State-of-the-art lymph node staging for breast cancer in the year 2000

Breast cancer. Part 2: present and future treatment modalities

This is the second article in a series of three on breast cancer. Part 1 discussed breast anatomy, the principles behind breast awareness and breast health, detailing common benign breast diseases, types of breast cancer and staging. In this article, treatment for breast cancer is discussed. The article will follow the usual order of modalities in the trajectory, starting with surgery, then chemotherapy, radiotherapy and endocrine treatment, finishing with a discussion of future and biological treatments.

Lymph node imaging: Basic principles

Lymph nodes are involved in a wide variety of diseases, particularly in cancer. In the latter, precise nodal staging is essential to guide therapeutic options and to determine prognosis. For long, imaging of the lymphatic system has been limited to lymph vessel,especially via the exclusive use of conventional lymphography, at the expense of invasive procedures and patient's discomfort. Three main technical advances, however, have recently completed the clinical armamentarium for lymph node imaging: first, the refinement of cross sectional imaging, i.e. CT and MRI, combined or not with dedicated contrast agents, has progressively replaced conventional lymphography in oncology situations; second, the development of intra-operative sentinel node mapping has profoundly modified the diagnostic and therapeutic procedures in several cancer situations, mostly melanoma and breast cancer; finally, the increased availability of functional imaging, especially through the use of FDG-PET, has greatly contributed to the accuracy improvement of nodal metastases identification. The aim of this review will thus be to briefly review the anatomy and physiology of the lymphatic systems and to overview the basic principles of up-to-date lymph node imaging.

Validation of lymphatic mapping and sentinel node biopsy in patients with symptomatic breast cancer

BACKGROUND

Lymphatic mapping and sentinel node biopsy in breast cancer aims to allow lymph node negative women to avoid axillary clearance by providing a minimally invasive means of staging the axilla. However, before its implementation into routine clinical practice, initiating departments must verify their expertise in each of the surgical, radiological and pathological components necessary for its successful performance. Here, we present our validation experience.

METHODS

Thirty patients with breast cancer of any stage (but without clinical axillary lymphadenopathy) undergoing definitive resection of their primary tumour underwent lymphatic mapping (using blue dye alone or in combination with radioisotope) and sentinel node biopsy concurrent with standard level II axillary clearance over a ten month period.

RESULTS

All patients had sentinel nodes identified intraoperatively. The sentinel node in 29 patients correctly predicted the status of axillary involvement. One patient had non-sentinel nodal disease without metastases being identified in their sentinel node. Such a single false negative out of thirty patients is considered acceptable by current guidelines.

CONCLUSION

Validation of expertise in sentinel node identification and analysis is feasible over a relatively short period of time in a regional symptomatic breast unit. We now feel confident in offering this procedure to selected patients with breast cancer in our catchment area in place of routine axillary clearance.

Intraoperative cytologic diagnosis of breast sentinel lymph nodes in the routine, nonacademic setting: a highly specific test with limited sensitivity

Intraoperative determination of metastatic breast carcinoma in sentinel lymph nodes (SLNs) by cytologic methods has been proposed as highly specific and sensitive. Much of these data are derived from academic institutes with highly trained personnel and without axillary dissection occurring as a direct result of the intraoperative interpretation. This prospective study was undertaken to assess the sensitivity and specificity of cytology in the routine, private-practice, intraoperative setting. A total of 207 SLNs from 96 breast carcinoma patients were evaluated by intraoperative cytologic preparations by general surgical pathologists; positive results led to axillary lymphadenectomy. Ten nodes were positive by intraoperative cytology (IC). Permanent section analysis confirmed the presence of carcinoma in the IC-positive cases and documented carcinoma in 19 of the IC-negative cases. IC sensitivity and specificity were 34% and 100%, respectively. False-negative IC interpretations occurred in nodes with occult micrometastases (12 of 19 nodes) and lobular carcinoma (6 of 19 nodes). Only one of eight grossly positive sentinel nodes resulted in a false-negative IC. While near-perfect specificity and high sensitivity can be achieved with grossly positive sentinel nodes by IC, sensitivity is quite low in cases with micrometastatic and lobular carcinoma.

Patterns of lymphadenopathy in thoracic malignancies

There are different lymphatic drainage pathways in the thorax that are relevant in the staging of lung cancer, breast cancer, lymphoma, esophageal cancer, and malignant mesothelioma. To properly search for metastatic spread, it is important to carefully evaluate the specific nodal stations that drain the thoracic structures from which a primary tumor originates. Because size criteria have limitations in the prediction of nodal status, pathologic confirmation is essential for accurate staging. Computed tomography (CT) is useful in helping the surgeon or interventional radiologist determine the most appropriate approach for nodal sampling. Fluorine-18 fluorodeoxyglucose (FDG) positron emission tomography (PET) has an increasing role in detection of diseased lymph nodes that appear normal at CT alone, particularly when FDG PET images are fused with CT images. However, the role of radiologic imaging extends beyond initial staging and the guidance of interventions to include posttreatment assessment and the detection of recurrent disease. Therefore, at all levels of cancer imaging, it is essential to identify the relevant lymph node regions and their relations to the primary tumor.

