Secondary malignant neoplasm is a malignant tumor whose cause is the treatment (usually radiation or chemotherapy) which was used for a prior tumor. It must be distinguished from

Metastasis Metastasis is a pathogenic agent's spreading from an initial or primary site to a different or secondary site within the host's body; the term is typically used when referring to metastasis by a cancerous tumor. The newly pathological sites, ...

from the prior tumor or a relapse from it since a secondary malignant neoplasm is a different tumor.

References

Medical terminology {{Oncology-stub