Worst pattern of invasion - type 4 (WPOI-4) and Lymphocyte host response should be mandatory reporting criteria for oral cavity squamous cell carcinoma: A re-look at the American Joint Committee of Cancer (AJCC) minimum dataset.

Abstract

A proportion of early-stage node-negative oral squamous carcinoma patients fail despite complete surgical resection. Adjuvant treatment in early oral cancer is controversial and is often individualized based on stage, depth, and margin status. We reviewed various histological markers in pT1/T2N0 cases, resected upfront with elective nodal dissection, with an emphasis on tumor-tissue interface characteristics of the worst pattern of invasion (WPOI), tumor cell nest size (sCNS), budding and lymphocytic host response (LHR), to assess their prognostic significance. Archived blocks of 95 cases were reviewed. Tumor stage, grade, size, depth of invasion, lymphovascular, and perineural invasion, WPOI, LHR, sCNS, and tumor bud (single cells or <5 cell clusters) score were recorded. Prognostic significance was statistically analyzed using SPSS software version 20. Depth of invasion (P = 0.008), WPOI- 4 and 5 (P = 0.033), sCNS (<5 cells) at tumor interface (P = 0.010), high bud count (≥3 buds/40 × hpf) (P = 0.021) and poor LHR (P = 0.019) correlated significantly with poor disease-free survival on univariate analysis. However, on multivariate analysis only LHR and WPOI-4 (that is presence of small cell nests or buds) were significant, with high hazard ratio of 4.351 (95% CI 1.290-14.676, P = 0.018) and 5.019 (95% CI 1.212-20.789, P = 0.026), respectively. We propose mandatory reporting of WPOI-4 at the tumor interface and absence of LHR, as significant markers of poor prognosis in early-stage oral cavity squamous carcinoma.