The Postconservation Breast: Part 1, Expected Imaging Findings

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1 Women s Imaging Pictorial Essay Chansakul et al. Imaging the Postconservation reast Women s Imaging Pictorial Essay CME SM The Postconservation reast Downloaded from by on 01/04/18 from IP address Copyright RRS. For personal use only; all rights reserved FOCUS ON: Thanissara Chansakul 1 Kenny C. Lai Priscilla J. Slanetz Chansakul T, Lai KC, Slanetz PJ Keywords: breast, breast cancer, breast conservation, mammography, radiation oncology DOI: /JR Received September 26, 2010; accepted after revision June 1, ll authors: Department of Radiology, Harvard Medical School and eth Israel Deaconess Medical Center, 330 rookline ve, oston, M ddress correspondence to P. J. Slanetz (pslanetz@bidmc.harvard.edu). CME/SM This article is available for CME/SM credit. JR 2012; 198: X/12/ merican Roentgen Ray Society The Postconservation reast: Part 1, Expected Imaging Findings OJECTIVE. The objectives of this article are to discuss the conventional imaging algorithms after breast-conserving surgery and radiation therapy and to review the expected chronologic imaging appearances of the conservatively treated breast. CONCLUSION. Imaging the treated breast presents challenges because of its limited compressibility and the overlapping features of benign posttreatment alterations and tumor recurrence. fter lumpectomy and radiation therapy, mammographic findings such as breast edema, skin thickening, fluid collections, architectural distortion, and calcifications have characteristic sequences of evolution toward stability. wareness of these normal chronologic imaging findings for the conservatively treated breast minimizes unnecessary recall from screening and permits early detection of recurrent breast carcinoma. fter breast-conserving surgery and radiation therapy, several alterations of the breast occur and evolve over time. Certain features of these benign changes may simulate radiologic patterns of tumor recurrence. Despite the overlap between posttreatment changes and breast carcinoma on mammography, the two entities can usually be distinguished by recognizing the characteristic features of posttreatment sequelae and by comparing interval findings on serial studies. fter completing this article, readers will be familiar with the common temporal changes of the conservatively treated breast on imaging. Mammography has been shown to reduce mortality from breast cancer up to 30% [1]. The widespread use of mammography has led to earlier detection of many breast cancers. Most of these cases are early stage and therefore are amenable to breast conservation therapy. reast conservation therapy achieves local tumor control by surgical removal of the cancer with a margin of normal breast tissue and is followed by whole-breast, moderate-dose radiation. The combination of conservative surgery and radiation therapy offers the additional advantage of preserving the breast, usually with a satisfactory cosmetic result. Given equivalent survival rates for breast conservation therapy and mastectomy [2 8], breast conservation therapy has become the treatment of choice for early-stage breast cancer. Meanwhile, technologists and radiologists are faced with increasing imaging and diagnostic challenges. For the technologist, irradiated breasts may be difficult to position adequately and to compress sufficiently. For the radiologist, interpretation of imaging findings can be difficult because imaging features after treatment may mimic or hide tumor recurrence. To be able to distinguish between the two entities, radiologists need to be familiar with the expected chronologic appearances of the conservatively treated breast. These benign mammographic alterations include masses, fluid collections, breast edema, skin thickening, architectural distortion, and calcifications. lthough certain posttreatment alterations such as edema and skin thickening may persist, most changes after breast conservation therapy diminish and regress over time and then remain stable. Stability, defined as the lack of interval change on two successive studies, on average occurs at 2 3 years after the completion of radiation therapy, which is around the time tumor recurrences typically begin to appear [9]. fter stability has been achieved, any increase in the changes or development of a new density or microcalcifications should raise suspicion for tumor recurrence. Imaging lgorithms Mammography of the conservatively treated breast is performed for several reasons including to confirm complete removal of the JR:198, February

