Breast-conserving surgery: the balance between good cosmesis and local control

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Breast-conserving surgery

the balance between good cosmesis and local control

J. Michael Dixon

Introduction

The aim of local treatment of breast cancer is to achieve long-term local disease control with the minimum of local morbidity. The majority of women presenting symptomatically to breast clinics and those who are diagnosed through screening programmes have small breast cancers, which are suitable for breast-conserving surgery.

The major advantages of breast-conserving treatment are as follows:

• breast-conserving treatment produces an acceptable cosmetic appearance in the majority of women with breast cancer;¹

• breast-conserving treatment results in lower levels of psychological morbidity, with less anxiety and depression and improved body image, sexuality and self-esteem, compared with mastectomy;^2,³

• two systematic reviews have shown equivalence in terms of disease outcome for breast-conserving treatment and mastectomy.^4,⁵

One of these reviews (search date 1995) analysed data from six randomised controlled trials that compared breast conservation treatment with mastectomy.⁴ A meta-analysis of data from five of these six trials involving 3006 women found no significant difference in the risk of death at 10 years (odds ratio 0.91, 95% confidence interval (CI) 0.78–1.05). The sixth randomised trial used different protocols. In the second systematic review, nine randomised controlled trials involving 4981 women randomised to mastectomy or breast-conserving treatment were included in the analysis.⁵ A meta-analysis of these nine trials found no significant difference in the risk of death over 10 years: the relative risk reduction for breast-conserving surgery compared with mastectomy was 0.02 (95% CI − 0.05 to + 0.09).⁵ There was also no difference in the rates of local recurrence in the six randomised controlled trials involving 3006 women where data were available: the relative risk reduction for mastectomy versus breast-conserving surgery was 0.04 (95% CI − 0.04 to + 0.12).⁴

Originally it was thought that local therapy had little influence on overall survival but it is clear that local failure is responsible, at least in part, for some patients developing metastatic disease.^6,⁷

It is thus important in patients selected for breast-conserving surgery to minimise local recurrence while at the same time achieving a good cosmetic outcome.

Selection of patients for breast conservation

Traditionally, single cancers clinically measuring 4 cm or less, without signs of local advancement, have been managed by breast-conserving treatment (Box 4.1). Different units have different size criteria and many units have a tumour size cut-off for breast-conserving surgery of 3 cm or less clinically.

Increasing tumour size does not equate with increasing local recurrence rates and limiting breast-conserving surgery to cancers below a certain size is illogical.

Clinical tumour size overestimates actual tumour size. There is a much better correlation between pathological tumour size and the size measured on imaging, with ultrasound assessment being more accurate than mammographic measurements.⁸ Magnetic resonance imaging (MRI) appears better than ultrasound in assessing disease extent, particularly in invasive lobular carcinoma.⁹ The problem with MRI is that it has a low specificity and a low positive predictive value in that only two-thirds of lesions identified by MRI as suspicious of malignancy are subsequently confirmed as malignant.¹⁰ The role of MRI in assessing patients for breast-conserving surgery has been investigated in a randomised study and the conclusions of this study were that routine use of MRI is not worthwhile.^8,¹¹ MRI did not reduce the rate of incomplete excisions and was not associated with a reduction in short-term local recurrence but did significantly increase the mastectomy rate in patients who were otherwise considered good candidates for breast-conserving surgery. It is the balance between tumour size as assessed by imaging and breast volume that determines whether a patient is suitable for breast-conserving surgery rather than tumour size per se. Options for patients with tumours considered too large, relative to the size of the breast, for breast-conserving treatment include neoadjuvant systemic therapy to shrink the tumour, an oncoplastic procedure (see Chapter 6) involving either transfer of tissue into the breast or remodelling of the breast with surgery to the opposite breast to obtain symmetry (see Chapter 6).^12,¹³ In a patient with small breasts, excision of even a small tumour may produce an unacceptable cosmetic result.

