Risk of internal mammary lymph node metastases and its prognostic value in breast cancer patients

Radiotherapy for initial clinically positive internal mammary nodes in breast cancer

Purpose

Internal mammary lymph node (IMN) involvement is associated with poor prognosis in breast cancer. This study investigated the treatment outcomes of initial clinically IMN-positive breast cancer patients who received adjuvant radiotherapy (RT), including IMN irradiation, following primary breast surgery.

Materials and Methods

We retrospectively reviewed data of 95 breast cancer patients with clinically detected IMNs at diagnosis treated with surgery and RT between June 2009 and December 2015. Patients received adjuvant RT to the whole breast/chest wall and regional lymph node (axillary, internal mammary, and supraclavicular) areas. Twelve patients received an additional boost to the IMN area.

Results

The median follow-up was 43.2 months (range, 4.5 to 100.5 months). Among 77 patients who received neoadjuvant chemotherapy, 52 (67.5%) showed IMN normalization and 19 (24.6%) showed a partial response to IMN. There were 3 and 24 cases of IMN failure and any recurrence, respectively. The 5-year IMN failure-free survival, disease-free survival (DFS), and overall survival (OS) were 96%, 70%, and 84%, respectively. IMN failure-free survival was significantly affected by resection margin status (97.7% if negative, 87.5% for close or positive margins; p = 0.009). All three patients with IMN failure had initial IMN size ≥1 cm and did not receive IMN boost irradiation. The median age of the three patients was 31 years, and all had hormone receptor-negative tumors.

Conclusion

RT provides excellent IMN control without the support of IMN surgery. Intensity-modulated radiotherapy, including IMN boost for breast cancer patients, is a safe and effective technique for regional lymph node irradiation.

Predictors of internal mammary lymph nodes (IMLN) metastasis and disease-free survival comparison between IMLN-positive and IMLN-negative breast cancer patients: Results from Western China Clinical Cooperation Group (WCCCG) database (CONSORT)

Limited studies performed a comprehensive assessment of risk factors for internal mammary lymph nodes (IMLN) metastasis, and disease-free survival (DFS) difference between IMLN-positive and IMLN-negative breast cancer (BC) patients undergoing IMLN dissection and systemic therapies was not clear.A retrospective study included 1977 BC patients from Western China Clinical Cooperation Group between January 2005 and December 2012. The impact of clinicopathological factors on the occurrence of IMLN metastasis was assessed in univariate and multivariate logistic regression analyses, and a nomogram (model) was constructed to predict the IMLN status. DFS difference was evaluated in univariate and multivariate Cox regression analyses between IMLN-negative and IMLN-positive patients, and univariate analysis was performed to compare DFS between individuals with high and low IMLN metastasis risk defined by proposed nomogram.Of 1977 enrolled patients, 514 cases underwent IMLN dissection and 1463 cases did not undergo IMLN irradiation or dissection. We found that initial disease symptoms and signs, mammographic calcification, tumor site, number of positive axillary lymph nodes (ALNs), American Joint Committee on Cancer pT stage, and human epidermal growth factor receptor 2 status were associated with IMLN metastasis (all P < .05). Those variables were included in nomogram, whose predictive ability was better than that of ALN classification (area under the curve: 0.82 vs 0.76, P < .001). Univariate cox proportional hazards model indicated that better DFS was observed in IMLN-negative patients than IMLN-positive group (hazard ratio [HR] = 1.87, 95% confidence interval [CI] = 1.05-3.34; P = .04), whereas no significant differences in DFS (HR = 0.99, 95% CI = 0.49-2.00; P = .97) were found after adjusting patient-, disease-, and treatment-related factors.Nipple inversion, mammographic calcification, larger tumor size, medial tumor site, negative HER-2 status, and more positive ALNs are independent risk factors for IMLN metastasis, and the individualized nomogram is a feasible tool to predict the status of IMLN. Equivalent DFS was found between positive and negative IMLN patients who all accepted IMLN dissection and systemic therapies.

