Measurement Of Early Toxicity

Early side effects may be graded based on their severity or on their impact to quality of life.


Endpoints are specific clinical situations which are seen following radiotherapy administration. They allow classification of radiotherapy reactions.

Scoring Systems

Scoring systems have been developed to grade radiation reactions. For early effects, measurement needs to be taken regularly (at least weekly) as they may develop rapidly. The establishment of scoring systems allows clinicians and institutions to compare and contrast different treatment schedules. Most scoring systems are based on a 6 tier model:

  • Grade 0 – No effect
  • Grade 1 – Mild, reversible, and heal spontaneously without any intervention
  • Grade 2 – Moderate side effects which require outpatient treatment and do not require cessation of radiotherapy
  • Grade 3 – Severe effects which usually necessitate hospital admission and intense supportive care. They may require cessation of radiotherapy or alteration of the treatment schedule.
  • Grade 4 – Life threatening effects which must be treated immediately to preserve life. Radiotherapy is permanently ceased.
  • Grade 5 – Lethal radiotherapy side effect

These grades are also used to measure late side effects.

Example of Scoring System

The WHO provides a scoring system based on these grades. In oral mucousitis, they are:

  • Grade 0 – No effect
  • Grade 1 – Soreness or erythema
  • Grade 2 – Erythema and ulceration, but able to eat solids (outpatient management)
  • Grade 3 – Ulceration necessitating liquid diet
  • Grade 4 – Alimentation not possible (life threatening situation)
  • Grade 5 – Death owing to side effects