Low muscle attenuation is a prognostic factor for survival in metastatic breast cancer patients treated with first line palliative chemotherapy.
BACKGROUND
Low muscle mass (LMM) and low muscle attenuation (LMA) reflect low muscle quantity and low muscle quality, respectively. Both are associated with a poor outcome in several types of solid malignancies. This study determined the association of skeletal muscle measures with overall survival (OS) and time to next treatment (TNT).


METHODS
A skeletal muscle index (SMI) in cm2/m2and muscle attenuation (MA) in Hounsfield units (HU) were measured using abdominal CT-images of 166 patients before start of first-line chemotherapy for metastatic breast cancer. Low muscle mass (SMI <41 cm2/m2), sarcopenic obesity (LMM and BMI ≥30 kg/m2) and low muscle attenuation (MA <41 HU and BMI <25 kg/m2 or MA <33 HU and BMI ≥25 kg/m2) were related to OS and TNT.


RESULTS
The prevalence of LMM, sarcopenic obesity and LMA were 66.9%, 7.2% and 59.6% respectively. LMM and sarcopenic obesity showed no significant association with OS and TNT, whereas LMA was associated with both lower OS (HR 2.04, 95% CI 1.34-3.12, p = 0.001) and shorter TNT (HR 1.72, 95% CI 1.14-2.62, p = 0.010). Patients with LMA had a median OS and TNT of 15 and 8 months respectively, compared to 23 and 10 months in patients with normal MA.


CONCLUSIONS
LMA is a prognostic factor for OS and TNT in metastatic breast cancer patients receiving first-line palliative chemotherapy, whereas LMM and sarcopenic obesity are not. Further research is needed to establish what impact LMA should have in daily clinical practice.
Department of Internal Medicine, Albert Schweitzer Hospital, Albert Schweitzerplaats 25, 3318 AT, Dordrecht, The Netherlands; Department of Medical Oncology, Erasmus MC Cancer Institute, 's-Gravendijkwal 230, 3015 CE, Rotterdam, The Netherlands. Electronic address: rier@asz.nl.
Hánah N
HN
Rier
Department of Medical Oncology, Erasmus MC Cancer Institute, 's-Gravendijkwal 230, 3015 CE, Rotterdam, The Netherlands.
Agnes
A
Jager
Department of Medical Oncology, Erasmus MC Cancer Institute, 's-Gravendijkwal 230, 3015 CE, Rotterdam, The Netherlands.
Stefan
S
Sleijfer
Department of Biostatistics, Erasmus MC, 's-Gravendijkwal 230, 3015 CE, Rotterdam, The Netherlands.
Joost
J
van Rosmalen
Department of Radiology, Albert Schweitzer Hospital, Albert Schweitzerplaats 25, 3318 AT, Dordrecht, The Netherlands.
Marc C J M
MCJM
Kock
Department of Internal Medicine, Albert Schweitzer Hospital, Albert Schweitzerplaats 25, 3318 AT, Dordrecht, The Netherlands.
Mark-David
MD
Levin
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use*; D001943:Breast Neoplasms / Q000150:complications / Q000188:drug therapy / Q000401:mortality* / Q000473:pathology; D005260:Female; D006801:Humans; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000000981:diagnostic imaging / Q000473:pathology*; D009133:Muscular Atrophy / Q000000981:diagnostic imaging / Q000209:etiology / Q000401:mortality*; D009362:Neoplasm Metastasis; D009426:Netherlands / Q000453:epidemiology; D010166:Palliative Care / Q000379:methods*; D015995:Prevalence; D011379:Prognosis; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed
Breast cancer; Muscle attenuation; Muscle mass; Overall survival; Sarcopenia