CyberKnife® Experience: Locally Advanced Melanoma
WHAT IS THE CYBERKNIFE SYSTEM:
WHY WE CHOSE TO TREAT WITH CYBERKNIFE SYSTEM:
Epic Care is a multi-specialty practice with five community cancer centers each with its own linac. We have 17 Medical Oncologists and 5 Radiation Oncologists. We needed our ablative platform to have the following features:
- Able to treat the entire body
- Minimize clinical overlap and cannibalization of our existing linacs
- Have marketing cachet and bring in self-referred patients
- Technology with regional market distinction
- Was not just a linac with added SRS capability
CLINICAL HISTORY:
Patient was originally diagnosed with early-stage uterine cancer treated with surgery alone. Low-risk features did not necessitate postoperative chemotherapy or radiation therapy. She was subsequently followed closely by Gyn. Oncology team. One year later she re-presented with an apparent vaginal recurrence. A biopsy was performed and pathology confirmed the presence of a melanoma. She underwent resection followed by post-operative brachytherapy and external radiation therapy.
Patient subsequently underwent multiple surgeries and multiple immunotherapy treatments which failed to control her cancer. She developed an ulcerating lesion on the inside of her thigh. The PET scan showed that the lesion extended more deeply than expected. Typically, electrons can be used to treat skin lesions but given the required depth and irregularity of the target, electrons were deemed clinically unsuitable.
Despite surgery and immunotherapy, she had persistently growing disease resulting in lower extremity edema and ulceration through the skin. The patient remained ambulatory and was referred for consideration of CyberKnife treatment.
WHO/WHERE
ABOUT EPIC CARE
TECHNOLOGY SOLUTIONS
CHALLENGE
Figure 1: Staging PET/CT
Figure 2a: Treatment plan isodoses
Figure 2b: Beam geometry for CyberKnife® System
TREATMENT DELIVERY:
- The patient was positioned supine, feet first with her lower extremeties immobilized using a vacuum bag, with the right leg slightly abducted
- Bolus was applied during treatment
- To track the tumor in real-time, a single fiducial marker was implanted in the dominant mass
- Treatment prescription: 60 Gy in 5 fractions (equivalent to eleven weeks of conventionally fractionated radiotherapy)
- 99 robotically delivered non-coplanar beams delivered using the CyberKnife System
POST-TREATMENT:
There was a month-long delay in response to treatment. There was some tanning and hyperpigmentation in the area; there was no discernible skin breakdown observed. Clinically, the ulcerating tumor disappeared within one month. A robust skin reaction was observed which was limited to a 1 cm zone around the tumor. Two months later, PET/CT showed a complete metabolic and anatomic response (Figure 3b).
Figure 3a:
Photograph of lesion
one-month post-treatment
Figure 3b:
Pre-treatment staging
PET/CT scan
Figure 3c:
Response PET/CT scan 2 months after completion of treatment
Important Safety Information:
Most side effects of radiotherapy, including radiotherapy delivered with Accuray systems, are mild and temporary, often involving fatigue, nausea, and skin irritation. Side effects can be severe, however, leading to pain, alterations in normal body functions (for example, urinary or salivary function), deterioration of quality of life, permanent injury, and even death. Side effects can occur during or shortly after radiation treatment or in the months and years following radiation. The nature and severity of side effects depend on many factors, including the size and location of the treated tumor, the treatment technique (for example, the radiation dose), and the patient’s general medical condition, to name a few. For more details about the side effects of your radiation therapy, and to see if treatment with an Accuray product is right for you, ask your doctor. Accuray Incorporated as a medical device manufacturer cannot and does not recommend specific treatment approaches. Individual results may vary.
