To the Editors:

Correct and universal terminology to define disease processes or therapies in medicine is an invaluable tool for precise communication among physicians and researchers. Medical oncology, as a quickly developing discipline in every aspects, crucially needs new terminologies. Systemic chemotherapy administration is categorized into several groups such as neoadjuvant, adjuvant, and palliative. In the “neoadjuvant” category, in addition to targeting micrometastatic malignant cells, the intent is usually to shrink a locally advanced tumor enough to be surgically removed. In the “adjuvant” category, our only aim is to eradicate micrometastatic tumor cells after the primary tumor is removed. In the “metastatic” category, the intent is to control malignancy, which is radiologically detectable, for extending survival or symptomatic palliation. However, not every clinical scenario fits into these criteria.

The latest developments in surgery and chemotherapy have enabled us to prolong the survival of, and even cure, patients via metastasectomy and chemotherapy, even though they have “metastatic” disease.1–3. The clinical scenario after surgery in patients without detectable cancer by imaging is called “no evidence of disease” (NED). The systemic chemotherapy administered in this setting does not fit into any of the categorizations defined above. Should we call it “adjuvant”? But the patient has metastatic disease even though the condition is NED. Should we call it “metastatic”? But the patient has no overt disease by imaging.

There is a crucial need for a new term to categorize the chemotherapy administration in the NED setting because neither the term “adjuvant” nor the term “metastatic” precisely cover it. We suggest the terms “m-neoadjuvant” and “m-adjuvant” for neoadjuvant and adjuvant administration in potential NED cases before and NED disease after metastasectomy, respectively. The “m” here stands for “metastatic.”