BREAST IMAGING
Note: This copy is for your personal non-commercial use only. To order presentation-ready copies for distribution to your colleagues or clients, contact us at www.rsna.org/rsnarights.
642
Update on Imaging of the Postsurgical Breast1 Nathaniel E. Margolis, MD Christopher Morley, MD Philip Lotfi, BS Sara D. Shaylor, MD Sarah Palestrant, MD Linda Moy, MD Amy N. Melsaether, MD Abbreviations: DIEP = deep inferior epigastric perforator, FDA = Food and Drug Administration, IDC = invasive ductal carcinoma, IGAP = inferior gluteal artery perforator, MRM = modified radical mastectomy, NAC = nipple-areola complex, SGAP = superior gluteal artery perforator, SIEP = superficial inferior epigastric perforator, TRAM = transverse rectus abdominis myocutaneous RadioGraphics 2014; 34:642–660 Published online 10.1148/rg.343135059 Content Codes: From the Department of Radiology, Breast Imaging Section, New York University School of Medicine, Langone Medical Center, 550 First Ave, New York, NY 10016. Recipient of a Cum Laude award for an education exhibit at the 2012 RSNA Annual Meeting. Received April 14, 2013; revision requested June 25 and received August 16; accepted August 18. For this journal-based SA-CME activity, the authors, editor, and reviewers have no financial relationships to disclose. Address correspondence to N.E.M. (e-mail: [email protected]). 1
See discussion on this article by Heller (pp 660–662).
SA-CME LEARNING OBJECTIVES After completing this journal-based SACME activity, participants will be able to: ■■Differentiate cutting-edge from conventional breast surgery techniques. ■■Understand
the limitations of imaging for cancer detection in the postsurgical breast. ■■Describe
the current state of siliconeimplant breast augmentation and reduction mammoplasty. See www.rsna.org/education/search/RG.
Oncologic, reconstructive, and cosmetic breast surgery has evolved in the last 20 years. Familiarity with cutting-edge surgical techniques and their imaging characteristics is essential for radiologic interpretation and may help avert false-positive imaging findings. Novel surgical techniques include skin- and nipple-sparing mastectomies, autologous free flaps, autologous fat grafting, and nipple-areola–complex breast reconstruction. These techniques are illustrated and compared with conventional surgical techniques, including modified radical mastectomy and autologous pedicled flaps. The role of magnetic resonance (MR) imaging in surgical planning, evaluation for complications, and postsurgical cancer detection is described. Breast reconstruction and augmentation using silicone gel–filled implants is discussed in light of the Food and Drug Administration’s recommendation for MR imaging screening for “silent” implant rupture 3 years after implantation and every 2 years thereafter. Recent developments in skin incision techniques for reduction mammoplasty are presented. The effects of postsurgical changes on the detection of breast cancer are discussed by type of surgery. ©
RSNA, 2014 • radiographics.rsna.org
Introduction
As modern oncologic and plastic surgery techniques for the breast continue to be developed, the responsibility of the breast imager to be informed of current practices has never been greater. Radiologists must cultivate an understanding of expected postsurgical imaging findings and be able to differentiate benign postsurgical changes from suspicious breast lesions. This article discusses the imaging characteristics of novel surgical techniques for mastectomy, including skin-sparing and nipple-sparing mastectomy, and for breast reconstruction, including autologous free flaps, fat grafting, and nippleareola–complex (NAC) reconstruction, and contrasts them with the imaging characteristics of conventional breast surgery techniques. In addition, cutting-edge techniques for reduction mammoplasty and silicone-implant breast augmentation are discussed.
RG • Volume 34 Number 3
Margolis et al 643
Figure 1. Diagram shows the surgical incisions (dashed red lines) used for modified radical mastectomy (MRM), skin-sparing mastectomy, and nipple-sparing mastectomy.
