Understanding risk benefits of treatments
Is Herceptin for early breast cancer a wonder drug?
The marketing of the breast cancer drug Herceptin for early stage breast cancer is a good example of hype trumping evidence with consequent confusion for patients and professionals alike about potential benefits and risks of treatment.
“Commercial companies are not alone in trumpeting the advantages of new treatments while down-playing drawbacks. Professional hype and enthusiastic media coverage can likewise promote benefits while ignoring potential downsides. And these downsides may include not only harmful side-effects but also diagnostic difficulties, as shown by events surrounding the breast cancer drug trastuzumab, better known by the trade name Herceptin.” Testing Treatments
In early 2006, demands from patients and professionals, fuelled by the pharmaceutical industry and the mass media, resulted in the NHS providing Herceptin for patients with early breast cancer before it was licensed and adequately tested for risks as well as benefits. Further, the potential benefits were only there for the one in five women who tested positive for a protein called HER-2; itself a difficult test to carry out at that time, resulting in a number of ‘false positives’.
Later that year the National Institute for Health and Care Excellence (NICE) issued a recommendation for the use of Herceptin as a treatment option for women with identified HER-2 positive early breast cancer. However, that recommendation was accompanied by a vital warning that Herceptin could adversely affect heart function. Current advice is that treatment should not be offered to women with certain heart conditions and heart function should be assessed every three months in those who are treated with the drug.
According to Breast Cancer UK, there is a clear benefit: in women with HER-2 positive operable breast cancer treatment with Herceptin plus standard chemotherapy is now known to reduce deaths from breast cancer by a third. However, there is also a significant risk: heart problems are five times more likely than for women receiving standard chemotherapy alone.
If 1,000 women got Herceptin for 1 year and other standard breast cancer treatments:
- about 933 would survive (33 more than women who didn’t get Herceptin)
- about 740 would have no recurrence (95 more than women who didn’t get Herceptin)
- about 26 would have a heart problem during or after treatment (21 more than women who didn’t get Herceptin)
A group of researchers analysed 361 UK newspaper reports from 1998 to 2006. They found that of these reports, many of which called for access to Herceptin, only 51 mentioned side effects at all, and only 22 reported an increased risk of heart problems (Wilson et al 2008).
Does this make you consider risk/benefit in a different way?
© Cardiff University