This study aims to explore the safety and outcome of lymph drainage mapping(LDM) to individually tailor the elective nodal irradiation (ENI) to the ipsilateral neck only. The goal is to exclude the contralateral negative neck from the irradiation fields when there is no contralateral draining sentinel node. In case contralateral lymph drainage is found on SPECT/CT, a contralateral sentinel node procedure (SNP) is performed to remove the draining node. The patient will only receive contralateral ENI if (micro/macro)metastasis are found in this contralateral sentinel node.

The SUSPECT2 study is a modified concept from the first SUSPECT study (N14SUS). The first study investigated whether lymph drainage mapping (LDM) using SPECT/CT was a safe and feasible method to exclude the contralateral neck from irradiation, or, in case of contralateral lymph drainage, to tailor the contralateral ENI field to the level containing the tracer accumulation. In this study, large dose reductions to most organs at risk were realized, as well as significant reductions of both short term (mucositis, dysphagia) and long term (xerostomia, dysphagia) toxicities.

Firstly, the SUSPECT2 study aims to expand the inclusion criteria of the original SUSPECT study. Secondly, it aims to further reduce the proportion of patients that undergoes bilateral ENI, by performing a contralateral sentinel node procedure (SNP) in case of contralateral lymph drainage. The patient will only receive contralateral ENI if (micro/macro)metastasis are found in this contralateral sentinel node.

Inclusion Criteria:

• Newly diagnosed and histopathologically proven primary HNSCC
• T1-4N0-2b
• Tumor does not cross midline
• WHO performance status 0 or 1
• Signed written informed consent

Exclusion Criteria:

• Distant metastatic spread at the time of inclusion
• Chemotherapy or surgery (for the present tumor), prior to inclusion
• Previous radiation treatment in the head and neck region, for any reason
• Previous neck dissection
• Recurrent or second primary tumor in the head and neck region
• Head and neck malignancies arising from skin, lip, nose, sinuses, nasopharynx, salivary glands, thyroid gland or esophagus
• Pregnancy or no active contraception for pre-menopausal women
• Known hypersensitivity to iodine or nanocolloid injection
• Having any condition (physical, mental, sociological) that interferes with the informed consent procedure and follow-up schedules