The preliminary findings came from the RENEW -- Reach-out to ENhancE Wellness -- trial. The study group included 641 people, all age 65 or older, who had been diagnosed with breast, prostate or colorectal cancer at least five years prior with no evidence of recurrence, were overweight and had no medical conditions prohibiting moderate exercise.

"We know that when people are diagnosed with cancer they're at risk for comorbid (co-existing) conditions and functional decline," Wendy Demark-Wahnefried of the University of Texas M.D. Anderson Cancer Center said in a statement. "For those 65 and over, data show they may become debilitated permanently, thus increasing healthcare costs and taking a toll on family members."

In the trial, 319 people received an intervention and 322 were wait-listed.

The intervention group participated in 15 telephone counseling sessions with a personal trainer and performed lower body strength exercises; walked 30 minutes a day; used portion-control plates, cups and bowls; consumed fewer than 10 percent of calories from saturated fat, and ate more fruits and vegetables.

The intervention group members also increased their physical activity to 44.9 minutes per week versus 29.7 minutes per week for the control group.

The intervention group experienced a 3 percent drop in body weight versus a 1 percent drop in the control group, the researchers found.

The findings were presented at the seventh annual American Association for Cancer Research Frontiers in Cancer Prevention Conference.