Breasts, cancer and getting older
April 22, 2021 7:18 AM Subscribe
Is there a proven link (via credible studies) between a rise in breast cancer risk, and the age of first pregnancy?
I have heard and read that studies show that the older a woman is at her first pregnancy, specifically age 35 and up, the higher the risk of developing breast cancer later in life. Unfortunately, I am not scientifically trained, nor especially well-versed in how the human body works, so what looks like a "good study" to me, may not be that at all. The information I have found so far seems to indicate that the reason this link exists (or may exist) is because a woman's breasts do not finish developing until she is pregnant. The sudden increase in cell growth and development apparently is a factor behind this risk, as is increased exposure to estrogen. If this is accurate, it is a pronounced enough risk to affect future decisions about whether I will ever get pregnant.
Recently, I was talking to my doctor about this, and I asked them about this link, in the context of my health. The doctor immediately waved my concerns away. "Oh no, if that were true, nobody would ever want to get pregnant," they said. When I tried to discuss it further, they got annoyed, cut me off, and gave me a lecture about how the risk of cancer increases the older one gets, full stop. That is something I am very well aware of and did not need a lecture on. Now I was annoyed, because they weren't listening to me. However, I kept silent and let them talk, because in the end they are medically trained and I am not. Now, though, this question is bugging me. Is there a definitive link between age of first pregnancy and an increased risk of breast cancer later in life, or not?
Any leads to credible studies on this question, one way or another, or information from anyone here who is in the field, who could clarify this question for me, would be much appreciated. (Not as my doctor, not as someone giving me medical advice, etc.)
I have heard and read that studies show that the older a woman is at her first pregnancy, specifically age 35 and up, the higher the risk of developing breast cancer later in life. Unfortunately, I am not scientifically trained, nor especially well-versed in how the human body works, so what looks like a "good study" to me, may not be that at all. The information I have found so far seems to indicate that the reason this link exists (or may exist) is because a woman's breasts do not finish developing until she is pregnant. The sudden increase in cell growth and development apparently is a factor behind this risk, as is increased exposure to estrogen. If this is accurate, it is a pronounced enough risk to affect future decisions about whether I will ever get pregnant.
Recently, I was talking to my doctor about this, and I asked them about this link, in the context of my health. The doctor immediately waved my concerns away. "Oh no, if that were true, nobody would ever want to get pregnant," they said. When I tried to discuss it further, they got annoyed, cut me off, and gave me a lecture about how the risk of cancer increases the older one gets, full stop. That is something I am very well aware of and did not need a lecture on. Now I was annoyed, because they weren't listening to me. However, I kept silent and let them talk, because in the end they are medically trained and I am not. Now, though, this question is bugging me. Is there a definitive link between age of first pregnancy and an increased risk of breast cancer later in life, or not?
Any leads to credible studies on this question, one way or another, or information from anyone here who is in the field, who could clarify this question for me, would be much appreciated. (Not as my doctor, not as someone giving me medical advice, etc.)
Here's what the National Cancer Institute has to say about this. So yeah, it seems to be established that age of first pregnancy is associated with breast cancer risk. But so are a lot of things, and it's not clear to me how much one's risk increases or decreases based on that factor. I'm a person with a lot of risk factors for breast cancer, and I tend to think that fixating on any particular risk factor is kind of crazy-making and probably not very productive.
posted by ArbitraryAndCapricious at 7:30 AM on April 22, 2021 [2 favorites]
posted by ArbitraryAndCapricious at 7:30 AM on April 22, 2021 [2 favorites]
No doctor should ever talk to you that way, nor should they be so cavalier or definitive when talking about cancer, particularly breast cancer. I would get a new doc asap. We learn more and more about breast cancers, the risks and treatments every day (no joke). I have spoken with many docs who are better informed and more empathetic and humble on this point: if you can, find you one of those.
posted by pazazygeek at 8:03 AM on April 22, 2021 [5 favorites]
posted by pazazygeek at 8:03 AM on April 22, 2021 [5 favorites]
Response by poster: I had actually already found the above links on my own, and I was referring to these when I spoke to my doctor. I am looking for links to studies or reports published in actual medical journals, if any such articles exist.
posted by Crystal Fox at 9:23 AM on April 22, 2021
posted by Crystal Fox at 9:23 AM on April 22, 2021
This? Along with links to similar articles.
