Actinic Keratoses (or AKs for short) are rough scaly spots which appear on the sun-damaged skin. Especially common in fair-skinned persons, they result from repeated sun exposure. Photo-damaged skin is dry and wrinkled and may form persistently scaly spots, actinic (solar) keratoses, even though the crust or scale is picked off.
The standard treatment of a AKs calls for removal of the defective skin cells. New skin then forms from deeper cells which have escaped sun damage. However, there is no evidence that treatment of most AKs is of any value. Removal of all AKs is quick and easy and very lucrative for a practicing physician.
While textbooks of dermatology state that around 10% of AKs progress to skin cancer (squamous cell carcinoma, SCC) if left untreated, this number was derived from no study and crept into the literature without any factual basis. The only study on the malignant transformation of AKs was performed in Australia by Professor Robin Marks, a research dermatologist.
This is an abstract of Robin Marks’ study:
Br J Dermatol 1986 Dec;115(6):649-655
Spontaneous remission of solar keratoses: the case for conservative
Marks R, Foley P, Goodman G, Hage BH, Selwood TS
One thousand and forty people aged 40 years and over, 616 (59.2%) of
whom had solar keratoses, were followed for 12 months. Two hundred and
twenty-four people (36.4%) had a spontaneous remission of at least one
of their solar keratoses. A total of 485 lesions (25.9%) underwent
spontaneous remission out of the 1873 lesions that were present at the
first examination of these 224 people. There was no significant
difference between the number of lesions present at the initial
examination in those who had a spontaneous remission compared with those
who did not. There was a 21.8% increase in the total number of solar
keratoses in the 1040 people studied in the 12-month period, due to new
lesions forming at the same time as remissions were occurring. The
incidence rate of squamous cell carcinoma occurring in the people with
solar keratoses was 0.24% for each solar keratosis present at the
original examination. With a substantial proportion of solar keratoses
remitting spontaneously, plus the low rate of malignant transformation
and the low potential for metastasis to occur from squamous cell
carcinoma arising in a solar keratosis, the rationale of treating all
solar keratoses appears questionable.
DJE Comment: Robin Marks could not get his study published in the United States or Australia. The reason was that dermatologists derive a significant proportion of their income from these usually banal lesions. The image of the dermatologist running from room to room with a spray bottle of liquid nitrogen is all too familiar to elderly patients.
There are lesions which look like AKs which need treatment. These are the hypertrophic AKs which can be indistinguishable from early squamous cell carcinomas. An experienced dermatologist will be able to tell the banal from the worrisome in most cases. However, it will be a long time before the average practitioner will give up income for the pursuit of truth – so it is caveat emptor.
My mother recently saw a dermatologist in her area. She’s a light complected Caucasian in her early 80s – thus fair game for the cryospray gun. Her dermatologist received around $200 from Medicare and AARP for less than 5 minutes work. You be the judge.
For the orthodox story on AKs go to http://www.dermnet.org.nz/