Background
Breast cancer is one of the most common cancers and the second leading cause of cancer mortality in US women. Breast malignancy accounts for nearly one in three cancers diagnosed in women in the United States. Hence much attention and resources have been directed at this disease – from attempts at prevention, to screening, treatment, and cure. Approaches range from the infinitesimal to the global, analyzing molecular markers of gene expression such as her-2/neu, genetic-based testing and screening such as BRCA 1 and 2, familial analyses, hormonal assays, population studies, and vaccine trials.
While the incidence of breast cancer continues to increase, fortunately mortality is starting to decline because of earlier detection prior to distant spread, attributable to the unequivocal success of mammographic screening efforts, as well as advances in management. With approximately 182 000 cases expected in 2008, the public health impact estimates are between $5 and $8.1 billion dollars annually spent on managing breast cancer. This expansive clinical volume has created a body of evidence that has been gathered, reviewed, published, and disseminated, leading to a decline in mortality from breast cancer over the last few decades.
Owing to research efforts directed at breast cancer, breast management has undergone significant evolutions in management – from the Halsted radical mastectomy to the modified radical mastectomy to breast conservation therapy combined with radiation. Paralleling these paradigmatic changes in oncologic management have been shifts and changes in the reconstructive algorithms to reconstruct breast cancer defects, whether they be mastectomy or partial defects.
To maximally benefit the patient with breast cancer seeking treatment, the complex interplay of radiation and plastic surgery must be thoroughly understood to offer the most appropriate treatments in the most appropriate sequence with the best anticipation of the likely outcomes. This requires an understanding of the physics, mechanisms of action of radiobiology, and pathophysiology associated with radiation and with wound healing.
The goals for oncoplastic breast surgery and radiation are (1) tumor eradication, (2) prolonging survival, and (3) maximizing quality of life via cosmetically acceptable breast preservation, or breast reconstruction to a close facsimile of the original. Data from the Early Breast Cancer Trialists’ Collaborative Group (EBCTCG) indicate that not only is there improvement in local control, but also an absolute survival benefit of approximately 5% in women who receive radiation.
Oncoplastic breast management exists at the nexus of four disciplines – surgical oncology, plastic surgery, radiation oncology, and medical oncology – and the timing, efficacy, and role of each of these modalities must be considered concomitantly. Often a tumor board or multidisciplinary breast center is a good forum to brainstorm and create a management plan which resonates with the expertise that is brought to bear from each specialty and with the patient’s goals, expectations, lifestyle, and particular tumor grade, histopathology, stage, genetics, and oncotype in mind.
Role of radiation
Radiation therapy has two principal roles in the management of breast carcinoma. It can be combined with lumpectomy as part of breast-conserving therapy (lumpectomy + XRT) or be utilized as adjuvant treatment for post-mastectomy treatment (PMRT). The specific removal of a breast tumor with an adequate margin is interchangeably called lumpectomy, quadrantectomy, or tumorectomy. The discussion in this chapter is limited to these two roles, although radiation might be used for palliation to mitigate symptomatology from an incurable lesion such as ulceration, bleeding, or pain either in the breast or at a metastatic site.
Basic science and biology
Radiation therapy is the use of ionizing energy to control malignancy. The energy (interpretable as high-speed particles or electro-magnetic waves) is targeted to the tumor and a surrounding zone of normal tissue to kill cancer cells preferentially.
The unit of measurement in radiation is the gray (Gy), the absorbed dose of 1 joule of radiation energy by 1 kilogram of matter, and may be used to denote any type of radiation. It does not describe the biological effect of that 1 joule in that 1 kilogram. The sievert (Sv) describes the biologically equivalent dose by a multiplier Q for the quality of radiation. For gamma and X-radiation, both of which are types of photons, Q = 1 and a sievert is equivalent to a gray:
One gray [ 1 Gy = 1 ( J / kg ) = 1 m 2 s − 2 ] is equivalent to 100 rads
Related posts:
Indications and Patient Selection for Oncoplastic Breast Surgery
Timing and Key Considerations in Reconstruction for Breast-Conserving Therapy
Breast Augmentation Technique (Biplanar) for Oncoplasty
Surveillance and Imaging Following Oncoplastic Breast Surgery
Volume Displacement and Volume Replacement Techniques
Complications of Oncoplastic Breast Surgery
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