ORLANDO, Florida – Cancer staging is the "common language of cancer" and has undergone some important changes that officially debut in January 2018, said a presenter here at the National Comprehensive Cancer Network (NCCN) 22nd Annual Conference.
Staging defines the extent and prognosis of a cancer and guides treatment, said Stephen Edge, MD, of the Roswell Park Cancer Center in Buffalo New York and the American Joint Committee on Cancer (AJCC).
"The NCCN guidelines all base their recommendations on cancer stage," he observed.
Dr Edge explained that since the 1940s, cancer staging has primarily been "anatomic" and has been based on three elements: tumor (T), lymph nodes (N), and distant metastases (M).
"Anatomic staging is the aggregate information resulting from T, N, and M," but these factors are "decreasingly relevant," he said.
Technologic advances have made biologic markers such as genomic profiles and molecular targets "increasingly important" and have spawned a new classification, known as "prognostic staging," that incorporates and supercedes anatomic staging, said Dr Edge.
"Prognostic stage will be the primary stage that is recorded in cancer registries in the United States," starting in about 9 months, he told the NCCN audience.
In the forthcoming eighth edition the AJCC Cancer Staging Manual, which will be effective for all cases diagnosed on January 1, 2018, and onward, there will be some "dramatic" staging changes in cancers in which biologic information now informs clinical care, said Dr Edge. (But not much will change in cancers that have yet to have nonanatomic factors, such as genomic profiles, discovered and validated.)
Breast cancer is one malignancy that will undergo big changes in the new staging system. Prognostic stage will require information on T, N and M, as well as grade, HER2, estrogen-receptor, and progesterone-receptor status. When appropriate, it will include genomic profiles (such as Oncotype DX and Mammaprint results).
Details of the major changes in breast cancer staging are outlined in an article published online March 14 in Cancer.
In the new scheme, a patient formerly designated as having a T2N0 or T1N1 HER2+ breast cancer will be classified as having a stage 1 cancer. This would not have been the case in the past, because, for example, any lymph node involvement (ie, N1) would have disqualified a case as being stage 1. "With treatment, the prognosis for those patients is truly excellent," explained Dr Edge.
With respect to breast cancer cases at diagnosis, it is estimated that with the new AJCC staging system, there will be more cases of stage I disease and fewer cases of stage IIA, IIB, and IIIA in the United States (estimated on the basis of more than 200,000 cases in the National Cancer Database).
"This will be a big culture change for all of us as we start talking to our patients," said Dr Edge.
"The new staging system is super important," said Randall Oyer, MD, medical director of the Ann Barshinger Cancer Institute at Lancaster General Health in Pennsylvania, who attended the meeting.
Dr Oyer told Medscape Medical News that he sat among a group of clinicians during Dr Edge's presentation. They all agreed the new AJCC staging system was "something we needed to understand and implement when we went back [home]."
"The concept of prognostic staging is terrific," he said. "It's the best of both worlds because you collate the anatomic stage and you put in the prognostic staging all in one place."
There will be some very practical benefits with the new staging system, he said.
Dr Oyer provided an example of a patient with colon cancer for whom it is unknown whether or not RAS staging was done. "You go looking in the lab section, you look in the pathology section, you look in the notes. You could always go back and find the tumor stage in the tumor registry, but you couldn't find this key piece of information. So, every time someone made a treatment decision, you had to go looking for this."
The new system solves that problem, says Dr Oyer.
The limitations of anatomic staging are obvious, he also pointed out.
"For many years, we've known that some people who had early-stage cancer didn't do well and needed better treatment, and some people who had advanced-stage cancer did well no matter what you did," he said.
Eventually, research indicated that biologic prognostic markers provided the explanation for these conundrums. "But there wasn't any clear way to incorporate that information into staging," observed Dr Oyer. Now there is, he pointed out.
There are three take-home messages, Dr Oyer summarized.
One, "the integration of prognostic markers and anatomic markers is an idea whose time has come."
Two, the new staging system provides a "central repository of case data" that is both searchable and updateable because is a digital tool. "I've been practicing medicine for more than 30 years. I've always used a paper staging manual," he said. But the utility of the paper approach has long past because of the increase in the number of prognostic tools, he said. "I would have to look at this page, that page, this page, that page."
Three, "it's going to be a lot of work to get going, but it will be worth it for our patients," he concluded.
Not Exactly a New Idea
The idea of using factors other than T, N, and M in staging is not exactly new.
For example, in 2009 in the seventh edition of the AJCC Manual, in the section on prostate cancer, prostate-specific antigen testing score and Gleason score were incorporated into staging groups.
In fact, the transition from anatomy as the ruling factor to prognostic staging has been ongoing. In the sixth and seventh editions, there has been a "marked increase" in the use of nonanatomic factors for defining stage groups, said Dr Edge.
However, he also acknowledged that many cancer types do not have validated nonanatomic factors to modify the anatomic findings and thus will not be affected by the new staging system.
Dr Edge and Dr Oyer have disclosed no relevant financial relationships.
National Comprehensive Cancer Network 22nd Annual Conference. Presented March 25, 2017.
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Cite this: New US Cancer Staging System Debuts in 9 Months - Medscape - Mar 28, 2017.