Thursday, September 4, 2014

Lifestyle Risks for Follicular Lymphoma

The Journal of the National Cancer Institute's Monographs has published a massive and fascinating study of risk factors in 11 types of Non-Hodgkin's Lymphoma, including Follicular Lymphoma. They come to some interesting conclusions, and they come with an important warning.

But first, the massive study itself: The International Lymphoma Epidemiology Consortium looked at 20 case-controlled studies of NHL (that is, studies that compared people with NHL to people without it), looking at a total of over 17,000 NHL patients and over 23,000 non-NHLers. They did some statistical wizardry to make sure everything was comparable, and then broke it all up into the 11 types of NHL to see what they could find. The studies came from a big chunk of the world -- North America, Europe, and Australia -- and they looked to see if there was any connection between getting an NHL subtype and factors such as medical history, family history, lifestyle, and occupation.

Of course, around here we're most interested in the Follicular Lymphoma study, aren't we?

For this study, they looked at 3,530 FL patients, comparing them with over 20,000 non-NHLers in the control group. Follicular Lymphoma has always been one of those funny cancers that hasn't had a lot of risk factors associated with it. Up until now, there seems to have been a connection between smoking and contracting Follicular Lymphoma, but most other factors have been big maybes. Maybe it's higher if you worked on a farm. Maybe it's higher if you were around certain chemicals. Maybe it's higher if you had serious infections. But nothing really definite.

This study did find some more definite connections. Comparing Follicular Lymphoma patients to non-NHL patients, they found that the risk of contracting Follicular Lymphoma is higher if you
  • have a first-degree relative with NHL 
  • had a high body mass index as a young adult
  • worked as a spray painter
  • are a woman with Sj√∂gren syndrome (an autoimmune disease)
On the other hand, risk is lower if you
  • have asthma, hay fever, and food allergy 
  • have received  blood transfusions 
  • have high recreational sun exposure 
  • have worked as a baker or miller
  • are a university/higher education teacher 
Now, to me, those are some really specific risk factors. (Do you know how many spray painters there are in the U.S. right now? Me neither, but it can't be many.)

So here are the important things to take away from this:

First, a risk factor does not automatically result in a health outcome. We've all known people who have smoked their whole lives who never developed lung cancer (or Follicular Lymphoma, for that matter). A risk factor shows an increased possibility of something, but not a definite outcome. From these lists, I have two of the factors that result in higher risk, and  two that result in lower risk. The two from the lower-risk helped me about as much as my non-cancer-sniffing dog has helped me. And there's no guarantee that the higher-risk factors resulted in my diagnosis.

Second, and maybe more importantly: I think we all have a tendency to want to know why we got this disease, especially because there's no obvious connection between risk factors and diagnosis. We can't say "Oh, I got it because I ate too many avocados as a kid. Everyone knows avocado eating leads to Follicular Lymphoma." There's nothing obvious that leads us to that conclusion.

And I think it's bad to try to make that connection. While it might satisfy our curiosity, I don't think it helps in any other ways. We have Follicular Lymphoma, and we're doing our best to educate ourselves about it and deal with it. Why dwell on the past? Does it help to say, "Oh, I never should have taken that job as a spray painter!" or "If only I'd taken that job as a baker, and spent my days off getting some recreational sun exposure!" That's done. That won't change the fact that we are Follicular Lymphoma patients right now. If knowing about risk factors just results in guilt, we're better off not knowing. We have enough negative emotions to deal with as it is.

So what's the point of a study like this?

Well, according to the researchers, it's not about individuals, and it's not about regretting the past. It's all about the future. If we can understand the kinds of risk factors that lead to different types of NHL, then maybe we can start to find clues about what causes it. There won't be a direct line between cause and effect -- cancer is never that easy. But maybe researchers can start asking some new questions about who gets NHL and who doesn't, and why. And maybe those broad questions lead to narrower ones, and they can start investigating things on a genetic level and figuring out why spray painting and BMI turns on some switches in our cells.

So, in some ways, this study doesn't matter. In others, it may matter a lot, some day.

For now, though, close this blog and leave the guilt behind.


Anonymous said...

Thanks for this.

I'm a fNHL patient with none of the factors that raise risk and three that lower risk. So, go figure.

One great thing about having had this disease is I don't worry about every other thing that might cause some other kind of cancer. Too late!

Lymphomaniac said...

I feel the same way. (But that doesn't mean you should start smoking or anything....)