Prophylactic mastectomy for the prevention of breast cancer: Review of the literature

The high incidence and recurrence rate of breast cancer has influenced multiple strategies such as early detection with imaging, chemoprevention and surgical interventions that serve as preventive measures for women at high risk. Prophylactic mastectomy is one of the growing strategies of breast cancer risk reduction that is of a special importance for breast cancer gene mutation carriers. Women with personal history of cancerous breast lesions may consider ipsilateral or contralateral mastectomy as well. Existing data showed that mastectomy effectively reduces breast cancer risk. However, careful risk estimation is necessary to wisely select individuals who will benefit from preventing breast cancer.

Postmastectomy radiation therapy in early breast cancer: Utility or futility?

Postmastectomy radiation therapy (PMRT) has been shown to reduce the risk of locoregional recurrence (LRR), in patients with locally advanced breast cancer who are considered of high-risk because of large tumors (>5 cm) or presence of axillary lymph-node involvement, as well as to reduce breast cancer mortality. However, controversy still remains with respect to indication of PMRT in case of early-stages invasive tumors. This review aims to analyze the impact that PMRT has on final results in women with breast tumors in different scenarios that would otherwise be considered as early breast cancer, such as extensive DCIS, tumors without axillary lymph-node involvement or with minimal microscopic nodal-involvement. The existence of risk factors including young age, premenopausal status, and presence of lymphovascular invasion (LVI), high grade or tumor size >2 cm has been associated with an increased risk of LRR in these patients at early-stages and advises to consider PMRT in selected cases.

Treatment patterns for ductal carcinoma in situ with close or positive mastectomy margins

BACKGROUND

Mastectomy remains an effective treatment for ductal carcinoma in situ (DCIS) but whether further therapy is warranted for close or positive margins is controversial. We aim to characterize the treatment practices of DCIS throughout the United States in patients who undergo mastectomy with close or positive margins to better understand the use of postmastectomy radiation therapy (PMRT).

MATERIALS AND METHODS

Using the 2004-2013 National Cancer Database, we identified all female patients with a diagnosis of DCIS who underwent mastectomy. Distributional characteristics were summarized for overall and margin-stratified samples. Characteristic differences were assessed by region and receipt of radiation. Chi-square and independent sample t-tests were used to assess differences for categorical and continuous variables, respectively.

RESULTS

In 21,591 patients who met inclusion criteria, 470 patients with close/positive margins were identified. Sixteen percent of patients with close/positive margins received PMRT compared to 1.5% with negative margins (P < 0.01). There was no difference in PMRT and patient race, insurance status, treatment facility, or endocrine therapy. Patients with close/positive margins who received PMRT were more likely to be in an urban setting from the Midwest (24.6%) and Northeast (21.8%) compared to the West (11.0%) and South (10.7%) (P < 0.01).

CONCLUSIONS

Use of PMRT for DCIS following mastectomy with close/positive margins differs across the country. Regional variations in treatment patterns reinforce a need to determine whether PMRT improves survival to establish treatment guidelines.

Ductal Carcinoma In Situ of the Breast: Evaluating the Role of Radiation Therapy in the Management and Attempts to Identify Low-risk Patients

Ductal carcinoma in situ of the breast has rapidly increased in incidence over the past several decades secondary to an increased use of screening mammography. Local treatment options for women diagnosed with ductal carcinoma in situ include mastectomy or breast-conserving therapy. Although several randomized trials have confirmed a >50% reduction in the risk of local recurrence with the administration of radiation therapy (RT) compared with breast-conserving surgery alone, controversy persists regarding whether or not RT is needed in selected "low-risk" patients. Over the past two decades, two prospective single-arm studies and one randomized trial have been performed and confirm that the omission of RT after surgery is associated with higher rates of local recurrence even after selecting patients with optimal clinical and pathologic features. Importantly, these trials have failed to consistently and reproducibly identify a low-risk cohort of patients (based on clinical and pathologic features) that does not benefit from RT. As a result, adjuvant RT is still advocated in the majority of patients, even in low-risk cases. Future research is moving beyond traditional clinical and pathologic risk factors and instead focusing on approaches such as multigene assays and biomarkers with the hopes of identifying truly low-risk patients who may not require RT. However, recent studies confirm that even low-risk patients identified from multigene assays have higher rates of local recurrence with local excision alone than would be expected with the addition of RT.

