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Table 1 Characteristics of cohort and case-control studies of the association between endometriosis and endometrial cancer or breast cancer

From: The association between endometriosis and risk of endometrial cancer and breast cancer: a meta-analysis

Study, publication year and country

Study type

follow up time

Average age of baseline (years)

Sample size of the study

Endometriosis assessment

Age at diagnosis of endometriosis (years)

Cancer ascertainment

Adjusted RR(95%CI)

Adjustments

The way of information collection

NOS score

Kyung Jin Eoh, 2021, Korean [19]

cohort study

NA

endometriosis cohort:40.4 ± 8.4 control:44.0 ± 17.0

263,273

ICD code

≥20

ICD code

endometrial cancer: 4.59 (3.56–5.91) breast cancer: 1.44 (1.31–1.58)

Adjusted for age, insurance type, and comorbidities (diabetes, hypertension, hyperlipidemia, chronic obstructive pulmonary disease, chronic kidney disease, liver cirrhosis, and heart)

database

7

Fanghua Shen, 2020, China [39]

case- control study

–

NA

876

medical records

all ages

medical records

endometrial cancer: 0.36 (0.094–1.381)

Adjusted by age at diagnosis and parity

database

6

Frida E. Lundberg, 2019, Sweden [32]

cohort study

control cohort: 23.4 yearsa infertile cohort: 25.8 yearsa

NA

2,882,847

ICD code

all ages

ICD code

endometrial cancer: 0.94 (0.76–1.17) breast cancer: 1.02 (0.96–1.07)

EC: Adjusted for age, calendar time, education level, country of birth, parity and age at first birth, salpingectomy and bilateral oophorectomy BC: Adjusted for age, calendar time, education level, country of birth, parity and age at first birth, salpingectomy, hysterectomy and bilateral oophorectomy

database

6

Hsing-Chi Hsu, 2019, China [37]

cohort study

NA

nurses cohort:34.0 ± 7.66 control:34.0 ± 7.74

178,870

ICD code

> 20

ICD code

breast cancer: 0.62 (0.22–1.78)

Adjust for study cohort, age, and comorbidities with significant crude HR (cradiovascular disease and diabetes mellitus)

database

7

Liisu Saavalainen, 2018, Finland [31]

cohort study

16.8 yearsa

endometriosis cohort:36.4 ±?

49,933

surgery

10–60

ICD code

breast cancer: 0.99 (0.94–1.03)

–

database

4

Eric S. Surrey, 2018, American [21]

cohort study

NA

endometriosis cohort:36.5 ± 8.2 control:36.4 ± 8.4

134,805

ICD code

18–49

ICD code

endometrial cancer: 2.4 (1.6–3.8) breast cancer: 1.4 (1.1–1.7)

Adjust for age, state, and insurance type. Models also controlled for 15 Charlson–Deyo comorbidities measured during year before index date

database

8

Carrie L Williams, 2018, UK [25]

cohort study

8.8yearsa

endometriosis cohort:34.5 ± 4.8

225,786

patient reported and clinic reported information

all ages

ICD code

endometrial cancer: 0.75 (0.35–1.43) breast cancer: 0.98 (0.86–1.12)

–

database

4

Chih-Ching Yeh, 2018. China [34]

cohort study

NA

NA

120,582

ICD code

all ages

ICD code

endometrial cancer: 1.89 (1.07–3.35) breast cancer:0.99 (0.80–1.23)

Adjusted for the birth year and geographicregion, occupation, urbanization, monthly income, comorbidity

database

6

Leslie V. Farland, 2016, American [35]

cohort study

24 years

endometriosis cohort:35.6 ± 4.2 control:34.3 ± 4.7

16,325

laparoscopy or laparotom

25–42

medical records

breast cancer: 0.96 (0.88–1.06)

Adjust for age, calendar time, family history of breast cancer, age at menarche, body mass index, body mass index at age 18 years, smoking, biopsy confirmed benign breast disease, alcohol intake, recent health seeking behavior, birth weight, parity +age at first birth, breastfeeding, oral contraceptive

questionaire

7

L Saraswat, 2018, UK [22]

cohort study

29 years

endometriosis cohort:32.1 ± 7.3 general population cohort:32.1 ± 7.3

281,937

laparoscopy or laparotom

all ages

ICD code

endometrial cancer: 1.14 (0.57–2.28) breast cancer: 1.28 (1.06–1.54)

