NEW YORK (Reuters Health), Aug 28 - "There is no strong evidence" that any significant subpopulation of breast cancer patients diagnosed in the 1980s and early 1990s was ever "cured," say researchers from the U.K.
Rather, these women have continued to face excess mortality risks due to their disease for more than 20 years after their "cure," according to a report in the August Annals of Oncology.
Dr. Laura Woods from the London School of Hygiene and Tropical Medicine and colleagues analyzed registry data on 80,313 breast cancer cases diagnosed in England and Australia between 1980 and 1995, in an attempt to identify cured subpopulations, defined as "the proportion of patients among whom no additional, or 'excess,' mortality is observed."
In estimates made with several statistical models, the excess mortality between the 15th and 23rd anniversaries of women diagnosed with breast cancer from 1980 to 1987 remained greater than zero for all extent-of-disease groups and for all women diagnosed before their 65th birthday, the authors report.
"This suggests that these groups of women continued to die as a consequence of their malignancy during the 16th to 23rd years of follow-up and, thus, that they could not be considered cured of cancer within 23 years of their diagnosis," the researchers say.
Results were similar between the 10th and 15th anniversaries for women diagnosed between 1988 and 1995.
Among some groups of women who were in the 65-69, 70-79, and 80-99 year age groups at diagnosis, the breast cancer-related mortality rate was negative, which implied to the investigators "that some groups of women who were diagnosed at older ages could be considered cured after their 80th birthday."
"Absence of cure among women with breast cancer is consistent with the majority of previous work, in which long-term excess mortality has been detected well into the second and third decades of follow-up," the authors comment.
Analyzing cure rates according to detection method and treatment, particularly with follow-up data for women diagnosed since 1995 and treated with newer regimens, would help to show whether these findings apply to all breast cancer patients, the researchers conclude.
"We have not yet seen the long-term impact of newer drugs like taxanes; targeted therapies like trastuzumab, lapatinib, aromatase inhibitors, extended hormonal treatment, bisphosphonates; and use of tumor genomics on survival of breast cancer," write Dr. M. K. Singhal and Dr. V. Raina from All India Institute of Medical Sciences, New Delhi, in a related editorial.
"There is no doubt that prolonged survival is being increasingly seen and in many cases it is behaving like a chronic disease characterized by multiple nonfatal relapses," the editorial concludes. "The jury is still out as to whether cure occurs in breast cancer, but with ever-prolonging survival it looks more and more likely."
Ann Oncol 2009;20:1291-1292,1331-1336.
Last Updated: 2009-08-28 8:43:09 -0400 (Reuters Health)
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