Trial Comparing Different Follow-up Strategies

Inclusion criteria

1. Histopathologically proven invasive HNSCC of the oral cavity (except lip), oropharynx, hypopharynx or larynx
2. ≥18 years of age
3. In non-surgically treated HNSCC: clinical/radiological stage II-IV (excluding M1) according to the UICC / TNM 8th ed. In surgically treated HNSCC: pathological stage II-IV (excluding M1) according to the UICC / TNM 8th ed.
4. Treatment with curative intent, regardless of treatment modality (mono- or multimodal), and FU planned at the participating study center.

   Remark: Patients with one synchronous HNSCC of the oral cavity, oropharynx, hypopharynx and larynx, all treated with curative intent and all in complete remission are eligible. Synchronous tumor must have a less advanced stage than the index tumor used for stratification or in case of equal stage, the synchronous tumor must be the tumor with the better prognostic. (Rules: Better to worse prognostic: Larynx \> Oropharynx \> Oral cavity \> Hypopharynx.) The modality of the treatment must be the same as for the index tumor or less intense.
5. Radiological confirmation of complete remission of disease and no SPM from the 3rd to 6th month after treatment for all stages (minimal demanded imaging: head and neck (H\&N) MRI or H\&N CT scan and CT scan covering chest to pelvis (with contrast if not contraindicated); or preferable whole-body 18FDG-PET/CT or PET/MRI for patients with ≥T3 and/or N+).

   Note: Patients with positive or equivocal imaging/clinical findings are allowed if the tumor is ruled out by multidisciplinary tumor board decision (e.g. as a consequence of biopsy and/or multiple imaging).
6. Clinical confirmation of complete remission of disease through H\&N examination including endoscopy of the pharynx and larynx at the time of enrolment, that is 6 months (+/- 4 weeks) after the last HNSCC treatment
7. Agreement for long term FU (5 years) and all visits are to be performed at the participating center
8. Written informed consent, signed by the patient and the investigator

Exclusion Criteria

1. Initial clinical stage I and/or M1 HNSCC (according to the UICC / TNM 8th ed.)
2. Nasopharyngeal cancer and carcinoma of unknown primary
3. Any other previously treated HNC (including parotid and thyroid gland cancer) except for curatively and adequately treated cutaneous carcinoma in-situ, basal cell carcinoma and locally confined T1 squamous cell carcinoma of the skin without any sign of tumor recurrence at the time of screening
4. Any other synchronous malignancy except for one curatively and adequately treated HNSCC of the oral cavity, oropharynx, hypopharynx and larynx, basal cell carcinoma, locally confined T1 squamous cell carcinoma of the skin, low-risk prostate cancer, carcinoma in-situ of the skin or uterine cervix without any sign of tumor recurrence at the time of screening.
5. Any other metachronous malignancy within the last 5 years except for curatively and adequately treated basal cell carcinoma, locally confined T1 squamous cell carcinoma of the skin, low-risk prostate cancer, carcinoma in-situ of the skin or uterine cervix without any sign of tumor recurrence at the time of screening.
6. Participation in another study entailing regular medical exams by ENT specialists or persons involved in the oncological treatment, or regular imaging
7. Pregnant or breastfeeding women
8. Presence of any conditions that potentially hamper compliance with the study protocol and FU schedule at the participating center