Simultaneous bilateral breast and high-resolution axillary MRI of patients with breast cancer: preliminary results

OBJECTIVE

The aims of this study were to develop a standardized one-step procedure for simultaneous high-resolution MRI of the axilla and bilateral breast MRI and to identify nodal features suggestive of metastatic involvement. SUBJECTS AND METHODS. We studied 16 women undergoing axillary lymph node dissection after combined bilateral breast MRI and high-resolution MRI of the axilla with a maximum in-plane resolution of 0.6 x 0.4 mm. MRI was performed using a standard double breast coil and a 15-cm round flexible surface coil adapted to the axilla. High-resolution axillary sequences, including inversion recovery T2- and spin-echo T1-weighted sequences, were performed before and after gadolinium chelates bolus injection. Axillary image analysis focused on nodal morphology including size, contour regularity, cortex and hilar appearance, signal intensity, and enhancement parameters. Axillary MRI findings were compared with the final pathogic results from axillary lymph node dissection in all patients. Patients were divided into groups according to the final pathologic axillary status. Differences in MRI lymph node features across the groups were tested using a t test for quantitative data and the chisquare test or Fisher's exact test for binary data.

RESULTS

The features of the axilla on high-resolution MRI that best discriminated between patients with positive pathologic findings and those with negative pathologic findings were the presence of nodes with irregular contours (p < 10(-4)), high signal intensity on T2 sequences (p < 10(-3)), marked gadolinium enhancement (p < 10(-3)), and round hila and abnormal cortexes (p < 0.05).

CONCLUSION

Breast tissue and axillary lymph nodes both can be analyzed on MRI in a one-step process using a bilateral breast coil combined with a surface coil. Morphologic features observed on high-resolution MRI of the axilla can improve the identification of metastatic nodes.

Imaging the lymphatic system: possibilities and clinical applications

The lymphatic system is anatomically complex and difficult to image. Lymph ducts are responsible for the drainage of part of the body's interstitial fluid. Lymph nodes account for the enrichment of lymph fluid, and can be involved in a large variety of diseases, especially cancer. For a long time, lymphatic imaging was limited to the sole use of conventional lymphography involving invasive procedures and patient discomfort. New contrast agents and techniques in ultrasound, nuclear medicine, and MR imaging are now available for imaging of both the lymphatic vessels and the lymph nodes. The objective of this review is to discuss the different imaging modalities of the lymphatic system, with a special focus on the new possibilities of lymphatic imaging including enhanced MR lymphography, sentinel node and positron emission tomography imaging, and contrast-enhanced ultrasound.

Minimally invasive lymphatic mapping using fluorescently labeled vitamin B12

BACKGROUND

We examined the usefulness of a new agent in the mapping and dissection of inguinal lymph nodes in the pig. Cy5-cobalamin bioconjugate is blue under visible light and fluoresces brilliant red with laser stimulation. The wavelength of the emitted red light is sufficiently long that it is visible through blood, subcutaneous fat, and fascia. Currently available surgical techniques of minimally invasive dissection are well suited for using fluorescent detection in a dark operating field with minimal modification of an existing Hopkins surgical telescope.

MATERIALS AND METHODS

We tested this concept in the live post-adolescent, female, nonlactating pig (30 kg). We insufflated the subcutaneous tissue over the groin and inserted three ports (1 x 10 mm and 2 x 5 mm) for dissection. We injected the Cy5-cobalamin bioconjugate in a dermal location on the hind limb. A HeNe laser stimulated the CobalaFluor in the lymphatics and the emitted fluorescence passed through a holographic notch filter to a three-chip camera.

RESULTS

Under white light, the lymphatic trunks and the sentinel node were visualized within minutes of injection. Both the lymphatic trunks and the node fluoresced bright red under stimulation with red laser light.

CONCLUSIONS

These preliminary studies establish the potential usefulness of this new agent in lymphatic mapping. This novel technology might be useful in visualizing cancers that spread to regional lymph nodes. This technique has the potential to map the lymphatic drainage and to identify the presence of malignant cells in that drainage with currently available minimally invasive technology.

Application of a Multigene Reverse Transcription-PCR Assay for Detection of Mammaglobin and Complementary Transcribed Genes in Breast Cancer Lymph Nodes

Background: Mammaglobin mRNA expression is found in 70–80% of primary and metastatic breast tumor biopsies. The potential breast tumor markers B305D, B726P, and γ-aminobutyrate type A receptor π subunit (GABAπ) complement the expression of mammaglobin. Collectively the expression profile of these four genes could be used as a diagnostic and prognostic indicator for breast cancer.

Methods: A multigene reverse transcription-PCR (RT-PCR) assay was established to detect the expression of mammaglobin, GABAπ, B305D, and B726P simultaneously. Specific primers and TaqMan® probes were used to analyze combined mRNA expression profiles in primary breast tumors and metastatic lymph node specimens.

Results: The multigene RT-PCR assay detected substantial expression signals in 27 of 27 primary tumor and 50 of 50 metastatic breast lymph node samples. Specificity studies demonstrated no significant expression signal in 27 non-breast cancer lymph nodes, in 22 various healthy tissue samples, or in 14 colon tumor samples.

Conclusion: The novel RT-PCR-based assay described here provides a sensitive detection system for disseminated breast tumor cells in lymph nodes. In addition, this multigene assay could also be used to test peripheral blood and bone marrow samples.