To add to your point, lymphoma is special because stage IV does not _inherently indicate mutagenic burden or tumor diversity. Metastatic solid tumors _have to

To add to your point, lymphoma is special because stage IV does not _inherently indicate mutagenic burden or tumor diversity. Metastatic solid tumors _have to had "privilege escalation" mutations. AND those _indicate an overall greater genetic diversity. As always diversity promotes adaptation and here evolutionary evasion of the disease. However, staging incidentally still correlates with survival in non-hodgekins lymphoma as it's generally a nasty tissue class misbehaving. Treatment options got much, much better tho, with monoclonal antibodies and immune therapy.