Excerpt from the abstract:
"It is well established that childless women and women having children later in life are at an increased risk of developing breast cancer. In particular, women having a first child before 20 years of age have a 50% reduction in lifetime breast cancer risk when compared with women who do not have children. This protective effect is specific for estrogen receptor positive breast cancer. Nevertheless, it remains unclear how parity decreases breast cancer risk..."
posted by kitcat at 9:32 AM on April 22, 2021
Excerpt from the abstract:
"It is well established that childless women and women having children later in life are at an increased risk of developing breast cancer. In particular, women having a first child before 20 years of age have a 50% reduction in lifetime breast cancer risk when compared with women who do not have children. This protective effect is specific for estrogen receptor positive breast cancer. Nevertheless, it remains unclear how parity decreases breast cancer risk..."
posted by kitcat at 9:32 AM on April 22, 2021
Go look in PubMed. You can find a lot of article abstracts and some full-text articles. Search terms you could use include "advanced maternal age" pregnancy "breast cancer".
I used to tell undergraduate students that they (like you) were not expected to fully understand scientific articles but if they could understand the abstract they should be brave and look through the article. I told them them to skip parts that they didn't understand the first time they read the article but to be sure to read the discussion and conclusions, and then go back and read it again.
Women who don't have kids seem to get breast cancer more too, so how do you balance it? If you really want to have kids then maybe you should. If you're just looking for yet another reason to NOT have kids that's ok too, but if that's the case then I wonder if there are people pressuring you to have kids.
posted by mareli at 9:52 AM on April 22, 2021
I used to tell undergraduate students that they (like you) were not expected to fully understand scientific articles but if they could understand the abstract they should be brave and look through the article. I told them them to skip parts that they didn't understand the first time they read the article but to be sure to read the discussion and conclusions, and then go back and read it again.
Women who don't have kids seem to get breast cancer more too, so how do you balance it? If you really want to have kids then maybe you should. If you're just looking for yet another reason to NOT have kids that's ok too, but if that's the case then I wonder if there are people pressuring you to have kids.
posted by mareli at 9:52 AM on April 22, 2021
Did you already look through the references for the first two links? They do direct you to the actual studies in medical journals (and textbooks) that the linked articles are summarizing.
For example, "This may explain why women who have their first child at a later age have a higher risk of breast cancer than women who have their first child at a younger age.1,3 " directs you to these two studies:
1. Lambe M, Hsieh C, Trichopoulos D, Ekbom A, Pavia M, Adami HO. Transient increase in the risk of breast cancer after giving birth. N Engl J Med. 331(1):5-9, 1994.
3. Willett WC, Tamimi RM, Hankinson SE, Hunter DJ, Colditz GA. Chapter 20: Nongenetic Factors in the Causation of Breast Cancer, in Harris JR, Lippman ME, Morrow M, Osborne CK. Diseases of the Breast, 4th edition, Lippincott Williams & Wilkins, 2010.
The second one is a book but for articles like #1 you can google the citations or look in pub med. Keep in mind that often the full text of the articles aren't available without a subscription (it looks like that one is available) but there are places or friendly mefites that can help you access them anyway.
posted by randomnity at 10:01 AM on April 22, 2021 [3 favorites]
For example, "This may explain why women who have their first child at a later age have a higher risk of breast cancer than women who have their first child at a younger age.1,3 " directs you to these two studies:
1. Lambe M, Hsieh C, Trichopoulos D, Ekbom A, Pavia M, Adami HO. Transient increase in the risk of breast cancer after giving birth. N Engl J Med. 331(1):5-9, 1994.
3. Willett WC, Tamimi RM, Hankinson SE, Hunter DJ, Colditz GA. Chapter 20: Nongenetic Factors in the Causation of Breast Cancer, in Harris JR, Lippman ME, Morrow M, Osborne CK. Diseases of the Breast, 4th edition, Lippincott Williams & Wilkins, 2010.