Validation study for the hypothesis of internal mammary sentinel lymph node lymphatic drainage in breast cancer

According to axilla sentinel lymph node lymphatic drainage pattern, we hypothesized that internal mammary sentinel lymph node (IM-SLN) receives lymphatic drainage from not only the primary tumor area, but also the entire breast parenchyma. Based on the hypothesis a modified radiotracer injection technique was established and could increase the visualization rate of the IM-SLN significantly. To verify the hypothesis, two kinds of tracers were injected at different sites of breast. The radiotracer was injected with the modified technique, and the fluorescence tracer was injected in the peritumoral intra-parenchyma. The location of IM-SLN was identified by preoperative lymphoscintigraphy and intraoperative gamma probe. Then, internal mammary sentinel lymph node biopsy (IM-SLNB) was performed. The fluorescence status of IM-SLN was identified by the fluorescence imaging system. A total of 216 patients were enrolled from September 2013 to July 2015. The overall visualization rate of IM-SLN was 71.8% (155/216). The success rate of IM-SLNB was 97.3% (145/149). The radiotracer and the fluorescence tracer were identified in the same IM-SLN in 127 cases, the correlation and the agreement is significant (Case-base, r_s=0.836, P<0.001; Kappa=0.823, P<0.001). Different tracers injected into the different sites of the intra-parenchyma reached the same IM-SLN, which demonstrates the hypothesis that IM-SLN receives the lymphatic drainage from not only the primary tumor area but also the entire breast parenchyma.

Internal mammary lymph nodes radiotherapy of breast cancer in the era of individualized medicine

Inclusion internal mammary lymph nodes as a part of regional nodal irradiation have a potential to reduce local recurrence, distant recurrence, and improve survival in breast cancer. However, the increased risk of cardiac toxicity and lungs injure associated with internal mammary lymph nodes irradiation has drew more and more attention. Estimating risk of metastasis in internal mammary lymph nodes based on axillary lymph nodes metastasis status is not always reliable: low-risk do not always mean negative in internal mammary lymph nodes and high-risk do not always indicate positive in internal mammary lymph nodes. Inaccurate prediction of in internal mammary lymph nodes metastasis might lead to over- or under-treatment of in internal mammary lymph node. Internal mammary sentinel lymph node biopsy is a minimally invasive technique which has a high potential to accurately evaluate the metastasis status in in internal mammary lymph nodes and improve accuracy of nodal staging. This technique might be a useful tool to guide individualized internal mammary lymph nodes irradiation.

Internal mammary lymph node metastasis in breast cancer: predictive models to assist with prognostic influence

BACKGROUND

Metastatic breast cancer in the internal mammary nodes (IMN) indicates a poor prognosis. Several recent epidemiological surveys have determined a reduction in survival for patients with medial compared to lateral sector tumors attributing this to a higher rate of unrecognized IMN metastasis and hence these patients are undertreated with adjuvant therapy.(1-6)

AIM

Through mathematical modeling based on large datasets we aim to quantify the impact on survival of IMN metastases at different tumor and axillary stages.

METHODS

Mathematical models were created to estimate the survival of patients with and without IMN metastasis. It was assumed that the different rate of survival between medial and lateral sector breast cancers was a result of the differential rate of unrecognized IMN metastases with resultant under-staging and under treatment. We applied these models on a retrospective database analysis from the Surveillance, Epidemiology and End-Results (SEER) registries from 1994 to 2003.

RESULTS

The 10-year odds of death (OOD) from breast cancer for patients with medial compared with lateral sector tumors ranged from 1.2 to 1.5 depending on stage. The predicted odds of breast cancer death for patients with unrecognized IMN metastases ranged from 2.4 to 20, with the highest OOD in the groups with small tumors and no axillary node metastasis.

CONCLUSIONS

Through modeling we have been able to predict and quantify the significantly worse survival outcomes for patients with undiagnosed IMN metastasis.

Should internal mammary chain (IMC) sentinel node biopsy be performed?

INTRODUCTION

Although the status of the regional lymph nodes is an important determinant of prognosis in breast cancer, harvesting sentinel nodes (SN) detected in the internal mammary chain (IMC) is still controversial.

AIMS

To determine in how many patients a positive IMC-SN might change the systemic or locoregional adjuvant therapy, with a possible benefit in outcome.

PATIENTS AND METHODS

During 6 1/2 years data of T1-2 breast cancer patients, having an SN procedure, were prospectively collected. Our policy was not to explore the IMC even if it was the only localization of an SN.

RESULTS

In 86 of 571 patients lymphoscintigraphy showed an IMC-SN. In 64 of these, the axillary SN was negative and only 25 of these patients did not have an indication for adjuvant systemic treatment based on their tumor characteristics. In the literature, IMC metastases are found in 0-10% of axillary negative patients. Routine IMC-SN biopsies would have resulted in an indication for adjuvant systemic therapy in 2-3 of our patients. Four parasternal recurrences were found during a median follow-up of 51 months.

