Tefft 1970

Methods	Retrospective cohort study
Participants	N of patients original cohort: nm; N of patients described study group: 99; N of patients study group of interest: 99; N of patients with liver function tests: 88 Tumour: Wilms' tumour, neuroblastoma, hepatoma; Time period diagnosis/treatment: nm; Age at diagnosis: 14% <1 yr, 56% 1‐4 yr, 30% >5 yra; Age at follow‐up: nm; F/M%: 55/45a; BMI: nm N of patients hepatitis virus infection: nm N of patients acute liver disease: 31/51 (60.8%) abnormal liver function within 6 months following radiotherapy Follow‐up duration: mean 3.9 (0.5‐13.3) yr after end of treatment; Completion of follow‐up: 88.9%
Interventions	N of patients chemotherapy: 88/88 (100%); Chemotherapy type: vincristine, actinomycin D and 5‐fluorouracil; Chemotherapy dose: nm N of patients radiotherapy involving the liver: 88/88 (100%); Radiotherapy field: right lobe (n=36), left lobe (n=35), entire liver (n=13), remaining liver after resection (n=4); Radiotherapy dose: <25 Gy (n=21), 25‐35 Gy (n=47), >35 Gy (n=20) N of patients hepatectomy: 4/88 (4.5%) N of patients BMT: nm N of patients blood transfusion: nm
Outcomes	Method of detection of hepatic late adverse effects: AST and other unspecified liver function tests (frequency of testing nm) Definition of hepatic late adverse effects: Abnormal liver function tests N of patients hepatic late adverse effects at end of follow‐up: 51/88 (58.0%) Risk factors: site of radiotherapy: 25/36 (96.4%) with right lobe irradiation abnormal liver function tests versus 16/35 (45.7%) with left lobe irradiation abnormal liver function tests versus 6/13 (46.2%) with whole liver irradiation abnormal liver function tests versus 4/4 (100%) with remaining liver irradiation abnormal liver function tests (ns); radiotherapy dose: 11/21 (52.4%) with <25 Gy abnormal liver function tests versus 27/47 (57.4%) with 25‐35 Gy abnormal liver function tests versus 12/20 (60.0%) with >35 Gy abnormal liver function tests (ns) (Univariate)
Notes	a Data of 115 patients
Risk of bias
Bias	Authors' judgement	Support for judgement
Representative study group	Unclear risk	Unclear if described study group consisted of more than 90% of the original cohort or if it was a random sample with respect to cancer treatment
Complete follow‐up assessment	Low risk	Outcome was assessed for more than 60% of the study group of interest
Blinded outcome assessor	Unclear risk	Unclear if outcome assessors were blinded to the investigated determinant
Adjustment important confounders	High risk	Important prognostic factors or follow‐up were not taken into account
Well defined study group	High risk	Number of patients with hepatitis virus infection was not mentioned
Well defined follow‐up	Low risk	Length of follow‐up was mentioned
Well defined outcome	High risk	Outcome definition was not objective and precise
Well defined risk estimation	Low risk	Chi2 was calculated