Evaluation of the Chemopreventative Effects of ALA PDT in Patients With Multiple Actinic Keratoses and a History of Skin Cancer
May 2012 | Volume 11 | Issue 5 | Original Article | 593 | Copyright © May 2012
Actinic keratoses (AKs) are in situ epidermal tumors that may progress to invasive squamous cell carcinomas (SCCs). Aminolevulinic acid with photodynamic therapy (ALA PDT) is a field treatment for AK.
To evaluate the time to development of new non-melanoma skin cancers (NMSC) within one year of ALA-PDT treatment in immunocompetent patients with AK and a history of skin cancer.
Methods and Materials:
One hundred forty anatomic sites in 114 patients were treated with topical ALA for a 1 to 3 hour incubation period followed by photodynamic therapy (PDT) with a blue light. All new NMSCs within the treatment areas were recorded over a 1-year observational period.
Eighty-three anatomic sites (59%) did not develop new skin cancers within 1 year. Additionally, 92%, 78%, and 64% of anatomic sites were free of new skin cancers at 3, 6, and 9 months after treatment was initiated. Although approximately 41% of patients treated on both the scalp and face developed new skin cancers within 1 year of treatment, the average time to develop skin cancer was longer for the face (7.09 months) than for the scalp (5.34 months).
In patients with a history of NMSC and multiple AKs, ALA PDT may be a valuable option for the prevention and delay of new NMSCs.
J Drugs Dermatol. 2012;11(5):593-597.
Discrete actinic keratoses (AKs) may be treated by
cryosurgery with liquid nitrogen, curettage with electrodessication, topical creams (imiquimod, 5-fluorouracil, diclofenac), or surgery; however, targeted therapeutic
modalities are not as effective for widespread and subclinical
lesions. In 1999, photodynamic therapy (PDT) with topical aminolevulinic acid (ALA) was approved by the FDA for treatment
of AKs on the face and scalp.1-3 ALA PDT indiscriminately treats
an entire area of skin, allowing for management not only of
discrete lesions, but also subclinical ones.3-15 Here we report the
presentation of new skin cancers in patients with a history of
NMSC and AKs 1 year after treatment with ALA PDT.
METHODS AND MATERIALS
Study Design and Patient Selection
This observational study with 1-year follow-up assessed the preventative effects of ALA PDT in patients with a history of skin cancer and the presence of AKs. Exclusion criteria included a history of
any adverse reaction to visible light exposure (such as photoexacerbated seizures), personal or family history of porphyrias,
and immunocompromised patients, such as those with organ
transplants. Once qualified for the study, patients were counseled
about ALA PDT risks and benefits and consent was obtained. All
patients were followed for 1 year after the initial treatment.
ALA PDT Treatment Technique and Follow-up Care
Live and photographic assessments were performed before
treatment sessions to document AK and NMSC lesions. Prior
to treatment, the skin was gently cleansed with soap and water,
followed by an acetone scrub. Ampules of 20% 5-aminolevulinic acid (ALA, Levulan Kerastick, DUSA, Wilmington, MA) were
prepared for application per manufacturer protocol (ampules
were crushed then shaken continuously for 3 minutes prior
to application). Topical ALA was applied liberally to the entire