Stereotactic Post-operative Radiotherapy for Intraparotid Metastatic Cutaneous Squamous Cell Carcinoma

This study is a phase II randomized trial where patients will be randomized in a 1:2 ratio to standard of care treatment with conventional fractionation PORT (Arm 1) vs. ultrahypofractionated stereotactic PORT (Arm 2). Patients will be stratified by pathologic nodal status (pN1 vs. pN2-pN3) per the American Joint Committee on Cancer (AJCC) 8th edition staging and use of immunotherapy (classified as neoadjuvant immunotherapy (with or without adjuvant immunotherapy) vs. planned for adjuvant immunotherapy only vs. no immunotherapy. Patients randomized to Arm 2 will be also compared to historical control data for primary endpoint of tumor local control at 2-years.

The objective of this study is to assess the clinical efficacy, toxicity and QOL of ultra-hypofractionated SABR compared to conventional fractionation for adjuvant radiation following resection of locally advanced, node-positive cutaneous SCC of the head and neck.

Primary endpoint

• Tumor control within the irradiated field at 2 years following adjuvant radiation completion defined as absence of clinical, radiographic or biopsy-proven recurrence within the irradiated field

Secondary endpoints

• Regional recurrence
• Disease-free survival (DFS)
• Overall survival (OS)
• Rate of salvage treatment (surgery in the ipsilateral neck) and freedom from unsalvageable recurrence in the ipsilateral parotid gland or neck
• Radiation-associated toxicity based on the Common Terminology Criteria for Adverse Events(CTCAE) version 5.0
• Patient-reported outcomes using the MD Anderson Symptom Inventory for Head and Neck Cancer (MDASI-HN) and the EuroQOL 5-Dimension 5-Level (EQ-5D-5L) questionnaires

Inclusion criteria

• Age ≥ 18 years
• Patient able to provide informed consent
• Eastern Cooperative Oncology Group (ECOG) performance status 0-2
• Patient is a candidate for curative intent treatment
• Patient is able to comprehend English adequately to complete patient reported outcome questionnaires
• Biopsy-confirmed cutaneous SCC
• Definitive resection of a primary cutaneous tumor within the head and neck
• Tumor stage T1-T4 (AJCC 8th edition); or tumor stage unknown (T0/Tx) with a positive intraparotid, peri-parotid or cervical node that is assumed to be from a head and neck cutaneous SCC by the treating oncologist
• Nodal stage N1-N3 (AJCC 8th edition)
• At least 1 indication for adjuvant radiation, including:

• T3 or T4 tumor stage
• Lymphovascular invasion (LVI)
• Perineural invasion (PNI)
• Positive or close (≤ 3 mm) margin
• ≥ 1 positive intraparotid, peri-parotid or cervical lymph node
• Multiple local recurrences or multi-focal disease
• Neoadjuvant or adjuvant immunotherapy is allowed

Exclusion criteria

• Definite metastatic disease at diagnosis
• Pregnant or breastfeeding women
• Significant health conditions or contraindications to receiving surgery and radiation
• History of previous head and neck cancer within 5 years, except for localized skin cancers (i.e. no nodal or distant spread)
• Prior head and neck radiation involving the ipsilateral parotid or neck. However, prior radiation to the index skin cancer that has led to the parotid nodal disease being treated on this trial is allowed, as long as there is no overlap, or inconsequential overlap, in the judgement of the treating oncologist.
• Indications for contralateral neck radiation (i.e. contralateral or bilateral lymph nodes)
• Previous invasive malignancy within 5 years, unless controlled with no evidence of disease