Photon Therapy Versus Proton Therapy in Early Tonsil Cancer.

Inclusion Criteria:

1. The patient must be at least 18 years old.
2. Histologically or cytologically confirmed, previously untreated squamous cellcarcinoma of the tonsil T1-2 (p16-positive or p16-negative) N0-1 M0 (p16-positive)/N0-N2b M0 (p16-negative) according to AJCC 8th edition, aimed forunimodal and ipsilateral treatment with radiotherapy with curative intent. Thetreatment may be followed but not preceded by surgery, which would be as a salvageprocedure and not part of the planned treatment. An excision of a lymph node, or atonsillectomy for diagnostic purposes does not exclude the patient from participation.
3. World Health Organisation/Eastern Cooperative Oncology Group (WHO/ECOG) performancestatus 0-1.
4. The patient must be able to understand the information about the treatment and give awritten informed consent.

Exclusion Criteria:

1. Patients judged to benefit from bilateral radiotherapy or concomitant chemotherapy
2. Concomitant or previous malignancies. Exceptions are adequately treated basal cellcarcinoma or squamous cell carcinoma of the skin, or in situ carcinoma of the cervixuteri with a follow-up time of at least 3 years, or other previous malignancy with adisease-free interval of at least 5 years.
3. Two or more synchronous primary cancers in the head and neck region at time ofdiagnosis
4. Previous surgery or radiotherapy in the head and neck region that may affect the studyresult, as judged by the investigator
5. Co-existing disease prejudicing survival (expected survival should be >2 years).
6. Psychiatric or addictive disorders or other medical conditions which in the view ofthe investigator might impair patient compliance
7. When dental fillings with amalgam or metal are present close to the tumour area itmust be considered if this may affect radiotherapy before inclusion.