Lumpectomy

Background

Lumpectomy is defined as an excision of a breast lump with a surrounding rim of normal breast tissue, as shown in the image below. ^[1]

Traditionally, a lumpectomy was performed only to diagnose a breast mass. However, this procedure can be performed as part of the definitive management of a breast malignancy or benign lesions that have previously been diagnosed by needle biopsy. ^{[2, 3, 4]}

Indications

The indications for performing a lumpectomy may be diagnostic or therapeutic.

Indications for a diagnostic lumpectomy include the following:

• Equivocal pathology obtained on core biopsy or fine needle aspiration cytology of a radiologically suspicious breast lump

• A lump classified as category 3 or 4 by the Breast Imaging-Reporting and Data System that is close to the pectoral muscle, which makes biopsy under radiologic guidance difficult

Indications for a therapeutic lumpectomy include the following:

• Benign breast lumps, such as fibroadenoma or phyllodes ^[5]

• Ductal carcinoma in situ or invasive breast cancer that is amenable for breast conservation based on the size of the lesion ^{[6, 7]}

Contraindications

A lumpectomy is not recommended without prior needle biopsy confirmation of the nature of the breast mass.

For proven cancers, a lumpectomy may be contraindicated because of the size of the lump or contraindications to radiotherapy.

When excision of the lump would involve removing more than 30% of the breast tissue, a lumpectomy is not recommended. In general, 3-4 cm is considered to be the safe cutoff for lumpectomy in medium to large breasts.

Patients undergoing lumpectomy for cancer must undergo postoperative radiotherapy to the chest wall to reduce the risk of local recurrence. A lumpectomy must not be performed for patients with severe psoriasis, sarcoidosis, or previous chest wall radiotherapy.

Equipment

A basic surgical set is required for performing a lumpectomy.

Important instruments include the following:

• Littlewood forceps, Lahey forceps, or skin hooks for lifting the flaps

• Langenbeck retractors (medium and small size)

• Small artery forceps

• Nontoothed and toothed forceps

• Metzenbaum scissors

• Unipolar diathermy

Patient Preparation

Anesthesia

A lumpectomy can be performed under local or brief general anesthesia.

Small lumps, particularly those that are away from the nipple, are suitable for a local anesthetic, provided the patient is cooperative.

Positioning

The patient is positioned supine on the table.

The arms should be stretched out in line with the shoulder on an armboard. This is particularly helpful for upper outer quadrant lumps.

For lumps in the upper half of the breast, the head end of the table can be tilted up by 30-40 degrees.

For tumors in the outer half of the breast, tilt the patient toward the opposite side to the one being operated upon.

Complications

Lumpectomy is a safe procedure that does not have many complications.

Routine postoperative complications include the following:

• Hematoma

• Infection

• Poor cosmesis

• Re-excision

Although re-excision is not a complication per se, it is something that needs to be explained clearly to the patient before surgery. A second operation to excise more breast tissue is needed in two circumstances:

• If tumor cells are found close to the margin of the excised lumpectomy specimen when the procedure has been performed for a diagnosed breast cancer ^{[8, 9]}

• If the final pathology reveals incompletely excised malignant or borderline phyllodes ^[4]

Approach Considerations

Mark the lump with an indelible marker on the skin prior to making the skin incision.

With lumpectomy for a benign lump, do not raise the flaps. Go down onto the surface of the lump with scissors or diathermy and excise it. Bleeding vessels can be managed as they arise.

With lumpectomy for a malignant lump, raise the flaps all around the lump and extend them to at least 1 centimeter beyond the palpable lump. Orient the excised lump with sutures or clips. Always reconstruct the breast by approximating the walls of the cavity with absorbable sutures. Drain placement is not recommended as it leads to poor cosmetic results.

Lumpectomy for Palpable Lumps

Making the incision

The placement of the incision is determined by the location of the lump. ^[10]

For central lumps, a periaerolar incision is best suited and heals well with minimal scarring.

For lumps in the outer halves of the breast, a curvilinear incision over the lump along the natural crease lines of the breast gives the best cosmetic result.

Raising the flaps

Using skin hooks and cat paws retractors or Littlewood forceps, lift up one side of the skin incision.

If the lumpectomy is being performed for a benign lump or for diagnostic purposes, do not lift the flaps but cut down straight onto the surface of the lump. Dissect around it, take care of bleeders as they occur, and excise the lump.

When the lumpectomy is being performed for a malignant lump, it is important to raise the flaps around the lump as one would do for a mastectomy. Lift the flap up using scissors or diathermy. Be careful not to thin the flap too much. The flap should be raised all around the dimensions of the lump and at least 1 centimeter beyond it. Excise the lump with a sufficient margin down to the pectoral muscle.

A novel method for predicting lumpectomy intraoperative margin status has been reported in which shaved cavity margins were evaluated with microcomputed tomography (micro-CT) scanning; this technique appears to show promise in the intraoperative identification of margin tumor involvement and reduction of reexcision rates. ^[11]  The investigators reported a 83.3% positive predictive value, a 94.7% negative predictive value, 83.3% sensitivity, and 94.7% specificity for micro-CT in assessing lumpectomy shaved cavity margins. ^[11]  More recently, a systematic review and meta-analysis of cavity shaving plus lumpectomy versus lumpectomy alone in patients undergoing breast-conserving surgery found additional cavity shaving was effective for reducing the positive margin rate and for avoiding reoperation, and it did not appear to have excessive excised tissue volume relative to lumpectomy alone. ^[12]

Closure of the cavity

When a lumpectomy is performed for a benign lump, the cavity tends to be small. This is because benign lumps push the surrounding breast stroma, which springs back to its normal place once the lump is excised. A few absorbable sutures may be placed to approximate the cavity before placing the skin sutures.

Malignant lumps tend to grow into the surrounding breast tissue; therefore, they leave a bigger cavity when excised. This should be approximated by mobilizing the surrounding breast tissue to allow for good cosmesis.

Lumpectomy for Impalpable Abnormalities

Wire-guided excision is performed for impalpable abnormalities. The radiologist inserts a wire either through or in close proximity to the abnormality. For lesions visible on ultrasonography, the wire is inserted under ultrasonographic guidance. ^[13] For those that are not visible on ultrasonography, this is done under stereotactic control.

The wire can be inserted up to a day prior to the actual surgery. After inserting the wire, another mammogram is taken and used as a guide during surgery.

In the operating room, the surgeon removes the dressing over the wire and determines the sitting of the incision, which is based on the spatial orientation of the lesion according to the original and confirming mammograms. The incision is generally placed close to the entry point of the wire if it is just anterior to the lesion.

If the entry point of the wire is at a distance from the actual position of the lesion, then the incision is made closer to the lesion. Once the skin flaps are raised, the wire is pulled through the skin into the wound.

Once the lesion is excised, a radiograph is obtained to ensure complete excision.

Oncoplastic Breast Surgery

Relatively recent years have seen the advent and increasing use of oncoplastic breast surgery, ^[14] which has allowed surgeons to excise larger volumes of breast tissue without compromising cosmesis. ^[15] The resultant breast defect after this surgery is filled either by tissue displacement techniques or by replacement with fat or muscle-based grafts.