Updated: November 2004

Surgery

Partial or total mastectomy combined with Level I and Level II axillary node dissection is indicated. "Sampling" of the axilla is not adequate for assessing the axillary nodal status which is still the most powerful predictor of the need for adjuvant therapy.

Partial Mastectomy, Axillary Dissection and Radiation Therapy

This is standard treatment for patients with tumours less than 5 cm providing:

1. the tumour is unifocal 
2. the tumour is sufficiently small in relationship to the size of the breast that wide local excision with a margin of normal tissue will leave a reasonable cosmetic result, and
3. there is no contraindication to radiotherapy:previous radiotherapy to the breast, pregnancy, collagen vascular disease (scleroderma and lupus), ataxia teleangiectasia, inability to lay down flat with arm abducted.

An acceptable ipsilateral breast tumor recurrence (IBTR) rate is £ 1% per year. Very young age is NOT a contraindication for BCT. However, young age is a known predictor in breast recurrence.

Resection Margins

It is important to obtain negative resection margins at the time of surgery ( tumour > 2 mm from an inked margin) for all patients with invasive disease or DCIS. Invasive or in situ disease at the margin is treated in the same manner. A positive margin is defined as tumour touching ink and (or transected tumor), a close margin is margin < 2 mm, anything in-between.

Guidelines for Re-excision and Boost Following Breast Conserving Surgery

Re-excision to obtain negative margins is recommended for patients with close or positive margin. If a margin is <2 mm and re-excision is declined or inappropriate, a radiation boost to the tumour bed is recommended.

Re-excision should be more strongly recommended where the risk of IBTR is high and systemic risk is low, for example: 

Margin <2 mm and

• extensive intraductal component present
• age < 50
• lobular histology
• lymphatic invasion present
• no systemic therapy given
• at multiple sites
• margin status unknown
• tumour touching inked margin at any site
• pure ductal carcinoma in situ

When the deep margin is positive, and the surgeon has dissected down to fascia, then a boost should be given.

Patients with close or positive margins who decline re-excision should be advised that the risk of IBTR is increased. The relative risks/benefits of re-excision vs boost in the context of local control and cosmesis should be discussed. 

The incision should be placed with regard to cosmetic considerations. Removal of skin adversely affects the cosmetic outcome. In general, it is not necessary to remove skin unless it is involved by tumour. The cavity of the local excision should be marked with four to six clips to aid in the localization of a subsequent radiotherapy boost field, should this prove to be necessary. The breast cavity should be examined for meticulous hemostasis and a drain should not be used. The axillary dissection should be done through a separate incision, unless the primary tumour is within the axillary tail of the breast. The extent of the axillary dissection is identical to that of a modified radical mastectomy.

Even with pathologically negative margins, 25% to 40% of women treated with partial mastectomy alone will recur in the breast within five to ten years of follow up. Therefore, all patients treated by partial mastectomy and axillary dissection should be reviewed by a radiation oncologist regarding radiation to the breast. Some may also require radiation to the axilla.  Two recent randomized breast conservation trials have examined the role of adjuvant tamoxifen alone, without adjuvant radiation to the breast (Huges, NEJM 2994:351:071 and Fyles, NEJM 2994; 351:963). These trials indicate that there may be a subset of patients where radiation may be omitted. Consultation with a radiation oncologist is required for all patients undergoing BCT.

Modified Radical Mastectomy

This traditional method of surgical treatment is equivalent to breast conservation.

If a modified radical mastectomy is performed, the scar should be located with appropriate consideration of the site of the primary tumour, at the same time recognizing that some patients will desire breast reconstruction. Both from the point of view of cosmesis and from the point of view of subsequent radiation therapy, if it should be required, the surgery should not be extended unnecessarily. The extent of the scar and any drains should be medial to the midaxillary line and above the sixth rib.

Modified radical mastectomy is the treatment of choice if:

1. there are multiple tumours in a single breast
2. the size of the tumour is such that removal of the primary tumour with an adequate margin of normal tissue will lead to considerable distortion of the breast
3. there are absolute or relative contra-indications to radiation therapy (see Contraindications to Radiation Therapy)
4. the patient is elderly, since modified radical mastectomy may be "easier" on the patient than a partial mastectomy, node dissection and 3-5 weeks of daily radiation therapy
5. the patient will not be available for follow-up, or
6. the patient is not interested in breast conservation
7. extensive micro calcifications through the breast on mammogram
8. positive margin on subsequent re-excision  

Classical Radical Mastectomy

This operation is rarely indicated although, for tumours which are tethered to the underlying pectoral fascia over a small area, extension of the modified radical mastectomy to include removal of some portion of the underlying muscle is not infrequently performed. A classical radical operation may be indicated in an occasional patient where an adequate margin cannot be otherwise accomplished.

Subcutaneous Mastectomy