A new study out of the Netherlands and published in Human Reproduction is making the news today. It is entitled "Risk of borderline and invasive ovarian tumours after ovarian stimulation for in vitro fertilization in a large Dutch cohort". Reuters picked it up as "Fertility treatment raises tumor risk in study".
It is of course understandable that Path2Parenthood's phones have been ringing off the hook. Women are alarmed by this report. Briefly, I wanted to share a few facts about the study and urge you to please relax while you read this.
This long term study compared women who had done in vitro fertilization (IVF) with two other groups of women; 1)the general population, and 2)sub fertile women who had not done IVF. The researchers reported an increased risk level for the IVF group of developing borderline ovarian tumors. The research also showed that the overall incidence of invasive ovarian cancer was not significantly elevated, but increased with longer follow up.
The important thing to note here is that borderline ovarian tumors are actually cysts of low malignant potential. I am not minimizing the value of this study However, the term as is being reported in Reuters and picked up by media outlets, that women are twice as likely to develop ovarian cancer after IVF, is misleading. Patient's individual risk of getting ovarian cancer if they do IVF is not 50% higher than it would be were they not undergoing treatment. The increased risk of acquiring invasive ovarian cancer for this group is around 1.76% greater after 15 years. If you however, put together the statistics for borderline ovarian tumors along with the statistics for ovarian malignancies, the rate goes up to 4.23%. That being said, we don't want women to wind up in either group if they can help it.
I reached out to Dan Potter, M.D. to get his opinion on the study. His comments, verbatim, were:
"This is no different than the study that was published here in the U.S. about 10 years ago. The lead author is an epidemiologist. Oftimes in studies such as this, the researcher starts with the conclusion they wish to arrive at and then they work backward to prove it. I'm not saying that's what happened here, but these are the most problematic issues that I see in this study.
1. They linked all of the ‘malignancies’ in the registry to patients in the two study groups (IVF and non-IVF) regardless of whether they returned the surveys or not. This creates a falsely high incidence. They compared them to ‘general population rates’ who basically have the equivalent of a survey return rate of 100%. See how they appeared to start at the conclusion and work backwards?
2. Borderline tumors, also known as tumors of ‘low malignant potential’ or LMP are not malignancies. There is no such thing as ‘invasive cancer’ and ‘non-invasive cancer’. Cancer is invasive. Borderline tumors are not cancer and while not benign have low malignant potential. The 5 year survival rate of borderline serous tumors (the most common type) is ….…100%.
3. They seem to speak of ‘invasive cancer’ and consider the borderline tumors ‘non-invasive’ cancer. The definition of malignancy is invasion so this simply does not make sense from a medical perspective.
4. Their control group is women diagnosed with infertility that did not do IVF. They did not stratify these patients as to whether they became pregnant or whether they were on the birth control pill, both known protective factors. In fact, there is not control for whether the patient even had a hysterectomy or oophorectomy for endometriosis. It is hard to get ovarian cancer when you do not have ovaries. Prior use of fertility drugs in the controls may have led to pregnancy so that they did not pursue IVF. Pregnancy, BCPs, oophorectomy are all protective.
5. There were 19,146 patients in the IVF group and 28 ‘invasive cancers’. Using their methodology they would have expected 21. Both of these number are very high compared to what we would expect in the US (about 10x higher). Not sure why they diagnose it more frequently there."
So, to sum it up. You should absolutely discuss this study with your physician and weigh your own personal risk, based on medical and family history and genetic background. And, if you want to talk about it, please feel free to call.