2 Chansakul et al. Downloaded from by on 01/04/18 from IP address Copyright RRS. For personal use only; all rights reserved biopsy-proven malignancy; to identify postprocedural fluid collections, scarring, and architectural distortion; to detect residual or recurrent tumor; and to screen for metachronous cancers in the affected breast and contralateral breast [9, 10]. There is currently no universal guideline for posttreatment mammographic surveillance. t many institutions, postsurgical mammograms are routinely obtained before the initiation of radiation therapy. t our diagnostic imaging center, postsurgical mammograms are obtained before radiation therapy in only selected cases to determine the completeness of tumor excision by identifying any residual calcifications within the breast. In most cases, however, mammograms of both breasts are obtained 6 months after the completion of radiation therapy. Images obtained at that time include craniocaudal and mediolateral oblique views. Magnification views of the lumpectomy bed are also routinely obtained at our institution even though there is no evidence to support improved outcome. Subsequently, annual mammography is performed. new baseline is established at 2 years after the completion of radiation therapy. Mammographic technologists are faced with challenges: The treated breast may be difficult to position because of surgical deformities or may be relatively noncompressible because of pain or radiation changes. dditional images, such as spot compression and tangential views, are often helpful to ensure adequate coverage of the entire breast and particularly of the lumpectomy bed. It is important for radiologists to recognize that radiation therapy often delays resolution of postsurgical changes. Mammograms should be evaluated in sequence and in comparison with several earlier studies to maximize early detection of recurrent breast carcinoma while minimizing unnecessary recall from screening. Expected Imaging Findings Masses and Fluid Collections common finding on posttreatment mammography is a mass representing a fluid collection at the lumpectomy site, which should not be confused with recurrent tumor. Dead space is intentionally left at surgery of a malignant breast neoplasm to allow fluid to fill in the space and, in this way, to achieve better cosmesis. In one study, approximately half of breast cancer patients had fluid collections at the surgical site at 4 weeks after surgery and about 25% at 6 months [9]. fluid collection typically appears as an oval or round circumscribed mass on mammography (Fig. 1) that is most commonly within the surgical bed or lower axilla, provided sentinel node biopsy or axillary node dissection is performed. Ultrasound of these collections often reveals a complex cystic mass with septations, loculations, thick walls, or a combination of these findings (Fig. 1). Over subsequent months, postoperative seromas and hematomas are gradually resorbed and are replaced by scarring and fibrosis. Fluid collections generally diminish in size over time and resolve completely by months after surgery, although they may persist in a minority of patients [9] (Fig. 2). ny increase in the size of a fluid collection over time should alert the radiologist to a possible recurrence. reast Edema and Skin Thickening reast edema and skin thickening are posttreatment findings with similar time courses for maximal change and regression after breast conservation therapy [9] (Fig. 3). Typically, postlumpectomy edema is localized to the area of the incision [10]. reast edema from radiation therapy, unlike focal postsurgical edema, usually encompasses the entire breast. reast edema may present as more of an accentuated trabecular pattern when the degree of edema is moderately severe or as overall increased breast density when the degree is marked [9 11]. Prominent periareolar edema is occasionally present as a result of surgical disruption of the lymphatics [10]. The perceived increased density in the irradiated breast may be explained also by suboptimal exposure at the time the image is obtained because the treated breast often is swollen and less compressible. Skin thickening during the period after radiation is secondary to breast edema from the damage of small vessels. The skin thickness after radiation therapy may reach 1 cm or even greater [9, 12]. reast edema and skin thickening are best appreciated when compared with the contralateral breast or with pretreatment mammograms. t mammography, maximal breast edema and skin thickening are usually seen during the first 6 months after completion of radiation therapy [9, 10]. These alterations then diminish and attain stability for many patients within 2 3 years [9, 12] (Fig. 4). Edema or skin thickening that increases after stability has been achieved should alert radiologists to the need for further investigation. The differential diagnoses of recurrent or worsening breast edema include lymphatic spread of cancer, obstructed venous drainage, congestive heart failure, and infection [13]. rchitectural Distortion rchitectural distortion in the treated breast develops secondary to postsurgical scar formation and fat necrosis. rchitectural distortion is commonly seen in the lumpectomy bed and within the lower axilla if sentinel node biopsy or axillary node dissection was performed (Fig. 5). Parenchymal scarring and fat necrosis can cause a spiculated or irregular, poorly marginated, softtissue density associated with skin retraction that mimics recurrent malignancy. However, the following mammographic features are more likely to suggest benign architectural distortion rather than tumor recurrence: the presence of central lucencies; a changing appearance on different projections [9] (Fig. 6); and thick, curvilinear spiculations [11]. Central lucencies suggest scarring because they represent fat trapped by fibrous stranding in the scar [9]. These differentiating features can often be helpful, although they are not always reliable. For instance, some breast carcinomas notably, infiltrating lobular may contain central lucencies and may not have a central mass [14]. rchitectural distortion usually diminishes in conspicuity and stabilizes over a 2-year period. In evaluating suspicious lesions, spot compression and magnification views are helpful in showing the features of scarring and in excluding recurrent tumor. nnual follow-up mammograms are necessary to show the sequential decrease in the size and prominence of the density to ensure its benignity (Fig. 7). If the scar grows in size or if it becomes denser or more masslike, recurrent tumor should be suspected and should prompt biopsy. enign Calcifications enign calcifications may develop at the postoperative site, with a reported incidence of 28% within the first 6 12 months after radiation therapy [9]. Dystrophic calcifications generally develop in areas of fat necrosis. Such calcifications are usually round and coarse or smooth, are typically large, and often have lucent centers (Fig. 8). The most pathognomonic type of calcifications observed in the conservatively treated breast presents as thin arcs of calcification defining the rims of radiolucent oil cysts [15, 16] (Fig. 9). The oil cysts are the results of fats reduced to fatty acids with the formation of a surrounding fibrous capsule [17]. The capsule frequently calcifies 322 JR:198, February 2012

