Falling incidence of ovarian cancer and oophorectomy

Oophorectomy-Corrected Ovarian Cancer Incidence, Survival, and Mortality by Subtype, Race, Ethnicity

https://tinyurl.com/tk4v75pj

Ovarian cancer is declining. This decrease is mostly attributed to hormonal contraception, which means fewer lifetime menstrual cycles. This effect has been noted for the almost 60 years that hormonal contraception has been available and has increased with time as the users aged. As other forms of contraception develop, oral hormonal contraception is now used by 11% of the US population.

Despite this, the incidence of ovarian cancer continues to fall; the reasons are not clear. One suggestion is that removal of ovaries (oophorectomy) for reasons other than cancer may have the effect of reducing ovarian cancer. This study looked at the SEER cancer registry. Almost 160000 cases of ovarian cancer were recorded during the period 2002-2019. The rate of ovarian cancer decreased by about 2% for white women and less, about 1.5% for black women.

The rate of prior oophorectomy for elderly women (aged 70+) remained stable at about 30%. If the population numbers are adjusted to allow for the oophorectomy, no further decrease in ovarian cancer incidence is seen.

The authors note that there has been an increase in fallopian duct cancer, especially for black women and that some of the decrease in ovarian cancer may be due to reclassification. Other factors such as decreased menstrual hormonal therapy and the longer lives of the oral contraception generation may be part of the reason for the decline; it remains unclear as to why this is so.