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PICTORIAL ESSAY - CLINICS IN MAMMOLOGY
Year : 2018  |  Volume : 4  |  Issue : 4  |  Page : 251-255

Mammographic and breast tomosynthesis findings in patients following breast conservative therapy


1 Department of Radio Diagnosis, Sanjay Gandhi Postgraduate Institute of Medical Sciences (SGPGIMS), Lucknow, Uttar Pradesh, India
2 Department of Endocrine Surgery, Sanjay Gandhi Postgraduate Institute of Medical Sciences (SGPGIMS), Lucknow, Uttar Pradesh, India

Date of Web Publication29-Oct-2018

Correspondence Address:
Neeraj Jain
Assistant Professor, Department of Radio Diagnosis, Sanjay Gandhi Postgraduate Institute of Medical Sciences (SGPGIMS), Lucknow - 226 014, Uttar Pradesh
India
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/astrocyte.astrocyte_45_18

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  Abstract 


Breast conservative therapy (BCT) involves removal of tumor along with tumor-free margin followed by radiotherapy. Owing to improvement in imaging methods, patient awareness, and screening programs, more and more patients are becoming eligible for BCT; however, this procedure results in various changes in breast parenchyma, whose mammographic appearances may be confused with residual or recurrent lesion. Therefore, awareness of expected and unexpected mammographic findings following BCT is essential for optimal evaluation of these patients. This pictorial essay intends to demonstrate digital mammographic findings in post BCT patients with emphasis on differentiation between expected and unexpected findings.

Keywords: Breast conservative therapy, digital mammography, digital breast tomosynthesis


How to cite this article:
Jain N, Mohindra N, Kumar S, Agarwal G. Mammographic and breast tomosynthesis findings in patients following breast conservative therapy. Astrocyte 2018;4:251-5

How to cite this URL:
Jain N, Mohindra N, Kumar S, Agarwal G. Mammographic and breast tomosynthesis findings in patients following breast conservative therapy. Astrocyte [serial online] 2018 [cited 2019 Jan 24];4:251-5. Available from: http://www.astrocyte.in/text.asp?2018/4/4/251/244297




  Introduction Top


Breast conservative therapy (BCT) involves removal of tumor along with a margin of normal breast tissue; it encompasses lumpectomy or segmental mastectomy followed by radiotherapy. BCT results in wide variety of expected changes on mammogram and other imaging modalities which are sometimes difficult to interpret and might be confused with recurrent or residual lesion if one is not aware of chronological changes that follows BCT. These two entities and other post BCT changes can be distinguished on mammography after recognizing characteristics findings and by comparing interval findings with previous studies.

The reported recurrence rate following BCT is reported to be around 7% at 5 years and 14% at 10 years.[1]


  Mammographic Evaluation Top


Mammographic evaluation should be preceded by detailed history, which includes any presenting complaints such as palpable lump, hardness or nipple discharge, etc., In addition, information regarding time of diagnosis, surgical details, histopathology or cytopathology reports, duration of radiotherapy, and correlation with preoperative and all postoperative mammograms are also collected.

The common indications following BCT include: confirmation of complete removal of the lesion, detection of residual or recurrent lesions, and screening for metachronous lesions in ipsilateral or opposite breast as patients with breast malignancy have higher risk of developing metachronous lesion in operated as well as healthy breast.

The first mammogram should be done 6 months after the completion of radiotherapy and thereafter annually. Treated breast is difficult to image as it is relatively noncompressible because of pain and edema from radiotherapy and also difficult to position appropriately because of surgical deformity.

The radiographer should be innovative, and if he/she is not able to get the standard mediolateral oblique and cranio-caudal projections, then should acquire at least two projections at different angles, with additional views such as spot compression, magnification, and tangential views if needed. The operated scar site should be marked with thin wire and image the scar in two different views.

In digital mammography, calcification and clips are sharply visualized; however, overlapping soft tissue may mask the underlying abnormality, particularly in patients with dense breast. Digital breast tomosynthesis partially addresses the problem of soft tissue overlap as it acquires a series of images in limited projections as X-ray tube rotate in an arc. It also helps in better characterization of lesion morphology, margin, demonstration of fat necrosis, and fluid–fluid level. However, metallic clips results in artifacts and calcification may appear blurred in some cases.


  Findings and Procedural Details Top


What to expect and not to expect at what time

At 6 months post BCT most of the patients show diffuse breast edema and skin thickening. Approximately, 25% of patients may show fluid collection at the operated site. Then in such condition ultrasonography helps in determining the nature of fluid collection. The recurrent lesion is not expected at this time.

