Head Medial Lateral Whole Breast Radiation Therapy – Post BCS <ul><li>Whole-breast radiation therapy is delivered using opposed tangential fields to a dose of 4,500 to 5,000 cGy at 180 to 200 cGy per fraction, single fraction per day, </li></ul><ul><li>5# per week, totally around 25 days, +/- boost 10-16Gy to the lumpectomy site. </li></ul>Dose and target volume of initial studies
APBI <ul><li>Most of the studies that tried partial breast irradiation also had an element of accelerated dose delivery – the dose is delivered in a shorter interval than the standard 5 – 6 weeks. This is coined as Accelerated partial breast irradiation. </li></ul>
<ul><li>Which Patients May Be The Most Appropriate for APBI? </li></ul>
INTERSTITIAL IMPLANTATION <ul><li>Post BCS the catheters are implanted immediately or after 2 – 3 weeks in the lumpectomy site </li></ul><ul><li>Simulation is done with CT imaging and transferred to the TPS </li></ul><ul><li>Loading of source, position and dose distribution is decided in the TPS </li></ul><ul><li>Dose – 34 Gy in 10 # , 3.4 Gy per # / two # per day / 5 days. </li></ul>
multiple catheters are generally positioned at 1- to 1.5-cm intervals, with the total number of catheters and planes employed dependent on the size, extent, and shape of the target.
Mammosite catheter <ul><li>Allows for insertion of HDR source at the centre of an inflatable balloon that can be placed in the lumpectomy cavity at the time of surgery or after surgery when the definite margin status is known </li></ul><ul><li>The MammoSite RTS was cleared by the US Food and Drug Administration (US FDA) in May 2002 </li></ul>
Mammosite catheter… <ul><li>Looks like a Foley's catheter of 18.7 cm length </li></ul><ul><li>Balloon is filled with saline mixed with contrast to allow radiographic imaging to verify optimal positioning </li></ul>70 cm Sq 4 – 5 I 125 cm sq 5 – 6 II Max inflatable volume Diameter Version
The MammoSite device was inserted using the scar entry technique, and sutures were placed around the incision to prevent opening of the scar Stolier et al. 2005, with permission
What to expect with MammoSite Therapy after the lumpectomy PLACEMENT TREATMENT REMOVA L 3 <ul><li>Adequacy of placement requires symmetry of the balloon, conformance of the balloon surface to the lumpectomy cavity, and a minimum distance between the surface of the balloon and skin of >5 mm (ideally >7 mm). </li></ul><ul><li>Treatment is delivered via a high dose rate remote afterloading system to a circumferential 1 cm distance from the balloon surface. </li></ul><ul><li>Dose prescription of 3.4 Gy delivered at 1 cm twice daily to a total dose of 34 Gy over 5 days. </li></ul>1 2
<ul><li>MammoSite ® </li></ul><ul><li>5-day Targeted Radiation Therapy </li></ul><ul><li>Radiation therapy is delivered from inside the breast directly to the area where cancer is most likely to recur </li></ul><ul><li>Using a highly targeted dose, treatment is complete in 5 days </li></ul>
MammoSite radiation therapy system. External appearance and sagittal view of balloon with dosimetric target coverage. Target is defined as tissue within 1 cm of balloon surface.
IORT <ul><li>Mobile Linacs of energy 3 – 10 MeV or electrons </li></ul><ul><li>Cylindrical applicators with diameter 4 – 10 cm and angulations of 45 degrees for electron beam collimation </li></ul><ul><li>Lead shields between breast and pectoralis fascia </li></ul><ul><li>Breast must be separated from subcutaneous tissue of 2.5 cm around the tumor for proper cosmesis </li></ul><ul><li>The prescribed dose is given in single # of 5- to 20-Gy at a depth of 1 and 2 cm, respectively . </li></ul>
Possible Benefits to Intra-Operative Radiation Therapy for Breast Cancer Patients <ul><li>No delay between surgery and radiation therapy (currently, patients wait approximately one month after surgery before beginning radiation therapy). </li></ul><ul><li>Significant reduction in the amount of time a woman must undergo radiation therapy since the radiation boost is given during the lumpectomy compared to the standard 5 – 6 weeks therapy. </li></ul>
Benefits… <ul><li>Provides a higher dose of radiation directly to the tumor site. </li></ul><ul><li>Minimizes the possibility of missing the tumor area because the radiation boost is given during surgery when the tumor area is visible. </li></ul><ul><li>Minimizes radiation to normal breast tissue. </li></ul><ul><li>Treatment may be less costly. </li></ul>
The Intrabeam machine contains a miniature electron gun and electron accelerator contained in an x-ray tube “Soft” x-rays (50 kVp) are emitted from the point source.
