Cancer staging

Cancer staging provides important information for the patient, the physician, and agencies that track cancer statistics and patterns.

The traditional staging systems, however, are undergoing an evolution in response to the increasing cellular and molecular markers used in cancer diagnosis.

"There have actually been three separate staging systems used in the United States," says Stephen Edge, M.D., chair of the Department of Breast Surgery and medical director of the Breast Center at Roswell Park Cancer Institute in Buffalo, N.Y.

The systems used by the National Cancer Institute and the Centers for Disease Control and Prevention to evaluate cancer incidence and deaths collect different data than the system used in medical settings to help guide therapy.

"This leads to confusion and duplication of effort on the part of the people who collect the information," says Edge, who is leading the ongoing overhaul of staging systems by American Joint Committee on Cancer (AJCC).

The new system, called Collaborative Staging (CS), aims to integrate the three different systems so that everyone – from local physicians to cancer registrars tracking national cancer statistics – is on the same page.

The system most familiar to doctors and patients – the TNM system of the AJCC and the International Union Against Cancer – is central to Collaborative Staging and is also undergoing significant changes to incorporate new molecular and cellular markers that predict the patient's outcome or how they might respond to therapy.

"The TNM system is still the anatomic basis," says David Page, M.D., a member of the executive committee of the AJCC. "What we're now trying to do is to add to that and integrate other factors."

"The ongoing revision of TNM is going to incorporate, wherever possible, factors beyond anatomy, including molecular tumor characteristics that affect prognosis," Edge says. "This will provide patients and physicians with a more robust system to help treatment planning."

"The Collaborative Staging System that allows for the integration of new factors associated with cancer prognosis and with response to treatment into the same data collection system will be the key element that supports these improvements," he says. "We think that the Collaborative Staging will provide doctors in the future with better means to collect and use information – molecular factors and factors associated with cancer outcome rather than the purely anatomic information previously used."

Mary Kay Washington, M.D., Ph.D., who is also involved in the AJCC's efforts, predicts this will have a major impact. "The better our data are, the more we can refine our staging system, and, ultimately, the better we can take care of the individual patient."

- by Melissa Marino