Patients with multiple tumours in the same breast have not previously been considered good candidates for breast-conserving treatment because they were reported to have a high reported incidence of in-breast recurrence ^14,¹⁵ and so have usually been treated by mastectomy, combined in appropriate patients with immediate reconstruction. Recent evidence has, however, demonstrated similar rates of local recurrence for both patients with unifocal and with multifocal and even multicentric disease.^16,¹⁷ If it is feasible to excise the separate cancers in different parts of the breast and produce an acceptable cosmetic outcome then such patients should no longer be treated routinely by mastectomy. Satisfactory rates of local control following breast-conserving treatment for multifocal or multicentric cancers are achieved providing all disease is excised to clear margins.^16,¹⁷ Early studies on multifocal and multicentric cancers often failed to achieve clear margins and this explains the high rates of local recurrence reported in these early series.¹⁵ Patients with bilateral cancers can also be treated by bilateral breast conservation. The rates of breast-conserving surgery vary significantly between countries and within countries. These rates are clearly influenced as much by the views of the surgeon treating the patient as the availability of radiotherapy locally. Failure to offer breast-conserving surgery to suitable and appropriate patients has become a medico-legal issue. If a patient who fulfils the criteria for breast-conserving surgery is treated by mastectomy then the exact reasons for the decision to proceed to mastectomy should be recorded legibly in the patient’s notes. Some patients choose mastectomy in preference to breast-conserving surgery but do so based on an inadequate understanding that outcomes for the two treatments are identical. In one series of patients choosing mastectomy rather than breast-conserving surgery, over half of patients did not know that mastectomy and breast-conserving surgery produces identical rates of survival.¹⁸

A range of clinical and pathological factors have influenced surgeons selecting patients for breast-conserving surgery because of their perceived impact on local recurrence. These include young age (under 35–39 years), the presence of an extensive in situ component associated with an invasive tumour, grade 3 histology and widespread lymphatic/vascular invasion. These are considered in detail below.

Breast-conserving surgery

Two surgical procedures have been studied extensively: quadrantectomy and wide local excision. Quadrantectomy was based on the belief that the breast is organised into segments, with each segment draining into its own major duct, and that invasive cancer spreads down the duct system towards the nipple.¹⁹ Both of these premises are incorrect.

A single major subareolar duct does not drain a localised segment of tissue but can drain widespread areas of the breast.

The effectiveness of quadrantectomy relates to the large amount of tissue excised around the tumour rather than to the removal of a cancer and its draining duct. In an early randomised study of lumpectomy or quadrantectomy, a significantly greater number of patients who had lumpectomy had incomplete local excisions.²⁰ Not surprisingly, therefore, local recurrence was more common after lumpectomy than after quadrantectomy, although survival was no different.²⁰ Other non-randomised studies have shown similar rates of local recurrence for both quadrantectomy and wide local excision, providing margins of excision are clear.²¹ Quadrantectomy or segmental excisions are no longer appropriate breast-conserving options because they produce identical rates of local recurrence to wide excision but produce a significantly poorer cosmetic outcome compared with wide excision.²²

Patients having breast-conserving surgery are adequately treated by wide local excision and do not require either a segmental or quadrantic excision.^23,²⁴

Special technical details: wide local excision

The aim of wide local excision is to remove all invasive and any ductal carcinoma in situ with a margin of normal surrounding breast tissue. Controversy has surrounded which incisions give the best cosmetic results. The predominant orientation of collagen fibres in the skin was described by Langer ²⁵ and these skin crease lines around the breast are essentially circular (Fig. 4.1). Subsequent work by Kraissl²⁶ demonstrated that the lines of maximum resting skin tension run in a more transverse orientation across the breast (Fig. 4.1). In general, scars that are parallel both to the lines of maximum resting skin tension and to the orientation of collagen fibres are quickest to heal and produce the best cosmetic outcomes, with the lowest rates of scar hypertrophy and keloid formation.

Figure 4.1 The direction of Langer’s lines (a) and lines of maximum resting skin tension in the breast (b) (so-called dynamic lines of Kraissl).

Incisions that follow the lines of maximum resting skin tension produce the most cosmetically acceptable scars.

