Purpose: It is well accepted that patients with oral cavity squamous cell carcinoma (OCSCC) with pT4 disease, positive or close margins, positive nodal disease and extracapsular spread (ECS) require adjuvant treatment with radiation versus chemotherapy radiation. However, controversy surrounds the role of adjuvant treatment in early stage (I or II, T1-T2N0) OCSCC with perineural invasion (PNI). Our objective was to determine whether PNI is an independent risk factor for early stage OCSS and whether adjuvant treatment improves disease control rates.
Method: We performed a retrospective cohort study of patients treated at a tertiary university hospital. Sixty-three patients OCSCC treated surgically and identified to be PNI positive on final pathology, 19 were stage I or II and pN0, and 44 were stage III or IV. Survival analysis using Kaplan-Meir followed by multivariate cox models was performed.
Results: Average survival for stage I or II PNI+ was 51 months compared to stage III or IV PNI+ 33. Nineteen patients were stage I/II with OCSCC PNI+, 9 treated with surgery alone, 2 adjuvant chemo/radiation, and 8 with adjuvant radiation alone. Although no significance (p=?) was observed, stage I/II patients with PNI+ demonstrated improved survival with adjuvant radiation (mean 57, std 3.4 months) and chemo/radiation (mean 60, std 0 months) compared to no adjuvant treatment (mean 43, std 7.6 months). We observed patients with stage I/II PNI+ OCSCC also had improved local regional control with adjuvant treatment (mean 44, std 21.8 months) compared to no adjuvant treatment (mean 25, std 25.5 months); however, this difference was not statistically significant (p=0.07).
Conclusion: We observed that PNI could be independent risk factor in early stage I/II OCSCC for both disease free survival and local regional control. Larger subset of patients would be required to demonstrate significance. To our knowledge this is the 2nd largest series cohort of stage I/II PNI+ OCSCC to be reported.