Background Oral potentially malignant disorders (OPMD) are associated with the risk of malignant transformation (MT) into oral cavity carcinoma (OCC). Oral lichen planus (OLP) is one of the most common OPMDs in western countries. Although there is a substantial amount of research on progression to cancer, a specific analysis of the clinical characteristics and prognosis of cancer developed in patients with a history of OLP versus patients without a history of OLP has not been investigated so far. Methods Retrospective evaluation of 82 patients treated for OCC with a known history of OLP compared to a representative sample of 82 patients treated for OCC without a known history of LP. Comparative analyses were performed on age at presentation, sex, TNM staging, clinical characteristics, pathology characteristics, 2‐ and 5‐year overall survival (OS), and disease‐free survival (DFS). Results It was shown that patients with a history of LP were significantly younger at first presentation than patients without a history of LP (mean age difference 6.7 years, 95% CI 3.1–10.3, p < 0.05). Also, patients with a history of OLP were in higher proportion females. The main pathological stage at presentation was significantly lower in the OLP group (p < 0.05). The 2‐year survival analysis showed that DFS and OS were significantly lower in patients without a known history of OLP, with a hazard ratio (HR) of 3.1 (95% CI 1.4–6.8) and HR of 2.6 (95% CI 1.3–5.3), respectively. The 5‐year survival analysis showed that DFS and OS were significantly lower in patients without a known history of OLP, with a hazard ratio of 3.1 (95% CI 1.6–6.2) and of 2.9 (95% CI 1.5–5.6), respectively. Conclusions Cancer arising from OLP has peculiar characteristics compared to cancer in naïve patients. It most commonly affects younger patients, women, and nonsmokers. It is usually diagnosed at earlier stages and appears to have less aggressive behavior at presentation. Moreover, when 2‐ and 5‐year survival is analyzed, it appears that patients in OLP group have an overall and a disease‐free survival advantage. These results suggest that cancer from OLP is less aggressive and thus has a potential biological difference with cancer arising in non‐OLP patients. Further clinical and basic investigations are needed to confirm the results of this study.

Background The submandibular gland (SMG) is routinely excised during neck dissection. Given the importance of the SMG in saliva production, it is important to understand its involvement rate by cancer tissue and the feasibility of its preservation. Methods Retrospective data were collected from five academic centers in Europe. The study involved adult patients affected by primary oral cavity carcinoma (OCC) undergoing tumor excision and neck dissection. The main outcome analyzed was the SMG involvement rate. A systematic review and a meta-analysis were also conducted to provide an updated synthesis of the topic. Results A total of 642 patients were enrolled. The SMG involvement rate was 12/642 (1.9%; 95% CI 1.0–3.2) when considered per patient, and 12/852 (1.4%; 95% CI 0.6–2.1) when considered per gland. All the glands involved were ipsilateral to the tumor. Statistical analysis showed that predictive factors for gland invasion were: advanced pT status, advanced nodal involvement, presence of extracapsular spread and perivascular invasion. The involvement of level I lymph nodes was associated with gland invasion in 9 out of 12 cases. pN0 cases were correlated with a reduced risk of SMG involvement. The review of the literature and the meta-analysis confirmed the rare involvement of the SMG: on the 4458 patients and 5037 glands analyzed, the involvement rate was 1.8% (99% CI 1.1–2.7) and 1.6% (99% CI 1.0–2.4), respectively. Conclusions The incidence of SMG involvement in primary OCC is rare. Therefore, exploring gland preservation as an option in selected cases would be reasonable. Future prospective studies are needed to investigate the oncological safety and the real impact on quality of life of SMG preservation.