Mastectomy
It is estimated that one in eight women born in the United States will be diagnosed with breast cancer during her lifetime. At least 2.7 million American women have a history of breast cancer, with 270,000 new cases diagnosed and 40,000 attributable deaths per year (1). Breast conservation therapy with lumpectomy and whole-breast radiation therapy has been the cornerstone of surgical management since the National Institutes of Health consensus conference on earlystage breast cancer treatment in 1991 (2). Today, more than one in three patients who are eligible for breast conservation therapy elect to undergo mastectomy instead, and recent data have shown that this number may be increasing (2–5). Although mastectomy rates decreased overall from 1998 to 2005, the use of mastectomy increased from 38.8% to 45% between 2005 and 2007 among patients with early-stage breast cancer in one statewide registry (2). In addition, at an institution with a high volume of breast surgery procedures, the rate of mastectomy surpassed that of lumpectomy, increasing from a share of 35% to 60% from 2004 to 2007, despite patient counseling about treatment options (5). This trend is multifactorial but is due in part to fear of cancer recurrence, perceived survival benefit, greater patient autonomy, increasing use of preoperative magnetic resonance (MR) imaging, and new cosmetically favorable breast surgery and breast reconstruction techniques, namely skin-sparing and nipple-sparing mastectomies (6,7). Traditional indications for mastectomy include multicentric disease, a large (>5 cm) tumor in relation to breast size, disease involving the skin envelope, or an inability to tolerate chemotherapy or radiation therapy (8,9). There has been a marked increase in prophylactic mastectomy, a
treatment option for high-risk patients who have a personal history of breast cancer or are BRCA gene mutation carriers (6,9). Newer mastectomy techniques include skinsparing mastectomy and nipple-sparing mastectomy (Fig 1). Although these techniques can offer improved cosmetic outcomes, there are questions surrounding their oncologic safety because of the risk of leaving residual breast tissue. However, studies to date show that breast cancer recurrence rates for patients who undergo these newer procedures are comparable to those for patients who undergo MRM, at about 1%–2% per year (1,10,11). The local breast cancer recurrence rate for patients who undergo breast conservation therapy is similar, at 1%–2.5% per year (12).
Modified Radical Mastectomy MRM involves complete removal of the breast tissue, skin envelope, NAC, and level I and II axillary lymph nodes. For the past 40 years, MRM has been the standard surgical treatment for locally advanced invasive and inflammatory breast cancer (3,13). It also is the procedure of choice for patients who do not plan to undergo immediate breast reconstruction (3). Imaging of the postmastectomy breast is seldom performed because patients are typically followed up clinically with serial physical examinations; no postmastectomy imaging guidelines are available (14–16). When imaging is performed, the type of mastectomy performed and the presence or absence of breast reconstruction will affect the postoperative imaging appearance. In the absence of reconstruction, the chest wall, subcutaneous fat, and skin can be evaluated with ultrasonography (US) for seroma, fat necrosis, radiation-induced fibrosis, lymphadenopathy, and cancer recurrence (15). In a study of patients after MRM without reconstruction who underwent
644 May-June 2014
radiographics.rsna.org
Figure 2. MR imaging findings after MRM. (a) Axial contrast-enhanced fat-suppressed T1-weighted MR image in a 67-year-old woman 8 years after right MRM and 1 year after radiation treatment for cancer recurrence in the chest wall shows enhancement of the subcutaneous fat in the right chest (arrow), a finding compatible with radiation change. The pectoralis major (M) and minor (m) muscles are thickened in the right breast compared with the left breast. (b) Axial contrast-enhanced T1-weighted MR image in a 64-year-old woman 12 years after left MRM who presented with a palpable mass in the left chest wall shows a mass (*) between the pectoralis major and minor muscles, a finding proved at biopsy to be infiltrating adenocarcinoma. Compared with the contralateral side, there is marked heterogeneous enhancement of the lateral pectoralis major muscle (arrow), a finding consistent with tumor invasion.
mammography and/or US, US was superior for detection of breast cancer recurrence, with an accuracy of 86%, a sensitivity of 91%, and a specificity of 64% compared with mammography, which had an accuracy of 51%, a sensitivity of 45%, and a specificity of 86%. Clinical examination in this study had a relatively high sensitivity (79%) but a low specificity (13%) and an accuracy of 66% (17). Another study with a small cohort (27 patients) reported that MR imaging was superior to US, with 100% sensitivity and specificity for cancer recurrence in the chest wall (Fig 2) (14).
