Mastectomy

Introduction

Performing a mastectomy can be accomplished using a wide variety of techniques, depending on the clinical setting. Any mastectomy should be sensitive to the aims and principles of oncoplastic breast surgery, namely that optimal treatment of the malignancy should be achieved with minimal impact on quality of life. Training in oncoplastic surgery often starts with the ‘simple’ procedure of mastectomy (and of course, an understanding of the options a woman has to avoid it if that is possible). However, the fact is that mastectomy should not be regarded as ‘simple’. From a surgical perspective, there are many ways to perform it and many ways to avoid complications and mitigate the psychological and physical effect of breast loss. Performing a mastectomy well requires thoughtful planning, careful tissue handling and a degree of artistry. Performed incorrectly, a mastectomy can be an ugly reminder of endured treatment, a common cause of complication or reconstruction failure or a contributor to disease recurrence.

Completeness of mastectomy

A mastectomy aims to remove as much breast tissue as is possible. In addition, it aims to achieve clearance of any malignancy. For locally advanced disease, the latter aim may require a mastectomy to include overlying skin or adjacent structures local to the disease, but in most cases, these structures can be preserved. As most mastectomies are performed for extensive disease not suitable for breast conservation, or for risk reduction, every effort should be made to ensure as complete a mastectomy as possible. However, it has long been recognised that almost all mastectomies will leave some breast tissue behind. This is true no matter how thin the mastectomy flaps are. In one study on cadavers, even when the skin flaps were made so thin that they resembled ‘full-thickness skin grafts’, residual breast tissue was found in 83% of specimens: on the pectoral muscle, at the periphery of the resection and on the overlying skin flaps. Residual breast tissue is located mostly at the outer quadrants and/or, in the case of nipple-sparing mastectomy, behind the nipple areola complex.

In terms of oncological outcomes, there are two consequences of ‘incomplete’ removal of all breast tissue. One is leaving residual breast tissue that may subsequently undergo malignant change, and as a consequence all women undergoing risk-reducing surgery should be counselled that there will be a small but real risk of breast cancer even after this procedure. The other is positive margins on histology for existing malignant disease. The predictive value for this has been questioned. However, it has been shown to be associated with an increased risk of local recurrence in those who did not have radiotherapy and those with inflammatory breast cancer. ^, The evidence of the importance of margins after mastectomy also comes from a recent meta-analysis. Positive margins were associated with increased local recurrence on multivariable analyses (hazard ratio [HR] 2.64, 95% confidence interval [CI] 2.01–3.46) and LR was higher regardless of the distance of the tumour from the margin defined as positive. After skin-sparing mastectomy, positive margins were associated with increased LR (HR 3.40, 95% CI, 1.9–6.2). In the four studies reporting distant recurrence, patients with involved margins had a significantly higher risk of this compared with patients with free margins (HR 1.53, 95% CI 1.03–2.25).

Usually, a mastectomy can be performed whilst leaving as much of the overlying subcutaneous tissue and skin as is desired for aesthetic purposes. The subcutaneous layer is the conduit for the vasculature supplying the skin after a mastectomy and preserving it; therefore, it reduces the risk of ischaemic complications and increases the quality of the tissue left resurfacing the chest or forming part of a breast reconstruction. This layer is of variable and unpredictable thickness and studies have shown that a distinct layer of fascia separating the breast tissue and breast fat from the subcutaneous layer of fat is evident in only half of cases and inconsistent in the majority. This ‘plane’ of mastectomy needs to be individually tailored as it will be thicker in some women and thinner in others and is usually thicker towards the periphery of the breast. There are different techniques for deciding upon the plane of dissection, as described later. The plane as visualised on mammography has been proposed as a guide to the thickness of the subcutaneous layer and, pragmatically, can be useful in this regard. However, compressed breast images may exaggerate the thickness of this layer and also do not convey the three-dimensional nature of it. Essentially this component of the mastectomy procedure is very surgeon dependent and there is no set thickness of mastectomy flaps that defines a properly performed mastectomy. ^,

In planning a mastectomy, the first question to answer is: What do I need to remove to achieve the aims of this operation? For instance, if the cancer is very close to overlying skin then plan to remove the overlying skin, and if the plan is to leave the skin over the cancer then the surgeon should err on leaving the subcutaneous layer thinner over such areas of disease. Thus, the ‘radical’ element of this operation is tailored to the patient and their disease. Striving for a ‘complete’ mastectomy by making every part of the mastectomy flaps as thin as possible is not only futile, it risks leaving skin and subcutaneous fat that is non-viable or severely compromised.