A knowledge of Langer’s lines and Kraissl’s lines thus allows a surgeon to make incisions that enhance the cosmetic outcome of breast-conserving surgery. It has been tradition to place an incision to excise a cancer directly over the lesion, but this can result in an unsightly scar, particularly if the cancer is high and medial. In such instances placing the scar some distance below in the skin crease lines and tunnelling up to the lesion produces a better cosmetic result. Cancers close to the nipple and even those some distance away in the upper half of the breast can be excised through circumareolar incisions. A cancer low in the breast close to the inframammary fold can similarly be excised through an incision placed in the fold. A cancer in the upper outer quadrant can be excised easily through an axillary incision. Excising skin directly overlying a cancer is only necessary if the skin is involved. It is not necessary to remove dimpled or tethered skin. The cosmetic result after breast-conserving surgery is influenced by the amount of skin excised, with poor results being obtained in those patients who have most skin removed. In patients with direct skin involvement, the aim should be to minimise the skin excised and to remove only enough skin to get microscopically clear margins.

Routine excision of skin when performing a wide excision cannot be justified.²³

Limiting the length of incision is also important, as longer incisions produce significantly poorer cosmetic outcomes. A knowledge of the depth of the cancer within the breast provided by preoperative or intraoperative breast ultrasound can be valuable when planning the extent of excision. For instance, if a cancer is 2 cm deep within the breast, then at least 1 cm of fat and subcutaneous tissue can be left on the skin flaps; leaving this tissue improves the cosmetic outcome. Whatever incision is used, it is important to have discussed the position of all scars with the patient prior to surgery.

Having made the skin incision, the skin and subcutaneous fat are dissected off the breast tissue. Care should be taken when elevating skin not to remove subcutaneous fat unnecessarily as thin skin flaps give a poor postoperative cosmetic result. Where the cancer is close to the skin, hydrodissection infiltrating 1 in 400 000 adrenaline in saline can help to separate the skin and subcutaneous fat from the breast tissue and breast fat, and facilitates skin elevation over the cancer. Skin flaps beyond the edge of the cancer for at least 1–2 cm are mobilised. This allows the fingers of the non-dominant hand to be placed over the palpable cancer. The breast tissue is then divided beyond the fingertips. The line of incision through the breast should be approximately 1 cm beyond the limit of the palpable mass. Having incised through the breast tissue, dissection continues under the cancer. In the majority of patients it is necessary to divide the whole thickness of breast tissue down to the pectoral fascia, to ensure that there is an adequate margin of tissue removed deep to the cancer. If the lesion is superficial, and there is a significant amount of breast tissue deep to the cancer, it may not be necessary to remove full thickness of breast tissue. Likewise if the lesion is deep, more tissue can be left superficially on the skin flaps. Having reached the deep margin, which is usually the pectoral fascia, the breast tissue and cancer are lifted from this fascia. It is not necessary to excise pectoral fascia unless it is tethered to the tumour or the tumour is involving it. If a carcinoma is infiltrating one of the chest wall muscles, then a portion of the affected muscle should be excised beneath the tumour, the aim being to remove sufficient muscle to get beyond the limits of the cancer. Having dissected under the cancer, the cancer and surrounding tissue are grasped between the finger and thumb of the non-dominant hand and excision of the cancer at the other margins is completed. The specimen should be orientated immediately following excision with Liga-clips, sutures or metal markers, prior to specimen radiography and submission to the pathologist.²⁷ Metal markers or Liga-clips are preferred because they can be seen on specimen radiography. Routine X-ray of orientated specimens is recommended because it has been shown to help the surgeon confirm the target lesion has been excised and allows assessment of completeness of excision at the radial margins.²⁷ If the specimen radiograph shows the cancer or any associated microcalcification is close to a particular margin, then further tissue can and should be removed from the margin of concern, before being orientated and sent to pathology.

A number of studies have evaluated the use of cavity shavings and bed biopsies, but few have compared these with standard assessment of margins. A minority of surgeons continue to take cavity shavings and bed biopsies routinely. Neither has been shown to be reliable indicators of local recurrence. A major concern of taking cavity shavings routinely is that significant amounts of extra breast tissue can be removed, particularly if the whole cavity is shaved; this unfortunately can adversely affect cosmetic outcome. Most importantly, however, centres who do not use these techniques report excellent local control rates, which have continued to fall over time.^28,²⁹ Wide excision with standard examination of margins thus provides sufficient information on margin status for clinical use. Bed biopsies or cavity shavings are only of value and warranted where there is concern at operation that one particular margin is involved.

