Thyroid supplementation for hypothyroidism. An latrogenic cause of breast cancer?
P. Mustacchi and F. Greenspan
In four subpopulations grouped by varying durations of thyroid
supplementation (none, one to five years, six to 15 years, and 15 years of
more), breast cancer frequency correlated positively with attained age. The
cancer experience of persons in the same age-group was relatively stable
regardless of how long women took thyroid supplements. The present data
support the provisional inference that breast cancer and duration of
thyroid therapy are both age-dependent and question the belief that
pretreatment with thyroid supplements increases the risk of breast cancer
development. Relationship of these two variables can only be determined by
prospective studies.