3 Imaging the Postconservation reast Downloaded from by on 01/04/18 from IP address Copyright RRS. For personal use only; all rights reserved to produce a crescent- or shell-like appearance [17 19]. Suture material left in the breast may also calcify, forming distinctive shapes such as knotlike, rod-shaped, and curvilinear [9] (Figs. 10 and 11). On magnification views, these benign forms of calcifications can often be recognized and differentiated from pleomorphic or indistinct microcalcifications associated with malignancy. t times, however, dystrophic calcifications simulate malignancy. For instance, early rim calcification of evolving fat necrosis may produce an appearance that is mammographically indeterminate. In such cases, careful inspection of the previous mammograms may help by showing regression of the calcifications over time or formation of the calcifications around a radiolucent center of fat, suggesting the benign nature. If calcifications cannot be distinguished from a possible malignant process radiographically, biopsy should be considered (Fig. 12). Conclusion Imaging the treated breast presents challenges because of its limited compressibility and the overlapping features of benign posttreatment alterations and tumor recurrence. fter lumpectomy and radiation therapy, mammographic findings such as breast edema, skin thickening, fluid collections, architectural distortion, and calcifications have characteristic sequences of evolution toward stability. wareness of these normal chronologic imaging findings for the conservatively treated breast minimizes unnecessary recall from screening and permits early detection of recurrent breast carcinoma. References 1. Nelson HD, Tyne K, Naik, et al. Screening for breast cancer: systematic evidence review update for the U.S. Preventive Services Task Force evidence review update no. 74. Rockville, MD: gency for Healthcare Research and Quality, 2009:HRQ publication no EF-1 2. Fisher, nderson S, Redmond CK, Wolmark N, Wickerham DL, Cronin WM. Reanalysis and results after 12 years of follow-up in a randomized clinical trial comparing total mastectomy with lumpectomy with or without irradiation in the treatment of breast cancer. N Engl J Med 1995; 333: Fisher, nderson S, ryant J, et al. Twenty-year follow-up of a randomized trial comparing total mastectomy, lumpectomy, and lumpectomy plus irradiation for the treatment of invasive breast cancer. N Engl J Med 2002; 347: Veronesi U, Cascinelli N, Mariani L, et al. Twenty-year follow-up of a randomized study comparing breast-conserving surgery with radical mastectomy for early breast cancer. N Engl J Med 2002; 347: van Dongen J, Voogd C, Fentiman IS, et al. Long-term results of a randomized trial comparing breast-conserving therapy with mastectomy: European Organization for Research and Treatment of Cancer trial. J Natl Cancer Inst 2000; 92: Jatoi I, Proschan M. Randomized trials of breast-conserving therapy versus mastectomy for primary breast cancer: a pooled analysis of updated results. m J Clin Oncol 2005; 28: Poggi MM, Danforth DN, Sciuto LC, et al. Eighteen-year results in the treatment of early breast carcinoma with mastectomy versus breast conservation therapy: the National Cancer Institute ran- domized trial. Cancer 2003; 98: Jacobson J, Danforth DN, Cowan KH, et al. Tenyear results of a comparison of conservation with mastectomy in the treatment of stage I and II breast cancer. N Engl J Med 1995; 332: Mendelson E. Evaluation of the postoperative breast. Radiol Clin North m 1992; 30: Peters ME, Fagerholm MI, Scanlan K, Voegeli DR, Kelcz F. Mammographic evaluation of the postsurgical and irradiated breast. RadioGraphics 1988; 8: Wolfe JN. Xeroradiography of the breast, 2nd ed. Springfield, IL: Charles C Thomas, 1983: Libshitz HI, Montague ED, Paulus DD. Skin thickness in the therapeutically irradiated breast. JR 1978; 130: Krishnamurthy R, Whitman GJ, Stelling C, Kushwaha C. Mammographic findings after breast conservation therapy. RadioGraphics 1999; 19:S53 S Mendelson E, Harris KM, Doshi N, Tobon H. Infiltrating lobular carcinoma: mammographic patterns with pathologic correlation. JR 1989; 153: assett LW, Gold RH, Mirra JM. Nonneoplastic breast calcifications in lipid cysts: development after excision and primary irradiation. JR 1982; 138: uckley JH, Roebuck EJ. Mammographic changes following radiotherapy. r J Radiol 1986; 59: Tabar L, Dean P. Teaching atlas of mammography. New York, NY: Thieme Stratton, 1985: Evers K, Troupin RH. Lipid cyst: classical and atypical appearances. JR 1991; 157: Orson LW, Cigtay OS. Fat necrosis of the breast: characteristic xeromammographic appearance. Radiology 1983; 146:35 38 JR:198, February

