Table I.
Characteristics of the 10 studies included in the meta-analysis to assess the risk of endometrial cancer in females with PCOS.
| First author, year | Country | Study design | Characteristics of participants | Diagnostic criteria for PCOS | Diagnostic criteria for EC | Controlled for BMI? | Research findings | (Refs.) |
|---|---|---|---|---|---|---|---|---|
| Escobedo, 1991 | USA | Case-control | 399 females with EC aged 20–54 years; 3,040 age-matched randomly selected controls | Self-reported to trained interviewers; criteria type not stated | Histologically confirmed; physician diagnosed. Infertility patients | N | OR for EC of 4.2 (95% CI, 1.7-10.4) for ‘ovarian factor’ infertility | (31) |
| Niwa, 2000 | Japan | Case-control | 134 females with EC aged 40–70 years (42 premenopausal and 92 postmenopausal); 376 controls | Clinical data; diagnosis based on the criteria of Goldzieher (39) | Histologically confirmed primary carcinoma; physician diagnosed | N | Higher frequency of EC in a group of females with PCOS aged <40 years | (30) |
| Wild, 2000 | UK | Cohort | 786 females with PCOS with a mean age of 56.7 years (range, 38–98 years); 1,060 age-matched controls | Clinical data from various hospital records; criteria type not stated | General practice records of diagnosis and self-reported in questionnaires | Y | OR for EC of 5.3 (95% CI, 1.5-18.6). OR adjusted for BMI was 6.1 (95% CI, 1.0-36.9) | (32) |
| Iatrakis, 2006 | Greece | Case-control | 81 females with EC with a mean age of 46.3 years (range, 43–48 years); 100 female controls aged 43–48 years | Self-reported; criteria type not stated | Histologically confirmed carcinoma; physician diagnosed | N | Higher frequency in females with PCOS aged <50 years | (33) |
| Pillay, 2006 | UK | Cross-sectional | 128 females with EC with an age range of 20–90 years; 83 age-matched controls | Presence of PCO morphology as a marker of PCOS | Histologically confirmed | N | PCO was more prevalent in females with EC aged <50 years | (15) |
| Zucchetto, 2009 | Italy | Case-control | 454 females with EC with a median age of 60 years (range, 18–79 years); 908 controls with a median age of 61 years (range, 19–79 years) | Self-reported to trained interviewers; criteria type not stated | Histologically confirmed <1 year before hospitalisation, no earlier diagnosis | N | PCOS not associated with overall EC risk (OR, 1.25; 95% CI, 0.72-2.16); an increased risk among premenopausal females (OR, 2.03; 95% CI, 0.76-5.38) | (34) |
| Fearnley, 2010 | Australia | Case-control | 156 females with EC aged 18–79 years; 398 age-matched controls. Analyses restricted to females aged <50 years | Self-reported; criteria type not stated | Histologically confirmed; physician diagnosed | Y | 4-fold significantly increased risk of EC in females with PCOS | (35) |
| Kilicdag, 2011 | Turkey | Case-control | 417 premenopausal females with a mean age of 34.9 years. 52 with EC; 365 controls | Clinical data; diagnosis based on the Rotterdam criteria (3) | Histologically confirmed | N | More abnormal histology, including EC, in females with PCOS (9.6 vs. 1.1%; OR, 9.6; 95% CI, 2.5-37) | (27) |
| Shen, 2015 | Taiwan | Cohort | 3,566 females with PCOS; 14,264 controls. Median age at enrolment was 27 years | Clinical data; diagnosis based on ICD-9-CM code 256.4 (40) | Histologically confirmed; physician diagnosed | N | HR for developing EC during follow-up period was 10 times greater for females with PCOS | (29) |
| Ding, 2018 | Taiwan | Cohort | 8,155 females with PCOS aged 15–49 years; 32,620 age-matched randomly selected controls | Clinical data; diagnosis based on ICD-9-CM code 256.4 (40) | Clinical records; diagnosis based on ICD-9-CM code 182 (40) | N | Significantly increased risk of EC in PCOS group | (28) |
CI, confidence interval; BMI, body mass index; EC, endometrial cancer; HR, hazards ratio; OR, odds ratio; PCO, polycystic ovary; PCOS, polycystic ovarian syndrome; Y, yes; N, no.