an essential prognostic factor for breast cancer patients, as it implies the necessity of systemic adjuvant treatment and locoregional irradiation. Axillary dissection (AD) contributes to improved local disease control and may increase survival. However, AD results in a 10%-25% incidence of long-term side effects, particularly lymphedema. Moreover, many small primary lesions with low risk of ANI are now discovered by screening, and it is not clear whether AD should be used routinely in all such patients. Sentinel lymph node biopsy (SLNB) is a selective procedure that allows selective staging of the axilla with few side effects. However, indications for SLNB are not precisely defined yet, so some patients may be understaged and the axillary relapse rate may increase. This study was conducted to help clinicians assess the risk of ANI and analyzed six clinical and histological parameters to optimally recognize patients who might benefit from SLNB, with a minimal risk of false-negative rate. We retrospectively analyzed the ANI risk among 893 women treated by conservative surgery and radiation for T0, T1, or T2 invasive tumours < 3 cm in size. All patients underwent AD with sampling of a minimum of seven lymph nodes. In each case, we assessed the clinical and pathological tumor size, histological subtype (including grading), tumor location, age at diagnosis, and breast size. The global ANI rate in the entire cohort was 25.3%. In multivariate analysis, three variables were significantly predictive of the ANI risk: tumor size (P < 0.0001), histological subtype (P = 0.0005), and breast size (P = 0.004). By combining these parameters, we were able to define three categories of women with low (< 20%), intermediate (21%-25%), and high (> 25%) ANI risk. We suggest that women with nonpalpable (T0), T1 grade 1/2, and T2 < 3 cm tumors of medullary, mucinous, tubular, or papillary histological subtype are the best candidates for SLNB. For other patients with a higher ANI risk tumor, AD may still remain the best procedure to obtain accurate staging and definitive local control.

Deaths from breast cancer: tackling multidimensionality and non-linearity by correspondence analysis

AIM

We investigated the use of non-linear, multidimensional factor analysis for the study of observational data on death from breast cancer. These data were obtained in the context of a clinical practice and not in a clinical trial. We looked into the correlations between patient characteristics and time of death and/or disease-free interval.

PATIENTS AND METHODS

We first analyzed the characteristics of a population of patients that had died from breast cancer (n = 295), then of a population including patients still alive 7 years after surgery (n = 344). We used correspondence analysis (CA) which is based on chi(2)-metrics, does not assume linear relationships, and provides graphic overviews.

RESULTS

The CA mapped variables (clinical stage, histoprognostic grade, node status, receptor positivity) in a way that fits in well with available knowledge on their importance as prognostic factors. We observed, however, that death occurred during three main periods (1-3, 4-7, < OR = 8 years after surgery) defined by different mixes of variables as if the disease progressed by stage rather than continuously. The CA distinguished long-term survivors (>7 years) from patients who died 8-10 years after surgery. Long-term survivors tended to be node-negative; those who died at 8-10 years tended to be the youngest patients (under 40).

CONCLUSIONS

Because correspondence analysis combines the advantages of multidimensional and non-linear methods, it is a valuable exploratory tool for describing multiple correlations within a population before attempting to establish statistical significance of selected variables by more classic methods.

The relationship between lymphatic vessell invasion, tumor size, and pathologic nodal status: can we predict who can avoid a third field in the absence of axillary dissection?

PURPOSE

Tangential (2-field) radiation therapy to the breast and lower axilla is typically used in our institution for treating patients with early-stage breast cancer who have 0-3 positive axillary nodes, as determined by axillary dissection, whereas a third supraclavicular/axillary field is added for patients with 4 or more positive nodes. However, dissection may result in complications and added expense. We, therefore, assessed whether clinical or pathologic factors of the primary tumor could reliably predict, in the absence of an axillary dissection, which patients with clinically negative axillary nodes have such limited pathologic nodal involvement that they might be effectively treated with only tangential fields. This would eliminate both the complications of axillary dissection and the added complexity and potential morbidity of a supraclavicular/axillary field.

METHODS AND MATERIALS

In this study, 722 women with clinical Stage I or II unilateral invasive breast cancer of infiltrating ductal histology, with clinically negative axillary nodes, at least 6 lymph nodes recovered on axillary dissection, and central pathology review were treated with breast-conserving therapy from 1968 to 1987. Pathologic nodal status was assessed in relation to clinical T stage, the presence of lymphatic vessel invasion (LVI), age, histologic grade, and the location of the primary tumor.

RESULTS

LVI, T stage, and tumor location were each significantly correlated with nodal status on univariate analysis. Ninety-seven percent of LVI-negative patients had 0-3 positive axillary nodes compared to 87% of LVI-positive patients. There was no association between T stage and extent of axillary involvement within LVI-negative and LVI-positive subgroups. In a logistic regression model, only LVI remained a significant predictor of having 4 or more positive nodes, although tumor size was of borderline significance. The odds ratio for LVI (positive vs. negative) as a predictor of having 4 or more positive nodes was 3.9 (95% CI, 2.0-7.6).

CONCLUSION

For patients with clinical T1-2, N0, infiltrating ductal carcinomas, the presence of LVI is predictive of having 4 or more positive axillary nodes. Only 3% of patients with clinical T1-2, N0, LVI-negative breast cancers had 4 or more positive nodes on axillary dissection. Such patients may be reasonable candidates for treatment with tangential radiation fields in the absence of axillary dissection.