Research on breast cancer survivors found that just 45 minutes of a specific type of exercise significantly suppressed the growth of triple-negative breast cancer cells by 29% and instantly boosted anti-cancer hormones in the body by 47%.
Rehabilitation physician Dr. Wang Sze-heng cited a study published in July 2025 in Breast Cancer Research and Treatment on his Facebook page. The study explored the effects of resistance training (weight training) and high-intensity interval training (HIIT) on inhibiting breast cancer cell proliferation and growth.
What Did the Study Find?
Researchers recruited 32 breast cancer survivors, average age 58, who had completed surgery, chemotherapy, or radiotherapy at least 4 months prior. They were randomly divided into two groups, each performing a single 45-minute exercise session:
- Weight Training Group: Performed 8 high-intensity exercises at 80% of their one-repetition maximum (1RM), 5 reps per set, for 5 sets.
- HIIT Group: Performed 30 seconds of all-out sprinting followed by 30 seconds of rest, 7 cycles per round, for a total of 4 rounds.
Researchers drew blood from participants at three key times: before exercise, immediately after exercise, and 30 minutes after exercise. They then placed the serum into culture dishes containing triple-negative breast cancer cells. After 72 hours of cultivation, they observed the cancer cells' growth. The results showed:
- Weight Training Group Serum: Blood drawn immediately after exercise reduced cancer cell growth by 21%; blood drawn 30 minutes after exercise still showed a 19% reduction.
- HIIT (Sweaty) Group Serum: Blood drawn immediately after exercise reduced cancer cell growth by 20%; blood drawn 30 minutes after exercise showed an even greater inhibitory effect, rising to 29%.
Overall, looking at the immediate post-exercise blood results, the HIIT group performed significantly better than the weight training group. The remarkable aspect of this study is that it wasn't an animal experiment; it used blood directly from breast cancer survivors. Just a single bout of exercise produced observable anti-cancer signals in the lab.
Fighting the Aggressive "Triple-Negative" Breast Cancer – Muscles Release 47% More Anti-Cancer Hormones
Wang explained that the researchers deliberately chose triple-negative breast cancer cells for testing because it is recognized as the most challenging and aggressive form of breast cancer. Other types, like hormone receptor-positive (can be controlled long-term with anti-hormone drugs) or HER2-positive (targeted drugs exist), have more options. However, triple-negative breast cancer lacks estrogen receptors, progesterone receptors, and HER2. Patients cannot take hormone drugs or use targeted therapies, leaving few options besides chemotherapy, and the risk of recurrence is extremely high. The experiment proved that if even this aggressive triple-negative cancer can be suppressed by 20-30% with post-exercise blood, it indicates that during exercise, the body indeed releases substances that cancer cells extremely dislike.
Wang points out that during exercise, muscles not only exert force but also act as mini endocrine organs, releasing large amounts of beneficial substances called myokines into the bloodstream. The study measured four types of myokines related to cancer suppression:
- Weight Training Group: Anti-cancer myokines (such as Decorin, SPARC, IL-6, etc.) increased by 9% to 23%.
- HIIT Group: The increases were extremely dramatic. IL-6 (the beneficial type induced by exercise, not the inflammatory type) surged directly by 47%!
Experts speculate that high-intensity interval exercise causes adrenaline to spike instantly, which directly triggers the muscles' switch, pushing the secretion of anti-cancer myokines to peak levels.
Exercise is a Powerful Adjuvant, Not a Replacement for Standard Treatment
While the results are very encouraging, Wang emphasizes a rational perspective and cautions against overinterpretation:
- Limitation of Petri Dish Experiments: While cancer cell growth slowed in the lab, this does not necessarily mean it would definitively kill cancer cells inside the human body.
- Never Abandon Standard Treatment: Surgery, chemotherapy, radiotherapy, and hormone therapy remain the mainstays of cancer treatment. Exercise plays a powerful adjuvant role but must never replace conventional medical treatment.
- Exercise Within Your Limits: Patients currently undergoing treatment, or who have just finished and wish to start exercising, must first discuss an appropriate exercise plan with their primary physician, rehabilitation doctor, or sports medicine expert. Do not start blindly training the day after reading an article.
What is Triple-Negative Breast Cancer? Why is it Difficult to Treat?
According to the Hong Kong Hospital Authority, breast cancer is the second most common cancer in Hong Kong, with 5,208 new cases in 2022. It is also the third leading cause of cancer death in women, with 792 female deaths in 2022. Breast cancer occurs when breast cells divide and grow uncontrollably, forming a tumor. Tumors can be benign or malignant.
Regarding "triple-negative breast cancer," Hong Kong medical oncologist Dr. Ziu Wing-yan once wrote that it is a highly aggressive cancer, accounting for about 10% of all breast cancer cases. These patients lack three receptors: estrogen receptor, progesterone receptor, and human epidermal growth factor receptor 2 (HER2).
She points out that triple-negative breast cancer is rapidly progressing and quite difficult to treat. In the past, only chemotherapy was available, and often, after first- or second-line treatment, there were no effective drugs left. More frighteningly, about 42% of patients relapse within 3 years of diagnosis. The risk of early distant organ metastasis and recurrence within 5 years is nearly 3 times higher than for non-triple-negative breast cancer patients.
Breast Cancer: 7 Symptoms and 9 High-Risk Groups
The Hospital Authority reminds that after developing breast cancer, the breast, nipple, and armpit may show the following changes:
- Breast: Presence of a lump of any size, change in shape or size, dimpling of the skin, vein dilation, or peau d'orange (orange peel) appearance.
- Nipple: Spontaneous discharge, bleeding, or inversion.
- Armpit: Swelling or enlarged lymph nodes.
High-Risk Groups for Breast Cancer:
- Gender: Breast cancer primarily affects women, but men can also develop it.
- Age: Risk increases with age.
- Genetics: Higher risk if mother, sister, or immediate family members have had the disease; about 5-10% of cases may be genetic.
- Menstrual History: Early menstruation (before 12) or late menopause (after 55).
- Diet: Long-term high intake of animal fat.
- Lifestyle: Smoking, heavy drinking, lack of exercise.
- Reproductive History: Never having given birth or first birth after age 35.
- Medication: Long-term use of oral contraceptives or hormone replacement therapy for more than 5 years.
- Personal Cancer History: Those with a history of certain cancers (e.g., Hodgkin's lymphoma, lung adenocarcinoma, colorectal cancer, or childhood cancer) have higher risk.
The Hospital Authority reminds that premenstrual breast tenderness or lumpiness is a normal physiological response to cyclical hormonal changes. However, if you suspect a breast lump, consult a doctor for examination to determine if it is benign or malignant. Most breast lumps are benign (e.g., cysts or benign fibroadenomas) and harmless.
Sources: Rehabilitation Physician Dr. Wang Sze-heng, Hospital Authority (Hong Kong), Breast Cancer Research and Treatment