CONCLUSIONS

Harvesting IMC-SNs is a procedure of which only a limited number of patients have therapeutical benefit. Even with a thorough selection of patients, the extra morbidity of the procedure should be weighed against the potential benefit for the patient.

Diagnosis of Recurrent and Metastatic Disease Using F-18 Fluorodeoxyglucose-Positron Emission Tomography in Breast Cancer

One of the major strengths of F-18 fluorodeoxyglucose-positron emission tomography (FDG-PET) in breast cancer imaging is in the evaluation of patients who have suspected loco-regional recurrence or distant metastasis. In general, FDG-PET is more sensitive than conventional imaging for the detection of recurrent disease. Because of its ability to more accurately stage patients who have advanced breast cancer, FDG-PET has a significant impact on choice of treatment and management in this patient group.

Sentinel lymph node biopsy as the new standard of care in the surgical treatment for breast cancer

During the recent years, based on the results of validation studies, the sentinel lymph node biopsy has replaced routine axillary dissection as the new standard of care in early breast cancer. The technique represents a minimally invasive, highly accurate method for axillary staging, which could spare approximately 65-70% of patients unnecessary axillary dissection and its related morbidity. Several technical and clinical controversies have been raised during the development of this new technique; the authors review the most important issues, some questions have already been answered and others are still under debate. As far as the technical aspects are concerned, mapping techniques, appropriate surgical training, options for pathological examination of sentinel lymph nodes and the issue of nonaxillary sentinel lymph nodes are discussed. An update on clinical controversies demonstrates that factors such as large tumor size, palpable axillary nodes, multifocality and multicentricity, previous breast and axillary surgery, and pregnancy are no longer regarded as absolute contraindications for sentinel lymph node biopsy. Feasibility, accuracy and timing of sentinel lymph node biopsy in patients undergoing neoadjuvant chemotherapy remain unsolved issues, as well as the indication of the technique for some subgroups of in situ lesions. Finally, one of the most attractive open forums for debate will be discussed: whether or not completion of axillary dissection in the case of positive SLN is always required.

Prospective evaluation of factors influencing success rates of sentinel node biopsy in 814 breast cancer patients

OBJECTIVE

This prospective multicenter study was performed to assess the reliability of sentinel lymph node (SLN) biopsy in breast cancer and to analyze factors potentially influencing success rates.

METHODS

In 21 departments, SLN biopsy and consecutive axillary lymph node dissection were performed in 814 breast cancer patients. The 80 surgeons involved were free in the choice of lymphography technique. The detection rate and the sensitivity, as well as the impact of lymphography technique, patient selection, technical procedure and learning curves, were evaluated.

RESULTS

The blue dye technique was used in 137 patients, radiocolloid in 169 patients, and combined blue dye/radiocolloid in 508 patients. The identification rate for the sentinel node was 83.9% for the entire group and showed a significant dependence on the lymphography technique (blue dye, 71.6%; radiocolloid, 78.8%; combined blue dye and radiocolloid, 89.6%). The overall sensitivity in detecting lymph node metastases was 91.3%. Immunostaining for cytoceratine revealed micrometastases in 19 (5.1%) of 374 patients in whom H/E staining was negative. The combined subdermal/peritumoral injection of the colloid showed a significantly higher identification rate than subdermal or peritumoral injection alone (96.8%, 84.6%, 78.6%; p < 0.001). There was also a significant higher detection rate in cases of SLN biopsy performed prior to lumpectomy, compared to SLN biopsy following lumpectomy (94.7% versus 82.8%; p < 0.001). Furthermore, there was a close correlation between the number of performed examinations and the detection rate.

CONCLUSION

SLN mapping predicts the axillary lymph node status accurately. Learning curves and several technical features influence the detection rate significantly. However, the false negative rate was independent of experience and injection technique.

Clinical practice guidelines for the care and treatment of breast cancer: 16. Locoregional post-mastectomy radiotherapy

OBJECTIVE

To provide information and recommendations to assist women with breast cancer and their physicians in making decisions regarding the use of locoregional post-mastectomy radiotherapy (PMRT).

OUTCOMES

Locoregional control, disease-free survival, overall survival and treatment-related toxicities.

EVIDENCE

This guideline is based on a review of all meta-analyses, consensus statements and other guidelines published between 1966 and November 2002. Searches of MEDLINE and CANCERLIT for English-language randomized controlled trials published between 1995 and November 2002 were also conducted to supplement the literature previously reviewed by the American Society of Clinical Oncology (ASCO) Health Services Research Committee panel in its published guideline. A nonsystematic review of the literature was continued through June 2003.

