Study shows possibility to have breaks in medication against hormone-sensitive breast cancer

Nov 30 2017

It is possible to have breaks in long-term medication against hormone-sensitive breast cancer - without the effect of the treatment appearing to have been influenced. Women also feel better if they take a three-month break from the hormone treatment each year, according to a medication study reported in The Lancet.

"It is not a fantastically big difference, but it is still discernible. Quality of life was a bit better, or a little less poorer, among those receiving treatment with a break," says Per Karlsson, Professor of Oncology at the Sahlgrenska Academy, consultant at the university hospital and responsible for the Swedish part of the study.

Bodily stiffness and brittle mucous membranes are common side-effects with anti-hormonal treatment of the kind being studied. For the women who took a three month-long break in their treatment each year, these problems lessened somewhat, compared with the control group.

"It is not an easy matter continuing with anti-hormonal treatment for a long time. Many of them are made to feel really poorly by the medicines and, for some of them, a break can be a reasonable option," says Per Karlsson.

"But this must not be misinterpreted as meaning that all of them feel they should take a break, especially not during the first five years. The standard treatment is still continuous medication," he continues.

A hormone-sensitive breast cancer is curable, but a relapse is also common after five years if, from the beginning, the cancer has affected many lymph glands. Making the extended treatments more tolerable remains a challenge, however. There are many who do not persevere and thus lose the protection against relapse.

Nearly 4,900 women from 22 countries took part in the study in total. All were post-menopausal and had already undergone about five years primary treatment with anti-hormonal drugs against hormone-sensitive breast cancer.

The study covered five years of extended treatment, with or without a break, involving the drug letrozole. The fact that the drug reduces the risk of metastases was already known, but not how breaks in the medication might affect the growth of tumors and quality of life.

During a break in treatment the hormone levels begin to be normalized. Earlier tests on animals have shown that letrozole, following a break in the medication, can have a new and greater effect on the actual development of the cancer. The pause can possibly contribute towards a suppression of the resistance development that takes place during long-term treatment. This particular response was not, however, clear in the study in question.

"Our primary hypothesis was that there could be fewer relapses with the pause, but it could not be demonstrated. It is possible that the pauses were too short and it was also possibly due to which drug the women had been given previously," says Per Karlsson.

"But it is good to know that the pause itself does not appear to be dangerous from a patient perspective. Relapses remained at the same level, with or without a pause; a point which is important to know for those who, because of problems, are considering taking a break in their anti-hormonal medication," he points out.

Source: http://sahlgrenska.gu.se/english/research/news-events/news-article//new-discoveries-can-open-the-way-for-pauses-in-certain-medication-for-breast-cancer.cid1532420