Breast cancer recurrence: Trials show additional treatment options help reduce recurrence rates

According to the Singapore Cancer Registry, more than 12,000 new cases of breast cancer were diagnosed in the five years from 2016 to 2020, and the number is increasing each year. More than 9 out of 10 cases are detected early.

At least 30-40% of early-stage breast cancer (EBC) cases are at high risk of recurrence, according to Professor Lee Soo Chin, Head and Senior Consultant, Department of Hematology and Oncology, National University Cancer Institute, Singapore.

To reduce the risk of the cancer coming back, doctors in Singapore were recently able to prescribe a drug known as abemaciclib to treat select high-risk EBC cases. It was used for about 2-3 years, after which the approval was extended to certain patients with EBC. These cases are considered high-risk by the patient’s physician based on the stage and aggressiveness of the cancer.

“Patients with high-risk EBC traditionally receive adjuvant chemotherapy and at least 5 years of adjuvant antihormonal therapy to eradicate micrometastases and reduce the risk of recurrence.” Lurin School of Medicine.

Adjuvant therapy is additional treatment given to patients after surgery or initial treatment to reduce the risk that the cancer will come back. Adjuvant treatments for EBC include radiation therapy, chemotherapy, antihormonal therapy, and immunotherapy, depending on the type and stage of cancer.

Micrometastases are small clusters of cancer cells that have moved from the original tumor to another part of the body.

Abemaciclib is indicated as adjuvant therapy in adult patients with hormone receptor (HR)-positive, human epidermal growth factor receptor 2 (HER2)-negative, node-positive early-stage breast cancer at high risk of recurrence. In hormone receptor-positive breast cancer, cells use estrogen, progesterone, or both to grow. HER2 negative means that cancer cells do not contain high levels of a protein known as HER2.

Abemaciclib works by blocking a protein that stimulates the division and proliferation of breast cancer cells.

“Abemaciclib is given in addition to adjuvant antihormonal therapy to further reduce the risk of cancer recurrence in high-risk patients. No,” says Professor Lee.

The drug is given orally along with standard anti-hormonal therapy to patients with hormone receptor-positive, HER2-negative EBC. Abemaciclib will be prescribed to him for two years, but standard adjuvant antihormonal therapy will be given for at least five years.

“In a large randomized trial, patients with high-risk early-stage breast cancer treated with adjuvant antihormonal therapy and abemaciclib had cancer recurrence after 4 years compared with those treated with adjuvant antihormonal therapy. Alone,” says Professor Lee.

The recurrence rate was 14.2% at 4 years in patients receiving both antihormonal therapy and abemaciclib and 20.6% in patients receiving antihormonal therapy alone.

The monarchE trial was an international study of 5,637 patients from 603 sites in 38 countries, including multiple countries in Asia, with participation from Singapore. Professor Lee said the test results are applicable here and that his 20% of patients in the study are from Asia.

Main side effects of drugs

“Up to 30 to 40 percent of patients taking abemaciclib may suffer from diarrhea, which is the drug’s main side effect,” she says. This can be managed with antidiarrheal medications.

“This drug can also cause low blood counts and mild abnormalities in liver enzymes, requiring more monitoring, at least during the first few months of treatment,” says Professor Lee. , can cause serious, life-threatening infections if not monitored closely. Many medical examinations and blood tests are required.