I'm not sure what the best thing to do for this is, but I just wanted to make you aware of the discussion a couple of days ago in case you hadn't seen it.
It seems to me that if Knochenmarkkrebs is frequently used to mean multiple myeloma, the current entry is misleading not to mention that and by omission to suggest that 'bone marrow cancer' is in fact a commonly used term for that more specific disease, when actually it's just a description that could apply to any of several cancers.
It seemed to me that it might be very helpful to add a second entry along the lines of
multiple myeloma [med.] - der Knochenmarkkrebs (ugs.)
or if not (ugs.), then (nicht fachspr.) or whatever.
However, if you don't feel it's commonly used enough for that, it might be possible at least to add a link to that thread.
By the way, I might also call the hyphenation to your attention -- none of the other entries in which 'bone marrow' is used as an adjective are hyphenated. Either form is probably acceptable, with or without a hyphen, but they should probably all be consistent, and I personally would be inclined to omit the hyphen because 'bone marrow' is a fixed combination and can't easily be misread.
Finally, in looking this up, I also noticed the following typo:
damages bone marrow [med.] - geschädigtes Knochenmark