General considerations in planning a mastectomy

The blood supply to the breast and the tissues overlying it is derived mainly from the internal mammary perforators (particularly the second), the lateral thoracic artery and the intercostal perforators. As a mastectomy removes most of the intercostal perforators and the mammary branch of the lateral thoracic artery, the vascularity to the overlying breast skin and subcutaneous tissue is compromised in all forms of mastectomy. As such, patient risk factors that further affect vascularity or wound healing become important cofactors in complications. These include:

• smoking;

• obesity;

• diabetes;

• poor skin quality;

• previous radiotherapy;

• previous surgery to the breast; and

• severe comorbidities.

Of these, smoking is the most commonly encountered factor that can be improved to optimise outcome within the timescale of the urgent case. This and other factors may affect technique selection. There are more than 4000 chemicals present in cigarette smoke, including nicotine and carbon monoxide. One effect of nicotine is to cause vasoconstriction of the dermal–subcutaneous vascular plexus. This has important consequences as mastectomy flaps rely on this plexus for survival. Hence, nicotine e-cigarettes are equally harmful. As well as inducing a hypoxic state and causing vasoconstriction, smoking can lead to increased platelet aggregation, which results in the formation of tiny thromboses in capillaries. This is detrimental to wound healing, which relies heavily on blood flow in newly formed capillaries. One study of 425 patients undergoing mastectomy and breast-conserving surgery identified smoking as an independent predictor for wound infection and skin necrosis regardless of the number of cigarettes smoked. Another study of 716 patients having free transverse rectus abdominis myocutaneous (TRAM) flaps showed mastectomy flap necrosis, abdominal flap necrosis and abdominal hernias were significantly higher in smokers. This study did demonstrate a dose effect, with smokers who had a history of more than a pack a day for 10 years being at increased risk of developing problems compared with smokers who had smoked for a smaller number of pack-years (55.8% vs 23.8%). One observation in this study was that delayed breast reconstruction in smokers was associated with a significantly lower rate of wound complications compared with immediate breast reconstruction. The risk of wound complications in delayed reconstructions in smokers was similar to the rate in non-smokers. Complications were also less common in women who stopped smoking four or more weeks before surgery. In the literature, there is no consensus on the optimal duration of preoperative smoking cessation but there is evidence from a variety of studies that there are potential benefits from even a brief period of abstention.

As a key determinant of mastectomy flap viability, surgical planning and technique should always take patient risk factors into account.

Considerations for simple mastectomy

In addition to general considerations, four questions should be answered:

• 1.

  Is it necessary/desirable to excise skin overlying the cancer?

  • In principle, skin is only required to be excised if the cancer involves the skin or is so close that a clear margin cannot clearly be achieved around the cancer without skin resection. If these criteria are met or are uncertain then mastectomy is an excellent opportunity to remove skin over a cancer and should be planned accordingly.

• 2.

  Is there likely to be a lateral ‘dog ear’/redundant tissue?

  • The all too frequently seen but completely avoidable complication of mastectomy is redundant tissue, also known as a dog ear, which is unsightly, causes difficulty with bra fitting and often chafes on the prosthesis, arm or bra ( Fig. 9.1 ).

    

• 3.

  Would the patient benefit from a contralateral breast reduction?

  • This is a simple and very effective option to enable women with a heavy breast to wear a lighter prosthesis and feel less unbalanced ( Fig. 9.2a ). If considered desirable, then it should be performed at the same time as the mastectomy. In rare cases a woman may choose a bilateral simple mastectomy to achieve better overall symmetry, although this may cause problems with bra fitting as there is no anchor for the bra or for external prostheses and such cases need careful consideration. In men, contralateral liposuction can aid postoperative symmetry in many cases.

    

• 4.

  Is a delayed breast reconstruction planned?

  • The scar should be sympathetic to the method of delayed reconstruction planned. In most cases a low scar is best (as in Fig. 9.2a ). A flap-based reconstruction is the most common type of delayed breast reconstruction and it allows this to be inset at the inframammary fold (IMF), with the upper scar low enough to be hidden in low-neckline clothes ( Fig. 9.2b ).

