Aims: Perineural invasion (PNI) and lymphovascular invasion (LVI) are independent risk factors associated with poorer prognosis for keratinocyte cancers. There are currently limited evidence-based management guidelines for this combination. Secondary analysis of the PNI study data has been performed to gain further insight into the outcomes of concurrent PNI and LVI. Interim data from the years 2009-2017 have been analysed to date.
Methods: The PNI study is a retrospective observational study, assessing outcomes of primary squamous cell carcinoma (SCC) or basal cell carcinoma (BCC). Histopathology reports were used to identify tumours with PNI involvement. This study involved performing secondary analysis of completed years to identify tumours with both PNI and LVI.
Results: 910 keratinocyte cancers with PNI have been identified, including 425 BCCs and 485 SCCs. 9.67% had concurrent PNI and LVI, of which 7 were BCCs and 81 were SCCs. Of the BCC cases, there was no associated metastasis or disease related death. Three of the BCCs were of mixed subtype, two solid, one morpheic, and one infiltrating. Of the SCCs, 9 underwent chemotherapy, 52 underwent radiotherapy, 14 had associated metastasis, and 20 cases listed SCC as a cause of death.
Conclusions: The analysis suggests that in SCC cases with PNI, LVI is not rare, but when present, confers a worse prognosis. Data also suggests that the combination is rarer in BCCs, but not associated with poorer prognosis. The findings highlight the importance of including LVI status in histopathology reports, as this combination requires appropriate treatment and surveillance.