RECOMMENDATIONS

Locoregional PMRT is recommended for women with an advanced primary tumour (tumour size 5 cm or greater, or tumour invasion of the skin, pectoral muscle or chest wall). Locoregional PMRT is recommended for women with 4 or more positive axillary lymph nodes. The role of PMRT in women with 1 to 3 positive axillary lymph nodes is unclear. These women should be offered the opportunity to participate in clinical trials of PMRT. Locoregional PMRT is generally not recommended for women who have tumours that are less than 5 cm in diameter and who have negative axillary nodes. Other patient, tumour and treatment characteristics, including age, histologic grade, lymphovascular invasion, hormone receptor status, number of axillary nodes removed, axillary extracapsular extension and surgical margin status, may affect locoregional control, but their use in specifying additional indications for PMRT is currently unclear. PMRT should encompass the chest wall and the supraclavicular, infraclavicular and axillary apical lymph node areas. To reduce the risk of lymphedema, radiation of the entire axilla should not be used routinely after complete axillary dissection of level I and II lymph nodes. A definite recommendation regarding the inclusion of the internal mammary lymph nodes in PMRT cannot be made because of limited and inconsistent data. The use of modern techniques in radiotherapy planning is recommended to minimize excessive normal tissue exposure, particularly to the cardiac and pulmonary structures. Common short-term side effects of PMRT, including fatigue and skin erythema, are generally tolerable and not dose-limiting. Severe long-term side effects, including lymphedema, cardiac and pulmonary toxicities, brachial plexopathy, rib fractures and secondary neoplasms, are relatively rare. The optimal sequencing of PMRT and systemic therapy is currently unclear. Regimens containing anthracyclines or taxanes should not be administered concurrently with radiotherapy because of the potential for increased toxicity.

VALIDATION

The authors' original text was submitted for review, revision and approval by the Steering Committee on Clinical Practice Guidelines for the Care and Treatment of Breast Cancer. Subsequently, feedback was provided by 11 oncologists from across Canada. The final document was approved by the steering committee.

SPONSOR

The Steering Committee on Clinical Practice Guidelines for the Care and Treatment of Breast Cancer was convened by Health Canada. COMPLETION DATE: November 2003.

Lymphoscintigraphic and intraoperative detection of the sentinel lymph node in breast cancer patients: the nuclear medicine perspective

The concept of sentinel lymph node biopsy in breast cancer surgery relates to the fact that the tumor drains in a logical way via the lymphatic system, from the first to upper levels. Therefore, (1) the first lymph node met (the sentinel node) will most likely be the first one affected by metastasis, and (2) a negative sentinel node makes it highly unlikely that other nodes are affected. Sentinel lymph node biopsy would represent a significant advantage as a mini-invasive procedure, considering that, after operation, about 70% of patients are found to be free from metastatic disease, yet axillary node dissection can lead to significant morbidity. Although the pattern of lymphatic drainage from a breast cancer can be very variable, the mammary gland and the overlying skin can be considered as a biologic unit in which lymphatics tend to follow the vasculature. Considering that tumor lymphatics are disorganized and relatively ineffective, subdermal, and peritumoral injection of small aliquots of radiotracer is preferred to intratumoral administration. (99m)Tc-labeled colloids with most of the particles in the 100-200 nm size range would be ideal for radioguided sentinel node biopsy in breast cancer. Lymphoscintigraphy is an essential part of radioguided sentinel lymph node biopsy, as images are used to direct the surgeon to the site of the node. The sentinel lymph node should have a significantly higher count than background. After removal of the sentinel node, the axilla must be re-examined to ensure all radioactive sites are identified and removed for analysis. The success rate of radioguidance in localizing the sentinel lymph node in breast cancer surgery is about 94-97% in Institutions where a high number of procedures are performed, approaching 99% when combined with the vital blue dye technique. At present, there is no definite evidence that a negative sentinel lymph node biopsy is invariably correlated with a negative axillary status, except perhaps for T(1a-b) breast cancers, with size < or =1 cm. Randomized clinical trials should elucidate the impact of avoiding axillary node dissection in patients with a negative sentinel lymph node on the long-term clinical outcome of patients.

Should the hunt for internal mammary chain sentinel nodes begin? An evaluation of 150 breast cancer patients

BACKGROUND

The aim of this study was to determine the visualization rate, identification rate, and clinical implications of biopsy of sentinel nodes in the internal mammary chain (IMC) in patients with breast cancer.

