Saturday, December 16, and Sunday, December 17 (the meeting ended midday on Sunday, so the following notes address both days)

Clinical

1. There were two presentations on the significance of micrometastases found on sentinel node biopsy. We all know that nodes with lots of cancer are significant, but there has been a growing controversy about what it means to have just a few cells (micrometastases) or even just one (isolated tumor cells or nanometastases). The real discussion is whether women with these findings need to have a full axillary dissection.

Dr. Rutgers, a pathologist from the Netherlands, distinguished between these two different types of metastases. He showed data that 19% of women with micrometastases were found to have other positive nodes while less than 8% of the women with nanometastases did. He recommended using a nomogram, a tool developed by Sloan-Kettering Cancer Center that can be used to calculate the likelihood that cancer has spread to additional lymph nodes under the arm.

Dr. Alberti, who spoke next, disagreed with Dr. Rutgers’ conclusion. He presented data on 377 women that indicated that 50% of women with either nanometastases or micrometastases were found to have other positive nodes, leading him to conclude that even isolated tumor cells were important.

However, the questions following these two presentations indicated that this is still a controversial issue. This is important because the side effects of sentinel node biopsy and axillary clearance are different as shown by an Australian study which showed that sentinel node biopsy has less swelling and symptoms than axillary clearance. You can read more about micrometastases here.


2. DCIS is considered precancerous and yet we seem to treat it as if it was really breast cancer: surgery, radiation, and tamoxifen. A study presented on Saturday showed that women with low- and intermediate-grade DCIS had a 6.1% rate of recurrence in the same breast and 3.7% rate of cancer in the opposite breast while women with high-grade DCIS has a 14.8% rate of recurrence in the same breast and a 4.2% rate of cancer in the opposite breast. The researchers concluded that women with low- and intermediate-grade DCIS may be able to avoid radiation therapy. You can learn more about DCIS here.


Prevention

Saturday afternoon was spent on my favorite topic prevention. It seems that there are currently two approaches: drugs--either hormone or not—and lifestyle. We know that taking tamoxifen or raloxifene for five years can decrease hormone-positive breast cancers. An interesting presentation on Sunday showed that this decrease lasts well after the drugs are stopped. The new aromatase inhibitors are being tested for prevention in postmenopausal women although the known side effects (fractures, cognitive difficulties and joint and muscle pain) may be a problem. People are thinking that there may be differences in the enzymes that make estrogen in different organs, which would make a drug that was a selective aromatase inhibitor the wave of the future.

Of course the hormone blockers only block hormone-positive breast cancer. There were several interesting presentations about reducing the risk of developing to hormone-negative cancers. Two good candidates are COX 2 inhibitors, which are currently being studied, and other drugs called retinoids and and rexinoids. One study has shown that the combination of a SERM and a rexinoid can prevent all breast cancer in mouse model.

New drugs are being tested as well. For example lapatinib which inhibits both erb B 2 (Her2) and erb B 1 has shown some success in inhibiting tumors with those characteristics.

The other approach, which gets less press, is lifestyle. The study presented on Thursday linking a dramatic decline in breast cancer incidence to the decreased use of hormone replacement therapy (HRT)—it appears that stopping HRT prevented 14,000 cases of breast cancer in one year—demonstrates that the best choice may not be adding more drugs but rather getting rid of some! The WINS study which looked at low-fat diet and breast cancer recurrence also showed a benefit although it was hard to distinguish between the low-fat or the weight loss as the reason.

I still think that exercise, weight control, and a healthy diet (low in animal fat and high in fruits and vegetables) is the best approach for most of us, and that only high-risk women should be considering drugs. However, Leslie Ford from the National Cancer Institute suggested that taking drugs to reduce breast cancer risk is really no different than taking drugs to lower cholesterol to reduce the risk of cardiac disease, and that no one thinks twice about that. Obviously, this is also a controversial topic, but I am at least encouraged that a whole afternoon was dedicated to this topic.

I finish this blog from San Antonio with a quote that my daughter sent through an instant message that I was able to read during the conference because the lecture hall provided free wireless connections!

"What is research except a blind date with knowledge?" -William Harvey