At 1 year breast edema and skin thickening are reduced and fluid collection resolves in majority of patients. During this period recurrent lesion is not usually seen, however, any increase in edema and skin thickening should raise a suspicion for recurrence.

By 2–3 years stability is achieved as edema and thickening reverts back to normal, however, in some patients fluid collection may persist. Recurrent lesions most commonly manifest at this time, and any appearance of or increase in breast edema and skin thickening at this time suggest high possibility of recurrence.

What is stabilization?

Lack of interval changes on two successive studies.[2] Mammographic stability is usually achieved around 2–3 years after breast conservative therapy, and at this time tumor recurrence first begins to appear. Hence any increase in breast density, skin thickening, edema, or new appearance or increase in size of mammographic asymmetry or lesion should alert the radiologist for the possibility of recurrence.

Mammographic findings in post BCT patients are as follows:

1. Masses and fluid collection:

Fluid collection is a common finding after BCT, which results from filling of dead space created after the surgery. In majority it resolves by 1 year, but may persist up to 2 years in some patients [Figure 1] and [Figure 2].
Figure 1: Recent Post BCT Status. (a and c) RCC and RMLO Views Showing well Defined Oval Mass at Post Operative site Suggestive of Fluid Collection (Confirmed on Ultrasound). (b and d) RCC and RMLO Views After 6 Months Showing Complete Resolution of Fluid Collection.

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Figure 2: (a and b) RCC and RMLO Post BCT Status at 2 Years Showing Large Well Defined Oval Lesion with Interspersed Lucent Areas at Post Operative Site Suggestive of Fluid Collection (Confirmed on Ultrasound as Located Fluid Collection), (c and d) RCC and MLO After 3 Years Showing Persistence of Loculated Fluid Collection.

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Seroma and hematoma are common types of fluid collection, which resolves spontaneously, however, some patients may develop abscess formation that requires medical or surgical management. Hence whenever a tender, painful swelling develops after the surgery and patient exhibits fever possibility of abscess should be considered.[2]

Fluid collection typically appears as a well-circumscribed, oval, or round and hyperdense to isodense mass on mammography. Ultrasonography helps in unequivocal cases and also reveals internal septations, loculations, and debris. Any increase in the size of fluid collection after the achievement of stability or presence of nodularity in its wall should alert the radiologist for a possible recurrence.[3]

2. Breast density and skin thickening

Edema and skin thickening are also common after BCT and both follows similar time course. Edema after lumpectomy is usually localized to the site of surgery, however, radiotherapy results in diffuse edema. Damage to the small vessels in skin and lymphatics in the breast are the common causes of skin thickening and breast edema, respectively [Figure 3].
Figure 3: Post BCT Status at 6 Months RCC and RMLO Views (a,c) DM and (b,d) DBT Shows Clips at Post Operative Site with Diffuse Trabecular and Skin Thickening Suggestive of Diffuse Breast Oedema.

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Normally skin thickness is <2 mm, but in post BCT patients it may increase up to 10 mm or greater.[4],[5] Parenchymal edema results in increase in breast density and trabecular thickening on mammography, which should be compared with contralateral breast and with previous mammogram for chronological changes. Both skin thickening and breast edema show gradual resolution over time and stability is usually achieved by 2–3 years. Any increase in edema or skin thickening or recent appearance of edema should alert the radiologist for possible recurrence.

Lymphatic spread of cancer, infection, congestive heart failure, and lymphatic obstruction are the causes of recurrent or worsening breast edema.

3. Calcifications

Calcification at the operated site is a frequent finding, and benign calcification usually develops around 6–12 months after the completion of radiotherapy. Approximately 28% of patients may develop benign calcification after the surgery within first 6–12 months after therapy.[4] However, our experience showed calcification in approximately 50% of post BCT patients.

Dystrophic calcifications are irregular in shape and usually more than 1 mm in size and often have lucent centers. Rim or egg shell calcifications are the most pathognomonic types seen in irradiated breast and are caused by calcification of fibrous capsule around oil cyst [Figure 4].[6]
Figure 4: Post BCT Status. LMLO DM and (b) LMLO DBT Showing Well Defined Lucent Lesion with Fine Rim of Calcification at Post Operative Site Consistent with Fat Necrosis. (c) LMLO and DBT After One Year Showing Decreased in Size of Lucent Lesion and Increase in Amount of Dystrophic Calcification.

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Smooth, round, needle-like, thick calcified plaques and coarse angular plaque-like cutaneous calcification are also of benign variety. Suture material results in knot-like, rod-shaped, and curvilinear calcification.

Amorphous, fine pleomorphic, coarse heterogeneous, and fine linear calcifications that are newly developed or increase in number at the operated site or elsewhere should raise the suspicion of recurrence or metachronous malignancy, respectively.[7],[8] In these cases, stereotactic biopsy should be done to rule out malignancy.

