Back to Top1. Introduction

Over the past two decades, breast conserving treatment, consisting of lumpectomy and external beam radiotherapy, has become a standard treatment option for patients with early stage cancer. It has been demonstrated to offer similar local control and survival results compared with mastectomy, while providing acceptable cosmetic outcome, and less emotional trauma. However, the primary disadvantages are 6 to 7 weeks of external beam treatment and potential side effects to the adjacent organs such as the underlying lungs and scatter radiation dose to the opposite breast.

Recurrence rates followinglumpectomy and whole breast external beam radiotherapy are approximately 10%. The majority of recurrences are in the vicinity of the lumpectomy site. The potential to reduce breast recurrence rates lies in maximizing the radiation dose to the breast tissue surrounding the lumpectomy site, which is the tissue most likely to harbor residual microscopic disease. Attempts to increase the radiation dose using external beam radiotherapy have resulted in increasing the side effects such as moderate to severe skin reactions (desquamations), and excessive doses to the underlying ribs and lung. The best method of increasing the dose to the lumpectomy site while minimizing the dose to the normal structures is HDR brachytherapy.

Back to TopTable of Content

1. Introduction
2. Advantage of HDR Brachytherapy
3. Surgery and HDR Procedure
4. Computer Dosimetry
5. Cosmetic Result

Back to Top2. The Advantages of HDR Brachytherapy

1. The overall treatment time is reduced to 5 to 7 days compared to a 6 to 7 week course of external beam radiotherapy.
2. Breast brachytherapy delivers a precisely targeted dose to the tissues most at risk for recurrence, increasing the likelihood of tumor control.
3. Reduces radiation dose to the lungs and opposite breast
4. Reduces radiation dose to the breast outside the brachytherapy treatment volume, avoiding potential long term adverse cosmetic side effects associated with whole breast external beam therapy, such as fibrosis and skin reactions.
5. Breast brachytherapy causes no delays in other treatments such as chemotherapy.
6. Conserve your breast and yield excellent cosmetic result .
   

Back to Top3. Surgery and HDR Procedure

The brachytherapy implant can be done at the time of lumpectomy or later, after the lumpectomy incision has healed. The patient is placed under general anesthesia. The brachytherapy physician places rows of thin hollow tubes, the treatment catheters, to encompass the tumor bed plus generous margins. These catheters will later hold the radioactive source. The catheters are left in place with the catheter ends protruding through the skin for the duration of the treatment course, which is about five days. On the first day of treatment, radiographic or CT images of the implant are obtained for treatment planning purposes. After the radiation dose plan is reviewed and approved by the physician, the treatments can begin.

Fig 1: Breast Implants

The protruding ends of the plastic catheters are connected via longer, transfer tubes to the treatment unit, called the afterloader, that contains the tiny radioactive source. The tiny (1mmx3mm) source is welded to the tip of a flexible stainless steel cable that travels in and out of the treatment catheters. The source steps through each of the catheters, stopping every 5mm to deliver the required radiation dose. After the treatment is delivered, the source retracts into the afterloader, the treatment catheters are disconnected from the transfer tubes, the nurses cover the implant with dressings and the patient goes home. The time the source spends in the catheters is about 10 minutes.

The breast is treated twice a day for five days, for a total of 10 treatments (also called "fractions"). After the last treatment, the physician removes the catheters. The catheters easily slip out of the breast with minimal bleeding. Antibiotic ointment is applied to the catheter insertion sites. The patient is instructed on skin care and given an appointment to return for a follow-up visit.

Back to Top4. Computer Dosimetry

Fig 2: 3D computer simulation showing radiation dose cloud.

The image on the left is the 3-D representation of the implant catheters (light blue), the 100% radiation dose "cloud" (blue) the underlying lung (yellow), and the skin (transparent yellow). The image on the right is a transverse CT cut showing the levels of radiation dose. Note how the dosimetrist has shaped the treatment volume to avoid the underlying ribs and lung and keep the skin dose at 50% of the prescription dose to avoid skin reactions.

Back to Top5. Cosmetic Result

Fig 3: 2 months after treatment.		Fig 4: 10 months after treatment.		Fig 5: 3 years after treatment, achieve excellent cosmetic result.