Diagnosis and assessment

Diagnosis and assessment

CLINICAL PRESENTATION AND DIAGNOSIS


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 :

  1. a lump in the breast or
  2. a diffuse change within the breast without a lump or
  3. nipple / skin change  or
  4. occasionally as metastatic disease
  5. occasionally as pain localised and persistant

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 :

  1. physical examination of the breasts
  2. imaging (mammography) and
  3. pathological evaluation (fine needle aspiration cytology or a core needle histology).

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 mammographyMagnetic Resonance ImagingRadionuclide 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

Advantages Disadvantages Complications
Rapid to perform and report

Cost effective

Out patient procedure

Minimal pain

No needle tract involvement by tumour. (needle tract to be excised at surgery)

Requires cytological expertise

Lack of cytological discrimination between insitu and invasive tumours.

Repeat FNAC within 1 – 2 weeks show reactive changes which are difficult to interpret.

Alteration in cell morphology by pregnancy / lactation / HRT use

Difficulty in performing hormone receptor studies.

Haematoma

False positive mammographic report if performed without a 2 week gap 70.

Acute mastitis

Pneumothorax (rare)

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

Potential advantages Potential disadvantages
Allows discrimination between insitu and invasive tumours.

Eliminates false positives

Enables grading of tumours

Enables assessment of hormone receptor status

More invasive than FNAC

Painful and hence requires local anaesthesia

Special equipment necessary

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 %.

INVESTIGATIONS

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.

Dr.Uma Krishnaswamy MS, FRCSEd, FAIS, MA
Consultant Breast Surgeon
Email :[email protected]

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