Author(s): MARZUCA-NASSR, G., ARTIGAS-ARIAS, M.1, CORTES-RIQUELME, J.1, SAFFIE, I.1, SAPUNAR, J.1,2, VILLA, D.1, HIRABARA, S.M.3, PITHON-CURI, T.C.3,4, CURI, R.3,4,5, MARZUCA-NASSR, G.N.2, Institution: UNIVERSIDAD DE LA FRONTERA, Country: CHILE, Abstract-ID: 2551

INTRODUCTION:
Neoadjuvant chemotherapy in women with breast cancer is associated with skeletal muscle mass and strength loss, which contributes to increased treatment-related toxicity and impaired functional capacity. Resistance exercise training (RET) has shown beneficial effects in other breast cancer settings; however, its impact during neoadjuvant chemotherapy (before breast surgery) remains unclear. This study compares the effects of prehabilitation based on RET versus usual care, before and after neoadjuvant chemotherapy, on skeletal muscle mass, strength, and functional capacity in women with breast cancer.
METHODS:
Thirteen women with breast cancer were enrolled in this randomized controlled trial. Participants were allocated to usual care (CON-UC; 48+/-6 years; BMI 28.5+/-5.2 kg·m−2; n=7) or to a supervised progressive high-intensity whole-body RET prehabilitation program (PRE-RET; 42+/-7 years; BMI 25.3+/-4.5 kg·m−2; n = 6), performed twice weekly over 18–24 weeks. Before and after neoadjuvant chemotherapy, quadriceps cross-sectional area (CSA; CT-scan), muscle strength (1RM knee extension and handgrip strength tests), and functional capacity (Timed Up and Go, TUG; 30-second Sit-to-Stand, 30sSTS; and 2-minute Step Test, 2MST) were assessed. Muscle fiber CSA of the pectoralis minor (histology), tumor size, and pathological complete response (pCR; MRI) were measured at surgery. Data were analyzed using t-test and repeated-measures ANOVA, with an alpha level of 0.05. Data are reported as means+/-SD.
RESULTS:
Following neoadjuvant chemotherapy, quadriceps CSA differed in response to RET between groups (time x group, P = 0.015). PRE-RET showed an increase of +5.8±2.8% (from 52.7±5.9 to 55.5±4.2 cm2, P = 0.031), whereas a non-significant decrease was observed in CON-UC (−2.9+/-1.7%, from 51.7±7.5 to 50.1±6.6 cm2, P = 0.074). In accordance with, muscle fiber CSA of the pectoralis minor from PRE-RET exhibited higher values when compared with CON-UC (2252.7+/-218.7 vs. 1818.4+/-406.1 µm², respectively; P = 0.044).
Also, PRE-RET increased 1RM knee extension (from 53.3+/-7.3 to 85.1+/-18.4 kg, P = 0.006) whereas a non-significant decrease was observed in CON-UC (from 52.9+/-19.6 to 47.2+/-18.6 kg, P = 0.551). No differences were observed for handgrip strength (P >= 0.05). Functional capacity improved in the PRE-RET compared with CON-UC, as evidenced by better performance in the 30sSTS (P = 0.044) and 2MST (P = 0.014), with no changes observed in the TUG test (P >= 0.05).
Tumor size decreased over time in both groups (from 2.3+/-0.6 to 0.4+/-0.8 cm in PRE-RET and from 2.9+/-1.2 to 0.6+/-0.9 cm in CON-UC; P < 0.001). No differences in the response to RET were observed between groups (time x group, P = 0.373). Similar pCR rates were observed between PRE-RET and CON-UC (67% vs. 57%, respectively).
CONCLUSION:
Prehabilitation based on prolonged high-intensity RET increases skeletal muscle mass, strength and functional capacity during neoadjuvant chemotherapy in women with breast cancer.