4 Chansakul et al. Downloaded from by on 01/04/18 from IP address Copyright RRS. For personal use only; all rights reserved C Fig. 1 Postoperative seroma in 54-year-old woman with history of invasive left breast carcinoma. and, Mediolateral () and mediolateral oblique () mammograms obtained 6 months after lumpectomy and radiation therapy show large, dense, well-defined, oval mass in outer left breast consistent with postoperative seroma. Surgical clips delineate site of tumor removal. C and D, Ultrasound images of outer left breast show large heterogeneous fluid-filled collection with internal septations; these findings, like those shown in and, are consistent with postoperative seroma given history of breast conservation therapy in this area. D 324 JR:198, February 2012

5 Imaging the Postconservation reast Downloaded from by on 01/04/18 from IP address Copyright RRS. For personal use only; all rights reserved C Fig. 2 Persistent postoperative seroma in 76-year-old woman with history of invasive right breast carcinoma treated with lumpectomy and radiation therapy. and, Craniocaudal () and mediolateral oblique () mammograms of right breast obtained 6 months after completion of radiation therapy show dense round mass in postsurgical bed representing postoperative seroma. C and D, Craniocaudal (C) and mediolateral oblique (D) mammograms obtained 4 years after and show that seroma has slightly diminished in size. D JR:198, February

6 Chansakul et al. Downloaded from by on 01/04/18 from IP address Copyright RRS. For personal use only; all rights reserved Fig. 4 Resolution of breast edema and skin thickening after breast conservation therapy in 57-year-old woman with history of invasive breast carcinoma., Mediolateral oblique mammogram of postlumpectomy left breast obtained before radiation shows area of mild architectural distortion and residual calcifications (arrow) in inferior left breast., Mediolateral oblique mammogram obtained 1 year after radiation therapy shows architectural distortion and trabecular and skin thickening. Scar site is marked by wire taped to skin. C, Obtained 2 years after completion of radiation therapy, mediolateral oblique mammogram shows that trabecular thickening and skin thickening have significantly improved, whereas architectural distortion in biopsy bed remains. Fig. 3 reast edema and skin thickening due to radiation therapy in 62-year-old woman with history of invasive right breast carcinoma. and, Mediolateral oblique mammograms of right () and left () breasts obtained 6 months after radiation therapy for right breast carcinoma show postradiation changes in right breast. Changes include increased breast density due to edema, which obscures lumpectomy bed, and skin thickening (arrow, ), which is most prominent in periareolar area. C 326 JR:198, February 2012

