40% of lymph node mets are of a different ER positivity/negativity, her2 positivity/n

[Lani]

negativity than the primary tumor

But since patients die of distant mets rather than lymph node mets, determining the ER, PR and her2 status of the lymph node is really not important compared to determining the ER, PR and her2 status of any distal mets or bone marrow infiltrates.

This is why it is so important to biopsy mets in order to be sure they are being treated with the agents most likely to be effective and why it may turn out to be important to do bone marrow sampling (perhaps even early) to determine if any tumor cells there match the primary tumors characteristics or not.

As I mentioned in my review of the recent San Diego meeting, Christoph Klein believes the latter is most important.

Food for thought

Here is the article from the BBC--


Breast cancer changes with spread



Nearly 40% of breast cancer tumours change form when they spread, a UK study shows.
The researchers say this could mean that patients require changes to their treatment regime.
They analysed 211 tumours which had spread to the lymph nodes in the armpit - the place where breast cancer tends to migrate first.
The study, by Breakthrough Breast Cancer scientists in Edinburgh, appears in Annals of Oncology.
Breast cancer is a complex disease with many different types which can be treated in different ways.
Breast cancer spreads to the lymph nodes in about 40% of the 46,000 women diagnosed with breast cancer in the UK each year.
Cancer cells which spread in this way are often more difficult to treat than those in the breast - so it is vital that women receive the most appropriate treatment.

This suggests there is a need to test which type of disease a woman has in the lymph nodes, because it could radically alter the course of treatment she receives

Researchers were surprised to find the disease changed in such a high proportion of patients, and in so many ways, when it had spread.
For example, 20 tumours changed from oestrogen receptor (ER) negative to ER positive.
This change would mean hormone therapies such as tamoxifen, which would not have worked for the original tumour, could help treat the disease if it has spread.
Other tumours changed from ER positive to ER negative, which suggests those patients may be given treatments which will not benefit them - experiencing side-effects unnecessarily.
Surprising result
Lead researcher Dr Dana Faratian said: "We were surprised that such a high proportion of tumours change form when they spread beyond the breast.