What do systematic reviews say?

Boost vs no boost

Boost showed no clear difference in disease‐free survival: disease progression/mortality at 5 years compared with no boost (low certainty).

• Tumour bed boost radiotherapy for women after breast‐conserving surgery 2017 · Cochrane Headline outcomes only
  HR 0.94 [0.87, 1.02]
  3 studies · 6549 participants
  Low

Accelerated radiotherapy with concomitant boost vs Conventional (standard) fractionation radiotherapy

• Interventions for the treatment of oral cavity and oropharyngeal cancer: radiotherapy 2010 · Cochrane All outcomes
  Accelerated/boost vs conventional, disease free survival: all four trials provided data; pooled estimate showed a statistically significant difference in favour of the accelerated/boost schedule, with statistical…
  4 studies · 1203 participants
  GRADE not reported

Accelerated radiotherapy (no split, boost or hyperfractionation) vs Conventional (standard) fractionation radiotherapy

• Interventions for the treatment of oral cavity and oropharyngeal cancer: radiotherapy 2010 · Cochrane All outcomes
  Accelerated vs conventional, disease free survival: both trials reported this, but substantial clinical and statistical heterogeneity (P = 0.0004, I2 = 92%) meant a pooled analysis was not reported (Analysis 1.3).
  2 studies
  GRADE not reported

Hyperfractionated/accelerated split-course radiotherapy vs Accelerated radiotherapy with concomitant boost

• Interventions for the treatment of oral cavity and oropharyngeal cancer: radiotherapy 2010 · Cochrane All outcomes
  Fu 1995: no significant difference in disease free survival; data not presented in a way that allows calculation of an HR.
  1 study · 75 participants
  GRADE not reported