Pancreatic Cancer Staging: WHO Grades

Last updated and reviewed on June 24, 2026.

Once pancreatic cancer is diagnosed, the next step is staging, which is the process of figuring out how far the cancer has grown or spread. Staging is essential because it is the most important factor in determining which treatments are possible, what the goals of treatment are, and what outcomes to expect. For pancreatic cancer in particular, staging is also closely tied to one of the most critical questions a patient will face: Is this tumor surgically removable?

Pancreatic cancer is staged using the TNM system developed by the American Joint Committee on Cancer (AJCC), which looks at three key features of the cancer. But in clinical practice, pancreatic cancer is also described in terms that are directly relevant to surgical decision-making: resectable (able to be surgically removed), borderline resectable (on the border of what surgery can safely reach), locally advanced (grown into major blood vessels or structures but not spread to distant organs), and metastatic (spread to distant organs). These surgical categories often guide treatment more directly than the formal TNM stage number.

The TNM Staging System

T stands for Tumor and describes the size and extent of the primary tumor in the pancreas.

TX	The primary tumor cannot be assessed
T0	No evidence of primary tumor
Tis	Carcinoma in situ: includes high-grade pancreatic intraepithelial neoplasia (PanIn-3), intraductal papillary mucinous neoplasm with high-grade dysplasia, intraductal tubulopapillary neoplasm with high-grade dysplasia, and mucinous cystic neoplasm with high-grade dysplasia
T1	Tumor limited to the pancreas, ≤2 cm in greatest dimension    T1a - Tumor ≤0.5 cm in greatest dimension    T1b - Tumor >0.5 cm and < 1 cm in greatest dimension    T1c - Tumor 1–2 cm in greatest dimension
T2	Tumor limited to the pancreas, >2 cm and ≤4 cm in greatest dimension
T3	Tumor >4 cm in greatest dimension
T4	Tumor involves the celiac axis, superior mesenteric artery, and/or common hepatic artery, regardless of size

N stands for Nodes and describes whether the cancer has spread to nearby lymph nodes.

Primary tumor (T)
TX	Primary tumor cannot be assessed
T0	No evidence of primary tumor
Tis	Carcinoma in situ: includes high-grade pancreatic intraepithelial neoplasia (PanIn-3), intraductal papillary mucinous neoplasm with high-grade dysplasia, intraductal tubulopapillary neoplasm with high-grade dysplasia, and mucinous cystic neoplasm with high-grade dysplasia
T1	Tumor limited to the pancreas, ≤2 cm in greatest dimension    T1a - Tumor ≤0.5 cm in greatest dimension    T1b - Tumor >0.5 cm and < 1 cm in greatest dimension    T1c - Tumor 1–2 cm in greatest dimension
T2	Tumor limited to the pancreas, >2 cm and ≤4 cm in greatest dimension
T3	Tumor >4 cm in greatest dimension
T4	Tumor involves the celiac axis, superior mesenteric artery, and/or common hepatic artery, regardless of size
Regional lymph nodes (N)
NX	Regional lymph nodes cannot be assessed
N0	No regional lymph node metastasis
N1	Metastasis in 1-3 regional lymph nodes
N2	Metastasis in ≥4 regional lymph nodes

M stands for Metastasis and describes whether the cancer has spread to distant organs, such as the liver, lungs, or peritoneum.

M0	No distant metastasis
M1	Distant metastasis

The Overall Stage Groups

Combining the T, N, and M values, doctors assign an overall stage from Stage I through Stage IV:

Stage	T	N	M
0	Tis	N0	M0
IA	T1	N0	M0
IB	T2	N0	M0
IIA	T3	N0	M0
IIB	T1,T2,T3	N1	M0
III	T1,T2,T3	N2	M0
T4	Any N	M0
IV	Any T	Any N	M1

The Surgical Resectability Classification

In clinical practice, the decision about whether surgery is possible is often described using a different classification system based on how the tumor relates to the major blood vessels near the pancreas.

• Resectable: Tumors are those that have not grown into major blood vessels and have not spread to distant organs. These tumors can be removed with surgery, with a reasonable expectation of removing all visible cancer. About 15 to 20 percent of patients have resectable disease at diagnosis.
• Borderline resectable: Tumors are those that are close to or next to major blood vessels but have not wrapped around them in a way that makes removal impossible. For these tumors, surgeons often recommend treating with chemotherapy and sometimes radiation first (called neoadjuvant therapy) to try to shrink the tumor and its relationship to the vessels before attempting surgery. This approach gives the best chance of achieving clear margins (removing all cancer tissue with a rim of healthy tissue around it).
• Locally advanced unresectable: Tumors have grown around major blood vessels (like the celiac artery or superior mesenteric artery) in a way that makes safe surgical removal technically impossible, but the cancer has not spread to distant organs. Treatment focuses on systemic chemotherapy, sometimes combined with radiation, with the goal of controlling the cancer and, in some patients, converting the tumor to a resectable state.
• Metastatic Disease: The cancer has spread to distant organs, most commonly the liver, lungs, or the lining of the abdomen (the peritoneum). Surgery on the primary tumor is not standard treatment for metastatic pancreatic cancer. The goals of treatment are controlling the cancer and maintaining quality of life.

What About Pancreatic Neuroendocrine Tumors?

Pancreatic neuroendocrine tumors (PNETs) are classified differently from PDAC. They use a WHO grading system based on how fast the tumor cells are dividing (measured by Ki-67 index or mitotic rate).

• Grade 1 PNETs are slow-growing and generally have an excellent prognosis.
• Grade 2 is intermediate.
• Grade 3 (also called poorly differentiated neuroendocrine carcinoma) is aggressive and behaves much more like PDAC.

The TNM staging system is also applied to PNETs, but with different implications for prognosis than in PDAC.

A note on second opinions: Determining the stage and resectability of pancreatic cancer requires high-quality imaging interpreted by experienced radiologists, and the surgical decision requires a pancreatic surgeon who performs high volumes of these operations. Studies consistently show that patients who have their pancreatic cancer surgery at high-volume centers have better outcomes than those who have it at low-volume centers. Getting a second opinion from a major medical center with a dedicated pancreatic cancer program is strongly encouraged before committing to a treatment plan.

 

 

Sources

1. American Cancer Society. Pancreatic Cancer Stages. https://www.cancer.org/cancer/types/pancreatic-cancer/detection-diagnosis-staging/staging.html
2. American Joint Committee on Cancer (AJCC). AJCC Cancer Staging Manual, 8th Edition. Pancreas chapter. 2026. https://emedicine.medscape.com/article/2007121-overview
3. National Cancer Institute. Pancreatic Cancer Treatment (PDQ) Patient Version. https://www.cancer.gov/types/pancreatic/patient/pancreatic-treatment-pdq
4. National Comprehensive Cancer Network (NCCN). NCCN Guidelines: Pancreatic Adenocarcinoma. 2024. https://www.nccn.org/guidelines/guidelines-detail?category=1&id=1455
5. Tempero MA, et al. Pancreatic Adenocarcinoma, Version 2.2021. Journal of the National Comprehensive Cancer Network. 2021;19(4):439-457. https://pubmed.ncbi.nlm.nih.gov/33845462/