Skin-sparing Mastectomy Skin-sparing mastectomy was developed in 1991 by Toth and Lappert to maximize skin preservation, which facilitates breast reconstruction and improves the cosmetic outcome compared with conventional MRM (3). Skin-sparing mastectomy involves complete removal of all breast tissue and the NAC while preserving the skin envelope and natural inframammary fold and is followed by immediate breast reconstruction (11). Indications for skin-saving mastectomy are similar to those for MRM except that the use of skin-saving mastectomy is limited by skin involvement in patients with locally advanced breast cancer. After skin-sparing mastectomy, breast imaging will demonstrate a skin flap or skin envelope, consisting of the native skin and subcutaneous fat, and either autologous or implant augmentation in place of the glandular tissue (Fig 3) (18). Torresan et al (19) reported that histologic review of the skin flap that would be left behind in skin-sparing mastectomy showed that 59.5% of flaps contained residual breast tissue and up
to 9.5% contained residual carcinoma. A skinflap thickness of more than 5 mm was associated with a greater number of terminal ductal units and the presence of residual disease. Residual breast glandular tissue in a reconstructed breast after mastectomy may manifest at MR imaging as dynamic contrast enhancement subjacent to the skin flap (20). An imaging finding of residual breast parenchymal tissue should be reported by the radiologist because long-term surveillance imaging may be indicated (21). At imaging after skin-flap mastectomy, varying degrees of subcutaneous fat are normally seen subjacent to the skin flap. The thickness of the subcutaneous fat layer decreases closer to the NAC, where the breast glandular tissue is more closely apposed to the skin (18).
Nipple-sparing Mastectomy Nipple-sparing mastectomy, also known as totalskin-sparing mastectomy or subcutaneous mastectomy, offers an optimal cosmetic outcome by preserving both the skin envelope and the NAC (Fig 4). Nipple-sparing mastectomy is used most often for prophylactic mastectomy in high-risk patients who will undergo immediate breast reconstruction. When nipple-sparing mastectomy is performed as a cancer treatment, tumors should be small (
Note: This copy is for your personal non-commercial use only. To order presentation-ready copies for distribution to your colleagues or clients, contact us at www.rsna.org/rsnarights.
642
Update on Imaging of the Postsurgical Breast1 Nathaniel E. Margolis, MD Christopher Morley, MD Philip Lotfi, BS Sara D. Shaylor, MD Sarah Palestrant, MD Linda Moy, MD Amy N. Melsaether, MD Abbreviations: DIEP = deep inferior epigastric perforator, FDA = Food and Drug Administration, IDC = invasive ductal carcinoma, IGAP = inferior gluteal artery perforator, MRM = modified radical mastectomy, NAC = nipple-areola complex, SGAP = superior gluteal artery perforator, SIEP = superficial inferior epigastric perforator, TRAM = transverse rectus abdominis myocutaneous RadioGraphics 2014; 34:642–660 Published online 10.1148/rg.343135059 Content Codes: From the Department of Radiology, Breast Imaging Section, New York University School of Medicine, Langone Medical Center, 550 First Ave, New York, NY 10016. Recipient of a Cum Laude award for an education exhibit at the 2012 RSNA Annual Meeting. Received April 14, 2013; revision requested June 25 and received August 16; accepted August 18. For this journal-based SA-CME activity, the authors, editor, and reviewers have no financial relationships to disclose. Address correspondence to N.E.M. (e-mail: [email protected]). 1
See discussion on this article by Heller (pp 660–662).
SA-CME LEARNING OBJECTIVES After completing this journal-based SACME activity, participants will be able to: ■■Differentiate cutting-edge from conventional breast surgery techniques. ■■Understand
the limitations of imaging for cancer detection in the postsurgical breast. ■■Describe
the current state of siliconeimplant breast augmentation and reduction mammoplasty. See www.rsna.org/education/search/RG.
