Revised Classification System Is Effective For Predicting Breast Cancer Outcome In Some Patients
- Date:
- August 7, 2005
- Source:
- University of North Carolina School of Medicine
- Summary:
- A revised and commonly used system for classifying the seriousness of cancer is effective for predicting relapse and survival in women with breast cancer who receive chemotherapy prior to surgery, according to research from the University of North Carolina at Chapel Hill Lineberger Comprehensive Cancer Center.
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CHAPEL HILL -- A revised and commonly used system for classifyingthe seriousness of cancer is effective for predicting relapse andsurvival in women with breast cancer who receive chemotherapy prior tosurgery, according to research from the University of North Carolina atChapel Hill Lineberger Comprehensive Cancer Center.
The findings may provide information that will help doctors shape subsequent treatment, researchers said.
The new study, appearing today (Aug. 3) in the Journal of the NationalCancer Institute, is the first to examine the ability of the revised(2003) American Joint Committee on Cancer tumor-node-metastasis (TNM)staging system to predict breast cancer outcome after neoadjuvantchemotherapy.
"Neoadjuvant" refers to treatment given to help the subsequent primary treatment proceed more successfully.
This type of therapy is being used increasingly in breast cancer whilethe tumor is still in place. Typically used for locally advanced breastcancer, or tumors three centimeters or larger in diameter, neoadjuvantchemotherapy may shrink malignancies, making them easier to removesurgically, said Dr. Lisa Carey, associate professor of medicine in theUNC School of Medicine's Division of Hematology/Oncology and thereport's lead author.
"You can actually measure the response of the tumor to thechemotherapy, and we have found it may improve the likelihood of havinga lumpectomy instead of mastectomy," she added.
Carey, also a member of UNC Lineberger, said the amount of residualtumor remaining after the chemotherapy has important implications forsurvival.
"A woman whose tumor is obliterated, where none remains after thechemotherapy, has a better outcome five years later than a woman whostill has cancer left in the breast."
However, debate has focused on the best way to measure that residual amount, Carey added.
"So our study looked at the revised AJCC TNM classification system todetermine if it was helpful for predicting outcome. And using the samedata set, we also compared the system with several other classificationmethods that have been used in clinical trials."
The TNM system was developed as a tool for doctors to stage differenttypes of cancer based on certain standard criteria. In breast cancer,it is based on the extent of the tumor in the breast, the extent ofspread to axillary (armpit) lymph nodes, and the presence ofmetastasis. The "T" category describes the original, or primary, tumor.
Once the criteria are determined, they are combined, and an overall"stage" of I, II, III or IV is assigned. Sometimes these stages aresubdivided as well, using letters such as IIIA and IIIB. In general,the lower the number, the less the cancer has spread. A higher numbermeans a more serious cancer. Stage I cancers are the least advanced andoften have a better prognosis, or outlook for survival. Higher stagecancers are often more advanced, but in many cases can still be treatedsuccessfully, according to the American Cancer Society.
The UNC study included 132 patients with locally advanced breast cancerwho had been diagnosed with clinical stage II or III disease, accordingto the 1988 AJCC TNM system. All had been treated at UNC in neoadjuvantchemotherapy clinical trials followed by surgery from January 1992through December 2000.
Using surgical tissue samples from each patient's breast and axillarylymph nodes, the researchers measured the pathologic, or disease, stageof the patients' residual tumor with the revised AJCC TNM stagingsystem. They then looked at the association between tumor stage in thesurgical specimens and five-year disease outcome.
After a median of five years, residual tumor stage as measured by therevised TNM was strongly associated with both distant disease-freesurvival and overall survival, the report said. A higher stage ofresidual tumor after neoadjuvant chemotherapy was associated with astatistically significant lower rate of disease-free survival.
"Before the revisions, the AJCC system didn't take into account thenumber of nodes that had cancer left in them very well," Carey said."It didn't emphasize the difference in prognosis between a person withone lymph with cancer and women who have 10 lymph nodes with cancer.
"There were other changes to the system, but that was the most relevantfor our study. The new system has been widely adopted, and now we knowthat it can give us very useful information about how to assess theresponse to neoadjuvant chemotherapy."
Funding for the study came from a UNC Breast Cancer SPORE Award fromthe National Cancer Institute, the Breast Cancer Research Foundationand the National Institutes of Health.
Carey's UNC co-authors include Dr. Richard Metzger, research assistant;Dr. E. Claire Dees, assistant professor of medicine; Dr. FrancesCollichio, assistant professor of medicine; Dr. Jan S. Halle, associateprofessor of radiation oncology; Dr. Carolyn Sartor, assistantprofessor of radiation oncology; Dr. David Ollila, associate professorof surgical oncology; Dr. Nancy Klauber-Demore, assistant professor ofsurgical oncology; Dr. Dominic T. Moore, biostatistician; Lynda Sawyer,research assistant; and Dr. Mark Graham, now in private practice,formerly at UNC.
UNC Lineberger is one of 39 National Cancer Institute-designatedComprehensive Cancer Centers and two Specialized Programs of ResearchExcellence (SPORE) in breast cancer and in gastrointestinal cancers.
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