Does Hysterectomy Increase Thyroid Cancer Risk?

The Research Linking Cancer and Hysterectomy

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According to a Finnish research study published in 2003, a woman's chance of developing thyroid cancer may be doubled in the first 18 months after the hysterectomy surgery. The researchers found that women who had a hysterectomy were twice as likely as other women to be diagnosed with thyroid cancer within 6 months to 18 months after the operation.

The authors note that the risk of thyroid cancer likely increases as a result of the conditions that cause a woman to undergo hysterectomy, and not from the procedure itself.

According to the study, the risk of thyroid cancer among women who underwent hysterectomy was almost 40% higher than average, but the risks drop substantially more than 18 months post-surgery.

The researchers have claimed that they do not believe that hysterectomy itself caused increased risk of thyroid cancer. Rather, there appears to be some sort of connection or common background between the reason for the hysterectomy -- usually benign tumors called uterine fibroids, or excessive menstrual bleeding--and thyroid cancer.

More Research Linking Hysterectomy and Cancer

In a study titled "Long-term cancer risk after hysterectomy on benign implications: population based cohort study," which was accepted for publication by the International Journal of Cancer in 2016, Swedish researcher more generally look at the incidence of cancer among people who receive hysterectomy for benign causes.

The researchers note that previous research has shown an increased risk of women developing not only thyroid cancer after hysterectomy but also ovarian and renal (kidney) cancer.

This increased risk is shown in women with hysterectomy who do not also have bilateral salpingo-oophorectomy (BSO), or removal of the ovaries. Apparently, when the ovaries stay in the body, the hormones that they produce might be linked to the development of cancer.

Here are some of the researcher's findings based on a population study:

  • For both women with hysterectomy alone and hysterectomy with BSO, there was a marginal overall decrease in the risk of all types of cancer.
  • For both women with hysterectomy alone and hysterectomy with BSO, there was an increase in the risk of thyroid and brain cancer.
  • For both women with hysterectomy alone and hysterectomy with BSO, there was no increase in the risk of breast, lung or gastrointestinal cancer.

Please note once again that the Swedish women studied by the researchers had hysterectomy for reasons other than cancer.

The Swiss researchers conclude that hysterectomy both with and without BSO probably doesn't increase risk of cancer by a more general mechanism but rather has something to do with hormones.

What Does an Association Between Hysterectomy and Cancer Mean?

Please keep in mind that the above research uses relative risks to explain an association between hysterectomy and cancer. In other words, even if the risk is increased, it's very possible that only small numbers of women actually develop thyroid cancer after hysterectomy.

In conclusion, if your physician confirms that you need a hysterectomy, you should still follow his or her advice -- despite concerns about increased cancer risk. However, it may be a good idea to keep the above research in mind in the months and years following surgery.

Specifically, you should be aware of any changes in your body that may indicate thyroid changes, or thyroid cancer. For example, thyroid enlargement, hoarseness, neck sensitivity, or tenderness in the neck can all be symptoms of thyroid nodules or cancer. If you notice any changes in your thyroid, follow-up with your physician immediately.

You should also consider making sure that a complete thyroid panel -- TSH, Free T4 and Free T3 tests -- are done annually after hysterectomy, to ensure that any developing thyroid conditions are not overlooked.

Selected Sources

Article titled "Long-term cancer risk after hysterectomy on benign implications: population based cohort study" by D Altman and co-authors accepted for publication in the International Journal of Cancer in 2016. Accessed on 1/28/2016.

American Journal of Obstetrics and Gynecology 2003;188:45-48.

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