Survival for patients with the most common forms of advanced breast cancer could be substantially improved if both younger and older patients had access to a group of anti-cancer drugs called CDK4/6 inhibitors, according to experts at the Advanced Breast Cancer Fifth International Consensus Conference (ABC5) in Lisbon.

In a session agreeing new guidelines for treating advanced breast cancer, they said there was now enough evidence that this class of medicines helps patients live longer and with the same or better quality of life.

However, they said the medicines were not being offered to the majority of patients who could benefit.

The experts also highlighted that difficulties with access to opioid pain relief around the world, including a lack of supply in poorer countries and a backlash against opioid addiction in the USA, are leading to breast cancer patients suffering unnecessarily and dying in pain.

A key aim of the Advanced Breast Cancer Conferences and the ABC Global Alliance is to double survival among patients with the disease by 2025.

Chair of the ABC5 Conference, Professor Fatima Cardoso, Director of the Breast Unit of the Champalimaud Cancer Centre in Lisbon, Portugal, said: “We now have a family of drugs, CDK4/6 inhibitors, that can substantially prolong life in the most common subtype of breast cancer. These drugs bring us much closer to our aim of doubling the time patients with advanced breast cancer live without their disease progressing, but we can only achieve that if they are available to everyone who needs them.”

Around 70 percent of advanced breast cancers are oestrogen receptor positive (ER ) and HER2 negative – also called hormone dependent cancers.

ER cancers are driven by the hormone oestrogen.

“For these cancers, CDK4/6 inhibitors should be the standard of care, both for younger, pre-menopausal and older, menopausal women, as well as men with advanced breast cancer,” said Prof Cardoso. “However, the major problem is the cost of these medicines and, at present, only a small proportion of patients around the world are being treated with them. The same occurs with anti-HER2 therapies, which can prolong survival substantially for another subtype of advanced breast cancer – HER2 positive breast cancer.

“There is unequal access to these medicines not only between countries, but within countries as well, and between pre- and post-menopausal women. Our panel of world experts on the treatment of breast cancer agrees that CDK4/6 inhibitors should be make available to every patient who could benefit from them, not just a small percentage,” added Prof Cardoso.

The experts also called on policy-makers worldwide to ensure that fears about the abuse of opioids should not limit cancer patients’ access to adequate pain control.

In the new guidelines, they state: “The advanced breast cancer (ABC) community is aware of limitations that are being imposed worldwide, as a consequence of the perceived abuse of opioids in certain areas of the world. The ABC community is united in insisting that cancer patients should not have restrictions placed that will limit their access to adequate pain control.”

Professor Eric Winer, Director of the Breast Cancer Program at Dana-Farber and the Dana-Farber/Harvard Cancer Center, Boston, USA, and co-chair of the conference, said: “Patients with advanced breast cancer can suffer pain and other symptoms, particularly towards the end of their lives. We need to ensure that appropriate pain medications and other symptom interventions are available to them.

“We acknowledge that the misuse of opioids is a big problem, particularly in the United States, but we need to make sure that in trying to deal with this problem we do not interfere with pain management in cancer patients. In addition, in some low- and middle-income countries, such as some in Africa, there are problems with patients being able to access any form of pain relief, and this needs to be addressed urgently,” explained Prof Winer. The panel of experts also called for further research into the use of cannabis for managing symptoms and pain in patients with advanced breast cancer.

However, they stressed that it should never replace existing medicines that have been proven to work, such as morphine.

“The panel encourages research on the potential role of cannabis to assist in pain and symptom control but strongly stresses that it cannot replace proven medicines, such as morphine, for adequate pain control,” the experts stated in their new guidelines. These issues were among several addressed by 1,500 experts and patients from approximately 90 countries around the world at the conference as they agreed new and modified guidelines for the treatment and management of all types of advanced breast cancer. The new guidelines will be published in Breast and Annals of Oncology in 2020.

There are no reliable figures for the numbers of women (and men) living with advanced breast cancer.

However, there are over two million new cases of breast cancer a year in the world and 0.6 million deaths.

About 5-10 percent of cases are either locally advanced or have spread to other parts of the body (metastasised) at diagnosis, and these figures reach almost 80 percent in developing countries.

About a third of all early breast cancer cases will become metastatic even with the best care, and the average overall survival for these patients is around three years.

Source: Advanced Breast Cancer Fifth International Consensus Conference (ABC5)