Women should regularly perform a breast self-examination every month to look for abnormalities, the Department of Medical Services (DMS) said as it raises breast cancer awareness.
Somsak Akksilp, director-general of the DMS, on Sunday said breast cancer is a common type of cancer found in Thai women.
Citing Public Health Ministry data, he said that last year, about 18,000 Thai women had breast cancer and about 4,800 died from the disease.
The tendency of Thai women to develop breast cancer is rising, and there may be 22,000 new patients next year, he said.
Dr Somsak added that breast cancer is one of the most worrying public health problems across the world.
The World Health Organization said there are approximately 2.3 million new patients worldwide and about 685,000 people die from it per year, he said.
"It is still unclear what causes breast cancer, but now more [risk] factors can be identified from patients' lifestyles, including whether they eat high-calorie food or lack exercise," he said.
"However, there are also uncontrollable factors like genetic disorders and old age."
Chayanut Rattadilok, a breast surgeon at the National Cancer Institute, said breast cancer is caused by abnormal tissues that later grow into cancer cells.
They can affect neighbouring tissues and other parts of the body, she said.
Older women have a higher risk of developing breast cancer, especially those over 40 years old or who have family members with cancer history, she said.
Breast cancer can be found in both men and women, but the risk of developing the disease is much lower in men, she said.
Dr Chayanut said people can recover from breast cancer, especially when they are diagnosed at an early stage. Everyone can follow self-screening guidelines or undergo regular health checkups, she said.
People from a family with cancer history should have a mammogram, she said, adding breast cancer can be treated using surgery, radiation and chemotherapy.
