A TCM Treatment for Aromatase-Inhibitor-Induced Bone and Joint Symptoms in Breast Cancer Patients on Letrozole

The Shiyong Zhongyiyao Zazhi (Journal of Practical Traditional Chinese Medicine), Vol. 40, No. 6 (Serial No. 377), June 2024, published a paper by Lu Liting, Lu Yingxue, Ni Huashui, and colleagues of the Maoming People's Hospital, Guangdong Province, titled "Observation on the Efficacy of Modified Huangqi Guizhi Wuwu Tang Combined with Buyang Huanwu Tang in Treating Letrozole-Induced Bone and Joint Symptoms." It describes a controlled study the hospital's team conducted on 50 breast cancer patients admitted from December 2020 to March 2021.

The patients were divided into two groups. Both groups were treated with letrozole tablets; the observation group additionally received modified Huangqi Guizhi Wuwu Tang combined with Buyang Huanwu Tang, while the control group received letrozole alone. The base formula for the observation group was: Huangqi (Astragalus) 50 g, Danggui (Angelica) 20 g, Guizhi (Cassia Twig) 15 g, Chishao (Red Peony) 15 g, Baishao (White Peony) 15 g, Honghua (Safflower) 10 g, Dilong (Earthworm) 10 g, Chuanxiong (Sichuan Lovage Rhizome) 10 g, Taoren (Peach Kernel) 10 g, Quanxie (Scorpion) 5 g, Wugong (Centipede) 1 piece (ground into powder and taken with the decoction), Shengjiang (Fresh Ginger) 3 slices, Dazao (Jujube) 5 pieces. For blood stasis, add Chuanxiong 12 g and Danggui 12 g; for qi deficiency, add Huangqi 36 g. One dose daily, decocted twice to yield 300 ml, taken morning and evening. Both groups were treated for 6 months.

After treatment, significant differences appeared between the two groups in bodily pain, physical functioning, mental health, role-emotional, social functioning, vitality, and general health; the observation group's efficacy was markedly superior to the control group's.

Letrozole is one of the endocrine therapy drugs commonly used in postmenopausal women with breast cancer. It blocks estrogen-receptor levels in peripheral tissues, thereby inhibiting breast cancer progression. However, a major side effect of letrozole is reduced bone mineral density, producing a series of musculoskeletal symptoms such as muscle weakness, muscle/bone/joint aching, and joint dysfunction.

In my own clinical practice I have seen many such letrozole side effects. Some patients have even had to abandon letrozole because of severe bone pain, yet letrozole contributes greatly to prolonging survival and improving quality of life in breast cancer. Finding a relatively safe TCM approach to reduce letrozole's side effects, combining Chinese and Western medicine, can therefore benefit breast cancer patients.

Both Buyang Huanwu Tang and Huangqi Guizhi Wuwu Tang used in this study are TCM formulas for bi syndrome (impediment). The bone and joint symptoms caused by letrozole resemble TCM's "bone bi," "bone wilting," and "bone pain."

Huangqi Guizhi Wuwu Tang (Astragalus Cassia Twig Five-Substance Decoction) comes from Zhang Zhongjing's Han-dynasty Jingui Yaolue (Essential Prescriptions from the Golden Cabinet), composed of Huangqi, Guizhi, Shaoyao, Shengjiang, and Dazao. TCM holds that it supplements qi and warms the channels, harmonizes blood and unblocks bi; it is indicated for blood bi causing numbness and insensitivity of the skin and flesh, with a fine, rough, tight pulse.

Buyang Huanwu Tang (Yang-Supplementing Five-Returning Decoction) comes from Wang Qingren's Qing-dynasty Yilin Gaicuo (Correction of Errors in Medical Classics), composed of Huangqi, Dangguiwei (Angelica Tail), Chishao, Dilong, Chuanxiong, Honghua, and Taoren. The original formula's most striking feature is its large dose of Huangqi up to 4 liang (120 g). Wang Qingren used Buyang Huanwu Tang for stroke of qi deficiency and blood stasis, presenting hemiplegia, drooping of the mouth and eye, slurred speech, drooling, frequent urination or enuresis, a pale dark tongue with white coating, and a slow, forceless pulse. Modern research shows that Buyang Huanwu Tang increases local blood perfusion and improves and accelerates nerve repair and conduction.

The authors of this study, on top of Buyang Huanwu Tang and Huangqi Guizhi Wuwu Tang, actually also incorporated another famous TCM formula, Zhijing San (Spasm-Stopping Powder), composed of Quanxie (Scorpion) and Wugong (Centipede). Zhijing San stops spasms and pain and is a common TCM formula for bone pain and bone bi; it also has some anti-tumor effect and can inhibit breast cancer progression.

Thus all three formulas used in this study are famous TCM formulas for bi syndrome; used together, they provide symptomatic treatment of bone and joint symptoms from multiple angles, which is why this prescription relieves letrozole-induced bone and joint symptoms.