PETER CHIN
BREAST CANCER
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DIAGNOSIS
Assessment of a breast problem is made by combining features in the clinical history & examination, breast imaging and tissue diagnosis. This is termed the “Triple Assessment” and is the standard approach in assessing a breast concern. The different components of the triple assessment must be concordant with each other. If the clinical features and breast imaging do not show any concerns, it may not be necessary to proceed with tissue diagnosis. The details of the triple assessment are described below:
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CLINICAL HISTORY AND EXAMINATION: A thorough history is taken from the patient, focusing on the symptoms and any high risk features in the personal and family history. Breast examination is performed to determine the nature of the concern and to check for any palpable lumps or nodal enlargement.
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BREAST IMAGING includes Diagnostic Mammogram and targeted Breast Ultrasound. Mammography is performed to check for any suspicious features, abnormal density or microcalcification. Ultrasound is used to complement Mammography by targeting the area of concern. Combining mammography and ultrasound increases the sensitivity of detecting any abnormality in the patient with a specific breast symptom. Occasionally, Breast MRI may be utilized to provide further information regarding an area of concern in the same breast, to determine the size of an involved area, to rule out any multifocality and to check on the opposite breast. Note: In Tauranga, there are 2 private providers of breast imaging service: Bay Radiology and Medex Radiology. Currently, there is no mammography setup within Tauranga Public Hospital and mammography investigation is subcontracted out to both providers.
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TISSUE DIAGNOSIS: This is usually obtained by performing a needle test. Core Biopsy can be performed either by palpation or with ultrasound guidance. If an area of abnormality is not palpable and not visible on ultrasound, a stereotactic core biopsy technique using mammography can be performed. Occasionally, further tissue is required for analysis and this may necessitate an excision biopsy of the area of concern.
SURGERY
The type of surgery for treatment of breast cancer depends on several factors which include tumour size and position as well as breast size. The choice is usually between Breast Conserving Surgery and a Total Mastectomy. This is usually combined with axillary nodal surgery (either sentinel node biopsy or axillary clearance) in the case of invasive cancer.
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BREAST CONSERVING SURGERY
Breast conserving surgery (also known as Wide Local Excision or Lumpectomy) is possible if the tumour size allows for removal with adequate clear margins as well as a satisfactory aesthetic outcome (Note: The term” partial mastectomy” is an old-fashion term that has an alarming connotation and should be avoided). In the context of invasive breast cancer, Breast Conserving Surgery is routinely combined with radiotherapy. This has been shown in research to result in a similar long term outcome when compared with Total Mastectomy. In other words, the chances of developing a local recurrence and the overall long term survival are similar for either approach.
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The term “Oncoplastic” breast cancer surgery is used to describe specialized techniques that allow removal of tumour while aiming for an optimal aesthetic result. The technique may involve mobilizing breast tissue to fill defects, using breast reduction techniques to remove large tumours or reconstructing a breast at the same time as a mastectomy. Oncoplastic breast cancer surgeons are specifically trained in these techniques so that the optimal surgical option can be offered to the individual patient.
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TOTAL MASTECTOMY
In some cases, breast conserving surgery may not be possible or recommended. A Total Mastectomy may be the only viable option. The patient will be counselled regarding options of reconstruction as appropriate depending on tumour staging (breast reconstruction will be described in a different section). For some patients, particularly the older population, a straightforward total mastectomy may be the better option whereby radiotherapy is usually not required and the patient can avoid the need for further surgery.
Peter will discuss all surgical options in detail with the patient so that an informed decision can be made by the patient regarding the optimal treatment choice.
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SENTINEL NODE BIOPSY
In cases of invasive cancer and some cases of extensive in situ cancer (DCIS), a sentinel node biopsy will be performed at the same time as the above surgery. If an invasive cancer is large (> 3 cm in diameter) or multifocal, it may be advisable to consider an Axillary Clearance instead. You surgeon will make a recommendation based on the clinical findings. Sentinel Node Biopsy has been shown to be safe in cases of invasive cancer where the size is less than 3 cm. The Sentinel node is the first lymph node/s which receives drainage from lymphatics within a specific region. By removing the sentinel node, one can determine whether cancer cells have spread to the node itself. This will help with predicting long term outcome and will guide further management. The sentinel node can be located by injecting radioisotope into the breast prior to surgery. Thereafter, a lymphoscintiscan is often performed to map out the site/s and number of sentinel nodes which are usually found in the axilla (armpit). Blue dye may also be injected during surgery to assist with sentinel node identification. The sentinel node is then removed and sent to the laboratory for microscopic analysis to check on whether there are tumour cells present.