New devices that use ultrasound or rely on the electrical properties of the tissue are in trials and are being used to assess whether they can detect margin involvement and facilitate increased rates of complete excision at the first operation.

Having excised the cancer from the breast, suturing the defect in the breast without mobilisation of the breast tissue usually results in distortion of the breast contour. Defects in the breast are best closed by mobilising surrounding breast tissue from the overlying skin and subcutaneous tissue and in some patients mobilisation from the underlying chest wall is required. Large defects (> 10% breast volume) that are left open fill with seroma, which often absorbs later, following which scar tissue develops and contracts and can result in an ugly distorted breast. Following large-volume excisions, after mobilisation it is usually possible to close the defect in the breast tissue by a series of interrupted absorbable sutures. Given the success of lipofilling or lipomodelling for improving some patients with poor cosmetic outcomes following breast-conserving surgery and radiotherapy, a number of surgeons are exploring whether immediate lipofilling after wide local excision can improve outcomes, particularly for women with small breasts. Very large defects require oncoplastic breast reshaping (see Chapter 6) or a latissimus dorsi miniflap.^12,¹³ Drains are not necessary after wide local excision and should not be used routinely. They do not protect against haematoma formation and increase infection rates. Breast skin wounds should be closed in layers with absorbable sutures, finishing with a subcuticular suture.

Staples and interrupted sutures do not produce satisfactory results and are not an acceptable method of wound closure in the breast.

Complications of wide excision include haematoma, infection, incomplete excision, seroma and poor cosmetic results. Haematoma requiring evacuation is uncommon but occurs in approximately 2% of patients. Infection requiring treatment affects 5–10% and is more common when combined with an axillary dissection. Incomplete excision rates should be in the range 10–25%. The most common problem following surgery by wide local excision is a poor cosmetic result. Factors influencing cosmetic outcome and methods of avoiding this are considered in detail below.

Excising impalpable cancers

Impalpable lesions can be localised prior to surgery using one of a number of different techniques, including skin marking, injection of blue dye, carbon or radioisotope, insertion of a hooked wire, or intraoperative ultrasound. Although excising an impalpable cancer is easier if the skin incision is made directly over the cancer, remote incisions produce the best cosmetic results. Most impalpable small cancers should thus be approached through a cosmetically placed incision. The location of the lesion can be determined in a number of ways: (i) the surgeon can calculate the position of the breast lesion from the mammogram taken after wire insertion; (ii) the radiologist or the surgeon can mark the skin overlying the lesion using ultrasound; or (iii) if radioactivity has been injected to localise the cancer, the surgeon can use a gamma probe to localise the area of maximum radioactivity. After making an appropriately sized and cosmetically placed skin incision, this is deepened. If a wire is in place, then dissection continues towards the wire in the plane between the breast and subcutaneous fat so that the wire can be located some distance before it enters the lesion. For instance, if a mammographic abnormality has been localised in the craniocaudal position, then it helps to identify the wire superiorally before it enters the cancer. Wires that are marked with beads or that change in diameter, or have a guide that can be placed over the wire, help the surgeon to determine exactly how far along the wire the lesion is situated. Ideally the hook of the wire should be 1 cm through the lesion rather than within its centre. The direction of the wire on the preoperative mammogram is not always a reliable guide to the course of the wire through the breast. Once the wire is in place standard mammographic views are not always possible and thus a lesion that is apparently lateral to the entry point of the wire may not be lateral on the check craniocaudal film once the compression from the breast has been released. The aim is to remove the mammographic lesion with a 1-cm clear radiological margin and in most women to excise tissue up to subcutaneous fat and down to pectoral fascia.

As for palpable lesions, all specimens should be orientated with Liga-clips or metal markers, or secured to an orientated grid so that an orientated specimen radiography can be performed. Radiography is best performed in an X-ray machine designed specifically to X-ray specimens, such as a Bioptics® machine. There have been conflicting reports about whether compressing the specimen affects the incidence of subsequent positive margins as reported by the pathologist. Orientated specimen radiography improves the rate of complete excision of impalpable cancers.²⁷ Cooperation between surgeon and pathologist is required so that the area of concern can be identified and assessed by the pathologist to ensure adequacy of excision.