METHODS

From January 1999 to December 2002, 691 sentinel node procedures were performed. Preoperative lymphoscintigraphy was performed after injection of (99m)Tc-labeled nanocolloid into the tumor (.2 mL; 115 MBq; 3.1 mCi). The sentinel node was surgically identified with the aid of patent blue dye and a gamma ray detection probe.

RESULTS

The sentinel node in the IMC could be harvested in 130 (87%) of the 150 patients in whom it was visualized on the images and contained metastases in 22 (17%) of these 130 cases. In nine patients (7%), the IMC sentinel node was tumor positive, whereas the axilla was tumor-free. Stage migration was seen in all patients with a tumor-positive IMC sentinel node (17%). There was a change of management in 38 (29%) of the 130 patients: institution or omission of radiotherapy to the IMC, adjuvant systemic therapy, or omission of an axillary lymph node dissection.

CONCLUSIONS

Pursuit of IMC sentinel nodes improves the staging of patients with breast cancer and enables treatment to be better adjusted to the needs of the individual patient.

Clinical role of FDG PET in evaluation of cancer patients

Positron emission tomography (PET) is a diagnostic imaging technique that allows identification of biochemical and physiologic alterations in tumors. Use of PET performed with 2-[fluorine-18]fluoro-2-deoxy-D-glucose (FDG) significantly improves the accuracy of tumor imaging. In terms of oncologic applications, FDG PET has already gained widespread acceptance in the initial staging of cancer, management of recurrent cancer, and monitoring the response to therapy. With conventional imaging modalities, size criteria are used to distinguish between benign and malignant disease in lymph nodes; conversely, FDG PET is based on identification of fundamental aspects of tumor metabolism. FDG uptake in tumors is proportional to the metabolic rate of viable tumor cells, which have an increased demand for glucose. The high sensitivity and high negative predictive value of FDG PET in most malignant tumors enable this technique to play an even greater role in tumor management at initial staging and follow-up.

Will early detection of non-axillary sentinel nodes affect treatment decisions?

Axillary lymph node involvement is the best prognostic factor for breast cancer survival. Staging breast cancers by axillary dissection remains standard management and is part of the UK national guidelines for breast cancer treatment. In the presence of involved axillary lymph nodes best treatment has been shown to be axillary clearance (Fentiman and Mansell, 1991), but clearly for women whose nodes are uninvolved avoidance of morbidity is optimal and this will be achieved by minimal dissection of the axilla. Thus, for node-negative women the introduction of the sentinel node biopsy technique may revolutionise the approach to the axilla. These will be women with mammographic screen detected small well and moderately differentiated tumours (Hadjiloucas and Bundred, 2000). The impact of sentinel node biopsy in women who have symptomatic large tumours is unproven, and around half of these women will require a second procedure to clear their axilla or radiotherapy as treatment. Even for those women found to have involved sentinel lymph nodes the ability to use early systemic chemotherapy followed by axillary clearance or radiotherapy may provide long-term survival gains. Sentinel node biopsy should not, however, become routine practice until randomised controlled trials have proven its benefit and safety in reducing morbidity. Several randomised controlled trials (including ALMANAC) are currently underway.

Thoracoscopic internal mammary sentinel node biopsy: an animal model of a new technique

BACKGROUND

The nodal status remains the most important prognostic factor in breast cancer. While evaluation of the axillary lymph nodes remains a standard of practice, evaluation of the internal mammary lymph nodes is no longer routinely performed. In the era of extensive radical mastectomies, it was shown that up to 40% of breast cancer patients had nodal metastases in the internal mammary chain. This resulted in up to 10% of presumed "node-negative" patients actually being node-positive when the internal mammary nodes were examined. In the era of sentinel node biopsies, hot internal mammary nodes on lymphoscintigraphy are sometimes encountered and confusion exists regarding the appropriate approach to these nodes. New advances in endoscopic surgery have enabled a minimally invasive approach to the mediastinum. The aim of this study was to evaluate the feasibility of thoracoscopic internal mammary sentinel node biopsy in an animal model.

MATERIALS AND METHODS

Five farm pigs were injected with isosulphan blue under the right upper nipple. After a sentinel node was identified, it was dissected thoracoscopically.

RESULTS

In all the animals, an internal mammary blue node was easily identified 1-5 min after the injection and dissected with thoracoscopic instruments without significant damage to other thoracic structures. The procedure length averaged 30 to 60 min.

CONCLUSIONS

Thoracoscopic internal mammary sentinel node biopsies are feasible, short, easy to perform, minimally invasive, and well focused toward a sentinel node. Well-planned phase I studies should be initiated to further evaluate this new technique.

