cN is the **clinical** assessment of whether cancer has spread to **regional lymph nodes**. It is part of the **TNM staging system**, which summarizes tumor extent before treatment. Clinicians assign cN using information from the exam, imaging, and sometimes needle biopsy. You will most often see cN in oncology clinic notes, pathology discussions, and staging reports.

pT is the **pathologic “T” category** in the TNM cancer staging system. It describes the **size and local extent of a primary tumor** based on tissue examined under a microscope. pT is most commonly assigned **after surgery** (or another procedure that provides enough tumor tissue). It is widely used in pathology reports and oncology care planning.

cT is the **clinical “T” category** in the TNM cancer staging system. It describes the **estimated size and local extent of the primary tumor** before any definitive treatment. cT is assigned using information from the **exam, imaging, endoscopy, and biopsy results** when available. It is commonly used in oncology clinics, tumor boards, and treatment planning conversations.

Stage IV is a cancer stage that usually means the cancer has spread beyond the original site. It is commonly used in solid tumors (such as breast, lung, colon, and prostate cancers). Stage IV can also be used differently in some cancers, depending on the staging system. It helps clinicians describe disease extent and plan treatment in a consistent way.

Stage III is a cancer stage that usually describes “locally advanced” disease. It commonly means the cancer is larger, has grown into nearby tissues, and/or has spread to regional lymph nodes. Stage III is used in many solid tumors as part of standardized staging systems. Its exact meaning depends on the cancer type and the staging method used.

Stage II is a cancer stage that generally means the cancer is more than very small or very early, but has not spread to distant organs. It is most commonly used in solid tumors and is often based on tumor size, depth of invasion, and nearby lymph node findings. The exact definition of Stage II depends on the specific cancer type and the staging system used.

Stage I is a cancer stage that usually indicates an early, localized cancer. It generally means the tumor is limited to the organ or tissue where it started. Stage I is commonly used in solid tumors (such as breast, colon, lung, prostate, and many gynecologic cancers). The exact definition of Stage I varies by cancer type and staging system.

Stage 0 is a cancer staging term that usually means **“in situ” disease**. It describes abnormal cells that look cancer-like under a microscope but **have not invaded deeper tissues**. Stage 0 is most commonly used for certain **solid tumors in lining tissues (epithelium)**, such as breast ducts, cervix, skin, and bladder. It is a way clinicians communicate how early the process is and what treatment intensity may be considered.

Pathologic staging is a way to describe how much cancer is present based on what is seen in tissue under a microscope. It is usually determined after a biopsy or surgery, when a pathologist examines the tumor and nearby tissues. It is commonly used for many solid tumors to guide treatment planning and follow-up care.

Clinical staging is a way clinicians describe how far a cancer has spread in the body using information available before major treatment. It combines findings from the medical history, physical exam, imaging, and selected lab tests and biopsies. Clinical staging is commonly used in oncology clinics, tumor boards, and treatment planning discussions. It helps create a shared “starting point” for care among different specialists.