For pediatric patients with localized diffuse large B-cell lymphoma being treated per COG ANHL 1131 in group B, do you feel it is necessary to complete all lumbar punctures with IT therapy?

For unresected group B/DLBL patients, most centers continue to give the IT therapy which included 9 prophylactic IT therapies. There is no published data that I am aware of reducing the IT dosing. We recently completed a pilot reducing the number of ITs to 5 by incorporating 2 doses of depocyt (which is no longer commercially available) in FAB group B patients with good results. I do admit to reducing/eliminating IT therapy in non-study patients with FAB group B disease on occasion. I recently had a child with isolated large cell lymphoma of bone that I felt had such a low risk of CNS disease that I just did the first diagnostic tap with IT but none of the others. But there is no data to support this!

I agree with @Dr. First Last that there is no evidence for reducing the number of IT treatments for patients treated according to ANHL 1131. But, notably, other successful treatments for stage 2 DLBCL use many fewer IT treatments. The NHL-BFM treatments include only 4 IT treatments for R2 risk group, which corresponds to group B low risk group on ANHL 1131. And the out-of-fashion but still useful POG 9219 protocol which included stage 1 and 2 DLBCL did not give ANY IT treatment to non-head and neck primaries, and 5 IT treatments to head and neck primaries.

So, I doubt it is necessary to give all IT treatments prescribed on ANHL 1131 for localized patients, it is hard to dissect out individual pieces of a protocol, and I err on the side of ca...