Please remember, this study was compiled prior to the use of adjuvant Herceptin in early stage bc.
MedWire News: The St Gallen International Consensus Guidelines are effective at identifying women with high-risk breast cancer who may benefit from adjuvant therapy, suggest study results.
Researchers used the St Gallen criteria to classify 902 women with breast cancer into low- (7%), intermediate- (63%), and high-risk (30%) categories. The corresponding average 5-year distant disease free survival (DDFS) rates for these patients were 100%, 63%, and 72%, respectively.
"This risk allocation system may be a potentially useful prognostic tool as well as an adjuvant therapy guideline," commented Tsz-kok Yau and colleagues from the Pamela Youde Nethersole Eastern Hospital in Hong Kong, China.
The St Gallen guidelines were modified in 2005 based on new evidence to include endocrine responsiveness as the most important selection factor for adjuvant chemotherapy and endocrine treatments. Two features not previously accepted as sufficiently reliable to predict breast cancer survival were also added - human epidermal growth factor receptor 2 (
HER2) gene overexpression and peritumoral vascular invasion.
The researchers used the revised guidelines to prospectively review breast cancers patients, aged a median of 56 years, who were referred to the Pamela Youde Nethersole Eastern Hospital between 1994 and 2002. All the women had invasive tumors with no distant metastases at diagnosis and underwent wide local excision or mastectomy. They also gathered information on relevant clinical and histopathological features.
The St Gallen guidelines proved effective at identifying women with breast cancer who had a poor prognosis.
In addition, patients in the high-risk category who had 1-3 positive nodes and
HER2 overexpression had a DDFS of 89%. This dropped significantly to 65% in patients with 4 or more positive nodes and normal HER2 expression.
Overall, women whose tumors overexpressed
HER2 had a 1.6-fold decrease in DDFS. Further analysis of subgroups revealed however that
HER2 overexpression reduced survival only in patients with 4 or more positive nodes.
The researchers were surprised by this finding and expressed concern over the immunohistochemistry testing of
HER2 status in their study.
Commenting in the journal
The Breast, Yau
et al warned: "In view of the important implication on prognosis and the use of potentially life-threatening and expensive treatment, the need for quality control of
HER2 testing cannot be overemphasized."
Breast 2007; Advance online publication
http://www.thebreastonline.com/
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