Detection of locoregional and distant recurrences in breast cancer patients by using FDG PET

Cases of recurrence of breast cancer can pose considerable diagnostic and therapeutic challenges for the oncologic team. The prognosis and management decisions are based on knowledge of the true extent of disease. Conventional staging methods, including physical examination, assessment of levels of tumor markers, cross-sectional imaging, and bone scintigraphy, may not reliably demonstrate the extent of disease in all cases. Physical examination and cross-sectional imaging (computed tomography [CT] or magnetic resonance imaging) can be problematic because (a) the sequelae of previous surgery and radiation therapy can be difficult to distinguish from recurrent neoplasms and (b) early metastatic disease (small lesions) can be difficult to distinguish from benign lesions that are too small to characterize. Positron emission tomography (PET) with 2-[fluorine-18]fluoro-2-deoxy-D-glucose (FDG) can help clarify inconclusive findings from physical examination and cross-sectional imaging. FDG PET is more sensitive than CT in detection of lymphatic spread of disease to locoregional and mediastinal nodes. Metastases at distant sites including the lung, bone, and the liver are also readily detected at FDG PET. FDG PET has been proved accurate in restaging cases of recurrent breast cancer and will likely aid in directing therapy in these cases.

Utility of internal mammary lymph node removal when noted by intraoperative gamma probe detection

BACKGROUND

Lymphatic mapping (LM) for breast cancer has made internal mammary node (IMN) detection practical and dependable. This study demonstrates the necessity of IMN removal when suggested by intraoperative radioguided surgery detection.

METHODS

From April 1998 to July 2000, 1273 patients underwent LM for breast cancer. LM was performed using the combined dye and radiocolloid technique. Patients were scanned operatively with a gamma probe over the IMN area, and most underwent preoperative lymphoscintigraphy. Nodes were removed from patients in whom radioactivity was detected in the internal mammary area.

RESULTS

Thirty of the 1273 (2.4%) patients mapped had at least one IMN removed. Twenty-two of 30 (73.3%) had inner quadrant lesions. Five of 30 (16.7%) patients had IMNs that were positive for metastatic disease. Three of these five had no metastatic spread to the axillary sentinel lymph node (SLN). One of thirty (3.3%) patients with IMN localization had neither hot nor blue nodes detected in an SLN procedure.

CONCLUSIONS

Radioguided SLN detection should be attempted in the IMN basin with all tumors. If an IMN is identified, it should be removed. IMN biopsy is a feasible, low-risk procedure when directed by radioguided LM and provides a guide for radiotherapy for patients with positive IMNs.

18fluorodeoxyglucose positron emission tomography to detect mediastinal or internal mammary metastases in breast cancer

PURPOSE

To determine the prevalence of suspected disease in the mediastinum and internal mammary (IM) node chain by 18fluorodeoxyglucose (FDG) positron emission tomography (PET), compared with conventional staging by computed tomography (CT) in patients with recurrent or metastatic breast cancer.

PATIENTS AND METHODS

We retrospectively evaluated intrathoracic lymph nodes using FDG PET and CT data in 73 consecutive patients with recurrent or metastatic breast cancer who had both CT and FDG PET within 30 days of each other. In reviews of CT scans, mediastinal nodes measuring 1 cm or greater in the short axis were considered positive. PET was considered positive when there were one or more mediastinal foci of FDG uptake greater than the mediastinal blood pool.

RESULTS

Overall, 40% of patients had abnormal mediastinal or IM FDG uptake consistent with metastases, compared with 23% of patients who had suspiciously enlarged mediastinal or IM nodes by CT. Both FDG PET and CT were positive in 22%. In the subset of 33 patients with assessable follow-up by CT or biopsy, the sensitivity, specificity, and accuracy for nodal disease was 85%, 90%, and 88%, respectively, by FDG PET; 54%, 85%, and 73%, respectively, by prospective interpretation of CT; and 50%, 83%, and 70%, respectively, by blinded observer interpretation of CT. Among patients suspected of having only locoregional disease recurrence (n = 33), 10 had unsuspected mediastinal or IM disease by FDG PET.

CONCLUSION

FDG PET may uncover disease in these nodal regions not recognized by conventional staging methods. Future prospective studies using histopathology for confirmation are needed to validate the preliminary findings of this retrospective study.

