Skin Cancer Disease, Diagnosis
and Treatment
It is estimated that over 2.8 million new skin cancer
cases are diagnosed annually worldwide and will continue
to increase at a rate of 4% each year. Over 95% of these
skin cancers are basal or squamous cell carcinomas. Other
skin cancer categories include mycosis fungoides, Kaposi's
sarcoma, Paget's disease and aprocrine carcinoma. The
annual death rate from skin cancer in the United States
is approximately 10,000. The primary treatment options
providing both high cure rate and low recurrence include
surgery and non-invasive superficial x-ray therapy. Annual
worldwide medical expenditures for treating skin cancer
exceed $2.5B.
The incidence of skin cancer has steadily increased over
the past 75 years. During the 1930's, 1 in 1500 developed
skin cancer. In 1960, the rate had risen to 1 in 600 and
in 2000, the rate increased to 1 in 66. The National Cancer
Institute estimates that 1 out of 7 are now at risk for
developing some form of skin cancer during their lifetime.
Increased exposure to the sun without skin protection
and a decreasing natural ozone layer are cited as the
chief causes of this increase.
Skin cancer, like all cancers, takes a long time to develop
from a single mutated cell to a visible change seen on
the skin. Older adults are more susceptible. 50% of skin
cancer cases occur in adults aged over 60, with males
more at risk than females by a factor of two. The US Census
Bureau projects that by the year 2025 the over 60-age
group will double in size from the year 2000. This is
further evidenced by the rising number of nursing convalescent
homes for the aged, which has steadily increased to over
17,000 in the United States.
Clinical Use of Superficial Radiotherapy
(SRT)
The traditional methods for treating skin cancer with
proven high cure rates above 90% - 95% and low recurrence
of less than 10% involve surgical procedures and non-invasive
Superficial Radiotherapy (SRT). Although other treatment
methods are emerging, many are still in development stages
requiring further clinical studies for cure rate/recurrence
outcomes and evaluation of after-effects such as edema,
permanent pigment loss, atrophy, hypertrophic scarring,
motor and sensory neuropathy. SRT has been a proven skin
cancer treatment method treating basal and squamous cell
carcinomas since the 1950's providing a high cure rate
and low recurrence. Medicare part B and most insurance
carriers readily accept SRT treatment for reimbursement.
SRT becomes a logical choice for primary lesions that
otherwise require difficult or extensive surgery with
sensitive structures in the head and neck regions - the
fold in the nose, eyelids, lips, corner of mouth, and
the lining of the ear that would otherwise lead to a poor
cosmetic outcome. SRT treatment procedures do not require
the use of anesthetics and eliminates the need for skin
grafting when surgery would result in an extensive defect.
Cosmetic results are rated excellent in comparison to
other treatments with a small amount of hypopigmentation
or telangiectasia at the treatment site.
Superficial X-ray Therapy is most advantageous for the
treatment of non-melanoma skin cancers in the head and
neck region and/or combined with the following patient
situations:
- Patients who refuse surgery due to fear of surgery
or needle phobia.
- Patients who may not be medically fit for surgery,
who may have contraindications for reconstructive surgery
such as patients receiving anti-coagulants and patients
unfit for general anesthesia.
- Patients in who x-ray therapy may give a better cosmetic
outcome, especially in the linings of the ear, the folds
in nose, the lip and corners of the mouth.
- Patients in who x-ray therapy may provide a simpler
option than extensive reconstructive surgery involving
skin grafting.
- Patients in who surgery may cause nerve damage or
functional impairment such as tumors overlying the spinal
accessory nerve or marginal mandibular nerve.
- Patients with deep or lateral marginal involvement
following excision of tumors where surgery is not feasible
or not likely to be tolerated or refused.
- Patients who have a high risk of residual microscopic
size disease such as a patient with a completely excised
tumor with perineural invasion and no clinical signs
or following surgery of poorly differentiated squamous
cell carcinomas.
- Patients with small volume or marginal recurrent disease
following surgery which may require x-ray treatment
of the full length of the scar and a safe margin clearance.
Source: Radiation Treatment & Radiation Reactions
in Dermatology, Johnson and Webster, 2004