Technique

Techniques of simple mastectomy are largely non-evidence-based. The following description is not intended to be prescriptive or dogmatic but merely a description of an approach to a commonly performed operation. Most scars can be based around the IMF. The incision pattern is drawn in theatre, initially with a line at or just below the IMF. Then with repeated upward and downward movement of the breast the planned transposition of this line on the breast skin can be marked ( Fig. 9.3 ). In most cases the upper incision line passes just above the areola. Attention should be paid to the degree of tension applied to the upward or downward breast movement as this represents the tension that will be exerted on the wound on closure. The upper and lower incision lines should be planned so that they meet comfortably but without excess laxity. Incisions should be planned to avoid any dog ear. To achieve this, it is often best to continue the incision along the bra line laterally, curving up slightly towards the posterior axillary fold, until the upper and lower lines meet ( Fig. 9.4 ) or, if there is doubt about how to fashion the lateral end, stop the incision at the lateral edge of the breast and fashion it once the mastectomy is complete, before closure (see comments regarding dog ear further in the chapter). Transverse mastectomy scars centred on the nipple are rarely indicated; they sit high on the chest, often show in the cleavage, promote lateral dog ears and represent an outmoded approach to simple mastectomy. It is beholden on all surgeons to be familiar with a range of mastectomy incisions and a degree of creativity is often required to design a scar that conforms to an individual’s anatomy, respects the oncological requirements and is as aesthetically acceptable as possible.

Inferior broad-based flaps can be designed to allow skin excisions in the upper pole if these are required. In breasts with a high nipple position or in cases where skin excision in the upper pole is desired, the lower incision line can be adjusted upwards to preserve skin on the lower flap. Such modifications to the inferior skin flap should be broad based. Other scar patterns to consider in such situations include the Wise pattern or dome-shaped scar ( Fig. 9.5 ).

For more locally advanced disease, the area of skin that is to be removed may be extensive. Again, it is better to first mark this out and then plan how the scar can be fashioned to allow closure. Skin can usually be recruited by upper abdominal advancement and sometimes lateral chest wall tissue can be useful either as a random lateral thoracic flap or a LICAP (lateral intercostal artery perforator) or LTAP (lateral thoracic artery perforator) flap (see Radical Mastectomy further in the chapter).

Managing the potential dog ear

Several techniques have been described for this. The first and most important is to avoid incisions that are very prone to it – such as a transverse mastectomy scar, which produces a ‘dog ear’ or ‘angel wings’ in most patients in whom it is used. One approach to reduce ‘dog ears’ is as follows. If the patient is thin, a flat lateral chest wall can be achieved by using an IMF scar as described earlier. In women with excess lateral tissue, it is often useful to complete the mastectomy with minimal extension of the scar laterally and then tidy this part of the scar. The easiest way to do this is to close the skin with temporary placement of skin staples. This then allows variations of lateral scar closure to be visualised before commitment to any particular one. The staples can be removed and replaced as many times as necessary to get the best and shortest scar. Final wound closure is with two layers of absorbable deep and superficial subcuticular absorbable sutures. Some lateral laxity can be accommodated by gathering the upper flap into the central part of the scar.

The three most useful techniques for lateral scar design in the author’s experience are lateral extensions of the IMF scar (towards the posterior axillary fold), liposuction and, occasionally, the fishtail technique ( Fig. 9.6 ). When performing fishtailing, use staples to approximate the wound edges and take the lateral end of the transverse incision and staple it medially to flatten out the lateral end of the wound to leave two smaller dog ears. Mark out incisions to excise these dog ears and then excise or de-epithelialise these (to preserve blood supply at the ‘T’ where the three wounds meet) to produce the fishtail pattern. To ensure that the wound is flat, liposuction is often needed. Liposuction of lateral and medial excess subcutaneous tissue is a very useful and simple adjunctive technique in many mastectomies. The technique is simple to learn, safe and requires little equipment.

Cases in which difficulty with the lateral tissue is predicted preoperatively can be performed either with the patient on their side (ideally) or with some degree of rotation. Women with a large excess of lateral tissue can be challenging cases and should be managed by those familiar with a range of flap-based surgery as well as with experience using liposuction, and be planned preoperatively. Glue provides a dressing that does not need to be changed, is waterproof (so patients can shower next day) and rarely produces skin reaction, so minimising further trauma to the skin surface around the flap edges.

Goldilocks mastectomy

Although it has been tradition to excise excess skin over the breast during a mastectomy to leave a flat chest wall, other options may very occasionally be considered. Skin that would normally be discarded may be de-epithelialised, shaped and buried to improve the cosmetic result. This may avoid the concave appearance that often results from mastectomy and in some cases can produce a small breast mound. Skin incisions are marked as normal but the skin between the upper and lower incisions is de-epithelialised. The de-epithelialised lower flap is then buried under the upper mastectomy flap. In large breasts, a Wise pattern mastectomy can allow a large de-epithelialised inferiorly based flap. The amount of tissue that can be preserved and used in this way will vary considerably, depending on risk factors for tissue viability and the amount of skin required to be removed for oncological reasons. Lateral chest wall tissue can usually be recruited to add volume in the form of a LICAP or LTAP flap. Care is required in wound closure to maintain the superficial vasculature ( Fig. 9.7 ).

