Should We Treat the Regional Nodes in Patients with Skin Cancer of the Head and Neck with Perineural Invasion
Presenter: A. Garcia-Serra
Presenter's Affiliation: Department of Radiation Oncology, University of Florida, Gainesville, FL, USA
Type of Session: Scientific
- 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.
- 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.
- 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.
- 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.
- 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.
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