Oncologic, reconstructive, and cosmetic breast surgery has evolved in the last 20 years. Familiarity with cutting-edge surgical techniques and their imaging characteristics is essential for radiologic interpretation and may help avert false-positive imaging findings. Novel surgical techniques include skin- and nipple-sparing mastectomies, autologous free flaps, autologous fat grafting, and nipple-areola–complex breast reconstruction. These techniques are illustrated and compared with conventional surgical techniques, including modified radical mastectomy and autologous pedicled flaps. The role of magnetic resonance (MR) imaging in surgical planning, evaluation for complications, and postsurgical cancer detection is described. Breast reconstruction and augmentation using silicone gel–filled implants is discussed in light of the Food and Drug Administration’s recommendation for MR imaging screening for “silent” implant rupture 3 years after implantation and every 2 years thereafter. Recent developments in skin incision techniques for reduction mammoplasty are presented. The effects of postsurgical changes on the detection of breast cancer are discussed by type of surgery. ©
RSNA, 2014 • radiographics.rsna.org
Introduction
As modern oncologic and plastic surgery techniques for the breast continue to be developed, the responsibility of the breast imager to be informed of current practices has never been greater. Radiologists must cultivate an understanding of expected postsurgical imaging findings and be able to differentiate benign postsurgical changes from suspicious breast lesions. This article discusses the imaging characteristics of novel surgical techniques for mastectomy, including skin-sparing and nipple-sparing mastectomy, and for breast reconstruction, including autologous free flaps, fat grafting, and nippleareola–complex (NAC) reconstruction, and contrasts them with the imaging characteristics of conventional breast surgery techniques. In addition, cutting-edge techniques for reduction mammoplasty and silicone-implant breast augmentation are discussed.
RG • Volume 34 Number 3
Margolis et al 643
Figure 1. Diagram shows the surgical incisions (dashed red lines) used for modified radical mastectomy (MRM), skin-sparing mastectomy, and nipple-sparing mastectomy.
Mastectomy
It is estimated that one in eight women born in the United States will be diagnosed with breast cancer during her lifetime. At least 2.7 million American women have a history of breast cancer, with 270,000 new cases diagnosed and 40,000 attributable deaths per year (1). Breast conservation therapy with lumpectomy and whole-breast radiation therapy has been the cornerstone of surgical management since the National Institutes of Health consensus conference on earlystage breast cancer treatment in 1991 (2). Today, more than one in three patients who are eligible for breast conservation therapy elect to undergo mastectomy instead, and recent data have shown that this number may be increasing (2–5). Although mastectomy rates decreased overall from 1998 to 2005, the use of mastectomy increased from 38.8% to 45% between 2005 and 2007 among patients with early-stage breast cancer in one statewide registry (2). In addition, at an institution with a high volume of breast surgery procedures, the rate of mastectomy surpassed that of lumpectomy, increasing from a share of 35% to 60% from 2004 to 2007, despite patient counseling about treatment options (5). This trend is multifactorial but is due in part to fear of cancer recurrence, perceived survival benefit, greater patient autonomy, increasing use of preoperative magnetic resonance (MR) imaging, and new cosmetically favorable breast surgery and breast reconstruction techniques, namely skin-sparing and nipple-sparing mastectomies (6,7). Traditional indications for mastectomy include multicentric disease, a large (>5 cm) tumor in relation to breast size, disease involving the skin envelope, or an inability to tolerate chemotherapy or radiation therapy (8,9). There has been a marked increase in prophylactic mastectomy, a
treatment option for high-risk patients who have a personal history of breast cancer or are BRCA gene mutation carriers (6,9). Newer mastectomy techniques include skinsparing mastectomy and nipple-sparing mastectomy (Fig 1). Although these techniques can offer improved cosmetic outcomes, there are questions surrounding their oncologic safety because of the risk of leaving residual breast tissue. However, studies to date show that breast cancer recurrence rates for patients who undergo these newer procedures are comparable to those for patients who undergo MRM, at about 1%–2% per year (1,10,11). The local breast cancer recurrence rate for patients who undergo breast conservation therapy is similar, at 1%–2.5% per year (12).
