We lost our beloved Chester this past June at age 12 1/2 to lymphoma. We were treating him, but in the end his back legs gave out. I read about cancer diets and I cooked for him, but to no avail. A litter mate of his passed at age 6 from cancer; that same guy had a cancerous growth in his first year that his owners had removed. I think the cancer was on the dam's side. The sire has had so many offspring that I can't track them, but he didn't pass from cancer. My sister and brother in law in Maryland (I am in NC) just lost their lab mix and a cat to lymphoma. The dog was around 11.
So we have our new pup, Gumbo, and at our first pup visit we reviewed the role of genetics in lymphoma. I love our vet, and I am picky when it comes to health care, whether for humans or my animals. He essentially said genetics is probably the culprit in an overwhelming majority of cases, but also believes nutrition is a factor. So we add fish oil to several of Gumbo's meals. He has some dry skin right now, so we would do that anyway, but will keep the fish oil in his diet. We give him baby carrots to teethe on, and he had his first taste of pumpkin this morning. The oils and the antioxidants in the carrots and pumpkin will hopefully help our LG have a long life. One of the reasons I chose his breeder is (1) she was breeding a descendant of Chester's sire and (2) several of her dogs have lived to 14 and 15. You have to do the research that helps you play the odds to your advantage and make educated decisions.
We are feeding him Purina Performance as recommended by our breeder. He gets filtered water. We have VPI coverage for him and plan to keep the wellness coverage going for the first two years and then we'll re-evaluate that - once the vaccinations are done and he is neutered (age 2) the wellness coverage might not be cost effective.
I'd stand on my head and pray to St. Francis if I thought it would keep LG happy and healthy for 14-15 years! The funny thing is, we had a mixed breed female that I rescued, had no clue regarding great canine nutrition, although I did feed her good food as opposed to cheap food, and she lived to 17 1/2. She was not a lab mix - more a terrier/corgi/loads of other things mix. My understanding is that mixed breeds live longer in general - despite not having the best diet, the oils, carrots, etc. So I think my vet is right about genetics.