Oral oestrogen blockers are used to treat hormonally-driven breast cancer, which accounts for about 70 per cent of cases. But because the drugs can cause joint discomfort, many women quit taking them, which puts them at a higher risk of relapsing.

"This gift will have a tremendous impact on our program," said Mili Arora, UC Davis associate professor of haematology and oncology.

"We thank the Safeway Foundation for supporting our efforts to help breast cancer patients live their lives to the fullest extent possible."

Turmeric, a flowering plant in the ginger family, is used by some arthritis sufferers who say it reduces their joint pain. The Safeway Foundation will help UC Davis test by giving turmeric in a pill in combination with oral anti-estrogen drugs.

The goal is to see if the spice can successfully reduce joint pain in breast cancer patients and explore whether it improves the quality of their lives.

"It's an honour to support the work of the UC Davis Comprehensive Cancer Center. Every day we learn about organisations that go above and beyond to help people and the cancer centre is an excellent example," said Wendy Gutshall, director of public affairs for Safeway.

The study will allow Dr Arora and her team to provide breast cancer patients with essential data on the safety and effectiveness of using turmeric with oral anti-estrogen therapy.

UC Davis Comprehensive Cancer Center is the only National Cancer Institute-designated centre serving the Central Valley and inland Northern California, a region of more than 6 million people.

Its specialists provide compassionate, comprehensive care for more than 15,000 adults and children every year and access to more than 150 active clinical trials at any given time.

Its innovative research program engages more than 225 scientists at UC Davis who work collaboratively to advance the discovery of new tools to diagnose and treat cancer. Patients have access to leading-edge care, including immunotherapy and other targeted treatments.

Its Office of Community Outreach and Engagement addresses disparities in cancer outcomes across diverse populations. The cancer centre provides comprehensive education and workforce development programs for the next generation of clinicians and scientists.