|Carcinoma of the breast presents as a self discovered mass in the majority of instances. In countries where screening mammography is well established, the second common method of presentation is by screen detection. Physician discovered masses in the breast account for less than one quarter of the presentation and imply the need for better training in clinical breast examination, particularly amongst primary care providers.
The presenting symptoms include :
Carcinoma breast presentation : Lump attached to skin and chest wall ; Diffuse change (Inflammatory carcinoma) ; Nipple retraction left breast
Evaluation consists of taking a history from the patient with particular refrence to the established risk factors. A nipple discharge has a 10 % likelihood of a breast cancer diagnosis if unilateral, persistant, spontaneous, clear/ blood stained / serous and testing positive for occult blood or is associated with a mass.
The majority of breast masses are benign and biopsies are expensive. But, a failure to diagnose a breast cancer has major consequences to both the patient and her doctor. Failures to diagnose arise because there is no single, reliable, quick and convinient diagnostic modality of sufficient sensitivity and specificity to make a definitive diagnosis.
Diagnosis is by a multimodality process of Triple Assessment consisting of :
The cumulative information from all three modalities gives the Triple Diagnosis . There is strong evidence that triple assessment provides a more accurate diagnosis than a fewer number of tests . When all three assessments concurr, the diagnostic accuracy is about 99 %. The accuracy tends to be lower in the younger age group.
Physical examination The accuracy of a physical examination as a sole modality of evaluation varies between 60 – 85 %, approaching 90 % if the diagnosis is “clearly benign” or “clearly malignant”. The physical evaluation of axillary node involvement is particularly unreliable. 30% of nodes thought to be clinically positive turn out to be histologically negative. 30% of nodes thought to be clinically normal turn out to be histologically positive. Similarly histological involvement of the nipple which occurs in 30 % of breast cancers is unsuspected clinically in 50 % of patients.
Imaging of the breasts is done by bilateral mammography even if the diagnosis of cancer is clinically obvious. The primary purpose of a mammogram is not to charecterise the mass but to evaluate the breasts for occult and bilateral lesions (found in 3% of women). The majority of the latter are identified by mammography alone. It is important to remember that mammography can be normal in the presence of a palpable cancer.
The exceptions to mammographic evaluation are women less than 35 years of age (or younger if there is a strong suspicion of carcinoma) and pregnant women. How ever, if there is a strong possibility of pregnancy associated breast cancer, mammography can be offered with abdominal lead sheilding with a radiation dose of less than 500 mGy to the foetus. But a gravid breast renders mammography inherently insensitive, and an ultrasound examination may be a better option.
Ultrasound examination of the breasts is inferior to mammography for the detection of early breast cancer masses. It has an useful role in : differentiating solid from cystic masses and in guiding target biopsy.
Other imaging modalities such as : Digital mammography, Magnetic Resonance Imaging, Radionuclide imaging with Technitium 99 M Sestamibi and Positron Emission tomography are under evaluation.
Pathological evaluation. Fine needle aspiration cytology (FNAC) is the commonly used method of evaluation because of it’s many advantages. It can be done free hand, by stereotactic technique or under ultrasound guidance. As part of a triple assessment, it’s overall diagnostic accuracy can be as high as 100% with very rare false positives and false negatives. The latter may depend on the skill and experience of the physician performing the aspiration.
Potential advantages, disadvantages and complications of FNAC
When aspirating cystic lesions, only blood stained fluid is assessed cytologically to detect the presence of partially cystic – partially solid carcinomas or intracystic carcinomas.
Core needle biopsy done by free hand, ultrasound guided or stereotactic techniques is a popular alternative to FNAC, though it is unclear whether it is more accurate.
Core needle biopsy : steps of placement, throw of needle and post firing
The potential advantages and disadvantages are listed below :
Potential advantages and disadvantages of core needle biopsy
Open biopsy While one should strive to have a preoperative diagnosis of breast cancer by triple assessment, open biopsy, performed under either local or general anaesthetic may be necessary if the results of triple assessment are inconclusive. Frozen section examination is no longer routinely used. False positives and false negatives may occur rarely, but the fact that false positives occur suggests that the technique be used judiciously.
Special techniques of biopsy
Needle / Wire/ Hook Localisation biopsy This is an alternative to guided or stereotactic FNAC or core needle biopsy. The objective is to remove minimal amount of breast tissue for diagnosis and radiological confirmation that the lesion has been excised.
Wire / Hook Localisation biopsy : specimen X – ray
Mammotome and Advanced Breast Biopsy Instrumentation use image guidance to resect large cores of tissue from impalpable lesions for both diagnostic and therapeutic purposes.
Sentinel lymph node biopsy Routine axillary clearence leads to the majority of patients who are node negative to undergo unnecessarily radical surgery and significant morbidity . Information on axillary status can be obtained by examining a sentinel lymph node, identified by lymphatic mapping (with technitium – 99m – labelled sulphur colloid lymphoscintigraphy or isosulfan blue dye).The technique is currently under evaluation and preliminary studies indicate it to be promising with a predictive value of about 95 %.
In patients with operable breast cancer (T1-2, N0-1), there is no evidence to support routine screening for asymptomatic metastatic disease. The yeild from routine screening for lung, liver or bone metastasis is less than 1 %. These patients need only minimal investigations, which includes a full blood count, chest x-ray and limited bioprofiling preoperatively. Patients with more advanced but operable disease (T3, N1-2), may require staging to exclude asymptomatic distant metastases as their identification may have the potetial to determine treatment. Patients with symptoms suggestive of metastases require appropriate investigations.
Lung metastasis are discovered on pre operative chest x-ray in approximately 6 % of patients at the time of diagnosis and in about 20 % of patients during the course of the disease. If the chest x-ray findings are suggestive or equivocal, further imaging by CT or MRI may be used. For routine post operative monitoring of asymptomatic patients, chest x-ray is not warranted.
Liver metastasis develop in a very small number of patients. The use of liver function tests to predict metastasis at the time of breast cancer diagnosis has a very low yeild. Patients with abdominal symptoms, hepatomegaly or altered liver functions will require evaluation by imaging modalities such as Ultrasound, CT scan or MRI. There is no data to suggest that earlier diagnosis of liver metastasis in breast cancer patients leads to improved survival .
Skeletal metastasis are found in 1 – 2 % of patients at the time of diagnosis and in about 30 % of patients during the course of the disease. Routine use of preoperative bone scans not only has a low yeild, but also a high false positive rate. Positive bone scans must be correlated with plain films and if the latter are equivocal, tomography, CT, MRI or a bone biopsy may be required to determine status. Patients with skeletal complaints or a raised serum calcium need to be scanned Post operatively, patients with positive nodes, skeletal complaints or a raised serum calcium need to be scanned.
Brain metastasis are a rare presentation and CT or MRI is necessary only if neurological symptoms are suggestive. Internal mammary nodes are involved in about 5 – 10 % of patients with negative axillary nodes. Their rate of involvement rises in medial lesions and in the presence of axillary node metastasis. Imaging modalities are unreliable and their routine sampling is controversial.
Consultant Breast Surgeon
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