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
•
•
•
•
1
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
Rogers HW, Martin A. Incidence estimate of nonmelanoma skin cancer in
the United States, 2006. Arch Dermatol 2010;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
PATIENT CHARACTERISTICS
N Subjects
N Lesions
122 Subjects
171 Lesions
Mean Age (Range)
73 Years (49-97)
Gender
63% Male 37% Female
Ethnicity
97% Caucasian non-Hispanic
• Mean Follow up 11 months (range 1-38 months)
• No Recurrences to Date
Tumor Characteristics
TYPE (N=171 LESIONS)
n
%
Basal Cell Carcinoma (BCC)
91
53%
Squamous Cell Carcinoma (SCC)
70
41%
Merkle Cell Carcinoma (MCC)
2
1%
Cutaneous T-cell Lymphoma (CTCL)
3
2%
Basal-Squamous Cell Carcinoma
1
1%
n
%
Tis
10
6%
T1
138
81%
T2
4
2%
Recurrence
15
9%
Not available
4
2%
STAGE (N=171 LESIONS)
Tumor Characteristics
LESION LOCATION (N=171 LESIONS)
n
%
Nose
49
29%
Face (forehead, temple, eyelid,
glabella, sideburn, cheek, lip, chin)
50
29%
Ear
22
13%
Extremity
24
14%
Scalp
14
8%
Torso
12
7%
Tumor Characteristics
TUMOR SIZE (N=171 LESIONS)
n
%
≤ 1CM
101
59%
> 1 CM TO ≤ 2CM
61
36%
> 2 CM TO ≤ 3CM
6
3%
>3 CM TO ≤ 4CM
2
1%
>4 CM TO ≤ 5 CM
1
1%
Number of Lesions Treated by
Applicator Size and Dose Depth
Applicator
Size
1 mm
Prescription Dose Depth
5
*
3 mm 4 mm
7 mm TOTAL
mm§
10 mm
2
64
1
9
0
76
20 mm
0
39
2
20
1
62
35 mm
0
5
2
22
0
29
50 mm
0
1
1
1
1
4
52
2
171
2 depths of109
TOTAL
Includes prescription dose
4.0 mm to 4.1 6
mm
*
§
Includes prescription dose depths of 4.75 mm to 5.6 mm
Treatment Time and Dose Depth by
Histopathology
Histopathology
(N=171 Lesions)
n
Treatment
Time: mean
(range)
Basal Cell Carcinoma
91
5.6 (4-8.2) min
Squamous Cell Carcinoma
70
5.8 (3.9-12.5) min
Merkle Cell Carcinoma
2
5.8 (4.6-6.9) min
Cutaneous T-cell Lymphoma
3
8.4 (5.7-13.8) min
Basal-Squamous Cell Carcinoma
1
5.2 (5.2-5.2) min
Not available
4
7.3 (4.5-11.2) min
Adverse Events: Late
6 MONTHS (N=52 LESIONS)
n
%
Hypopigmentation
4
8%
Alopecia
2
4%
Hyperpigmentation
1
2%
Atrophy
1
2%
n
%
Hypopigmentation
5
9%
Alopecia
2
3%
n
%
4
13%
1
3%
1 YEAR (N=58 LESIONS)
2 YEARS (N=30 LESIONS)
Hypopigmentation
Alopecia
• All Hypopigmentation was Grade 1 (mild)
• No Grade 3 or higher Adverse Events
Cosmesis
100 ––
Percent of
Lesions with
Good or
Excellent
Cosmesis
89%
92%
95%
93%
N=122 N=81
N=52
N=55
N=29
80 ––
75%
60 ––
40 ––
20 ––
0–
1
3
6
12
24
Post-Treatment Visit Month
• No Patients with Fair or Poor Cosmesis
CASE EXAMPLES
Squamous cell carcinoma on right cheek
Treated with 40 Gy to a 5 mm depth
Pre-treatment
Fraction 7
1 Mo
3 Mo
6 Mo
2 Yr
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 arm
Treated with 40 Gy to a 5 mm depth
Pre-treatment
2 Yr
Basal cell carcinoma on left tip of nose
Treated with 40 Gy to a 3 mm depth
Pre-treatment
23 Mo
Basal cell carcinoma on right tip of nose
Treated with 40 Gy to a 5 mm depth
Pre-treatment
22 Mo
Squamous cell carcinoma below left eye
Treated 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 antihelix
Treated with 40 Gy to a 3 mm depth
Pre-treatment
1 Yr
Basal cell carcinoma on right upper eyelid
Treated with 40 Gy to a 3 mm depth
Pre-treatment
6 Mo
Squamous cell carcinoma on left postauricular scalp
Treated 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