Targeting Muscle-Bone Crosstalk Through Physical Therapy in Cancer Cachexia

Cancer-induced cachexia (CIC) is a complex multifactorial syndrome characterized by progressive loss of skeletal muscle mass, systemic inflammation, metabolic dysregulation, and functional decline. The physiological interplay between skeletal muscle and bone tissue-known as muscle-bone crosstalk-is regulated through humoral signaling pathways involving myokines and osteokines. Key myokines, such as myostatin (an inhibitor of muscle growth), Interleukin-15 (IL-15, which promotes hypertrophy and fat oxidation), and decorin (which binds to myostatin to promote muscle growth), play pivotal roles in maintaining musculoskeletal homeostasis. Contractile activity during physical exercise can favorably modulate these myokine levels, reducing protein degradation and improving metabolic function. Despite the established systemic benefits of physical exercise, significant knowledge gaps remain regarding the clinical efficacy of structured physical therapy protocols specifically targeting muscle-bone crosstalk in young to middle-aged adults undergoing active cancer treatment. Furthermore, there is limited clinical data quantifying exercise-induced biological changes in circulating myokines (e.g., IL-15, decorin, SPARC) within non-metastatic cancer populations receiving neoadjuvant chemotherapy. This study is designed as a prospective Randomized Controlled Trial (RCT) to evaluate the therapeutic potential of a 3-month exercise intervention in patients aged 40-60 years with Grade 2/3 non-metastatic cancer undergoing neoadjuvant chemotherapy. Eligible participants are randomized into two parallel groups: Control Group: Receives standard care consisting of neoadjuvant chemotherapy accompanied by a structured nutritional support course following cachexia onset. Experimental Group: Receives a progressive 3-month physical therapy program in addition to standard neoadjuvant chemotherapy and nutritional support following cachexia onset. The 3-month physical therapy intervention combines structured aerobic and resistance training protocols: Aerobic Exercise: Treadmill walking performed 3 to 5 times per week (aiming for 150 minutes per week) at a progressive intensity ranging between 40% and 85% of maximum heart rate ($\\text{HR}_{\\text{max}}$). Resistance Exercise: Progressive strength training performed 2 to 3 times per week consisting of 2 sets of 8 to 10 repetitions at 50% to 70% of 1-repetition maximum (1RM)

Inclusion criteria

• Adults aged 18 years or older.

Confirmed diagnosis of non-metastatic cancer (Grade 2 or Grade 3).

Diagnosed with Cancer-Induced Cachexia (CIC) based on international consensus criteria (weight loss >5% in past 6 months, OR weight loss >2% in individuals with BMI <20 kg/m², OR appendicular skeletal muscle index consistent with sarcopenia).

Scheduled for or currently receiving standard neoadjuvant chemotherapy.

Ability to provide written informed consent and follow a structured physical therapy program.

ECOG Performance Status of 0 to 2.

Exclusion criteria

• Evidence of distant tumor metastasis (Grade 4 cancer).

Severe orthopedic, neurological, or cardiovascular conditions preventing participation in safe physical therapy exercise.

Uncontrolled cardiovascular disease (e.g., unstable angina, recent myocardial infarction, severe cardiac arrhythmias).

Severe bone metastases or pathologic fracture risk that contraindicates weight-bearing exercises.

Prior participation in regular structured aerobic or resistance exercise training within the past 6 months.

Cognitive impairment or psychiatric conditions interfering with treatment compliance or informed consent.