4. Architectural distortion

Architectural distortion is a frequent finding after the BCT in which parenchyma is distorted with no visible mass and includes thin straight lines or spiculations radiating from a point, focal retraction, distortion, and straightening at the anterior or posterior edge of the parenchyma.[9] Fat necrosis, parenchyma scarring, and recurrent cancer all may result in architectural distortion; therefore, it is essential to differentiate between benign scarring and recurrence.

Features of benign scarring[4],[10] [Figure 5] and [Figure 6]:
Figure 5: Serial Mammogram Appearance of Fat Necrosis. Pre Operative Mammogram Showing Dense Mass in Right Upper Outer Quadrant. Post BCT Status (6 Month) Showing Diffuse Breast Deem and Surgical Clips in Right Upper Outer Quadrant. Mammogram at 1 Year Shows Presence of Breast Edema, Skin Thickening and a Well Defined Lucent Oval Lesion in Right Upper Outer Quadrant with Thick Rim (d, e) DM and DBT Mammogram at 2 Year Shows Lucent Oval Lesion with Rim Calcification in Right Upper Outer Quadrant Suggestive of Fat Necrosis, Better Seen on DBT (e).

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Figure 6: (a and b) Early Post BCT Status (1 year) RCC (DM and DBT and RML Views Showing Dense Scar with Adjacent Clips. (c and d) 2 Year Post BCT Images Showing Decrease in Density of Scar. (e and f) 3 Year Post BCT Images Showing Further Reduction in Density and Size of Scar.

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  1. Presence of central lucencies or interspersed fat (most characteristic)
  2. Changing appearance on different projections
  3. Absence of central mass
  4. Thick curvilinear spiculations


Similar to other findings architectural distortion also diminishes over time and stabilizes at the end of 2 years.[3] Biopsy should be done if any increase in the size or density of scar is noted on sequential mammograms.

5. Recurrence

In the National Surgical Adjuvant Breast and Bowel Project (NSABP) B-17 trial, local recurrence rates after breast conserving surgery and radiation therapy were reported to be 7% at 5 years and 12% at 8 years.[11],[12] Recht et al.[13] reported peak recurrence rate of 2.5% between 2 and 6 years.

Majority of recurrences are noted after the 2–3 years of completion of radiotherapy and after achievement of stabilization.

Mammographic depicters of recurrence [Figure 7], [Figure 8], [Figure 9], [Figure 10]:
Figure 7: Post BCT Status (1 year), (a) LMLO (DM) Showing Heterogeneous Breast Parenchymal Density with Diffuse Trabecular and Skin Thickening and Multiple Clips in situ. No Suspicious Calcification or Mass Noted. (b and c) 3 Year Post BCT DM and DBT LMLO View Showing Fine Linear Calcifications at Post Operative Site in Upper Outer Quadrant. (d) Specimen Mammogram Showing Resection of Calcified Area, Histopathology Revealed High Grade Ductal Carcinoma in situ.

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Figure 8: 3 Year Post BCT Status RMLO (a) DM and (b) DBT View Showing Irregular Mass in Upper Outer Quadrant at Post Operative Site, Having Indistinct Margins and Fine Pleomorphic Calcifications, Highly Suggestive for Recurrence.

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Figure 9: 2 Year Post BCT Status (a) RCC DM, (b) RCC DBT, (c) RMLO and (d) RCC DBT, Showing Irregular Dense Three Contiguous Masses with Indistinct Margins at the Post Operative Site, Highly Suspicious for Recurrence (Histopathology Revealed Invasive Ductal Carcinoma) Note is also Made of Lucent Lesions Adjacent to These Masses Suggestive of Fat Necrosis, Better Seen on DBT.

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Figure 10: (a and b) Post BCT Status 1 Year LCC (DM and DBT) Showing Heterogeneous Dense Parenchyma with Diffuse Trabecular and Skin Thickening Suggestive of Diffuse Breast Oedema and No Obvious Mass. (c and d) Post BCT Status (2 Year) LCC (DM and DBT) showing a Small (around 10 mm size) Dense Mass with Indistinct Margins in Left Upper Outer Quadrant Highly Suspicious of Recurrence of Disease, Histopathology Reveals Invasive Ductal Carcinoma.

Click here to view


  1. Presence of central mass in scar
  2. Increasing asymmetry
  3. New or enlarging mass in the operative field
  4. Fine straight spiculations from the scar
  5. Increase in size and nodularity of scar
  6. Increase in edema, skin thickening, and density after the stabilization
  7. Appearance of amorphous or fine pleomorphic calcification


It is very important to compare the postoperative mammogram with all the previous mammograms, not only with the recent one because one may miss subtle progressive finding, and also to carefully evaluate contralateral breast, which is also at high risk of developing malignancy.

