The trouble with this meeting is that it is like going to a lavish buffet: you can only eat (absorb) so much. By today I am stuffed! Instead of summarizing everything, I will confine myself to areas where I think I can add something to the media reports or tell you about something I think the media is missing.
Hormonal Therapies & Bisphosponates
Researchers presented findings from two studies that looked at adding a new bisphosphonate (drug to prevent bone loss) to goserelin (brand name Zoladex–a drug used to induce temporary menopause). In this study, half of the women were given the bisphosphonate along with goserelin, while the other group was only given goserelin. While the addition of this new bisphosphonate did maintain bone, the study also found that women who did not take the bisphosphonate regained most of their bone after they stopped the goserelin.A second trial looked at taking the bisphosphonate Zoledronate (brand name Zometa) with the aromatase inhibitor letrozole (brand name Aromasin). One group of women started the bisphosphonate at the same time they started on Aromasin. The other group started taking the bisphosphonate only if there were symptoms. The study found that both approaches worked to increase bone density, but those who started it right away did slightly better in terms of their bone density. However, there were no differences in fractures.The real question to me is whether we should be treating the test, bone density, or the disease, fractures. This was addressed in the ATAC trial, which compared tamoxifen to the aromatase inhibitor anastrozole (brand name Arimidex). Although there was an initial increase in fractures in the women on anastrozole, once they stopped taking it there were no new fractures. The researchers recommended that women only use a bisphosphonate if their baseline bone density is abnormal before they start taking an aromatase inhibitor. This is also a good argument for dividing the five years of hormone therapy between tamoxifen and an aromatase inhibitor (2.5 years of tamoxifen and then 2.5 years of an aromatase inhibitor or 2.5 years of an aromatase inhibitor and then 2.5 years of tamoxifen), since tamoxifen is as good as the drug raloxifene at building bone.Researchers also presented a 5-year update of the overall ATAC data. The study continues to show a benefit of the aromatase inhibitor over tamoxifenâ€”it is now a 4.8 percent absolute benefit in decreasing recurrence. However, there was no difference in overall survival at five years. It was pointed out that it took ten years to demonstrate an overall survival benefit for tamoxifen, so a survival benefit could show up. So, time will tell!
MRI and Imaging
MRI certainly dominated the discussions of imaging. Most interesting was the update of a Dutch study that used clinical breast exam, mammography, and MRI to follow high-risk women, including women who have a BRCA 1 or BRCA2 mutation. This was the study that put MRI on the map as a sensitive (finds more tumors) but not so specific (finds lots of irrelevant stuff too) test for screening breast cancer, and that resulted in the recommendation that MRI be used for mutation carriers.
This update had good and bad news. The good news is that MRI is finding DCIS in women who have BRCA 2. However, mammography was still better at finding DCIS than MRI. The disappointing news was that 37 percent of BRCA 1 carriers had interval cancers. This means the MRI missed the cancer, as it was found during the interval between annual screening tests. The women also had more tumors over 2 cm and more frequently had positive nodes. This probably reflects a more aggressive biology, but it also suggests that yearly screening may not be enough. Whether this means we should do screening more often or that prophylactic surgery is indicated in these women is not yet clear. It certainly says to me that the biology of the tumor dictates when it is found rather than the technique that is looking for it!
Another intriguing MRI study from Germany showed that mammography is good at finding DCIS that has calcifications but that MRI is actually better at finding high-grade DCIS and DCIS without calcifications. Since the DCIS that can be identified by mammography depends on finding microcalcifications, we sometimes forget that pathologically only 50 percent of DCIS actually has microcalcifications. In this study MRI was more sensitive for high-grade DCIS than mammography. This is intriguing, as it suggests that MRI is best at finding the subset of DCIS that is more predictive of invasive disease and indeed more important to find. Itâ€™s too early to suggest that we all have MRI, but itâ€™s intriguing.
Other interesting new imaging approaches were also reported demonstrating the continuing effort to find the perfect imaging technique. I think itâ€™s becoming clear that the limitations are not the imaging techniques but the biology of the disease. We need to stop focusing on finding cancers that are there and focus on finding precancerous conditions and preventing this disease.