7 Imaging the Postconservation reast Downloaded from by on 01/04/18 from IP address Copyright RRS. For personal use only; all rights reserved Fig. 5 rchitectural distortion due to lumpectomy and axillary dissection in 68-year-old woman who developed invasive right breast carcinoma., Mediolateral oblique mammogram of right breast obtained before treatment shows ill-defined spiculated mass in upper breast (arrow) corresponding to biopsy-proven invasive carcinoma. Several normal-appearing axillary lymph nodes are seen in lower axilla., Mediolateral oblique view obtained 6 months after lumpectomy and axillary dissection reveals areas of architectural distortion in lumpectomy bed and in lower right axilla; these findings are consistent with postsurgical changes. Fig. 6 rchitectural distortion in 52-year-old woman with history of left breast carcinoma. Images were obtained for follow-up 3 years after lumpectomy and radiation therapy., Craniocaudal mammogram of conservatively treated left breast shows amorphous parenchymal scar with thin spiculations (arrow)., Mediolateral oblique mammogram shows radiolucencies of fat trapped by fibrous tissue within area of scar site (arrow). Notice also how architectural distortion is more apparent on craniocaudal projection than on mediolateral oblique projection, which is characteristic of benign postsurgical changes. JR:198, February

8 Chansakul et al. Downloaded from by on 01/04/18 from IP address Copyright RRS. For personal use only; all rights reserved Fig. 7 Resolving parenchymal scar and breast edema after breast conservation therapy in 67-yearold woman with history of invasive right breast carcinoma., Craniocaudal mammogram of right breast obtained 2 years after lumpectomy and completion of radiation therapy shows area of parenchymal scar in lumpectomy bed; scar site is marked by wire taped to skin., Craniocaudal mammogram obtained 1 year after shows expected decreased size of parenchymal scar and decreased overall breast density; these findings are consistent with improved breast edema. Fig. 8 Dystrophic calcifications in 81-year-old woman with history of right breast carcinoma. and, Craniocaudal () and mediolateral oblique () mammograms of right breast obtained 28 years after lumpectomy and radiation therapy. Thin wire placed on skin marks postoperative area. Large coarse calcifications (arrows), representing dystrophic calcifications, are seen within tumor excision site. 328 JR:198, February 2012

9 Imaging the Postconservation reast Downloaded from by on 01/04/18 from IP address Copyright RRS. For personal use only; all rights reserved Fig. 9 Calcifying oil cyst in 72-year-old woman with history of invasive breast cancer that was treated with lumpectomy and radiation therapy. and, Magnified craniocaudal () and magnified mediolateral () mammograms of posttreatment breast show rim-calcified lucent lesion at postsurgical site; this finding is consistent with calcifying oil cyst, which is indicative of benign fat necrosis. Fig. 10 Sutural calcifications in 74-year-old woman with history of left breast cancer that was treated with lumpectomy and radiation therapy. C, Craniocaudal (), mediolateral oblique (), and magnified mediolateral (C) mammograms of postlumpectomy-postradiation left breast show curvilinear and knot-shaped calcifications. These findings are characteristic of sutural calcifications, which are most commonly seen in irradiated breast and are rarely observed after benign breast biopsy. C JR:198, February

10 Chansakul et al. Downloaded from by on 01/04/18 from IP address Copyright RRS. For personal use only; all rights reserved Fig. 11 Dystrophic and sutural calcifications in 53-year-old woman with history of invasive breast carcinoma that was treated with lumpectomy and radiation therapy. In this magnified craniocaudal projection, both smooth large dystrophic calcifications consistent with fat necrosis and curvilinear sutural calcifications are seen within operative bed. Fig. 12 Linear calcifications in 61-year-old woman with history of right breast ductal carcinoma in situ that was treated with lumpectomy and radiation therapy. In this magnified mammogram obtained 18 months after completion of radiation therapy, linear calcifications (arrow) are seen within lumpectomy bed; these findings are concerning for tumor recurrence. Stereotactic core needle biopsy of calcifications was subsequently performed given indeterminate imaging finding. Pathology showed calcifications associated with fat necrosis. FOR YOUR INFORMTION This article is part of a self-assessment module (SM). Please also refer to The Postconservation reast: Part 2, Imaging Findings of Tumor Recurrence and Other Long-Term Sequelae, which can be found on page 331. Each SM is composed of two journal articles along with questions, solutions, and references, which can be found online. You can access the two articles at and the questions and solutions that comprise the Self-ssessment Module by logging on to clicking on JR (in the blue Publications box), clicking on the article name, and adding the article to the cart and proceeding through the checkout process. The merican Roentgen Ray Society is pleased to present these SMs as part of its commitment to lifelong learning for radiologists. Continuing medical education (CME) and SM credits are available in each issue of the JR and are free to RRS members. Not a member? Call (from the U.S. or Canada) or to speak to an RRS membership specialist and begin enjoying the benefits of RRS membership today! 330 JR:198, February 2012