By Anna C. Greene, PhD, NETRF Chief Scientific Officer
The language used to describe neuroendocrine cancer is complex, and it is not always used consistently.
Patients encounter an alphabet soup of terms: NET, NEN, NEC, neuroendocrine cancer, carcinoid, neuroendocrine differentiation, well differentiated, poorly differentiated, high grade, low grade. Some describe different diseases. Some are older names that remain in use. Some are appropriate in one organ but not another. And sometimes the same term is used differently by different specialists.
If that sounds confusing, it is.
The problem starts upstream. Researchers, pathologists, and clinicians do not always use these terms consistently. Those inconsistencies then flow into scientific publications, pathology reports, educational materials, advocacy resources, and ultimately the language patients encounter when trying to understand their diagnosis.
A paper about classification illustrates the problem
A 2025 review in Endocrine Pathology, “Reappraisal of Neuroendocrine Tumor Classification of the Prostate Gland: Translating Molecular Insights into Clinical Practice,” provides a striking example.
The paper examines how neuroendocrine cancers of the prostate should be classified. Yet the terminology within it demonstrates how difficult that task has become.
The authors frequently use “neuroendocrine tumor,” or NET, broadly for neuroendocrine cancers of the prostate, including entities such as small cell and large cell neuroendocrine carcinomas. Elsewhere, they use the broader term “neuroendocrine neoplasms,” or NENs, consistent with current World Health Organization terminology.
That difference may sound minor. It is not.
Under the common classification framework developed by the International Agency for Research on Cancer and the World Health Organization, neuroendocrine neoplasm is the broader category:
NEN: neuroendocrine neoplasm
– NET: well-differentiated neuroendocrine tumor
– NEC: poorly differentiated neuroendocrine carcinoma
Under this framework, a neuroendocrine carcinoma is therefore not a type of neuroendocrine tumor. NET and NEC describe different categories of neuroendocrine cancer.
Yet a reader of this paper can encounter “NET” being used both as a specific pathological category and, effectively, as shorthand for the entire group.
For a specialist immersed in the prostate cancer literature, the intended meaning may be apparent from context. For everyone else, it may not be.
How did we get here?
Neuroendocrine cancers can arise in many organs, and historically they were classified within those individual organ systems. Gastrointestinal, thoracic, endocrine, genitourinary, and other specialties developed their own terminology and diagnostic traditions.
The effort to create a common WHO framework for neuroendocrine neoplasms was intended, in part, to address exactly this problem. But changing a classification system does not instantly erase decades of medical language.
“Carcinoid” is one example. Many patients still encounter the term in medical records, publications, and conversations. Today, NET is generally preferred for well-differentiated neuroendocrine neoplasms, but carcinoid has not disappeared entirely. Typical carcinoid and atypical carcinoid, for example, remain established terms for lung NETs.
Prostate cancer has its own additional vocabulary, including neuroendocrine prostate cancer, or NEPC, treatment-related NEPC, neuroendocrine differentiation, and neuroendocrine carcinoma. Those terms do not necessarily describe the same biological phenomenon.
The vocabulary is trying to describe genuinely complicated biology. But sometimes the vocabulary adds another layer of complexity rather than helping us understand it.
Why words matter
It would be easy to dismiss this as a debate among pathologists about nomenclature.
Patients do not have that luxury.
Imagine being newly diagnosed and reading “neuroendocrine carcinoma,” or NEC, on your pathology report.
You search for that exact diagnosis. One source explains that NEC is distinct from a neuroendocrine tumor, or NET. Another uses “neuroendocrine tumor” broadly enough to include neuroendocrine carcinomas. A scientific paper may use an organ-specific term such as neuroendocrine prostate cancer. Older literature may use terminology that is no longer preferred.
Now you have a very reasonable question: Are all of these sources talking about my cancer?
That uncertainty is not created by the patient. It reflects inconsistent terminology in the medical and scientific literature, which then carries into educational materials, advocacy resources, and online information.
The distinction matters because NETs and NECs can have very different biology, clinical behavior, imaging characteristics, treatments, and clinical trials.
The consequences also extend beyond patient education. Inconsistent terminology can complicate literature searches, research databases, registries, epidemiologic studies, grant portfolios, and efforts to understand how much research is actually being conducted in a particular neuroendocrine cancer.
Words are not the biology. But words determine how we organize and communicate what we know about that biology.
This is not about blaming individual authors
The prostate pathology paper is useful not because it is uniquely problematic, but because it shows how persistent this terminology problem is.
This is a review paper written by experts in classification and published in a pathology journal. The point is not that these authors are uniquely getting the terminology wrong. Rather, the paper illustrates how difficult it can be to reconcile long-standing, organ-specific language with an increasingly standardized NEN framework.
At the same time, greater consistency does not mean eliminating every organ-specific term. Some terminology reflects real biological differences, historical classifications, and established clinical practice. Those distinctions may still be useful and appropriate.
The goal is not uniformity for its own sake. It is clarity. When different terms are needed, their meaning and relationship to the broader NEN, NET, and NEC framework should be clear.
We can do better
At NETRF, we have developed our own terminology and style guide to help us communicate about neuroendocrine cancer consistently. It gives our staff a common framework for deciding which terms to use across research communications, patient education, donor materials, and other resources.
For scientific audiences, we generally use neuroendocrine neoplasm, or NEN, when referring broadly to both NETs and NECs. For patients and the public, we often use neuroendocrine cancer as the broader, more accessible term. When the biology is specific, we use the more precise diagnosis: a NET is a NET, and a NEC is a NEC.
Our guide also establishes preferred terminology when multiple names remain in circulation. For example, we generally refer to well-differentiated neuroendocrine tumors of the lung as lung NETs rather than using “carcinoid” as the primary disease name. WHO still classifies lung NETs into typical carcinoid and atypical carcinoid, so we use those terms when the specific subtype matters. In broader communication, however, “lung NET” keeps our terminology consistent and clarifies its relationship to other NETs.
This matters in our research programs as well. NETRF funds studies across the spectrum of neuroendocrine cancer. Clearly identifying which disease is being studied helps us evaluate the science, recognize research gaps, and build a portfolio that reflects the diversity of these cancers.
The same precision matters in patient education. Through our educational programs and resources, we work to explain not only what terms such as NET, NEC, grade, and differentiation mean, but also why patients may encounter different language in pathology reports, medical records, research papers, and online resources.
Patients should not have to become experts in the history of cancer classification simply to understand what disease they have.
If doctors and researchers have difficulty using these terms consistently, how are patients supposed to know what their diagnosis means?
Neuroendocrine cancer is biologically complex. Some of that complexity is unavoidable. Confusing language is not.
Clearer terminology will not make these diseases simple. But it can help ensure that when a pathologist, oncologist, researcher, advocacy organization, and patient use a term such as NET or NEC, they are talking about the same thing.
That shared language matters. It is essential for interpreting research, communicating diagnoses and treatment options, and helping patients find information they can trust.
Patients should not have to translate the field’s inconsistencies for themselves.
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To learn more about neuroendocrine cancer, explore NETRF’s Patient Knowledge Center and NETWise podcast. You can also explore NETRF’s Research Portfolio to see the research we are funding across the spectrum of neuroendocrine cancer.