Clinical and dosimetric experience with MammoSite-based brachytherapy under the RTOG 0413 protocol

Jadwiga B Wojcicka, Donette E Lasher, Ronald Malcom, Gregory Fortier, Jadwiga B Wojcicka, Donette E Lasher, Ronald Malcom, Gregory Fortier

Abstract

MammoSite balloon brachytherapy is a relatively new technique for partial breast irradiation. The present paper focuses on the treatment planning, dosimetry, and quality assurance aspects of that treatment, based on the Radiation Therapy Oncology Group 0413 randomized prospective trial (RTOG 0413) protocol. We investigate the usefulness of evaluating implants for treatment appropriateness according to the full set of RTOG criteria as compared with the manufacturer's guidelines. We describe our methods to improve MammoSite balloon implants that would otherwise not comply with the protocol. The initially acquired computed tomography (CT) images are evaluated for tissue conformance, balloon surface-to-skin distance, and balloon symmetry. If the implant fails to meet the foregoing criteria, corrective action such as delay in the CT scan, balloon manipulation, or fluid volume adjustment is taken, and the patient is re-scanned. If the corrective action appears to be successful, three dimensional treatment planning and dose-volume histogram analysis is performed to evaluate the geometric and dosimetric parameters with regard to the RTOG 0413 protocol. The evaluated parameters include, volume ratio of the lumpectomy cavity to the ipsilateral breast, target volume coverage, tissue-balloon conformance, balloon symmetry, minimal balloon surface-to-skin distance, maximum skin dose, and normal breast tissue dose-volume parameters V150 and V200. Among our implants, 21.7% did not initially meet the RTOG 0413 acceptance criteria. Asymmetry and poor conformance values reduce the target volume coverage, and so an implant with moderate conformance and asymmetry can be within the manufacturer's guidelines, but still not meet the RTOG criteria. Our intervention corrected all but one of the implants that failed to meet the criteria. Manipulating the cavity and adjusting the balloon volume may salvage an implant and meet the strict geometric and dosimetric criteria imposed by the RTOG 0413 protocol.

Figures

Figure 1
Figure 1
The MammoSite balloon with components identified. (Image provided courtesy of Cytyc Corporation and affiliates.)
Figure 2
Figure 2
RTOG 0413 volumes of interest. The balloon, PTV_EVAL, ipsilateral breast, and air volumes are depicted. The balloon is contoured at the edge of the contrast medium. PTV_EVAL is a 1‐cm expansion from the balloon surface, excluding the balloon volume, the chest wall and pectoralis muscle, and the first 5 mm inside the skin surface. Air pockets inside the treatment volume are contoured, but air pockets within the balloon are not included. The ipsilateral breast is contoured as are all tissues within the standard tangential field borders, except the lung.
Figure 3
Figure 3
Pre‐ and post‐manipulation images of patient 2. The images are multi‐planar reconstructions of the computed tomography scan of the implant. The image on the left is the implant in its postoperative state. The image on the right is the implant after a net addition of 10 cm3 to the balloon volume. The size of the air pocket has been reduced, with an acceptable 0.25 mm increase in asymmetry.
Figure 4
Figure 4
Pre‐ and post‐manipulation images of patient 5. The images are multi‐planar reconstructions of the computed tomography scan of the implant. The image on the left is the implant in its postoperative state. The image on the right is the implant after addition of 10 cm3 fluid to the balloon and massage of the implant area. The air pocket has been eliminated, with an acceptable 0.5 mm increase in asymmetry.

References

    1. 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(16):1227–1232.
    1. Fisher B, Anderson S, Bryant 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(16):1233–1241.
    1. Farrow DC, Hunt WC, Samet JM. Geographic variation in the treatment of localized breast cancer. N Engl J Med. 1992;326(17):1097–1101.
    1. Dolan JT, Fanchi TS, Miller CC 3rd, Brunicardi FC. Low use of breast‐conservation surgery in medically indigent populations. Am J Surg. 1999;178(6):470–474.
    1. Morrow M, White J, Moughan J, et al. Factors predicting the use of breast‐conserving therapy in stage I and II breast carcinoma. J Clin Oncol. 2001;19(8):2254–2262.
    1. Dickler A, Kirk MC, Chu J, Nguyen C. The MammoSite breast brachytherapy applicator: a review of the technique and outcomes. Brachytherapy. 2005;4(2):130–136.
    1. Radiation Therapy Oncology Group (RTOG) . NSABP Protocol B‐39, RTOG Protocol 0413: a randomized phase III study of conventional whole breast irradiation (WBI) versus partial breast irradiation (PBI) for women with Stage 0, I, or II breast cancer. Philadelphia (PA): RTOG; January 2005. [Available online at: ; cited November 21, 2005]
    1. Keisch M, Vicini F, Kuske RR, et al. Initial clinical experience with the MammoSite breast brachytherapy applicator in women with early‐stage breast cancer treated with breast‐conserving therapy. Int J Radiat Oncol Biol Phys. 2003;55(2):289–293.
    1. Edmundson GK, Vicini FA, Chen PY, Mitchell C, Martinez AA. Dosimetric characteristics of the MammoSite RTS, a new breast brachytherapy applicator. Int J Radiat Oncol Biol Phys. 2002:52(4):1132–1139.
    1. Arthur D, Vicini F, Kuske R, et al. Accelerated partial breast irradiation: an updated report from the American Brachytherapy Society. Brachytherapy. 2002;1(4):184–190.
    1. The American Society of Breast Surgeons . Consensus statement for accelerated partial breast irradiation. Columbia (MD): The American Society of Breast Surgeons; April 30, 2003. [Available online at: ; cited September 18, 2007]
    1. Kutcher GJ, Coia L, Gillin M, et al. Comprehensive QA for radiation oncology: report of AAPM Radiation Therapy Committee Task Group 40. Med Phys. 1994;21(4):581–638.
    1. Vu KN, Dragun AE, Cole DJ, Jenrette JM. Accelerated partial breast irradiation using MammoSite brachytherapy: a multidisciplinary approach to breast‐conservation therapy. Commun Oncol. 2005;2(6):477–482.
    1. Nath R, Anderson LL, Luxton G, Weaver KA, Williamson JF, Meigooni AS. Dosimetry of interstitial brachytherapy sources: recommendations of the AAPM Radiation Therapy Committee Task Group No. 43. American Association of Physicists in Medicine. Med Phys. 1995;22(2):209–226.

Source: PubMed

Sponsorit ja yhteistyökumppanit

Sairaudet

Huumeiden interventiot

3
Tilaa