Friday, February 17, 2012

Muscle Mass Is Cancer Prevention

Very interesting study, skip to conclusions below if you don't like (as I don't) reading geek-speak in studies.
BACKGROUND: Several hypotheses proposed to explain the worse prognosis for older melanoma patients include different tumor biology and diminished host response. If the latter were true, then biologic frailty, and not age, should be an independent prognostic factor in melanoma.
METHODS: Our prospective institutional review board (IRB)-approved database was queried for stage III patients with computed tomography (CT) scans at time of lymph node dissection (LND). Psoas area (PA) and density (PD) were determined in semi-automated fashion. Kaplan-Meier (K-M) survival estimates and Cox proportional-hazard models were used to determine PA and PD impact on survival and surgical complications.
RESULTS: Among 101 stage III patients, PD was significantly associated with both disease-free survival (DFS) (P = 0.04) and distant disease-free survival (DDFS) (P = 0.0002). Cox multivariate modeling incorporating thickness, age, ulceration, and N stage showed highly significant association with PD and both DFS and DDFS. DDFS was significantly associated with Breslow thickness (P = 0.04), number of positive nodes (P = 0.001), ulceration (P = 0.04), and decreasing muscle density (P = 0.01), with hazard ratio of 0.55 [95% confidence interval (CI) 0.35-0.87]. PD also correlated with surgical complications, with odds ratio (OR) of 1.081 [95% CI 1.016-1.150, P = 0.01]. CONCLUSIONS: Decreased psoas muscle density on CT, an objective measure of frailty, was as important a predictor of outcome as tumor factors in a cohort of stage III melanoma patients. On multivariate analysis, frailty, not age, was associated with decreased disease-free survival and distant disease-free survival, and higher rate of surgical complications.

Read more here:

It's difficult to know without reading the whole study how they separated causality - IOW, were the folks that were more frail more frail because their cancer was detected later?  They had already had more treatment?  These obviously would confound the result, it would be nice to think they were ahead of those issues.

The BL:  the more I learn about it, the less significance cardiorespiratory endurance seems to have to health.  Strength is a much more relevant measure of health (or muscle mass, a correlate of strength).  In some ways this seems like a blinding flash of the obvious - if you have the strength to get up and down from the floor, up and down stairs and hills, can push a lawn mower, and so forth - you'll be able to be independent, mobile and active.  The fewer the restraints on your activity, the more alive you are almost by definition.  Running, or jogging, is great, but leaves a lot on the table in terms of health.  By adding squats, pushups, pullups, or any degree of strength training, you can significantly improve you chances of aging well - and apparently, of surviving illness, too.

No comments:

Post a Comment