Table 1.
Conversions of the National Cancer Institute (NCI) and GRADE (grading of recommendations assessment, development and evaluation) scoring systems4,5 used by the present working group
| NCI levels of evidence | GRADE | GRADE | |
|---|---|---|---|
| Quality score | Strength score | ||
| NCI strength of study endpoints (A–D) | NCI strength of study design (1–3) | A = highest quality study | 1 = strong |
| A Total mortality (or overall survival from a defined time) | 1 Randomized controlled trial | ||
| (i) Population-based, consecutive series | |||
| (ii) Consecutive cases (not population-based) | |||
| B Cause-specific mortality (or cause-specific mortality from a defined time) | 2 Non-randomized controlled trials | B = high quality study | 2 = weak |
| C Carefully assessed quality of life | 3 Case series | C = low quality study | |
| (i) Population-based, consecutive series | |||
| (ii) Consecutive cases, (not population-based) | |||
| (iii) Non-consecutive cases | |||
| D Indirect surrogates | D = lowest quality study | ||
| (i) Event-free survival | |||
| (ii) Disease-free survival | |||
| (iii) Progression-free survival | |||
| (iv) Tumour response rate |