Dear editor, Thank you for the opportunity of reviewing this interesting article on the cut-off point related to trismus in head and neck cancer patients. The article describes the confirmation of the cut-off point of 35 mm or less for trismus in 671 patients treated for head and neck cancer.

I would like revision on the following points:

Materials and methods It is stated that rare tumours were excluded from analyses, however, in the Netherlands salivary gland cancer is also a rare cancer (see: https://www.iknl.nl/docs/default-source/PDF_Docs/kib_zeldzame_kanker_digitaal.pdf?sfvrsn=2; page 88). Therefore, specify the excluded rare head and neck cancers in this section.

Add the codes of the World Health Organization International Classification of Diseases Oncology for the different locations of the tumours.

The MMO should be corrected for the dental state (dentate, partially dentate and edentate) of the analysed patients. So add this information in the methods section and recalculate the outcomes presented in the results section.

Discussion Give more evidence based information related to: “post irradiation symptoms develop more gradually”.

There are new analyses and outcomes described in the discussion (Mann Whitney U tests and multivariate logistic regression analyses). Add an extra objective to the study, add the statistical analyses to the methods section and describe these outcomes in the results section.