The majority of wide excisions of palpable and impalpable cancers are performed under general anaesthesia, but it is possible to perform these procedures under local anaesthesia.

Factors affecting local recurrence after breast-conserving surgery

Until recently there was a reported large variation between different centres in recurrence rates following breast-conserving surgery combined with whole breast radiotherapy for invasive breast carcinoma. Over 80% of all local recurrences were reported to be located adjacent to the site of initial excision. This is no longer true and an increasing percentage of ‘recurrences’ in treated breasts are actually second primaries.²⁵ Megavoltage radiation therapy delivered to the whole breast in a dose of 4000–5000 cGy given over 3–5 weeks continues to be used in most patients after breast-conserving surgery because radiotherapy both reduces the rate of local recurrence and improves overall survival.³⁰ Studies continue to evaluate whether localised radiotherapy delivered either during or within a few days of surgery is as effective as whole-breast radiotherapy. As yet it has not been possible to identify groups of patients who do not require radiotherapy. However, there is likely to be a group of older patients with low-risk cancers (completely excised, node negative and hormone receptor positive on hormone treatment) and women of any age whose cancers have an extremely good prognosis (small grade 1 or special type cancers that are completely excised, node negative and hormone receptor positive on hormone treatment) whose rates of local recurrence without radiotherapy are acceptable. Following whole-breast radiotherapy, it is possible to increase the local dose of radiotherapy by boosting the tumour bed. This reduces local recurrence rates, particularly in younger women, although there are cosmetic penalties associated with the use of boost.³¹

The rates of in-breast tumour recurrences continue to fall over time ^28,²⁹ (Fig. 4.2). Whereas a 1 % annual rate of in-breast cancer events was formerly considered acceptable, rates are now less than 0.5 % per annum. The rates of in-breast tumour events continue at a similar rate for at least 20 years. This needs to be borne in mind when considering surveillance programmes for such patients.

Figure 4.2 Local recurrence rates in Edinburgh over four separate time periods showing a significant and continued fall in local recurrence rates over time. (Data unpublished, courtesy of Gill Kerr, Edinburgh Cancer Centre.)

Patient-related factors

Local recurrence following breast-conserving therapy is significantly more common in younger patients.32–35

In contrast, local recurrence is much less of a problem in older patients (> 65 years).

Recurrence is less frequent in women with large breasts but whether this relates to the larger excisions that can be performed in these patients or to alterations in steroid metabolism (fat is known to be an important site of conversion of androgens to oestrogens) is uncertain.³⁶ A family history of breast cancer, particularly carriage of a mutation in one of the breast cancer genes, predisposes a patient to an increased rate of second primary cancers in both the treated and contralateral breast unless these women undergo a prophylactic oophorectomy, when local recurrence rates fall to levels similar to those of the general population.^37,³⁸

Tumour-related factors

Tumour location, tumour size, the presence of skin or nipple retraction, and the presence or absence of axillary node involvement have not been shown consistently to predict for local recurrence after breast-conserving surgery.39–42 The hormone receptor status of a breast cancer does not seem to exert any influence on local control rates.^31–35,^39–42 In-breast tumour recurrence has been reported to be more common in human epidermal growth factor receptor (HER2)-positive cancers.

Tumour size

Size is not significantly associated with local recurrence. Only 3 of 28 series that have examined the relationship of tumour size and occurrence have shown any significant association between tumour size in breast recurrence.^43,⁴⁴ A large study from Boston⁴⁴ demonstrated that cancers over 4 cm in size that were treated by breast conservation surgery had a rate of recurrence similar to that of smaller cancers (Table 4.1).

Table 4.1

Size of tumour related to local recurrence

Size (cm)	Local recurrence (%)
0–1	21
1.1–2	8
2.1–3	13
3.1–4	17
4.1–5	4

Data from Eberlein TG, Connolly JN, Schnitt JS et al. Predictors of local recurrence following conservative breast surgery and radiation therapy. The influence of tumour size. Arch Surg 1990; 125:771–9.