What do systematic reviews say?

Concomitant (concurrent) chemoradiotherapy vs Radiotherapy alone

Concomitant (concurrent) chemoradiotherapy led to lower disease-free survival, concurrent chemoradiotherapy vs radiotherapy… compared with radiotherapy alone (non-resectable tumours); GRADE not reported.

• Interventions for the treatment of oral cavity and oropharyngeal cancer: chemotherapy 2021 · Cochrane All outcomes
  HR 0.74 [0.67, 0.80]
  13 studies
  GRADE not reported

PET-CT following chemoradiotherapy (neck dissection only if no/incomplete response) vs Planned neck dissection before or after chemoradiotherapy

• Interventions for the treatment of oral cavity and oropharyngeal cancers: surgical treatment 2023 · Cochrane All outcomes
  Disease-free survival: outcome not reported in a usable way (Mehanna 2017: disease-specific and other-cause mortality did not differ, P=0.80 and 0.41).
  1 study
  GRADE not reported

Tyrosine kinase inhibitor (erlotinib, gefitinib or lapatinib) plus standard therapy (radiotherapy or chemoradiotherapy) vs Standard therapy alone (radiotherapy or chemoradiotherapy)

It is very uncertain whether tyrosine kinase inhibitor (erlotinib, gefitinib or lapatinib) plus… changes disease-free survival compared with standard therapy alone (radiotherapy or chemoradiotherapy) (very low certainty).

• Interventions for the treatment of oral and oropharyngeal cancers: targeted therapy and immunotherapy 2015 · Cochrane All outcomes

  40 to 60 months · Gefitinib + radiotherapy (oral cavity)
  HR 1.51 [0.61, 3.71]
  1 study · 60 participants
  Very low