Close or positive resection margins are not associated with an increased risk of chest wall recurrence in women with DCIS treated by mastectomy: a population-based analysis

Mastectomy is effective treatment for ductal carcinoma in situ (DCIS) but some women will develop chest wall recurrence. Most chest wall recurrences that develop after mastectomy are invasive cancer and are associated with poorer prognosis. Past studies have been unable to identify factors predictive of chest wall recurrence. Therefore, it remains unclear if a subset exists of women with DCIS treated by mastectomy experience a high rate of recurrence in whom more aggressive treatment may be of benefit. We report outcomes of all women in Ontario (N = 1,546) diagnosed with pure DCIS from 1994 to 2003 treated with mastectomy without radiotherapy and evaluate factors associated with the development of chest wall recurrence. Treatments and outcomes were validated by chart review. Proportional differences were compared using Chi square analyses. Survival analyses were used to study the development of chest wall recurrence in relation to patient and tumor characteristics. Median follow-up was 10.1 years. Median age was 57.1 years. 36 patients (2.3%) developed chest wall recurrence. The 10-year actuarial chest wall recurrence-free survival rates and invasive chest wall recurrence-free survival rates were 97.6 and 98.6%, respectively. There was no difference in cumulative 10 year rates of chest wall recurrence by age at diagnosis (<40 years = 5.2%, 40–44 years = 1.3%, 45–50 years = 2.9%, >50 years = 2.1%; p = 0.19), nuclear grade (high = 3.0%, intermediate = 1.4%, low = 1.0%, unreported = 2.5%; p = 0.41), or among women with close or positive resection margins (positive = 3.0%, 2 mm or less = 1.4%, >2 mm = 1.5%, unreported = 2.8%; p = 0.51). On univariate and multivariable analysis, none of the factors were significantly associated with the development of chest wall recurrence. In this population cohort, individuals treated by mastectomy experienced low rates of chest wall recurrence. We did not identify a subset of patients with a high rate of chest wall recurrence, including those with positive margins.

Determinants of optimal mastectomy skin flap thickness

Background

There is a limited evidence base to guide surgeons on the ideal thickness of skin flaps during mastectomy. Here the literature relevant to optimizing mastectomy skin flap thickness is reviewed, including anatomical studies, oncological considerations, factors affecting viability, and the impact of surgical technique and adjuvant therapies.

Methods

A MEDLINE search was performed using the search terms ‘mastectomy’ and ‘skin flap’ or ‘flap thickness’. Titles and abstracts from peer-reviewed publications were screened for relevance.

Results

A subcutaneous layer of variable thickness that contains minimal breast epithelium lies between the dermis and breast tissue. The thickness of this layer may vary within and between breasts, and does not appear to be associated with obesity or age. The existence of a distinct layer of superficial fascia in the breast remains controversial and may be present in only up to 56 per cent of patients. When present, it may not be visible macroscopically, and can contain islands of breast tissue. As skin flap necrosis occurs in approximately 5 per cent of patients, a balance must be sought between removing all breast tissue at mastectomy and leaving reliably viable skin flaps.

Conclusion

The variable and unpredictable thickness of the breast subcutaneous layer means that a single specific universal thickness for mastectomy skin flaps cannot be recommended. It may be that the plane between the subdermal fat and breast parenchyma is a reasonable guide for mastectomy flap thickness, but this may not always correspond to a subcutaneous fascial layer.

Cadmium is a potent inhibitor of PPM phosphatases and targets the M1 binding site

The heavy metal cadmium is a non-degradable pollutant. By screening the effects of a panel of metal ions on the phosphatase activity, we unexpectedly identified cadmium as a potent inhibitor of PPM1A and PPM1G. In contrast, low micromolar concentrations of cadmium did not inhibit PP1 or tyrosine phosphatases. Kinetic studies revealed that cadmium inhibits PPM phosphatases through the M1 metal ion binding site. In particular, the negative charged D441 in PPM1G specific recognized cadmium. Our results suggest that cadmium is likely a potent inhibitor of most PPM family members except for PHLPPs. Furthermore, we demonstrated that cadmium inhibits PPM1A-regulated MAPK signaling and PPM1G-regulated AKT signaling potently in vivo. Cadmium reversed PPM1A-induced cell cycle arrest and cadmium insensitive PPM1A mutant rescued cadmium induced cell death. Taken together, these findings provide a better understanding of the effects of the toxicity of cadmium in the contexts of human physiology and pathology.

Incidence and consequence of close margins in patients with ductal carcinoma-in situ treated with mastectomy: is further therapy warranted?

BACKGROUND

The impact of close margins in patients with ductal carcinoma-in situ (DCIS) treated with mastectomy is unclear; however, this finding may lead to a recommendation for postmastectomy radiotherapy (PMRT). We sought to determine the incidence and consequences of close margins in patients with DCIS treated with mastectomy.

METHODS

The records of 810 patients with DCIS treated with mastectomy from 1996 through 2009 were reviewed. Clinical and pathologic factors were analyzed with respect to final margin status. Median follow-up was 6.3 years.

