The purpose of this study is to investigate the risk of recurrence and metastasis in patients treated with different surgical margins (5mm vs 10mm) for a T1 squamous cell carcinoma of the lip.

The incidence of head and neck tumors, including lip carcinomas, in increasing. Exact incidences are lacking because in the Dutch National Cancer Registry (NCR) lip carcinomas are registered both as oral cavity carcinomas and skin carcinomas. In 2021, 136 patients with lip cancer were registered in the Netherlands. 90% of patients with lip cancer have localized disease (stage 1) with a 5-year survival rate of more than 90%.

Lip carcinomas usually involve squamous cell carcinomas (SCC). In most cases, the SCC is located on the sun-exposed lower lip. In approximately 90% of lower lip SCCs, the tumor is smaller than 2cm in diameter. According to the current eight edition of the Tumor Node Metastasis (TNM) classification of the American Joint Committee on Cancer (AJCC) and the ninth edition of the Union for Internation Cancer Control (UICC), it is classified as tumor stage I.

Surgery is the conventional treatment for a T1 SCC of the lip, where tumor margins can be verified via histologic examination. A histologic margin of less than 2mm is associated with an increased risk of local recurrence and metastasis.

In the Netherlands, surgical treatment of lip carcinomas is performed by dermatologists, plastic and reconstruction surgeons, oral and maxillofacial surgeons (OMFS), and otorhinolaryngologists (ENT). There is currently no international consensus regarding the appropriate surgical margins for excision of a T1 SCC on the lip. According to the AJCC, a surgical margin of 5mm is appropriate, while according to the UICC, a surgical margin of 10mm is appropriate. Scientific evidence is limited regarding differences in tumor clearance and the risk of recurrence or metastasis after excision of T1 SCCs with a surgical margin of 5mm versus 10mm.

We aimed to investigate whether there is a significant difference in tumor-free survival in patients with surgically treated T1 lip SCC with a surgical margin of 5mm versus 10mm.

A retrospective descriptive multicenter data study will be conducted with four different centers in the Netherlands (Maastricht University Medical Center+), Radboud University Medical Center (RadboudUMC) Nijmegen, Catharina Hospital Eindhoven (CZE), and Zuyderland Medical Center Heerlen/Sittard. Data will be obtained from the Dutch Cancer Registry (NKR) and the Dutch Pathological Anatomical National Automated Archive (PALGA).

The primary outcome is the difference in tumor-free survival in patients treated with surgical margins of 5mm and 10mm. The secondary outcome is the difference in tumor-free survival in patients with different histologic free margins. To evaluate the risk of surgical and histologic margins on the risk of local recurrence and metastasis, a Kaplan-Meier analysis, log-rank test and cox-proportional hazard models will be used.

Inclusion Criteria:

• patients of 18 years and older
• with a T1 cutaneous squamous cell carcinoma of the lip (including the cutaneous lip, vermillion border, vermillion and mucosal involvement).
• who received surgical treatment
• treated at one of the following centers: Maastricht University Medical Center+ (MUMC+), Radboud University Medical Center (Radboudumc), Zuyderland Medical Center (Zuyderland MC), Catharina Hospital Eindhoven (CZE).

Exclusion Criteria:

• malignancies other than cutaneous squamous cell carcinoma
• Oropharyngeal cancer
• patients with stage T2-T4 cutaneous squamous cell caricnomas of the lip

Data from patients are collected retrospectively using data from the Pathological Anatomical National Automated Archive (PALGA). These are data from patients treated at one of the following four centers in the Netherlands: MUMC+, Radboudumc, Zuyderland MC, CZE.