WHO grades

This month's British Journal of Haematology has an article titled "Clinical Significance of the WHO Grades of Follicular Lymphoma in a Population-Based Cohort of 505 Patients with Long Follow-Up Times."

As titles go, it doesn't exactly roll off the tongue like Mourning Becomes Electra, but it does have some significant findings. First off, a word about WHO (World Health Organization) grading systems: for Follicular NHL, each diagnosis is classified by a stage (where in the body the lymphoma is located) and a grade (a measure of how aggressive the lymphoma is). The grading classifications have changed over the years, but the most recent system assigns each lymphoma as grade 1, grade 2, grade 3a, or grade3b. This study tries to help solve the controversy over the 3a/3b distinction.

The researchers found, in examining 505 biopsy samples, that grades 1,2, and 3a can be considered indolent (slow-growing) and incurable. Grade 3b, however, is found to behave much like Diffuse Large B-Cell Lymphoma, a much more aggressive NHL. It also found that, unlike the other stages, 3b is curable for many patients, assuming they are treated early and aggressively, with anthracycline-based treatment (like CHOP).

This seems to back up one way of thinking about the 3a/3b distinction, the way that treats them as being different. There are still others who believe 3a and 3b are more alike than different, and that probably won't change.

It seems to me that there will be some other important things that come out of this.

First has to do with treatment. In addition to 3b, like DLBCL, being successfully treated with CHOP, the study also found that 3a responds well to Rituxan, like the other indolent lymphomas (grade 1 and 2). Put those two together and I think you'll have even more movement away from CHOP as a standard treatment for fNHL, unless it is the more aggressive 3b. It will probably be more and more reserved as a treatment for transformed fNHL.

Second, I think the study will provide even more evidence for distinguishing between fNHL types on a genetic level. The authors point out that the genetic change that creates fNHL (chromosomes 14 and 18 switch with one another) is found in 73% of 3a cases, but only 13% of 3b cases. On the other hand, other chromosomal changes are more likely to be in 3b. There's lots of science there, but the point is, if you look at the diseases at the smallest level, 3a and 3b seem to be distinct. I see this confirmation as important for personalization purposes: the more we know about what separates the two types, the more likely we can tailor effective treatments to the patients who exhibit those properties.

Of course, as someone who is mostly grade 1 with a little grade 2, this study doesn't directly affect me. But I do think it has some important implications for the Follicular NHL population as a whole.