Internal mammary lymph nodes and sentinel node biopsy in breast cancer

The long-term follow-up of patients treated with extended radical mastectomy has proved that the internal mammary node (IMN) status is an important prognosticator of breast cancer. Patients with isolated IMN involvement seem to have the same outcome as those with limited axillary disease, and these patients may therefore be overstaged in the TNM system. Sentinel node biopsy (SNB) of IMNs may be an ideal staging procedure, but lymphatic mapping studies demonstrate that data from extended radical mastectomy series cannot be extrapolated to patients suitable for SNB, where the IMN involvement is <5% overall, and around 1% for IMN metastases without axillary disease. Current evidence does not allow internal mammary SNB to be recommended as a standard procedure, but as patients with IMN involvement may benefit from adjuvant systemic treatment, internal mammary SNB should be further studied in this context.

Postmastectomy radiotherapy: clinical practice guidelines of the American Society of Clinical Oncology

OBJECTIVE

To determine indications for the use of postmastectomy radiotherapy (PMRT) for patients with invasive breast cancer with involved axillary lymph nodes or locally advanced disease who receive systemic therapy. These guidelines are intended for use in the care of patients outside of clinical trials.

POTENTIAL INTERVENTION

The benefits and risks of PMRT in such patients, as well as subgroups of these patients, were considered. The details of the PMRT technique were also evaluated.

OUTCOMES

The outcomes considered included freedom from local-regional recurrence, survival (disease-free and overall), and long-term toxicity.

EVIDENCE

An expert multidisciplinary panel reviewed pertinent information from the published literature through July 2000; certain investigators were contacted for more recent and, in some cases, unpublished information. A computerized search was performed of MEDLINE data; directed searches based on the bibliographies of primary articles were also performed.

VALUES

Levels of evidence and guideline grades were assigned by the Panel using standard criteria. A "recommendation" was made when level I or II evidence was available and there was consensus as to its meaning. A "suggestion" was made based on level III, IV, or V evidence and there was consensus as to its meaning. Areas of clinical importance were pointed out where guidelines could not be formulated due to insufficient evidence or lack of consensus.

RECOMMENDATIONS

The recommendations, suggestions, and expert opinions of the Panel are described in this article.

VALIDATION

Seven outside reviewers, the American Society of Clinical Oncology (ASCO) Health Services Research Committee members, and the ASCO Board of Directors reviewed this document.

Factors Affecting Axillary Lymph Node Metastases in Patients with T1 Breast Carcinoma

The purpose of this study was to determine factors associated with the incidence of axillary lymph node metastases (ALNM) in T1 tumors and cases in which axillary dissection could be omitted. Data from 195 patients with T1 primary invasive breast cancer (size ≤2 cm) who underwent either mastectomy or wide local excision of the tumor and axillary dissection were reviewed. ALNM was found in 59 of 195 patients with T1 tumors (30.3%). Tumor size was found to be the only independent predictor of ALNM, having a directly analogous relationship with the probability of invaded nodes: T1a (≤5 mm) tumors had 0 per cent ALNM, whereas T1b (5 mm < T1b ≤ 10 mm) and T1c (10 mm < T1c ≤ 20 mm) tumors had 25.7 per cent and 33.8 per cent ALNM respectively. Among the other factors studied (patient age, tumor site, hormone receptor status, histologic type, and grade of the tumor) only the histologic grade of the tumor cells appeared to correlate with the incidence of lymph node involvement, but this was not statistically significant. In conclusion only tumor size has statistically significant correlation with the incidence of ALNM. Routine axillary dissection could be omitted only in patients at minimal risk of ALNM (ductal carcinoma in situ and T1a) and when treatment decisions were not influenced by lymph node status (e.g., elderly patients with clinically negative axilla). Axillary dissection (at least levels I and II) should be performed in all cases with primary invasive breast cancer with tumor size >5 mm.

Should internal mammary nodes be sampled in the sentinel lymph node era?

BACKGROUND

Controversy exists regarding internal mammary lymph nodes (IMNs) in the staging and treatment of breast cancer. Sentinel lymph node identification with radiocolloid can map drainage to IMNs and directed biopsy can be performed with minimal morbidity. Furthermore, recent studies suggest that IMN drainage of breast tumors may be underestimated. To gain further insight into the prognostic value of IMNs, we reviewed the outcome of patients in whom the IMN status was routinely assessed.

METHODS

A retrospective review of 286 patients with breast cancer who underwent IMN dissection between 1956 and 1987 was conducted.

