Introduction to laser treatment
of basal cell carcinomas
Basal cell carcinoma (BCC) is a non-melanoma
skin cancer (NMSC). One of the latest non-invasive
methods of NMSC treatment is by laser ablation
and photodynamic therapy (PDT). The two are a much
sought after non-surgical option for NMSCs like
basal cell carcinoma (BCC), squamous cell carcinoma
(SCC) and actinic keratoses (AKs). Among the variety
of lasers that have been developed for the treatment
of diseases afflicting various body organs, non-coherent
light sources and laser-assisted PDT has been the
most common treatment forms for NMSCs.
Photodynamic therapy (PDT)
PDT is a most updated treatment regimen for NMSCs
(including BCC) that initially involved the use
of photosensitizing drugs and light. Later penetration
enhancers were also added to the treatment regimen
for the destruction of cancer cells.
PDT was first researched as a way to destroy malignant
tissues in the beginning of the 20th century. It
began as a combination of systemic photosensitizing
medication, light and oxygen and was implemented
for the treatment of tumors in various body organs.
When compared to surgical methods, PDT had the
advantage of clearing tumors with satisfactory
cosmetic outcomes and no marked scars, substantial
patient comfort and short restorative period. However,
it had the disadvantage of long-term phototoxicity
due to the use of systemic photosensitizers.
In 1990, when 5-aminolevulinic acid (ALA) and
methylester of ALA (mALA), both potent topical
photo-sensitizers, were developed and introduced
to the PDT therapy for skin cancers, the disadvantage
of phototoxicity was considerably reduced. Topical
5-ALA-PDT proved really beneficial in the treatment
of NMSC without the side effects of phototoxicity.
However, there have been no systematic published
studies comparing ALA-PDT with standard surgery,
electrodesiccation and curettage, irradiation,
or topical cytotoxic agents.
The light component in PDT has originally been
large and intricate lasers. Currently a variety
of coherent and non-coherent light sources are
Most common ones are:
- Dye lasers
assisted by argon or metal vapor lasers
- The most recent femtosecond
Non-laser lights like tungsten filament, xenon
arc, metal halide, and fluorescent lamps are also
used. The latest additions have been light-emitting
Disadvantages of these light sources pertain
to the degree of penetration, spot size and
definite parameters so far as the most effective
syndrome-based irradiance, wavelength of the
light and dosage suitable for various light
concerned. Side effects in case of BCC are generally
pain, though anesthesia is not required.
A certain study group also pointed out the disadvantage
of using coherent and incoherent light sources
for the therapy of large or multiple BCCs. The
most common drawbacks were tedious treatment period
and soaring overhead expenses. PDT for BCC has
also been considered best suited for tumor cells.
Studies regarding CO2 laser therapy for the treatment
of BCC are small and there are no available published
reports based on large-scale research. The small
studies have suggested partial effectiveness of
this treatment mode and most have reported no major
side effects. In fact, the success rate is pegged
at 100% clearance of superficial BCCs when ablation
is achieved till the middermis. Most have also
reported that CO2 laser therapy was comparatively
speedier and cheaper than standard surgical procedures.
Effectiveness of laser assisted treatment of basal
However, there are still no conclusive results
available so far as the specific function of laser
and light-emitting sources either used alone or
in combination with photodynamic therapy (PDT),
for the treatment of nonmelanoma skin cancers (NMSCs).
Various studies have been conducted over decades
with varying results.
Moreover, the exact degree of clearance achieved
and recurrence of superficial and nodular BCC and
SCC after laser and PDT therapy are also unknown.
Some studies have suggested that PDT may have the
potential of a clearance quotient similar to BCC
treatment with radiation. But one thing is for
certain, that despite technological advancements,
PDT treatment of BCC is still less effective than
surgical removal and Mohs surgery so far as reappearance
rates are concerned. Statistics report that in
the latter it is less than 10%. Hence, it is advised
that laser and PDT should be applicable only for
patients whose condition cannot be managed with
standard surgical therapy procedures for BCC and
5-aminolevulinic acid–PDT is somewhat better
rated when used in combination with penetration
enhancers and given in multiple treatment sessions
for BCC treatment. Research is on to develop more
effective light sources and photosensitizers for
treatment of BCC and other NMSCs.
Though, laser and PDT therapy have brought new
hope in the treatment of NMSCs like BCC, especially
for patients with multiple or large NMSCs or for
whom surgery is difficult, there needs to be more
definite research about their effectiveness and