Should We Treat the Regional Nodes in Patients with Skin Cancer of the Head and Neck with Perineural Invasion

Reviewer: William Levin, MD
OncoLink
Last Modified: October 7, 2002

Presenter: A. Garcia-Serra
Presenter's Affiliation: Department of Radiation Oncology, University of Florida, Gainesville, FL, USA
Type of Session: Scientific

Background

Once the decision to treat a patient with radiation therapy has been made, the next most important isuue is to dermine what area to treat.
While increasing the size of the radiation field allows for better coverage of subclinical disease this practice also increases exposure of normal tissue and the potential for side-effects.
In the current study, investigators try to determine the optimal treatment fields for skin cancer of the head and neck.
They have focused the study on patients who have microscopic or clinical perineural invasion (PNI), potentially representing high-risk disease.

Materials and Methods

This is a retrospective analysis of 135 patients.
All patients had non-melanomatous skin cancer and either microscopic or clinical PNI.
Clinical PNI was defined as cranial nerve involvement either by physical exam or by radiographic study.
Median radiation dose to the primary site was 65 Gy.
In 60% of patients with only microscopic PNI, elective neck lymph node irradiation was not performed.
Minimum follow-up was 2 years.

Results

The 5 year local control rates without salvage therapy were 87% for microscopic PNI-only, and 55% for patients with clinical PNI.
Overall, 88% of the local failures were associated with positive surgical margins.
Almost half of the recurrences in patients with microscopic PNI were limited to the first-echelon lymph nodes (usually the parotid region).
In the patients with clinical PNI, 90% of recurrences took place at the primary site.
Cranial nerve deficits rarely improved after treatment.
In patients with clinically progressive disease, radiographic abnormalities remained stable 30% of the time.

Author's Conclusions

First-echelon lymph nodes should be treated in all patients who have microscopic or clinical evidence of PNI.
Local control rates are poor for patients with clinical evidence of PNI.

Clinical/Scientific Implications

This study confirms the belief that PNI (either clinical or microscopic) represents high risk disease and requires elective neck node irradiation.
Clincal PNI represents especially bad disease and is not well controlled with radiation therapy alone at current radiation doses.

Oncolink's ASTRO Coverage made possible by an unrestricted Educational Grant from Ortho Biotech.