It is important that the sentinel node biopsy operation is performed by a surgeon who is specifically trained in the technique and regularly performs the procedure. This ensures the highest chance of success in finding and removing the true sentinel node/s.
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If a sentinel node is involved with tumour cells, further surgery is often necessary to remove the rest of the lymph nodes in the axilla. This will ensure that any remaining tumour cells are adequately removed from that region. This operation is known as Axillary Node Dissection or Axillary Node Clearance. A drain is inserted after a nodal clearance to drain seroma fluid which is naturally produced by the body and secreted into the tissue space. This drain is removed once the drainage decreases and this can take up to 1 – 2 weeks after surgery (sometimes longer). Once the drain is removed, it is not uncommon for the body to continue to produce seroma fluid within the operative site. This is usually reabsorbed over time but if a large volume is produced, it may result in a visible swelling which can become uncomfortable. This usually requires needle aspiration which may be repeated as often as necessary until resolution of the collection.
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BREAST CANCER THERAPY
Further treatment may be necessary after surgery. This can be in the form of:
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1. RADIOTHERAPY: This is routinely given after breast conserving surgery for invasive breast cancer and occasional given in cases of insitu cancer (DCIS).For Bay of Plenty patients, radiotherapy is administered at the Kathleen Kilgour Centre in Tauranga for a period of 3 or 5 weeks depending on the treatment regime chosen. Side effects will be discussed with the patient and this can include tiredness, discomfort and local radiation effect on the skin and surrounding tissue.
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2. HORMONAL THERAPY: This is an effective treatment that comes in a tablet form and used in cases where the breast cancer have been found to be oestrogen receptor positive. There are several types that can be used and these include Tamoxifen, Anastrazole (Arimidex), Letrozole (Letara, Femara) and Exemestane (Aromasin). The tablet is usually taken once a day for a period of 5 years, sometimes longer. Studies have shown that it significantly reduces the incidence of recurrence in patients who have oestrogen receptor positive cancer.
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3. CHEMOTHERAPY: This is sometimes recommended, particularly in younger premenopausal patients and is dependent on tumour staging. There are several chemotherapeutic drugs that are effective in breast cancer treatment (anthracycline and taxanes) and chemotherapy is usually administered over a 4 – 6 months period depending on the drug combination used. In the Bay of Plenty, chemotherapy is administered locally at the Cancer Centre in Tauranga Hospital or at the cancer clinic in Whakatane Hospital. If required, a referral will be made by the surgeon to the Medical Oncologist so that the patient can have a thorough discussion regarding the benefit and risks of having chemotherapy.
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4. HERCEPTIN: 20% of breast cancers have been found to over-express a specific type of receptor on the tumour cells. These so called Her2 receptors are growth factor receptors involved in the signalling pathway for cell growth. Trastuzumab, a drug more commonly known by it’s trade name Herceptin, is an effective treatment agent and acts by blocking these receptors . Studies have shown a significant decrease in the risk of recurrence and also improvement in overall survival. At this stage, Herceptin is given concurrently with chemotherapy and once the chemotherapy course is completed, the Herceptin treatment is continued for a total treatment period of one year.
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5. OTHER DRUG TREATMENTS are being studied in ongoing research with promising results. For example, PARP inhibitors and Immunotherapy shows promising results in specific settings and various other projects are underway to look at new targets of treatment.
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SCREENING
The aim of breast screening is to detect cancers at an early stage so that treatment can be offered in a timely fashion. Breast Screen Aoteoroa provides free 2 yearly breast screening for the asymptomatic population between the age of 45 to 69 years old. Screening mammogram is performed and ultrasound is only used if an abnormality is seen on mammography.
If you are aware of a breast lump, it is important that you seeks urgent medical attention and be referred for a diagnostic mammogram and ultrasound, which is performed by a radiology provider separate from the breast screening program. As mentioned above, the aim and focus of Breast Screen Aoteoroa is to screen the asymptomatic population.
Younger women often have high breast density which makes it more difficult to detect smaller lesions on mammography. As a result, more frequent annual screening mammography should be considered. For this reason, we recommend annual screening mammography for women between the age of 40 to 50 years old.
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RESOURCES:
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Breast Cancer Foundation:
www.breastcancerfoundation.org.nz/
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Support Services, Tauranga