L. Buchanan , B. De’Ambrosis , K. DeAmbrosis T. Warren , S. Huilgol , H.P. Soyer , B. Panizza
This presentation by the Perineural Invasion (PNI) Registry
aims to clarify clinical and histopathological ambiguities
surrounding perineural invasion in nonmelanoma skin
cancer (NMSC). PNI is reportedly present in approximately
2–6% of cases of NMSC and is associated with greater rates
of morbidity and mortality. The distinction between clinical
PNI and incidental PNI is somewhat unclear, especially in
regard to management and prognosis. One important objective
of the PNI registry, is to develop a standardised method
of classifying perineural invasion. Hence, in this presentation
we propose a deﬁnition for PNI and for its subclassiﬁcation.
This presentation also provides a critical analysis of the current literature regarding the treatment of incidental PNI by evaluating the key cohort studies that have investigated the use of surgery and/or radiotherapy in the management of incidental PNI. At present, there are no universal clinical guidelines that specify acceptable treatment of NMSC exhibiting incidental PNI. Subsequently, patients often receive surgery with varying wider margins, and/or radiotherapy despite the limited evidence substantiating such management options. It is evident from the existing literature that current opinion is divided regarding the beneﬁt of adjuvant radiotherapy. Certain prognostic factors have been proposed such as the size and depth of tumour invasion, nerve diameter, the presence of multifocal PNI and the type of tumour. The PNI registry is a web-based registry that has been developed to assist in attaining further data pertaining to incidental PNI in NMSC. It is envisaged that this information will provide the foundation for identifying and deﬁning best practice in managing incidental PNI.