The second one is a book but for articles like #1 you can google the citations or look in pub med. Keep in mind that often the full text of the articles aren't available without a subscription (it looks like that one is available) but there are places or friendly mefites that can help you access them anyway.
posted by randomnity at 10:01 AM on April 22, 2021 [3 favorites]
I’ll say (as a scientist but not in this field) that the papers that the NCI and Susan G. Komen Foundation reference are from reliable peer-reviewed journals, and that the papers they link to, in turn, are likely to be as well. What peer review means is that at least 3 people in their fields who read those papers agree that the science and the conclusions make sense. I would start with those. If you come to a paywall, I’d reach out to a librarian in your community, because they probably know ways of accessing those papers for you. (Paywalls for scientific papers are not an indicator of quality one way or the other.)
Another route would be to look up the “corresponding author” for any of those papers that touch on the kinds of things you’re interested in. They probably have a page with their full list of papers somewhere, sometimes with links straight to PDFs, and again are likely to be people doing real science.
That being said, sometimes papers disagree. Who’s right? That is one if the hard things about science, and from a scientist’s point of view what I’d say is that contradicting papers probably means that things are messy and we don’t have all the answers yet. Which is annoying if you are trying to base life decisions on science!
posted by tchemgrrl at 10:09 AM on April 22, 2021 [4 favorites]
Another route would be to look up the “corresponding author” for any of those papers that touch on the kinds of things you’re interested in. They probably have a page with their full list of papers somewhere, sometimes with links straight to PDFs, and again are likely to be people doing real science.
That being said, sometimes papers disagree. Who’s right? That is one if the hard things about science, and from a scientist’s point of view what I’d say is that contradicting papers probably means that things are messy and we don’t have all the answers yet. Which is annoying if you are trying to base life decisions on science!
posted by tchemgrrl at 10:09 AM on April 22, 2021 [4 favorites]
Response by poster: This is the information I wanted. Thanks everyone who chimed in. It really makes me feel better that I wasn't spouting random nonsense at the doctor, that there was in fact a valid basis for what I was thinking, whether or not the doctor is ultimately correct in their assumption.
posted by Crystal Fox at 4:20 PM on April 22, 2021
posted by Crystal Fox at 4:20 PM on April 22, 2021
Another scientist here (but not in this field). I would suggest that what you really want is a review article. That's what I look for when I'm unfamiliar with a field. It summarizes the current understanding of a question, drawing on many primary journal articles (the ones who did the studies). These review articles are peer-reviewed too, usually MUCH easier to read than primary articles, and helps a person not an expert in the field put all the individual studies in perspective.
Here's one.
posted by pH Indicating Socks at 4:48 PM on April 22, 2021 [1 favorite]
Here's one.
posted by pH Indicating Socks at 4:48 PM on April 22, 2021 [1 favorite]
Here's a better one, because newer and it puts maternal age in context of other risk factors.
posted by pH Indicating Socks at 4:55 PM on April 22, 2021
posted by pH Indicating Socks at 4:55 PM on April 22, 2021
Just wanted to be very clear that having a full-term pregnancy is a important protective factor (see pH's link). So more babies (up to 5) at a younger age is best, and if I'm understanding it right, no babies is worse than being older when you have babies. Breast feeding is also a protective factor (but of course correlated with having babies in the first place).
You may already know this but sometime readers forget that all of these are relative the underlying base line risk. The lifetime risk is 12.4% so a 25% increase doesn't mean your risk of getting goes up 25 percentage points (12.4 % to 37.4%) but rather 25% compared to the base. (12.4% to 15.5%)
Personally, having a child such a huge, life-changing commitment that I would be doing what felt right for me (and my partner) with regard to child birth and focus more on managing the other risk factors (obesity, smoking, alcohol, exercise, vitamin D) but that's not the question you asked.
posted by metahawk at 12:00 PM on April 23, 2021 [4 favorites]
You may already know this but sometime readers forget that all of these are relative the underlying base line risk. The lifetime risk is 12.4% so a 25% increase doesn't mean your risk of getting goes up 25 percentage points (12.4 % to 37.4%) but rather 25% compared to the base. (12.4% to 15.5%)
Personally, having a child such a huge, life-changing commitment that I would be doing what felt right for me (and my partner) with regard to child birth and focus more on managing the other risk factors (obesity, smoking, alcohol, exercise, vitamin D) but that's not the question you asked.
posted by metahawk at 12:00 PM on April 23, 2021 [4 favorites]
This thread is closed to new comments.
posted by SageTrail at 7:26 AM on April 22, 2021 [1 favorite]