Debra L. Monticciolo MD, Abstract Co-Author: Nothing to Disclose

Kelly William Biggs MD, Presenter: Nothing to Disclose

Ashley Kallina Gist MD, Abstract Co-Author: Nothing to Disclose

Spencer Sincleair MD, Abstract Co-Author: Nothing to Disclose

Rodney Hajdik, Abstract Co-Author: Nothing to Disclose

Michael L. Nipper MD, Abstract Co-Author: Nothing to Disclose

James Brian Schnitker MD, Abstract Co-Author: Nothing to Disclose

et al, Abstract Co-Author: Nothing to Disclose

To evaluate and compare the imaging sequela and complications of accelerated partial breast irradiation (APBI) with those occurring in patients treated with standard external beam therapy.

The records of all patients treated with lumpectomy from September 2004 through October 2007 were reviewed. Patients included those who met the criteria for ABPI: age 45 or older; cancer stage T1N0M0 or DCIS 3cm or less, and negative surgical margins. Data collected included patient and tumor characteristics, surgical cavity size, balloon size and PTV (APBI), radiation dose/duration, and complications. All images pre-treatment and at least 5 months post-treatment were then separately reviewed by 4 radiologists blinded to the imaging reports. The following were assessed: breast density; and the presence of distortion, seroma formation, skin edema (focal vs generalized), stromal thickening (focal vs generalized), calcifications, and fat necrosis.

252 patients met the initial criteria (185 IDC; 67 DCIS); of these 197 had complete records and films available for review. 97 (49%) were treated with APBI and 100 (51%) were treated with external beam. The two groups were well matched in age, tumor size and type. Imaging findings for APBI vs external beam were: distortion 90 (93%) v 83 (83%); seroma 67 (69%) v 7 (7%); skin edema 52 (54%) v 47 (47%); increased stroma 75 (77%) v 66 (66%); calcifications 10 (10%) v 6 (6%) and fat necrosis 12 (12%) v 6(6%). For APBI, skin and stromal edema was more commonly focal. On imaging, only the seroma rate was statistically significantly different between the two treatment modes (p<0.0001). For patients treated with APBI, seroma formation was not related to balloon size and only weakly related to lumpectomy cavity size. The complication rate was similar for both (15 v 13%) but the types of complications and treatment differed.

The rate of visible seroma formation at the lumpectomy site is significantly higher for patients treated with ABPI than those treated with external beam radiation. Seroma formation is not related to balloon or lumpectomy cavity size; rather it is likely solely the result of intense focal radiation. Other post-treatment imaging findings are similar for the two techniques.

The imaging consequences of APBI are important for follow and management of breast cancer patients, who all require continued cancer imaging surveillance.

Monticciolo, D, Biggs, K, Gist, A, Sincleair, S, Hajdik, R, Nipper, M, Schnitker, J, et al, , Breast Conserving Therapy with Accelerated Partial Breast versus External Beam Whole Breast Irradiation: Comparison of Imaging Sequela in a Matched Population.  Radiological Society of North America 2008 Scientific Assembly and Annual Meeting, February 18 - February 20, 2008 ,Chicago IL. http://archive.rsna.org/2008/6011963.html