Stereotactic radiation has been implemented more than 3 decades ago, initially to radiate benign and later malignant tumors within the brain. Doses up to 24 Gy in one session have been used. Hundreds of thousands of patients have been treated worldwide with very good outcomes . Over the last decade, the stereotactic radiation techniques have been implemented to treat extra-cranial tumors. The challenges of extra cranial tumors were in part target motion during the radiation session, but also accurate re positioning of the patient and of the target volume at time of radiation treatment. Specific immobilization devices are now available to improve accuracy of target localization. Stereotactic radiation therapy is widely available, non-invasive for the patient and less operator dependent as the planning process (from target volume to dose calculation) can be done and verified by different operators through a quality assessment procedure. Stereotactic radiation is a complex type of 3D CRT that is a very attractive technique making the 3D CRT more conformal and more accurate delivery of the prescription dose within the target volume with a very good sparing of surrounding normal tissue. The principles of stereotactic radiation are the following: precise image definition of target volume and OARs, very conformal radiation treatment.
The GammaPod is a new external beam radiotherapy device dedicated for stereotactic radiotherapy of breast cancer (Xcision Medical Systems, LLC, Columbia, Maryland). The design goal of the GammaPod has been the ability to deliver ablative doses with sharp gradients under stereotactic image guidance. Highly focused radiation is achieved at the isocenter due to the cross-firing from 36 radiation arcs generated by rotating 36 individual Cobalt-60 beams.In order to immobilize the breast during imaging and treatment and in order to get a stereotactic localization of the breast target volume, a vacuum-assisted breast immobilization cup with built-in stereotactic frame is used. The patient can be imaged on a CT or MRI wearing the vacuum-assisted breast cup and then be transferred to the GammaPod for treatment. Then, the planner is required to delineate the gross tumor volume (GTV) and its subclinical extensions. Multiple targets within a breast are allowed.Different doses can be prescribed to different targets.One benefit of using the GammaPod over the cyberknife for breast SBRT, is elimination of the need for internal gold fiducial markers, which are required for the cyberknife treatment. Using a stereotactic technique for APBI allows smaller margins in comparison to a 3DCRT technique. The total expansions on the RAPID trial (3DCRT APBI) were 1.0 cm CTV expansion on the lumpectomy cavity and an additional 1.0 cm for PTV, for a total expansion of 2.0 cm. As a 3DCRT technique was used on the RAPID trial limited number of radiation beams were employed, no Intensity Modulated Radiation Techniques allowed, and the margins used to create a PTV were relatively large (total margin 2 cm). As the GammaPod will allow us to minimize the volume of normal breast being irradiated, and decrease the PTV volume we hypothesize that a stereotactic technique with the GammaPod will allow us to improve on the 3 year global cosmesis rates (physician and patient) reported in the RAPID trial (3DCRT) by 40% despite 5 daily fractions of SBRT (in contrast to 38.5Gy/10 fractions 3DCRT BID on the RAPID trial) The GammaPod was FDA approved 12-2017.
Study Type
INTERVENTIONAL
Allocation
NA
Purpose
TREATMENT
Masking
NONE
Enrollment
74
Patients will receive 5 fractions of radiation. These should not be on consecutive days. At least 40 hours between each fraction and a maximum of 21 days to complete, i.e.: Tuesday, Thursday, Monday, Wednesday, Friday.
University of Maryland Medical Center
Baltimore, Maryland, United States
UT Southwestern Medical Centre
Dallas, Texas, United States
Patient Cosmesis
To determine the 3 year patient overall global cosmesis score (on scale excellent, good, fair, or poor) and adverse cosmesis using SPBI with the GammPod using a 5 fraction escalated dose regimen (a more hypofractionated regimen compared to conventional APBI regimens). Cosmesis will be determined using patient cosmesis.
Time frame: 3 Years
Ipsilateral Breast Recurrence Rate
The definition of treatment failure is histologic evidence of recurrent carcinoma, either invasive or non-invasive (except LCIS) in the ipsilateral breast or chest wall. Clinical evidence of carcinoma by physical examination and/or mammograms will not be construed as evidence of treatment failure without biopsy proof but will be considered as suspicious for recurrence. Ipsilateral breast recurrences will be considered local (infield) if they occur within the prescription isodose volume; they will be considered peripheral if they occur between the prescription isodose volume and a volume 2 cm outside of the prescription isodose volume. Ipsilateral recurrences will be considered non-contiguous or extra field if they are beyond the peripheral volume described above. Exact binomial method will be also used to estimate ipsilateral breast recurrence rate and late toxicity rate along with the corresponding 95% confidence interval.
Time frame: 3 Years
Disease Specific Survival
Kaplan-Meier method will be used to estimate disease-specific survival. Specific survival will be measured from the date of study entry to the date of death due to breast cancer. The following will be considered as failure events in assessing disease specific survival: Death certified as due to breast cancer. Death from other causes with active malignancy. Death due to complications of treatment, irrespective of the status of malignancy. Death from other causes with previously documented relapse as defined above but inactive at the time of death will not be considered in disease-specific survival, but will be analyzed separately.
Time frame: 3 Years
Distant Disease-Free Interval
Defined as the time from registration to first diagnosis of distant disease. The distant disease-free interval will be measured from the date of registration until the date of first diagnosis of distant disease.
Time frame: 3 Years
Recurrence Free Survival
Kaplan-Meier method will be used to estimate recurrence-free survival. Time from registration to first diagnosis a local, regional, or distant recurrence.
Time frame: 3 Years
Treatment Related Toxicity
To determine treatment related toxicity (Toxicity will be assessed via NCI's Common Toxicity Criteria for Adverse Events (CTCAE) toxicity criteria as well as RTOG-EORTC (Radiation Therapy Oncology Group - European Organization for the Research and Treatment) Late Radiation Toxicity scales.)
Time frame: 18 Months
Evaluation of Cosmesis from Serial Photography
Photographs of both breasts will be taken twelve months from the start of therapy and at yearly intervals thereafter up to 3 years after treatment. Digital Photographs will be evaluated using the BCCT.core proprietary software developed by INESC Porto Breast Research Group (50-51) and an independent panel.
Time frame: 3 Years
Evaluation of Patient Cosmesis
To determine three year adverse Cosmesis results by an independent expert panel review. Cosmesis will be graded by the patient using the EORTC (European Organization for the Research and Treatment) scale, at baseline, and twelve months from the start of therapy and at yearly intervals thereafter up to 3 years after treatment. Cosmesis forms using the EORTC scale will be completed by the patient.
Time frame: 3 Years
Physician Cosmesis
Cosmesis will be graded by the radiation oncologist using the EORTC (European Organization for the Research and Treatment) scale, at baseline, and twelve months from the start of therapy and at yearly intervals thereafter up to 3 years after treatment. Cosmesis forms using the EORTC scale will be completed by physician.
Time frame: 3 Years
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