HOUSTON, June 17 (MedPage Today) -- In an international consensus statement described as practice-changing, new treatment guidelines for early-stage breast cancer call for use of systemic therapies on the basis of individual tumor characteristics.
Treatment decisions should focus on the scientific justification for using endocrine therapy, anti-HER2 treatment, and chemotherapy, authors of the 2009 St Gallen International Expert Consensus concluded in guidelines published online in Annals of Oncology.
Though recognizing the heterogeneous nature of breast cancer, the consensus recommendations call for development of a personalized treatment plan for each patient.
The guidelines include a new treatment algorithm based on advances in knowledge about how to match therapy with tumor characteristics to achieve the best outcomes.
"Because these decisions are based on quite separate criteria, previous attempts to produce a single-risk categorization and a separate therapy recommendation are no longer considered appropriate," the authors said.
In a prepared statement, panel member Richard Gelber, MD, of Harvard and Dana-Farber Cancer Institute in Boston, said the consensus "further refines the treatment algorithm by identifying 'thresholds for indication' of each type of systemic treatment modality based on criteria specific to each modality.
"We expect the refined algorithm to change clinical practice because it clarifies the indications for each treatment modality available today."
Knowing the specific tumor characteristics is essential for deciding which treatment or combination offers a patient the best chance for success. Consistent with that approach to decision making, the panel set forth some general principles for treatment selection:
- Adjuvant endocrine therapy is recommended for most patients with any detectable level of estrogen receptor (ER).
- Anti-HER2 therapy, currently limited to trastuzumab (Herceptin), is recommended for almost all patients with HER2-positive disease.
- Reflecting the more complicated decision-making process surrounding adjuvant chemotherapy, the consensus panel said chemotherapy should be the mainstay of treatment for patients with triple-negative breast cancer. For HER2-positive patients, clinical trial evidence for trastuzumab is limited to its use with or after chemotherapy. Less consensus exists about its use in patients with estrogen receptor (ER)-positive, HER2-negative disease.
The corollary to recommendations about endocrine and anti-HER2 therapy is that "ER and HER2 must be reliably and accurately measured."
Any method of ER staining is acceptable. However, the panel recommended adherence to American Society of Clinical Oncology/College of American Pathologists guidelines for assessing HER2 status.
The consensus guidelines include summaries of the state of knowledge in disciplines relevant to early breast cancer, as presented and discussed at the consensus meeting.
Examples include chemoprevention with selective estrogen receptor modulators, the role of stem cells in breast cancer, implications of circulating tumor cells, angiogenesis, pharmacogenetics, novel imaging techniques, and novel systemic therapies.
Although focused on systemic therapy, the consensus panel expressed support for continued refinement of surgical and radiation techniques to ensure the best possible outcome with the least possible morbidity.
The panel was circumspect on use of genetic testing in making treatment decisions, reflecting the controversy surrounding the issue.
Panelists avoided the term "gene assay," and said genetic testing might have some value if doubt remains after reviewing all other factors and a test is readily available.
"There was clearly a division of opinion, largely on geographic grounds," panelist Alan Coates, MD, of the University of Sydney, Australia, said in an interview.
"Many of the U.S. representatives and some Europeans were keen to say these tests are now established sufficiently, and that they are not only useful for prognosis, but also helpful to decide whether it will be valuable at prediction of the additional benefit of chemotherapy.
"Others felt that because two of the principal trials investigating markers for exactly that purpose have yet to report any results, as such, it is premature to make that conclusion. I must say I tend toward the second point of view, but there was a clear division on the panel."
The 43-member panel drafted the recommendations in March at the 11th St Gallen (Switzerland) consensus meeting, which had a total attendance of almost 5,000.
The published consensus did not include disclosures of potential conflicts of interest.
Primary source: Annals of Oncology Source reference: Goldhirsch A, et al "Thresholds for therapies: highlights of the St Gallen International Expert Consensus on the primary therapy of early breast cancer 2009" Ann Oncol 2009; DOI:10.1093/annonc/mdp322.
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