Stockton 2000.

Methods	A retrospective study in women with colon, rectal, breast, melanoma, bladder, and ovarian cancers. A total of 14,527 cases registered by the East Anglian cancer registry and diagnosed between 1989 and 1993 were included. The data were analysed by cancer type so it was possible to report the results for ovarian cancer (n = 989)
Participants	989 women with ovarian out of a total of 14,527 women with all cancer types in the study 719 (73%) women were under the age of 75 and 270 (27%) were 75 years of age or older 20% and 24% of women had stage 1, 13% and 11% stage 2, 39% and 34% stage 3, 11% and 12% stage 4 and 17% and 20% were not staged in the specialised and general hospital groups, respectively
Interventions	Women treated at a hospital with radiotherapy and oncology departments Addenbrooke's in Cambridge, the Norfolk and Norwich hospital and Ipswich hospital (n = 475) Women treated at a district general hospital without radiotherapy and oncology departments data from six such hospitals was collected (n = 514)
Outcomes	Overall survival: District general hospital vs hospital with radiotherapy and oncology department (specialised centre): model 1 adjusted for 10‐year age band and sex; (HR= 1.12; 95% CI 0.97 to 1.30) model 2 after adjustment of the above factors and TNM tumour stage at diagnosis; (HR= 1.17; 95% CI 1.01 to 1.35) we changed the reference group to general hospital so that it was consistent and could be pooled in the meta‐analysis (HR= 0.89; 95% CI 0.77 to 1.03) and (HR= 0.85; 95% CI 0.74 to 0.98) using adjustments in models 1 and 2 respectively. We carried out a sensitivity analysis which included both estimates in the meta‐analysis)
Notes	The authors concluded that for the patients included in the study, survival up to 5 years after diagnosis was significantly worse for patients with ovarian, rectal, and breast tumours if they were aged under 75 years at diagnosis, and had their main treatment in hospitals without radiotherapy and oncology departments
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	High risk	Retrospective study
Allocation concealment (selection bias)	High risk	Concealment of allocation irrelevant to this study
Blinding (performance bias and detection bias) All outcomes	Unclear risk	Not reported
Incomplete outcome data (attrition bias) All outcomes	Low risk	Percentage analysed: 989/989 (100%)
Selective reporting (reporting bias)	Unclear risk	Insufficient information to permit judgement
Other bias	Unclear risk	Insufficient information to assess whether any additional bias may have been present
Relevant assignment criteria	Low risk	All invasive cancers for the sites fitting our inclusion criteria described below, diagnosed between 1989 and 1993 (to allow survival analyses to be performed for patients followed up until the end of 1998) and registered by the East Anglian Cancer Registry were identified. The inclusion criterion was defined as all cancer sites being considered by the Anglia and Oxford NHS Executive for which the registry has an adequate (at least 70%) proportion of cancers staged over the period. Thus we included colon, rectal, breast, melanoma, bladder and ovarian cancers. For local purposes, the data were initially analysed by individual hospital then grouped so that hospitals with radiotherapy and oncology departments (Addenbrooke’s in Cambridge, the Norfolk and Norwich Hospital, and Ipswich Hospital) [group 1] (7000 patients) could be compared with the six district general hospitals without radiotherapy and oncology departments [group 2] (7527 patients)
Representative intervention group	Unclear risk	Authors report Table 2 which shows percentage of patients presenting at each TNM tumour stage (UICC classification) at diagnosis by tumour type and age stratum, but it remains unclear whether the two groups are representative of women with ovarian cancer. They are certainly not representative of women with gynaecological cancer
Representative comparison group	Unclear risk	As above
Comparability of groups	Low risk	"Cox’s proportional hazards regression models (Cox, 1972) were analysed to investigate survival differences for patients treated at group 1 compared to group 2 hospitals adjusting for sex, age (in 10‐year age bands) and tumour stage at diagnosis"