Allogeneic Transplant A Cure for FL?

Very interesting research from the journal Bone Marrow Transplantation that says an Allogeneic Stem Cell Transplant might cure some patients with Follicular Lymphoma.

There's a lot going on here, and maybe some background information required to understand all of this. It's going to be harder because I don't have access to this journal (and I can't afford to access it), so I'm going only by the abstract to the article (which is called "Allogeneic Hematopoietic Cell Transplantation as Curative Therapy for Non-Transformed Follicular Lymphomas").  I'm going to be very careful about letting you know what I don't know, since I haven't seen the whole article.

First off, a quick review of what a Stem Cell Transplant (or Hematopoietic Cell Transplant) is.

For some blood cancer cancer patients, the best course of action is to essentially wipe out their immune system. If the source of their cancer is their bone marrow, for example, using strong chemotherapy (or other treatment like radiation) destroys the bone marrow and thus the source of the cancer cells. The problem is, the bone marrow is also the source of the immune cells that do the normal job of protecting the body. That means the patient is unprotected while the body rebuilds the bone marrow and the immune cells. On its own, this can take up to a month. A Stem Cell Transplant cuts that time down by putting immune cells into the blood. Instead of a month, the immune system can be rebuilt in 7-10 days, so the body gets protected that much sooner.

Sometimes the immune cells that are put into the body come from the patient (they are removed before the heavy chemo is given) -- this is called an Autologous Stem cell Transplant (or Auto SCT). Sometimes the cells come from someone else (maybe a family member) -- this is called an Allogeneic Stem Cell Transplant (or Allo SCT).

Auto SCT is "gentler" on the body because the cells are already recognized by the patient's body and won't be rejected, which is a danger with an Allo SCT (when that happens, it's called Graft vs Host Disease, and is a very bad thing). But Auto SCT also has the danger of having some of those saved immune cells be the cancer cells that the patient is trying to get rid of, so Allo SCT is often more effective. But either type of SCT has the risk of severe infection if that 7-10 days without an immune system becomes a problem.

(If you want to learn more about Stem Cell Transplants, Lymphomation.org does its usual good job of giving way more detail than I can give here.)

Now, as far as Stem Cell Transplants being a cure for Follicular Lymphoma, there have been some small studies in the last few years that suggest that this might be true. And this is another one.

Once again, let me be clear that I am only seeing the abstract, a summary of the research, so I don't have all the details. But here's what I can tell:

The researchers are aware that Allo SCT (that is, a Stem Cell Transplant where the cells come from a donor) might cure FL. They are interested in figuring out which sub-groups of patients might benefit most from the procedure.

This is a retrospective study, which means they looked back at patients from the past to see how they did after getting an Allo SCT. The researchers looked at the records of 146 patients from Germany who received an Allo SCT between 1998 and 2008. The Overall Survival for the group was 67% for 1 year, 60% for 2 years, and 53% for 5 years. Those numbers are kind of low for Follicular Lymphoma, but Allo STC is usually given to patients with pretty aggressive disease, so those numbers make sense. 100 Day NRM was 15% (that is, after 100 days, Non-Relapse Mortality, or the number of patients who died from something other than the disease, was 15%. The 100 days is a standard measure, since many problems like Graft vs Host Disease will occur in that time.)

What they found was that certain subgroups seem to do very well with Allo SCT -- those who had limited Graft vs Host Disease issues, were 42 years old or younger,  and who had Total Body Irradiation as their conditioning (in other words, their immune system was wiped out with radiation rather than chemotherapy, or in addition to chemotherapy). This makes sense to me, given what I know about Stem Cell Transplants. Graft vs Host Disease is a big problem, so not having it will be good news. I have heard of oncologists who recommend SCT for younger patients, so that makes sense, too. And I have read that TBI is an excellent conditioning, since it suppresses anything left of the immune system, which cuts down on Graft vs Host, and also kills some cancer cells on its own.

So no big surprises there. But they also say that patients over 55 benefited, too, so that may be the key finding here -- even older folks can be cured (though they recommend patients 42 and under are the preferred group).

So, once again I will say, I haven't seen all of the details here. But the recommendation is clear -- SCT should be considered as a potential cure. But SCT comes with a whole lot of potential dangers, too (again, see the Lymphomation.org piece linked above), so it's not going to be for everyone.

Given that it's a pretty aggressive approach, it kind of goes against the trend of using less aggressive, more targeted treatments that might control the disease instead of curing it. But a cure is certainly still a valid approach, with the big risks to go with the big reward.

If nothing else, it's a good reminder that we do have that arrow in the quiver -- that option for a treatment that hasn't been talked about much these days.