RESULTS

Overall, 94 patients (11.7 %) had close margins (positive, n = 5; negative but ≤1 mm, n = 54; 1.1-2.9 mm, n = 35). Independent risk factors for close margins included multicentricity, pathologic lesion size ≥1.5 cm, and necrosis, but not age, use of skin-sparing mastectomy, or immediate reconstruction (p > 0.05). Seven patients received PMRT, and none had a locoregional recurrence (LRR). Among the remaining 803 patients, the 10-year LRR rate was 1 % (5.0 % for margins ≤1 mm, 3.6 % for margins 1.1-2.9 mm, and 0.7 % for margins ≥3 mm [p < 0.001]). The 10-year rate of contralateral breast cancer was 6.4 %. On multivariate analysis, close margins was the only independent predictor of LRR (p = 0.005).

CONCLUSIONS

Close margins occur in a minority of patients undergoing mastectomy for DCIS and is the only independent risk factor for LRR. As the LRR rate in patients with close margins is low and less than the rate of contralateral breast cancer, PMRT is not warranted except for patients with multiple close/positive margins that cannot be surgically excised.

Oncologic safety of skin-sparing and nipple-sparing mastectomy: a discussion and review of the literature

Breast conservation therapy has been the cornerstone of the surgical treatment of breast cancer for the last 20 years; however, recently, the use of mastectomy has been increasing. Mastectomy is one of the most frequently performed breast operations, and with novel surgical techniques, preservation of the skin envelope and/or the nipple-areolar complex is commonly performed. The goal of this paper is to review the literature on skin-sparing mastectomy and nipple-sparing mastectomy and to evaluate the oncologic safety of these techniques. In addition, this paper will discuss the oncologic importance of margin status and type of mastectomy as it pertains to risk of local recurrence and relative need for adjuvant therapy.

Is there a role for postmastectomy radiation therapy in ductal carcinoma in situ?

Background. DCIS treated by mastectomy ensures high local control rates. There is limited data on risk for relapse and lack of clear indication for adjuvant radiation therapy (RT). We report a retrospective review on a population of DCIS patients treated with mastectomy. The objective was to identify the overall incidence of relapse, risk factors for local recurrence, and accordingly for whom adjuvant postmastectomy RT may be considered. Methods. This is an IRB-approved retrospective study on a prospective breast cancer database. From 1997 to 2007, we identified 969 patients with diagnoses of DCIS, among them 211 breasts in 207 patients were treated with mastectomy and comprise the study group. Results. With a median followup of 55 months (4.6 years) the 10-year relapse-free survival is 97%. Two of 211 breasts (0.9%) treated with mastectomy developed a local-regional recurrence. Both the relapses were among patients defined as having <1 mm final mastectomy margin. Conclusions. The rare local relapse after mastectomy limits our ability to reliably identify risk factors for relapse. The consideration for postmastectomy RT should be based on an individualized risk evaluating surgical technique used, presence of BRCA mutation, grade and extent of tumor, and proximity of lesion to the margin of resection.

Analyzing the risk of recurrence after mastectomy for DCIS: a new use for the USC/Van Nuys Prognostic Index

BACKGROUND

Patients with ductal carcinoma in situ (DCIS) who are treated with mastectomy seldom recur locally or with metastatic disease. When patients with DCIS recur with invasive cancer, they are upstaged and their lives are threatened. We questioned whether histopathologic data could be used to predict these infrequent events.

METHODS

We reviewed a prospective database of 1,472 patients with pure DCIS. All patients were scored from 4 to 12 using the USC Van Nuys Prognostic Index, an algorithm based on DCIS size, nuclear grade, necrosis, margin width, and patient age. Probabilities of recurrence and death were calculated using the Kaplan-Meier method.

RESULTS

A total of 496 patients with pure DCIS were treated with mastectomy. None received any form of postmastectomy adjuvant treatment. Average follow-up was 83 months. Eleven patients developed recurrences, all of whom scored 10-12 using the USC/VNPI. No patient who scored 4-9 recurred. All 11 patients who recurred had multifocal disease and comedo-type necrosis. The probability of disease recurrence after mastectomy for patients scoring 10-12 was 9.6% at 12 years, compared with 0% for those scoring 4-9. There was no difference in overall survival.

CONCLUSIONS

There were no recurrences among mastectomy patients who scored 4-9 using the USC/VNPI. Patients scoring 10-12 were significantly more likely to develop recurrence after mastectomy. At risk were young patients with large, high-grade, and multifocal or multicentric tumors. For every 100 patients with USC/VNPI scores of 10-12, 10 patients will recur by 12 years and 2-3 will develop metastatic disease.