Ribociclib
A medication used in combination with endocrine therapy for treating breast cancer. It belongs to a class of drugs called CDK4/6 inhibitors that help stop cancer cells from growing and dividing. This medication is taken orally and works by blocking specific proteins that promote cancer cell growth.

Endocrine Therapy (ET)
A treatment that blocks or lowers the amount of hormones in the body to stop or slow down the growth of hormone receptor-positive breast cancer. This therapy can include different types of hormone-blocking medications that either lower estrogen levels or prevent estrogen from attaching to cancer cells.

Hormone Receptor-Positive Breast Cancer – A type of breast cancer where cancer cells grow in response to hormones estrogen and progesterone. The cancer cells have proteins called hormone receptors that become activated when hormones attach to them. This disease typically develops in the breast tissue and can spread to nearby lymph nodes. The cancer cells display specific receptors on their surface that respond to natural hormones in the body. This condition represents the most common form of breast cancer.

HER2-Negative Breast Cancer – A form of breast cancer where the cancer cells do not have high amounts of a protein called HER2 on their surface. This cancer tends to grow more slowly than HER2-positive cancers. The disease develops when breast cells begin to divide uncontrollably without elevated levels of the HER2 protein. This type of breast cancer typically responds differently to treatments compared to HER2-positive cases.

Early Breast Cancer – A stage of breast cancer where the disease is contained within the breast or has only spread to nearby lymph nodes. At this stage, the cancer is localized and has not spread to distant parts of the body. The disease is typically discovered during early screening or when a small lump is detected. This represents the initial phase of breast cancer development.