Does this patient with pT2N0M0, Grade 1-2 (G1-2) Squamous Cell Carcinoma (SCC) of the left lower lip require elective nodal radiotherapy (RT) following excision with a depth of invasion (DOI) of 3 mm and positive margin for intraepidermal carcinoma (IEC)?

From the Guidelines

Elective nodal radiotherapy is not indicated for this patient with pT2N0M0 G1-2 squamous cell carcinoma of the left lower lip. The patient's tumor has a depth of invasion of 3mm, clear margins for the invasive component, and no lymphovascular or perineural invasion, which are all favorable prognostic factors 1. The CT scan confirms no evidence of nodal involvement or metastatic disease. The primary concern is the positive margin for intraepidermal carcinoma (IEC) at the 9 o'clock position, which represents in-situ disease rather than invasive cancer. This positive IEC margin can typically be managed with close observation or re-excision rather than radiotherapy. Some key points to consider in this case include:

• The absence of high-risk features such as perineural invasion, lymphovascular invasion, or nodal involvement significantly reduces the risk of occult nodal metastasis.
• For early-stage (T1-2N0) lip SCC without high-risk features, the risk of occult nodal metastasis is generally low, and observation of the neck is a reasonable approach 1.
• Elective nodal irradiation would expose the patient to potential toxicities without clear evidence of benefit in this specific case.
• Close follow-up with regular clinical examination of the neck is recommended to monitor for any regional recurrence. Given the current evidence, the approach with the best outcome in terms of morbidity, mortality, and quality of life would be to manage the positive IEC margin with close observation or re-excision, and to monitor the patient closely for any signs of recurrence or metastasis 1.

From the Research

Patient Overview

• The patient has a pT2N0M0 G1-2 SCC of the left lower lip
• Excision was performed on 21/2/25, with a 16 mm SCC and a depth of invasion (DOI) of 3 mm
• The margins were clear for invasive cancer, but there was a positive margin for intraepidermal carcinoma (IEC)
• There was no lymphovascular invasion (LVI) or perineural invasion (PNI)

Treatment Considerations

• The patient's CT scan showed no evidence of metastatic disease or nodal involvement
• The use of adjuvant radiotherapy is being considered due to the positive margin for IEC
• Studies have shown that radiotherapy can be an effective treatment for cutaneous squamous cell carcinoma (cSCC) 2, 3, 4
• However, the role of elective nodal irradiation (ENI) in the treatment of cSCC is still being debated 5

Elective Nodal Irradiation

• ENI involves irradiating tumor-associated draining lymph nodes (DLN) to prevent nodal metastases
• A study found that ENI can attenuate the combinatorial efficacy of stereotactic radiation therapy and immunotherapy 5
• The study suggested that irradiation of the DLN can restrain adaptive immune responses and affect long-term survival
• However, the decision to use ENI should be made on a case-by-case basis, taking into account the individual patient's risk factors and tumor characteristics

Adjuvant Radiotherapy

• Adjuvant radiotherapy can be used to reduce the risk of recurrence in patients with high-risk features, such as positive margins or close margins 2, 3, 4
• The use of adjuvant radiotherapy in this patient's case may be considered due to the positive margin for IEC
• However, the decision to use adjuvant radiotherapy should be made after careful consideration of the patient's individual risk factors and tumor characteristics, as well as the potential benefits and risks of treatment 6, 2, 3, 4