Table 2 Effect estimates of cancer risk and mortality in studies comparing patients with untreated to treated subclinical hypothyroidism or euthyroidism

Kuijpens 2005 [8]

NA

NA

OR

1.9

0.8–4.9

More prevalent in women with previous or current diagnosis of breast cancer.

There was no association between subclinical hypothyroidism and the risk of breast cancer. However, women with a history of breast cancer were more likely to have anti-TPO antibodies.

Hellevik 2009 [15]

12,389

2149

HR

0.96

0.82–1.12

NA

There was no association between the risk of overall cancer incidence and TSH level of > 3.5mIU/L.

Mondul 2012 [60]

800 prostate cancer patients

401 controls

OR

0.71

0.47–1.06

NA

Men with elevated TSH levels were associated with a decreased risk of prostate cancer.

Razvi 2012 [16]

1634 (age 40–70);

819 (age > 70)

1459(age 40–70); 823 (age > 70)

HR

0.59 (age 40–70)

0.51 (age > 70)

0.21–0.99 (age 40–70)

0.24–1.09 (age > 70)

NA

Treatment of SCH was associated with a decreased risk of cancer mortality among adults age 40 to70 years.

Waring 2012 [64]

1248 (men age ≥ 65)

89 (men age ≥ 65)

RH

0.88

0.44–1.74

NA

Subclinical hypothyroidism was not associated with cancer mortality among men ≥65 years of age.

Boursi 2015 [7]

20,990 colorectal cancer patients

82,054 controls

OR

1.16

1.08–1.24

NA

SCH was associated with an increased risk of colorectal cancer.

Fighera 2015 [61]

NA

NA

OR

2.57

1.41–4.70

NA

Risk of thyroid carcinoma increased with increasing TSH levels above 1.64mIU/L.

Tseng 2015 [63]

113,905

1841

RR

1.51

1.06–2.15

NA

SCH was associated with an increased risk of cancer mortality.

Pinter 2017 [62]

548

69

HR

2.1

1.3–3.3

NA

Higher free thyroxine levels (i.e. > 1.66 vs. < 1.66 ng/dl) was associated with a higher overall survival of patients with HCC.