Decreased Skeletal Muscle Mass is Associated with an Increased Risk of Mortality after Radical Nephrectomy for Localized Renal Cell Cancer.
OBJECTIVE
We evaluate the association between severe skeletal muscle deficiency or sarcopenia, and disease progression, cancer specific mortality and all cause mortality in patients with localized renal cell carcinoma treated with radical nephrectomy.


METHODS
The baseline lumbar skeletal muscle index of 387 patients treated with radical nephrectomy for nonmetastatic renal cell carcinoma between 2000 and 2010 was measured on preoperative computerized tomography. Sarcopenia was classified according to gender specific consensus definitions as male-skeletal muscle index less than 55 cm(2)/m(2) and female-skeletal muscle index less than 39 cm(2)/m(2). Progression-free, cancer specific and overall survival was estimated with the Kaplan-Meier method. Associations with progression, cancer specific mortality and all cause mortality were summarized with hazard ratios.


RESULTS
Of 387 patients 180 (47%) had sarcopenia. Patients with sarcopenia were older, more likely to be male (77% vs 56%, p <0.001), to have a smoking history (67% vs 55%, p=0.02), and to have nuclear grade 3 or greater disease (67% vs 60%, p=0.05), but were otherwise similar to patients without sarcopenia. Median postoperative followup was 7.2 years. Patients with sarcopenia had inferior 5-year cancer specific survival (79% vs 85%, p=0.05) compared to those without sarcopenia, as well as significantly worse 5-year overall survival (65% vs 74%, p= 0.005). As a continuous variable, increasing skeletal muscle index was linearly associated with a decreased risk of cancer specific mortality and all cause mortality. Moreover, on multivariable analysis sarcopenia was associated with increased cancer specific mortality (HR 1.70, p=0.047) and all cause mortality (HR 1.48, p=0.039).


CONCLUSIONS
Sarcopenia is independently associated with cancer specific mortality and all cause mortality after radical nephrectomy for renal cell carcinoma. These findings underscore the importance of assessing skeletal muscle index for risk stratification, patient counseling and treatment planning.
Department of Urology, Mayo Clinic, Rochester, Minnesota.
Sarah P
SP
Psutka
Department of Urology, Mayo Clinic, Rochester, Minnesota.
Stephen A
SA
Boorjian
Department of Radiology, Mayo Clinic, Rochester, Minnesota.
Michael R
MR
Moynagh
Department of Radiology, Mayo Clinic, Rochester, Minnesota.
Grant D
GD
Schmit
Division of Medical Oncology, Department of Medicine, Mayo Clinic, Rochester, Minnesota.
Brian A
BA
Costello
Department of Urology, Mayo Clinic, Rochester, Minnesota.
R Houston
RH
Thompson
Department of Urology, Mayo Clinic, Rochester, Minnesota.
Suzanne B
SB
Stewart-Merrill
Department of Health Sciences Research, Mayo Clinic, Rochester, Minnesota.
Christine M
CM
Lohse
Department of Pathology, Mayo Clinic, Rochester, Minnesota.
John C
JC
Cheville
Department of Urology, Mayo Clinic, Rochester, Minnesota.
Bradley C
BC
Leibovich
Department of Urology, Mayo Clinic, Rochester, Minnesota.
Matthew K
MK
Tollefson
D000367:Age Factors; D002292:Carcinoma, Renal Cell / Q000401:mortality* / Q000601:surgery*; D002423:Cause of Death; D018450:Disease Progression; D005260:Female; D006801:Humans; D053208:Kaplan-Meier Estimate; D007680:Kidney Neoplasms / Q000401:mortality* / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D060787:Neoplasm Grading; D009392:Nephrectomy / Q000379:methods*; D012307:Risk Factors; D055948:Sarcopenia / Q000150:complications* / Q000000981:diagnostic imaging; D014057:Tomography, X-Ray Computed
body mass index; carcinoma; nephrectomy; renal cell; sarcopenia; survival rate