In equivocal cases, ultrasound and MRI may be helpful in differentiating between tumor recurrence and postoperative spiculated scar when performed 12–18 months after the surgery;[14] however, image-guided biopsy is often needed to confirm the diagnosis.

Teaching points

It is of paramount importance to differentiate benign expected changes after BCT and tumor recurrence. Following are the salient mammographic features that can help the reader do differentiation between them and plan further course of management.

  1. Reassuring signs


    1. Chronological decrease in breast edema, density, and skin thickening
    2. Central lucencies in scar or poorly marginated postoperative site with interspersed fat
    3. Changing scar appearance in different projection
    4. Coarse dystrophic, smooth round, and rim calcification


  2. Worrisome signs


    1. Presence of central mass in scar
    2. Amorphous, fine pleomorphic, and fine linear calcification
    3. Increase in breast edema, density, and skin thickening after stability
    4. Recurrent breast edema


Disclosure

This work has been presented as a poster in European Congress of Radiology, 2018 titled “Spectrum of digital mammographic finding in post breast conservative therapy patients with impact of digital breast tomosynthesis.”

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.



 
  References Top

1.
Kurtz JM, Amalric R, Brandone H, Ayme Y, Jacquemier J, Pietra JC, et al. Local recurrence after breast-conserving surgery and radiotherapy: frequency, time course, and prognosis. Cancer 1989;63:1912-7.  Back to cited text no. 1
    
2.
Krishnamurthy R, Whitman GJ, Stelling CB, Kushwaha AC. Mammographic findings after breast conservation therapy. Radiographics. 1999;19 Spec No: S53-62; quiz S262-3.  Back to cited text no. 2
    
3.
Chansakul T, Lai KC, Slanetz PJ. The postconservation breast. Part 1: Expected imaging findings. AJR Am J Roentgenol 2012;198:321-30. doi: 10.2214/AJR.10.7298.  Back to cited text no. 3
    
4.
Mendelson EB. Evaluation of the postoperative breast. Radiol Clin North Am 1992;30:107-38.  Back to cited text no. 4
    
5.
Libshitz HI, Montague ED, Paulus DD. Skin thickness in the therapeutically irradiated breast. AJR 1978;130:345-7.  Back to cited text no. 5
    
6.
Bassett LW, Gold RH, Mirra JM. Nonneoplastic breast calcifications in lipid cysts: development after excision and primary irradiation. AJR 1982;138:335-8.  Back to cited text no. 6
    
7.
Stomper PC, Recht A, Berenberg AL, Jochelson MS, Harris JR. Mammographic detection of recurrent cancer in the irradiated breast. AJR 1987;148:39-43.  Back to cited text no. 7
    
8.
Hassell PR, Olivotto IA, Mueller HA, Kingston GW, Basco VE. Early breast cancer: detection of recurrence after conservation surgery and radiation therapy. Radiology 1990;176:731-5.  Back to cited text no. 8
    
9.
ACR BIRADS atlas 2013.  Back to cited text no. 9
    
10.
Wolfe JN. Xeroradiography of the breast, 2nd ed. Springfield, IL: Charles C Thomas, 1983; 405-35.  Back to cited text no. 10
    
11.
Fisher B, Costantino J, Redmond C, Fisher E, Margolese R, Dimitrov N, et al. Lumpectomy compared with lumpectomy and radiation therapy for the treatment of intraductal breast cancer. N Engl J Med 1993;328:1581-6.  Back to cited text no. 11
    
12.
Fisher ER, Dignam J, Tan-Chiu E, Costantino J, Fisher B, Paik S, et al. Pathologic findings from the National Surgical Adjuvant Breast Project (NSABP) eight-year update of protocol B-17: intraductal carcinoma. Cancer 1999; 86:429-38.  Back to cited text no. 12
    
13.
Recht A, Silen W, Schnitt SJ, Connolly JL, Gelman RS, Rose MA, et al. Time-course of local recurrence following conservative surgery and radiation therapy for early stage breast cancer. Int J Radiat Oncol Biol Phys 1988;15:255-61.  Back to cited text no. 13
    
14.
Viehweg P, Heinig A, Lampe D, Buchmann J, Heywang-Köbrunner SH. Retrospective analysis for evaluation of the value of contrast-enhanced MRI in patients treated with breast conservative therapy. MAGMA 1998;7:141-52.  Back to cited text no. 14
    


    Figures

  [Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6], [Figure 7], [Figure 8], [Figure 9], [Figure 10]



 

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