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Non-Melanoma Skin Cancer Treated with Electronic Brachytherapy: Results at Two Years. Ajay Bhatnagar MD, MBA Cancer Treatment Services Arizona Casa Grande, AZ University of Pittsburgh, School of Medicine Pittsburgh, PA. Disclosure. I have received research funding from
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Non-Melanoma Skin Cancer Treated with Electronic Brachytherapy: Results at Two Years Ajay Bhatnagar MD, MBA Cancer Treatment Services Arizona Casa Grande, AZ University of Pittsburgh, School of Medicine Pittsburgh, PA
Disclosure I have received research funding from Xoft — a subsidiary of iCAD, Inc., Sunnyvale, CA, as the Principal Investigator for this study.
Background • Non-melanoma skin cancer (NMSC) is the most common malignancy in the US • Affects 2 to 3 million people each year1 • High dose rate (HDR) brachytherapy using surface applicators has shown efficacy in the treatment of NMSC • An electronic brachytherapy (EBT) system permits treatment of NMSC without the use of a radioactive isotope • Xoft Axxent® eBx® system • A miniature, electronic, HDR, low energy X-ray tube produces X-rays of 50 keV maximum energy 1Rogers HW, Martin A. Incidence estimate of nonmelanoma skin cancer in the United States, 2006. Arch Dermatol2010;146:283-287.
Ir-192 HDR Surface Applicator vs. Xoft eBx Surface Applicator
Dose Profile of Xoft 35mm Surface Applicator vs. Ir-192 Liepzig Applicator • For 10 sources over the 80% field width (per AAPM TG25) • Flatness (Mean and S.D.): 3.2 % +/- 1.2% • Symmetry (Mean and S.D.): 4.2 % +/- 2.1% • Superior Dose Profile with Xoft Applicator • Potential to decrease margins compared to Ir-192
Study Purpose • The objective of this IRB approved study was to assess adverse effects, cosmesis, and recurrence rates up to two years following HDR electronic brachytherapy for the treatment of non-melanoma skin cancer.
Methods • July 2009 – February 2012, 122 patients with 171 NMSC tumors were treated with eBx using surface applicators • All received same dose fractionation • 5.0 Gy x 8 fractions = 40.0 Gy, 2 fractions per week • Prescription depth • Empirically 3 mm for most lesions • Determined by CT only for thick lesions • Surface applicator size (10, 20, 35, and 50 mm) was selected to allow for complete coverage of target lesion with acceptable margin • Patient care included • Petrolatum ointment during treatment • Aloe vera gel through 1 month post-treatment • Adverse Events Assessment: NCI CTCAEv4 criteria • Cosmesis Assessment: RTOG scale
Treatment setup for patient with facial lesion showing a) thermoplastic mask cut out around lesion; b) surface applicator in contact with skin; c) shielding and applicator setup; and d) electronic brachytherapy controller to the right of the patient. a b c d
Results • Mean Follow up 11 months (range 1-38 months) • No Recurrences to Date
Number of Lesions Treated by Applicator Size and Dose Depth * Includes prescription dose depths of 4.0 mm to 4.1 mm § Includesprescription dose depths of 4.75 mm to 5.6 mm
Adverse Events: Late • All Hypopigmentation was Grade 1 (mild) • No Grade 3 or higher Adverse Events
Cosmesis 100 –– 80 –– 60 –– 40 –– 20 –– 0 – 95% 93% 92% 89% Percent of Lesions with Good or Excellent Cosmesis 75% N=122 N=81 N=52 N=55 N=29 1 3 6 12 24 Post-Treatment Visit Month • No Patients with Fair or Poor Cosmesis
Squamous cell carcinoma on right cheek Treated with 40 Gy to a 5 mm depth Fraction 7 Pre-treatment 1 Mo 3 Mo 2 Yr 6 Mo
Basal cell carcinoma on chin Treated with 40 Gy to a 3 mm depth Pre-treatment 2 Yr
Basal cell carcinoma on right nostril and nasal bridge Treated with 40 Gy to a 5 mm depth Pre-treatment 2 Yr
Squamous cell carcinoma on left armTreated with 40 Gy to a 5 mm depth Pre-treatment 2 Yr
Basal cell carcinoma on left tip of noseTreated with 40 Gy to a 3 mm depth Pre-treatment 23 Mo
Basal cell carcinoma on right tip of noseTreated with 40 Gy to a 5 mm depth Pre-treatment 22 Mo
Squamous cell carcinoma below left eyeTreated with 40 Gy to a 3 mm depth Pre-treatment 20 Mo
Squamous cell carcinoma on left cheek Treated with 40 Gy to a 5 mm depth Pre-treatment 1 Yr
Squamous cell carcinoma on right antihelixTreated with 40 Gy to a 3 mm depth Pre-treatment 1 Yr
Basal cell carcinoma on right upper eyelidTreated with 40 Gy to a 3 mm depth Pre-treatment 6 Mo
Squamous cell carcinoma on left postauricular scalpTreated with 40 Gy to a 5 mm depth Pre-treatment 3 Mo
Conclusions • As of date, treatment of non-melanoma skin cancer with HDR electronic brachytherapy using surface applicators was effective and convenient comparable to Ir-192 HDR brachytherapy • Cosmesis was good to excellent up to 2 years post-treatment • Toxicities were acceptable • No recurrences to date, but longer follow up is being collected • Brachytherapy (electronic or traditional) is an ideal modality for patients (especially elderly patients) with NMSC given the excellent results and convenient schedule • We (Radiation Oncology) need to take a more prominent role in the treatment of NMSC