NcXHF

PROGNOSTIC FACTORS AND ADJUVANT RADIATION THERAPY IN NON-MELANOMA SKIN CANCER
nerve that are proximal and distal to the tumor site, skin that
is innervated by the involved nerve, major communicating
branches, and the compartment in which the nerve is embedded,
such as the parotid gland for CN VII. 29
ADJUVANT RADIATION THERAPY VOLUMES AND
DOSES
The preferred minimum clinical target volume (CTV) margin
on the resected primary tumor is 1.0 cm, although this
may not always be possible depending on its proximity to
organs at risk. For resected node disease, the preferred minimum
CTV margin is 0.5 to 1.0 cm.
The doses used in adjuvant RT are similar to those used in
mucosal head and neck cancer, and are not based on prospective
data specifıc to NMSC. The NCCN guidelines provide
recommendations on doses. 6
Typically, it is recommended to give 60 Gy in 30 fractions
over 6 weeks to the site of resected disease; for patients with
smaller lesions, or in cases where shorter fractionation is preferred
and optimal long-term cosmesis is not a clinical priority,
there is the option of hypofractionated schedules, in
which radiotherapy is given as a dose of 50 Gy in 20 fractions
over 4 weeks or as 45 Gy in 15 fractions over 3 weeks. In the
presence of positive microscopic margins, a dose of 66 Gy in
2 Gy fractions may be recommended.
For resected regional node disease in the presence of ECE,
the NCCN guidelines recommend a dose of 60 Gy to 66 Gy in
30 to 33 fractions over 6.0 to 6.6 weeks; when ECE is not present,
the guidelines recommend a dose of 56 Gy to 60 Gy in 28
to 30 fractions over 5.6 to 6 weeks. 6
In the TROG 05.01 study, the recommended dose/fractionation
to the surgically perturbed neck in the absence of
disease was 54 Gy in 27 fractions over 5.5 weeks and, for the
surgically unperturbed elective neck, the recommended
dose/fractionation was 50 Gy in 25 fractions over 5 weeks.
CONCLUSION
Evidence, mainly from retrospective series, has identifıed adverse
prognostic factors that predict for locoregional relapse
in patients with NMSC; however, there is a lack of confırmatory
prospective data examining the benefıt of adjuvant RT in
these patients. And although there is strong retrospective
data supporting the role of adjuvant RT in high-risk disease—for
example, in disease with metastatic regional nodal
involvement—the data is less certain about the ways in which
adverse features and the extent of disease should factor into
the consideration of treatment with adjuvant RT. As a result
of this uncertainty, the use of adjuvant RT in the treatment of
NMSC is predominantly based on individual institutional
policy. Further prospective studies in this area are warranted.
Disclosures of Potential Conflicts of Interest
The author(s) indicated no potential conflicts of interest.
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