ABCs Practice Guidelines for Accelerated Partial Breast Irradiation (APBI)
General Selection Criteria: APBI is an acceptable treatment option for women with unicentric breast cancers that are less than 3 cm in maximum extent, negative axillary lymph nodes or metastatic involvement of up to 3 nodes without extracapsular extension, with clear surgical margins by 1 mm or greater. We do accept synchronous bilateral breast cancers with bilateral APBI if each breast cancer meets the above criteria. Women with breast augmentation are also eligible for APBI if their cancers meet the above requirements. Recurrences or new primary breast cancers after prior radiotherapy may also be re-treated with APBI.
Certain patient subsets should be treated on clinical trial, if the patient is willing:
- Metastases to 1 - 3 axillary nodes;
- Young women under the age of 50 years;
- Estrogen receptor negative;
- Patients undergoing neoadjuvant chemotherapy whose post-chemo pathology stage and features fit the general criteria noted above.
If patients are eligible for clinical trial and refuse participation or decline randomization, they may receive APBI only by initialing on the consent form that they are choosing a treatment outside current guidelines.
Documenting unicentricity: In older women with fatty-replaced breast tissue, mammography and ultrasound may suffice to document that there is only one lesion in the breast. In younger women or patients with dense breasts or where mammography/ultrasound is not definitive, breast MRI can be helpful in ruling out multicentric breast cancer.
APBI techniques available at ABCs:
- MammoSite or MammoSite-ml;
- SAVI mini-6, SAVI 6-1, SAVI 8-1, SAVI 10-1;
- Contura balloon;
- CT-guided interstitial brachytherapy with the Kuske Template;
- Ultrasound-guided interstitial brachytherapy.
- External Beam 3-d Conformal APBI (only for patients resolutely afraid of any device/catheter in her breast)
Choosing the optimal technique:
- Communicate with the surgeon as they may have preferences, and ask if they prefer inserting or do they prefer us providing the service;
- Perform breast ultrasound and/or CT at ABCs to evaluate the size and shape of the cavity;
- Tumor and patient characteristics may influence your decision, such as grade, size, margins, ER status, nodal involvement, or young age, since the PTV margin of expansion varies with different methods;
- If the skin separation to the anterior wall of the cavity is < 3 mm without any single entry device in place, then SAVI or interstitial brachytherapy would be the best choice;
If the cavity and seroma are no longer present (for example, the surgeon has sutured the cavity shut, or performed oncoplastic breast surgery, or so much time has elapsed that the seroma has been absorbed or become solid), then interstitial brachytherapy would provide the best option for APBI.
Most breast cancer patients with breast augmentation will require pinch-view interstitial brachytherapy with the template, with the exception being those women with surprisingly ample breast tissue or tumors in the axillary tail of breast above the implant.
Common dose schedules: 340 x 10 fractions over 5 treatment days is our gold standard. When holidays or patient's vacation/work schedules come into play, other fraction schemes can be prescribed: 400 cGy x 8 over 4 days or 370 cGy x 9 over 4.5 days. For patients with prior RT exposure, we have used 300 cGy x 12 over 6 days.
Logistics: All planned brachytherapy procedures should be cleared through the Brachytherapy Scheduler at each office. The scheduler will coordinate the schedules of the surgeon, radiation oncologist, the medical physicist, the therapists running the HDR unit, and nursing.
Antibiotics: We do not routinely prescribe prophylactic antibiotics, but we have a low threshold for initiating them (usually Keflex or Cipro or Levaquin or Clindamycin or a Z-pack) if symptoms such as fever, chills, tender swelling, red-streaks, or pus arise. Excellent daily nursing care and patient/husband catheter care over weekends usually eliminates the need for antibiotics.
Follow-up: At one-week out from the end of brachytherapy, you will be scheduled for an appointment with your physician to check for a delayed infection or response to antibiotics during therapy. Then at one month out, you will come back so your physician can evaluate your healing after treatment. At 6 months after brachytherapy, you will have a mammogram and visit your physician with the mammogram films in hand for our review. Then, we will see you every 6 months for the first 5 years and yearly thereafter.
Photography: Digital frontal pictures of both breasts for symmetry and an oblique close-up of the treated breast at each and every follow-up visit are taken.