Modified Radical Mastectomy MRM involves complete removal of the breast tissue, skin envelope, NAC, and level I and II axillary lymph nodes. For the past 40 years, MRM has been the standard surgical treatment for locally advanced invasive and inflammatory breast cancer (3,13). It also is the procedure of choice for patients who do not plan to undergo immediate breast reconstruction (3). Imaging of the postmastectomy breast is seldom performed because patients are typically followed up clinically with serial physical examinations; no postmastectomy imaging guidelines are available (14–16). When imaging is performed, the type of mastectomy performed and the presence or absence of breast reconstruction will affect the postoperative imaging appearance. In the absence of reconstruction, the chest wall, subcutaneous fat, and skin can be evaluated with ultrasonography (US) for seroma, fat necrosis, radiation-induced fibrosis, lymphadenopathy, and cancer recurrence (15). In a study of patients after MRM without reconstruction who underwent
644 May-June 2014
radiographics.rsna.org
Figure 2. MR imaging findings after MRM. (a) Axial contrast-enhanced fat-suppressed T1-weighted MR image in a 67-year-old woman 8 years after right MRM and 1 year after radiation treatment for cancer recurrence in the chest wall shows enhancement of the subcutaneous fat in the right chest (arrow), a finding compatible with radiation change. The pectoralis major (M) and minor (m) muscles are thickened in the right breast compared with the left breast. (b) Axial contrast-enhanced T1-weighted MR image in a 64-year-old woman 12 years after left MRM who presented with a palpable mass in the left chest wall shows a mass (*) between the pectoralis major and minor muscles, a finding proved at biopsy to be infiltrating adenocarcinoma. Compared with the contralateral side, there is marked heterogeneous enhancement of the lateral pectoralis major muscle (arrow), a finding consistent with tumor invasion.
mammography and/or US, US was superior for detection of breast cancer recurrence, with an accuracy of 86%, a sensitivity of 91%, and a specificity of 64% compared with mammography, which had an accuracy of 51%, a sensitivity of 45%, and a specificity of 86%. Clinical examination in this study had a relatively high sensitivity (79%) but a low specificity (13%) and an accuracy of 66% (17). Another study with a small cohort (27 patients) reported that MR imaging was superior to US, with 100% sensitivity and specificity for cancer recurrence in the chest wall (Fig 2) (14).
Skin-sparing Mastectomy Skin-sparing mastectomy was developed in 1991 by Toth and Lappert to maximize skin preservation, which facilitates breast reconstruction and improves the cosmetic outcome compared with conventional MRM (3). Skin-sparing mastectomy involves complete removal of all breast tissue and the NAC while preserving the skin envelope and natural inframammary fold and is followed by immediate breast reconstruction (11). Indications for skin-saving mastectomy are similar to those for MRM except that the use of skin-saving mastectomy is limited by skin involvement in patients with locally advanced breast cancer. After skin-sparing mastectomy, breast imaging will demonstrate a skin flap or skin envelope, consisting of the native skin and subcutaneous fat, and either autologous or implant augmentation in place of the glandular tissue (Fig 3) (18). Torresan et al (19) reported that histologic review of the skin flap that would be left behind in skin-sparing mastectomy showed that 59.5% of flaps contained residual breast tissue and up
to 9.5% contained residual carcinoma. A skinflap thickness of more than 5 mm was associated with a greater number of terminal ductal units and the presence of residual disease. Residual breast glandular tissue in a reconstructed breast after mastectomy may manifest at MR imaging as dynamic contrast enhancement subjacent to the skin flap (20). An imaging finding of residual breast parenchymal tissue should be reported by the radiologist because long-term surveillance imaging may be indicated (21). At imaging after skin-flap mastectomy, varying degrees of subcutaneous fat are normally seen subjacent to the skin flap. The thickness of the subcutaneous fat layer decreases closer to the NAC, where the breast glandular tissue is more closely apposed to the skin (18).
Nipple-sparing Mastectomy Nipple-sparing mastectomy, also known as totalskin-sparing mastectomy or subcutaneous mastectomy, offers an optimal cosmetic outcome by preserving both the skin envelope and the NAC (Fig 4). Nipple-sparing mastectomy is used most often for prophylactic mastectomy in high-risk patients who will undergo immediate breast reconstruction. When nipple-sparing mastectomy is performed as a cancer treatment, tumors should be small (
