If you are diagnosed with cancer, then the “cancer stage” is one of the most important factors to determine how your medical team will help you to manage the disease.

“Cancer stage determines how much cancer is in the body and where it’s located. It’s the common language that all physicians use to classify cancer and determine outcome, and is the driving force in guiding the treatment that will follow,” said Mahul B. Amin, M.D. Dr. Amin is the Editor-in-Chief of the American Joint Committee on Cancer (AJCC) TNM Cancer Staging Manual, Eighth Edition. The TNM Staging System, developed and maintained by the AJCC and the Union for International Cancer Control, is the most commonly used staging system by medical professionals around the world.

Data driven

Cancer stage is based on the size of the tumor, whether it has spread to lymph nodes, which are the tiny glands that clear toxins from specific regions of the body, or whether it has spread into nearby organs or distant organs. There are various cancer stages, and each one provides information about how the tumor is likely to behave or should be treated. Cancer stage is largely population-based, which means it is derived from data from thousands of patients with the same stage and type of cancer who were treated in a similar way, Dr. Amin explained.

“Each advance in cancer staging allows doctors to provide an individualized estimate of the outcome and more specific treatment of cancer.”

As science and the medical understanding of cancer advances, the staging system is updated to reflect more current information. For example, researchers have recently learned that cancer arises because of genetic mutations, or mistakes in the genetic code, which allow it to grow and spread to other organs, Dr. Amin said. Mutations are very individualized for each tumor, which means two tumors can look the same under a microscope, but each one has its own genomic structure.

A new approach

The staging paradigms developed by the AJCC in its new Eighth Edition increasingly use individualized genomic data to build upon traditional staging and thus take an age-old population-based approach to a more contemporary personalized one. The Eighth Edition is effective for all cancer cases diagnosed on or after January 1, 2018.

These new additions to the staging system are promising news for patients. “Each advance in cancer staging allows doctors to provide an individualized estimate of the outcome and more specific treatment of cancer,” Dr. Amin said.