Weight loss

Though my husband's tumor is stable, at least as of last month's MRI, he continues to struggle with weight loss. He barely eats 750 calories a day. He's lost over 25 lbs, mostly muscle mass. I know that this is partly from the side-effects of chemo but some of this pre-dates chemo and must be tied directly with the tumor. His tumor is in the right frontal lobe. A neighbor who is an emergency nurse recommended Megestrol Acetate to increase appetite. It has been used for other cancers and HIV/AIDS patients. Does anyone here grapple with the same issue? The other thing that is compounding the problem is Provigil, which he takes to stay awake but is also an appetite suppressant.