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Introduction
CHAPTER 37 Superficial Radiation
Therapy and Electronic Brachytherapy
Mark S. Nestor Jonathan Chan
SUMMARY
Superficial radiation therapy (SRT) relies on low-energy photon radiation.
SRT is a viable nonsurgical option for the treatment of select nonaggressive
primary BCCs and SCCs in patients where surgical intervention is refused or inadvisable.
An understanding of basic radiobiology is a prerequisite for utilizing any form of
radiation therapy.
Beginner Tips
The timeโdoseโfractionation (TDF) table provides a choice of protocols for a course
of SRT based on the total dose of radiation, number of fractions, and duration of treatment.
Hyperfractionated dosing regimens may yield an improved outcome.
Ideally, radiation treatment for keloids should be administered within 2 days of
surgical excision.
Expert Tips
Various fractionation protocols may be used to accommodate the needs of each patient
based on the size and location of the tumor, vascularity of the tissue, and the sensitivity of the tumor to radiation.
Protocol modifications may include reducing the fraction size, increasing the number
of fractions and total radiation dose, and changing the overall duration of treatment from the first fraction to the last.
Modifying the size and number of the fractions and the total dose of administered
radiation can prevent or minimize the occurrence of acute and latent radiation reactions while still optimizing the cure rate.
Donโt Forget!
While there is no immediate scarring from SRT, significant long-term scarring is
possible, especially over time.
Importantly, none of the recent SRT studies had a mean duration of follow-up greater
than 5 years; therefore, long-term results should be viewed with caution.
Pitfalls and Cautions
Acute reactions are defined as adverse events occurring within 90 days of
administration of the first dose fraction.
Latent reactions are defined as reactions occurring more than 90 days following the
administration of the first fraction.
Dyspigmentation and telangiectasias are seen frequently, and unlike surgical scars,
which tend to improve over time, long-term sequelae of SRT tend to worsen over years and decades.
Patient Education Points
While there is no surgical scar after SRT, it is not a scar-free procedure, and
dyspigmentation, textural changes, and telangiectasias tend to increase over time.
Therefore, this approach should be used with extreme caution in younger patients.
Billing Pearls
Each SRT treatment should be billed using CPT code 77401. This code should only be
used as a single unit, regardless of the number of areas treated per day.
CHAPTER 37 Superficial Radiation