Bilateral simple mastectomy

Ideally these should be symmetrical. Bilateral IMF-based scars work well. It is important to leave a skin bridge in the midline and not have a continuous scar across the chest, which tends to contract along its length. A small amount of liposuction in the midline, between the scars, can prevent medial ‘dog ears’.

Undesirable scar patterns

High transverse and most diagonal scars should be historical other than in salvage situations. Likewise any scar that does not leave a flat surface with a contoured lateral chest wall should be avoided. In general, a transverse scars rarely leave a satisfactory result and almost never indicated.

Radical mastectomy

This still has a role to control locally advanced disease. Formal removal of all the pectoralis major muscle is, however, rarely required and partial excision removing the area of muscle involved with a margin of surrounding normal muscle is usually sufficient. If disease involves muscle clinically, then excision margins should be generous. In escalating order, the following options for wound closure should be considered:

• abdominal advancement flap;

• lateral chest wall perforator flap;

• split-skin graft;

• latissimus dorsi (LD) flap (muscle sparing or full myocutaneous);

• deep inferior epigastric perforator/TRAM flap; and

• omental flap.

All have a potential role depending on the size of defect, patient fitness and suitability of donor sites.

Considerations for mastectomy with immediate reconstruction

Of the general considerations listed earlier, smoking is a particular concern and the major risk factor for flap necrosis and wound problems after skin-sparing mastectomy. Most studies have found that neoadjuvant chemotherapy is not associated with an increased risk of complications. ^,

The following questions should be considered:

• 1.

  Is it necessary/desirable to excise skin overlying the cancer?

  • Although immediate breast reconstruction is enhanced by preserving most (if not all) of the breast skin, in general terms, it is sensible to apply the same principles as one would for simple mastectomy in deciding what skin should be removed to ensure clearance of disease. In other words, if the cancer is close to skin such that a healthy margin of normal tissue cannot easily be excised around it, then the overlying skin should be resected. An important principle of oncoplastic surgery is that treatment must not be compromised for the sake of cosmesis. The art of oncoplastic surgery is to perform an oncologically safe operation but still achieve an acceptable aesthetic outcome. Different designs of skin-sparing mastectomy can allow skin excisions at any site.

• 2.

  Is overall reduction or augmentation planned?

  • This will obviously influence the scar pattern and position to facilitate overall adjustment in breast size and obtain optimal symmetry.

• 3.

  What scar design will give the optimum balance of access and aesthetic result?

  • Access to perform the mastectomy adequately cannot be compromised. Minimal access mastectomy is possible but is more technically challenging and requires training in the techniques to achieve it. Familiarity with a range of different options will enable the best outcome. In this regard, one additional question could be: Am I the best surgeon to be performing the type of mastectomy that is required in this case? Designs will vary according to method of reconstruction, as described later.

• 4.

  Is the nipple–areola complex to be excised?

  • Preserving the nipple is increasingly considered an option for all women who require or choose a mastectomy. Various approaches to mastectomy allow nipple preservation for any woman undergoing a mastectomy where the nipple does not need to be removed for oncological reasons. However, scars, techniques and the ease with which nipples can be preserved vary greatly (see later).

Planning a mastectomy with reconstruction

Examine and mark up with the patient standing. Different techniques are best described according to whether tissue-based or implant-based reconstruction is being performed. As a general principle, tissue-based reconstruction requires more access but will always be more forgiving of mastectomy-related complications than implant-based.

Tissue-based reconstruction

Circumareolar

This is perhaps the most commonly employed technique. It gives excellent access to all but very large breasts. It can be extended easily by a lateral or inferior extension or by widening the circular skin excision. The resulting defect is replaced with skin from the flap, often with nipple reconstruction at the same time ( Fig. 9.8 ).

Wise pattern

This is another commonly employed technique that can be used for any ptotic breast. The design is more conservative than would be used for a standard breast reduction and is often best planned as very conservative, with adjustment of the vertical limbs at the time of closure according to viability and tension. A vulnerable part of this design is the inverted ‘T’ closure. In one study the rate of mastectomy flap necrosis was significantly greater in patients undergoing inverted-T mastectomy compared to a horizontal ellipse (25.6% vs 11.0%), although rates were very high in both. With division of the lateral thoracic vessels as part of the mastectomy, the lateral part of the ‘T’ closure often ends up as the most ischaemic part of the mastectomy flap. Designing an inverted ‘V’ component to the lower incision that will release tension at the ‘T’ junction is often prudent ( Fig. 9.9 ). Preservation of a section of lower flap skin until the time of closure enables the option of wider skin excision if viability is a concern or, after de-epithelialisation, this can be tucked under the closure, allowing double-breasting the scar.

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