Adjust for age, socio-economic status and duration of follow up

database

6

Elizabeth M. Poole, 2017, America [36]

cohort study

18 years

endometriosis cohort:44.5 ± 4.5b control:44.5 ± 4.6b

107,721

self-report

all ages

medical records

endometrial cancer: 0.74 (0.39–1.42)

Adjusted for BMI, parity, duration of post-menopausal hormones (by type), age at menopause, age at menarche, menstrual irregularity, infertility history, and duration of oral contraceptive use

questionaire

7

Julie Brøchner Mogensen, 2016, Denmark [20]

cohort study

642,403 person-years

NA

45,790

clinical diagnoses

25–49

ICD code

endometrial cancer: 2.13 (1.77–2.55) breast cancer: 1.05 (1.00–1.11)

_

database

6

Hann-Chin Yu, 2015, China [33]

cohort study

10 years

_

139,392

ICD code

all ages

ICD code

endometrial cancer: 2.83 (1.49–5.35)

Adjusted HRs were adjusted for patients’ age, urbanization level, monthly income, geographic region, hypertension, hyperlipidemia, obesity, and diabetes mellitus

database

8

Victor C. Kok, 2015, China [29]

cohort study

endometriosis cohort:9842 patients-years control cohort:36274 person-years

_

11,330

ICD code

> 20

ICD code

endometrial cancer: 4.05 (1.20–13.66) breast cancer: 1.15 (0.61–2.15)

Adjusted for age group, diabetes mellitus, chronic kidney disease, liver cirrhosis, rheumatoid arthritis, and use of medroxyprogesterone acetate, norethindrone acetate, danazol, and GnRH agonist

database

8

Stefanie Burghaus, 2015, German [42]

case- control study

–

endometrial cancer cases:65.6 ± 10.5 controls:60.9 ± 9.3

1305

self-report

all ages

histopathology reports

endometrial cancer: 2.63 (1.28–5.41)

Adjusted for age, BMI, oral contraceptive use, pregnancies

questionnaire

6

Shu-Chun Chuang, 2015, China [41]

case- control study

–

–

24,420

ICD code

all ages

ICD code

breast cancer: 1.44 (1.15–1.80)

Adjusted for occupation, screen tests (never, once, and twice or above), and average ambulatory visit per year

database

6

Louise A. Brinton, 2014, American [30]

cohort study

30.0 yearsa

_

12,193

self-report

all ages

self-report and medical records

breast cancer: 1.12 (0.93–1.35)

Adjusted for study site, calendar year of first infertility evaluation and gravidity at first clinic visit

database and questionnaire

4

Jaime L. Matta, 2013, American [23]

case- control study

–

breast cancer cases:56.3 ±? controls:52.1 ±?

991

self-report

all ages

histopathology reports

breast cancer: 0.5 (0.30–0.90)

Adjusted by age, BMI, family history of breast cancer, menopause, alcohol use, smoking, multivitamin use, marital status, and saturated fat consumption

questionnaire

7

Luisa Morales, 2013, Puerto Rico [24]

case- control study

–

breast cancer cases:56.4 ± 12.6 controls:52.3 ± 12.5

1126

self-report

all ages

histopathology reports

breast cancer: 0.61 (0.30–1.00)

Adjusted by age, BMI, family history of breast cancer, menopause, number of children, alcohol use, smoking, vitamin use

questionnaire

4

Ingrid J. Rowlands, 2011, Australia [40]

case- control study

–

endometrial cancer cases:61.29 ± 9.5 controls:60.83 ± 9.8

2938

self-report

all ages

histopathology reports

endometrial cancer: 1.47 (1.00–2.17)

Adjusted for age (in years), age at menarche (in years), parous (no, yes), duration of OC use (never, b 60 months; ≥60 months), HRT use (≥ 3 months,<  3 months), smoking (ever, never), BMI (kg/m2)

questionnaire

6

Hazel B. Nichols, 2011, American [38]

case- control study

–

breast cancer cases:66.2 ± 7.4 controls:65.0 ± 7.5

10,046

self-report

all ages

medical records

breast cancer: 0.99 (0.80–1.21)

Adjusted for age, US state, age at menarche, duration of oral contraceptive use, parity, age at first birth, age at menopause, postmenopausal hormone use, body mass index, mammography screening, and family history of breast cancer

telephone interview

7

  1. NA Information not available, RR Relative risk, CI Confidence interval;-a medium follow-up time;-b at midpoint of follow-up