Radiotherapy Guidelines 2025 DAHANCA

1. All steps in immobilisation, scanning, image reconstruction, image transfer and co-registration should be quality assured (D)

2. All scans used for target delineation in radical radiotherapy should be less than 3 weeks old (D)

3. The responsible oncologist should take part in all parts of the target definition in complex cases (D)

Planning CT

4. A planning CT scan of optimal quality with the use of metal artefact reduction should be acquired with a maximal slice thickness of 2 mm (D)

Recommended MRI sequences for delineation

5. MRI sequences for target delineation should be T1 with and without contrast + T2 with and without fat suppression (STIR/ Dixon) (D)

PET-CT

6. The procedures related to PET/CT should follow EANM guidelines from 2015 (D)

Pharynx and oral cavity

7. PET-CT and MRI should be used for target delineation of cancers in the pharynx and oral cavity. Areas of special attention are perineural invasion, bone and skull base invasion (D)

Larynx

8. PET-CT and MRI should be used for target delineation of cancers in the larynx (D)

9. In case of tumours not visible on the diagnostic scans (e.g. T1N0 larynx cancer), PET and MRI are not indicated (D)

10. Examination in general anaesthesia, drawings or photos should be used for the delineation of superficially spreading tumours (D)

Cancer of nasal cavity, paranasal sinuses and the salivary glands

11. PET-CT and MRI should be used for target delineation of sinonasal and salivary gland cancers (D)

Nodal metastases

12. The choice of imaging modality follows the primary tumour. In case of unknown primary, it follows either the guidelines for post-operative radiotherapy (MRI only) or radical radiotherapy (PET-CT + MRI) (D)

Post-operative radiotherapy

13. The indication for postoperative radiotherapy is decided at a multidisciplinary team conference (D)

14. All cases of T3/T4, ENE, high risk histology and non-radical surgery, must be discussed at the multidisciplinary team conference (D)

Target definition

15. For postoperative radiotherapy, all available information must be used for target delineation (D)

16. Optimal naming and marking of the surgical specimen are essential for optimal delineation of e.g. extranodal extension (ENE) or R1 resections (D)

17. Complicated targets should be defined with the operating surgeon (D)

Imaging

18. MRI should be used for target delineation in post-operative radiotherapy, except when there was no visible pre-operative target and no reconstruction, e.g. T1 glottic larynx (D)

19. There is no indication for PET-CT in immediate post-operative radiotherapy, unless macroscopic tumour is suspected, or the neck needs evaluation (D)

20.
The nomenclature of volumes by the ICRU should be applied, and the definitions of nodal levels according to international consensus guidelines should be followed (D)

DAHANCA principles for target delineation

21. CTV1 includes GTV with 5 mm geometric margin, modified for natural borders for tumour spread (D)

22. CTV2 includes GTV with 10 mm geometric margin, modified for natural borders for tumour spread (D)

23. CTV3 includes CTV2 and elective areas (D)

GTV and CTV in postoperative radiotherapy

24. CTV1 includes the pre-operative non-radical operated tumour (R1 or R2) with an isotropic margin of 5 mm modified for barriers for tumour spread (D)

25. CTV2 includes preoperative GTV with 10 mm margin modified for barriers for tumour spread (D)

26. CTV3 includes CTV2, surgical bed and elective volumes (D)

GTV and CTV in radiotherapy after induction chemotherapy (nasopharynx, sinonasal cancer)

27. After induction chemotherapy, the actual target may be delineated. It should be considered to include, pre-chemotherapy involved volumes especially concerning bone, skull base and involved sinuses (B)

28. The nomenclature (D), dose-volume constraints (C), and definition of volumes (D) should follow the guidelines of Table 1 and Appendix 1.

29. A cumulated treatment plan, even corrected for recovery and fractionation, may be beneficial for the planning of re-treatment, but physical and biological uncertainties should be considered (D)

30. Dose planning should attempt to comply with the tolerance levels for target-coverage and normal tissue sparing described in Table 2 (D)

31. Dose planning should strive to achieve the tolerances for target-coverage and normal tissue sparing mentioned in table 2 (D)