The impact of worst patterns of invasion on survival outcomes in oral cavity cancer: implications for adjuvant therapy and prognostic stratification.

Purpose: To examine the impact of the worst patterns of invasion (WPOI) on survival outcomes and possible implications for adjuvant treatment decisions in squamous cell oral cavity cancer patients.

Methods: The loco-regional progression-free survival (LRPFS) and the distant metastasis-free survival (DMFS) were calculated for 162 patients. Univariate and multivariate analyses were done according to prognostic predictors of stage (early/T1-2 or N0; locally advanced /T3-4 or N +), grade, depth of invasion, WPOI, perineural (PNI), and lymphovascular (LVI) invasion and margin status. WPOI-V, PNI, and LVI were also analyzed for their positive status.

Results: The median follow-up was 46 months (3-77 months). A total of 32 events, as loco-regional (n = 16), systemic progression (n = 14), and second primary lung cancer (n = 2) were observed. The presence of locally advanced disease, PNI or LVI, and WPOI-V were significantly worse prognostic factors for LRFS and DMFS. The 5-year LRPFS (74% vs. 92.8%, p = 0.001) and DMFS (74% vs. 94%, p < 0.0001) were significantly worse in patients with WPOI-V present. In multivariate analysis, WPOI-V patients had a worse prognosis for loco-regional relapse (p = 0.037) in early-stage cancer. There were no triple-positive patients in the early-stage group. LRRFS (90.4% vs. 59.7%, p < 0.0001) and DMFS (97% vs. 42.9%, p = 0.013) were significantly better in triple-negative patients compared to triple-positive patients.

Conclusion: WPOI-V indicates a poor prognosis for locoregional progression and distant metastasis. Survival outcomes are significantly worse in triple-positive patients. These results need further evidence for adjuvant radiotherapy for early and systemic therapy for triple-positive locally advanced-stage patients.