Treatments for Breast Cancer
All patients diagnosed with breast cancer should be discussed within the multidisciplinary team (MDT) meeting, occupied by amongst other breast surgeons, radiologists, oncologists, pathologists, and breast care nurses, to provide the most suitable and patient-focused management plan available.
Breast conserving treatment is only suitable for individuals with localised operable disease and no evidence of metastatic disease.
A Wide Local Excision (WLE) is the most common breast conserving treatment and involves excision of the tumour, typically ensuring a 1cm margin of macroscopically normal tissue is taken along with the malignancy.
This option is typically only suitable for single cancers <4cm in diameter and will also be dependent on the size of the tumour, its location, and the size of the breast.
A mastectomy removes all the tissue of the affected breast, along with a significant portion of the overlying skin, with the muscles of the chest wall left intact. The amount of skin that is excised is often dependent on whether a reconstruction is being performed.
Mastectomies are indicated when there is a localised invasive cancer with a significant proportion of the surrounding tissue with non-invasive disease, when a WLE would lead to an unacceptable cosmetic result*, or simply through patient choice.
*This may be if there is more than one focus of invasive disease or if the malignancy is >4cm in diameter
Axillary surgery is most commonly performed alongside WLE and mastectomies, in order to assess the sentinel lymph node, as this indicates prognosis of the disease.
A sentinel node biopsy involves removing the nodes responsible for draining the tumour; the nodes are identified by injecting a blue dye with associated radioisotope into the skin overlying the malignancy. A radioactivity detection or visual assessment (for the nodes which become blue) is then carried out to establish the location of the sentinel nodes. Once identified the nodes are removed and sent for histological analysis.
Axillary node clearance involves removing all nodes in the axilla, being careful not to damage many important structures located in the axilla. Common complications from this operation include paresthesia, seroma formation, and lymphedema in the upper limb.
A risk-reducing mastectomy is an operation to remove healthy breasts in order to reduce the risk of developing breast cancer.
Risk-reducing mastectomy is only suitable for patients with a high risk of developing breast cancer and requires appropriate counseling to reach this difficult decision. In cases of suspected genetic risks, then patients are often referred to a genetic counsellor.
Factors conferring risk include:
- A strong family history of breast or ovarian cancer
- Testing positive for genetic mutations, such as BRCA1 or BRCA2, PTEN, or TP53 mutations
- Previous history of breast cancer
In malignant but non-metastatic disease, therapy for breast cancer is adjuvant so as to reduce the risk of relapse. Medical treatment is commenced usually after primary surgery, yet medical treatment is often the treatment of choice in elderly patients or in those unfit for surgery.
Although there are several treatment options available, such as chemotherapy, radiotherapy, and immunotherapy, hormone manipulation is the biggest contributor to improved survival.
Aromatase inhibitors, such as Anastrozole, Letrozole, or Exemestane, act through binding to oestrogen receptors to inhibit further malignant growth and preventing further oestrogen production. They also block the conversion of androgens to oestrogen in peripheral tissues. They should be avoided in premenopausal women
Tamoxifen is used typically if an aromatase inhibitor is not appropriate. It acts through blockade of oestrogen receptors and is also used as prophylaxis against breast cancer in women. However, it is known to increase the risk of thromboembolism during and after surgery or periods of immobility.
Immunotherapy may be used in patients whose cancers express specific growth factor receptors.
One of the most common targets is the human epidermal growth factor receptor (HER-2 positive malignancies) for which Herceptin (Trastuzumab) is a monoclonal antibody that targets its activity.
Herceptin is given IV or SC and forms part of adjuvant therapy, or can be administered as monotherapy in patients who have received at least two chemotherapy regimens for metastatic breast cancer*.
*A common side-effect of treatment is cardiotoxicity, hence cardiac function must be monitored before and during treatment
In recent years, oncoplastic surgery has emerged as a new approach for either extending techniques to allow breast conserving surgery or to reconstruct the breast following mastectomy.
There are several surgical reconstructive techniques in the oncoplastic treatment of breast malignancy, broadly divided into mammoplasty and flap formation
A therapeutic mammoplasty involves a WLE combined with a breast reduction technique. The end-result is a smaller and uplifted breast, with the nipple and areola preserved along with their blood supply and the nipple relocated to suit the new breast.
A Latissimus Dorsi Flap involves a portion of the Latissimus Dorsi muscle and its overlying skin used to reconstruct the removed breast, either as a free or pedicle flap. Only a certain amount of muscle can be used and so this technique is only useful for reconstructing smaller breasts.
A Transverse Rectus Abdominal Muscle (TRAM) flap involves the abdominal muscle, skin, and fat to reconstruct the removed breast, also either as a free or pedicle flap. This has the benefit of removing abdominal fat but the disadvantage of reducing abdominal muscle strength.
A Deep Inferior Epigastric Perforator (DIEP) flap uses tissue from the abdomen and its overlying skin to reconstruct the breast, yet is only ever performed as a free flap. The advantage of the DIEP flap is that, unlike the TRAM flap, no muscle is used therefore abdominal muscle strength is usually maintained.