Targeted intraoperative radiation therapy (TARGIT). A Various-sized sterile applicators for intraoperative delivery of radiation. B The applicator is in place and deep purse-string sutures have been placed to facilitate conformity of the applicator to the cavity wall. C Tungsten barrier in place just prior to treatment (photographs courtesy of Dr. Dennis R. Holmes, Kenneth Norris Comprehensive Cancer Center, Keck School of Medicine, University of Southern California)
<ul><li>The Milan group is also testing the same approach using (a mobile linear accelerator (Novac7) in a randomized trial (ELIOT). </li></ul><ul><li>It delivers electron beams at four different nominal energies: 3, 5, 7, 9 MeV radiation. </li></ul>Intra et al. 2002; Veronesi et al. 2001
<ul><li>Although external beam conformal radiation has been developed only recently, it is the one that is most widely employed in the ongoing randomized trial. </li></ul><ul><li>Recent data suggest that over 70% of patients in the randomized trial are opting for the three dimensional conformal (3D-CRT) & IMRT technique. </li></ul><ul><li>This APBI technique with conformal EBRT is attractive to both physician and patient alike because it is </li></ul><ul><li>(1) noninvasive, </li></ul><ul><li>(2) delivers a homogeneous dose with decreased procedural trauma to the breast, and </li></ul><ul><li>(3) offers a potential reduction in normal breast tissue toxicity </li></ul>3D-CRT & IMRT
J Clin Oncol 23:1726-1735. . 2005 by American Society of Clinical Oncology
J Clin Oncol 23:1726-1735. . 2005 by American Society of Clinical Oncology
Between 1998 and 2004 258 selected patients with T1 N0-1mi, Grade 1-2, nonlobular breast cancer without presence of extensive intraductal component And resected with negative margins were randomized after breast-conserving surgery 50 Gy/25 fractions WBI either 7 x 5.2 Gy high-dose-rate (HDR) multicatheter brachytherapy or 50 Gy/25 fractions electron beam (EB) irradiation.
RESULTS At a median follow-up of 66 months CONCLUSIONS : PBI using interstitial HDR implants or EB to deliver radiation to the tumor bed alone for a selected group of early-stage breast cancer patients produces results similar to those achieved with WBI. Significantly better cosmetic outcome can be achieved with carefully designed HDR multicatheter implants compared with the outcome after WBI. p(WBI/PBI) =0.009. 62.9% 77.6% cosmetic result no significant difference 90.3% 88.3% disease-free survival no significant difference 96.0% 98.3% cancer-specific survival no significant difference 91.8% 94.6% 5-year probability of overall survival p = 0.50 3.4% 4.7% 5-year actuarial rate of local recurrence WBI PBI
<ul><li>Clearly, the ongoing phase III NSABP B39/RTOG 0413 trial which allows treatment with any of these three methods on the APBI arm will allow controlled analysis between them, but more importantly will allow comparison with the current standard of care of whole-breast radiotherapy. </li></ul>
Take home…, <ul><li>potential paradigm shifts in breast cancer treatment </li></ul><ul><li>Rationale: 75% local recurrence - within 2 cm from tumor edge </li></ul><ul><li>APBI can be considered for selected T(<3cm), N0,M0, margin negative, Infiltrative Ductal Ca. pts </li></ul><ul><li>Shorter treatment time and normal breast spared </li></ul>
Take home…, <ul><li>Local recurence rates comparable with whole breast RT </li></ul><ul><li>Good cosmesis </li></ul><ul><li>APBI should not yet be considered a “standard of care” untill more long term data are available </li></ul>