RESULTS

Median follow-up is 186 months, age was 52 years (range, 21-85 years), tumor size was 2.5 cm, and number of IMNs removed was 5 (range, 1-22); 44% received chemotherapy, 16% endocrine therapy, and 5% radiotherapy. Presence of IMN metastases correlated with primary tumor size (P < .0001) and number of positive axillary nodes (P < .0001) but did not correlate with primary tumor location or age. Overall, the 20-year disease-free survival is significantly worse for the 25% of patients with IMN metastases (P < .0001). In patients with positive axillary nodes and tumors smaller than 2 cm, there was a significantly worse survival (P < .0001) in the patients with IMN metastases. This difference in survival was not seen in women with tumors larger than 2 cm.

CONCLUSIONS

Patients with IMN metastases, regardless of axillary node status, have a highly significant decrease in 20-year disease-free survival. Treatment strategies based on knowledge of sentinel IMN status may lead to improvement in survival, especially for patients with small tumors. At present, sentinel IMN biopsies should be performed in a clinical trial setting.

Tagging sentinel lymph nodes: a study of 100 patients with breast cancer

The aim of this study was to evaluate in breast cancer patients the feasibility of sentinel lymph node (SLN) identification and the sensitivity of this technique to detect node metastases. Between January and July 1997, SLNs were tracked with Evans Blue dye in 100 patients with breast cancer who then underwent complete level I/II axillary lymph node dissection (ALND). All SLNs were examined by haematoxylin-phloxin-saffron (HPS) staining and immunohistochemistry (IHC) of multiple sections. The findings for the SLNs were compared with results on ANLD. Axillary SLNs were identified in 83 patients (detection rate = 83%; 95% confidence interval (CI) 74-90%). Axillary SLNs were detected in 58/83 cases (70%) at level I only, and in 69/83 (83%) at levels including level I. Histologically positive axillary SLNs were found in 45% (37/83) of patients, including 2 patients with malignancy (micro-metastases) detected by IHC only. The sensitivity of axillary SLN to detect axillary lymph nodes metastases was 37/39 = 95% (95% CI 83-99%). SLNs of the internal mammary chain (IMC) were dissected for 33 tumours of the median or inner quadrants and detected in 26/33 = 79% of cases (95% CI 61-91%). In our experience, the overall sensitivity of SLN identification as a predictor of node (axillary or IMC) metastases was 41/43 = 95% (95% CI 84-99%), confirming the usefulness of the procedure.

The Role of Internal Mammary Lymph Node Metastases in the Management of Breast Cancer

We reviewed the literature regarding internal mammary lymph node metastasis in the management of breast cancer. Internal mammary dissection or radiotherapy provides no survival advantage in breast cancer patients. However, internal mammary nodal metastasis is an important independent prognostic factor. Patients with such metastases are candidates for systemic adjuvant hormonal therapy and/or chemotherapy. Moreover, in patients with histologically confirmed internal mammary metastases, irradiation of the nodes is appropriate for local control. Noninvasive techniques, such as internal mammary lymphoscintigraphy, parasternal sonography, computed tomography, and magnetic resonance imaging, are not satisfactory for the practical diagnosis of internal mammary metastasis. At present, biopsy of the internal mammary nodes in the first and second intercostal spaces is indicated for assessing nodal status and planning treatment.

Tumorigenesis of rat mammary epithelial cells by N-nitroso-N-methylurea in an in vitro system: characterization of the microtumors

Chemical carcinogenesis is a lengthy process that involves the rather loosely defined stages of initiation, promotion, and progression. Several model systems of mammary carcinogenesis have been designed to elucidate the mechanisms of chemical carcinogenesis. Most of these systems have included animal models. While organ specific chemical carcinogenesis can be initiated in these systems, the subsequent stages of promotion and progression are difficult to study in detail. Investigations on in vitro carcinogenesis have shown transformation of mammalian cells in culture; the transformational event, however, is difficult to discern within the monolayer culture. We have recently reported the development of an in vitro carcinogenesis system that allows both the initiation as well as the progression of mammary cells in a collagen gel matrix culture system. The cells transformed by a chemical carcinogen develop into discernible microtumors within the three dimensions of a collagen gel culture. Isolation of these microtumors from the collagen gel and subsequent culture in monolayer has produced cells capable of colony formation in soft agar. The present study further characterizes these microtumors originated in vitro by analysis of cell growth kinetics versus parallel control cells. In addition, flow cytometric and cytogenetic studies have been performed to investigate the chromosomal stability of these cells. It was also observed that the microtumors, produced in vitro from mammary epithelial cells of an inbred strain of rats, show the ability to form tumors upon transplantation into the fat pad of syngeneic hosts.