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Cancer Explained

Disponible en español: Cómo entender el grado del cáncer

Beginner 4 min read Verified

Understanding Cancer Grade

A plain-language explanation of tumor grade — how abnormal cancer cells look — and how it differs from stage. Based on the National Cancer Institute.

NCI source

Last reviewed: 2026-07-07

The short answer

Grade describes how abnormal cancer cells look under a microscope and how quickly they are likely to grow. Low-grade cancers look more normal and grow slowly; high-grade cancers look more abnormal and grow faster. Grade is different from stage.

  • Grade describes how abnormal cancer cells look under a microscope.

  • Low-grade cells look more like normal cells and tend to grow slowly.

  • High-grade cells look more abnormal and tend to grow and spread faster.

  • Grade is different from stage, which describes how far a cancer has spread.

Choose how you want to understand this

The full explanation.

The simple version

When doctors look at cancer cells under a microscope, they note how abnormal the cells look. That is the grade. Grade is not the same as stage — it describes the cells themselves, not how far the cancer has spread.

Low grade vs. high grade

In general:

  • Low grade — cells look more like normal cells and tend to grow slowly
  • High grade — cells look more abnormal and tend to grow and spread faster

Grade is not stage

A cancer has both a grade and a stage, and they answer different questions. Grade asks how abnormal the cells look and how fast they may grow. Stage asks how big the cancer is and whether it has spread.

Grade describes the cells; stage describes how far the cancer has spread.

Why it matters

Grade helps doctors predict how a cancer may behave and choose treatment. A higher-grade cancer may call for more aggressive treatment, while a low-grade one may be managed less intensively. Your team uses grade along with stage and other factors to plan care.

Words to know

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Common questions

What is tumor grade?

Grade is a measure of how abnormal cancer cells look under a microscope compared with normal cells, and how quickly they are likely to grow and spread.

What do low and high grade mean?

Low-grade cancer cells look more like normal cells and usually grow slowly. High-grade cells look more abnormal and tend to grow and spread more quickly.

How is grade different from stage?

Grade is about how the cells look and behave. Stage is about how large the cancer is and whether it has spread. A cancer has both a grade and a stage, and they mean different things.

Why does grade matter?

Grade helps doctors predict how a cancer may behave and choose treatment. Higher-grade cancers may need more aggressive treatment.

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  1. Q1.What does grade describe?
  2. Q2.Low-grade cancer cells...
  3. Q3.How is grade different from stage?

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Related learning map

How this explanation connects to 10 other things you can explore — related topics, terms, questions, practice, and its NCI source.

Understanding Cancer Grade