I can't believe what you have been through with the loss of your precious dogs, and my heart goes out to you.
K9data.com is partially helpful in checking the lines of future pups for longevity, and it is a tool that will help you find your pup. Unfortunately, many causes of death and death dates are not recorded, but quite a few are. You can ask the prospective breeder directly to fill in dogs you cant find information about.
There is no doubt many cancers have a genetic component in dogs and humans. Raleigh's oncologist told me that, in choosing a puppy, dogs in the background who suffer cancer before age 7 are especially statistically significant bc then it is not a disease of older age past nature's reproductive period, but a prime of life cancer with grave implications for offspring. My vet thinks Boxers,Bernese MT dogs, and Goldens do have a higher propensity for 4 types of cancer than other breeds they see frequently or mixed breeds.
There are several threads here about Gold Rush- both for and against the efforts of that influential kennel to address the cancer issue. You can read them by searching. Since it's a sensitive topic for several people, I'm not going to comment.
I do know I went way too far in the other direction as a knee-jerk reaction to losing Raleigh to hemangiosarcoma. I looked fanatically for a very outcrossed breeding with no cancer in the pedigree in a dog under ten - however, I sacrificed orthopedics and conformation in exchange. Next time, I hope to be more balanced in looking for a pup who, yes, has longevity in parents& grandparents and their littermates, but also has a breeder who knows their lines through and through and through on both sides. I just considered a beautiful first pick puppy, but then there were too many young deaths for me to feel comfortable.
I want to second Hotel4Dogs' commendation of Rhonda Hovan's kindness and work ethic revolving around cancer prevention in goldens. She took the time to write me two detailed emails about what she herself does concretely with the Faera dogs now- things studied and things promising but not yet proven. I dont want to quote it here without her explicit permission, but I will email and ask if I can. Tally is Starlight and Future Classic, and QB is linebred on Thunder. A few things: keeping dogs lean, buffered 81 asprin daily with a stomach guard, vitamin D, good tick&flea prevention, age of neutering, low carbs (one theory is cancer feeds on carbs)no golf courses/lawn chemicals seem promising to at least help. My vet believes the low dose asprin will one day be recommended for cancer-prone breeds, but right now there is too much risk of stomach bleeding and no definitive proof.
Whenever I get too worried, I like to think about my golden Joplin who lived, basically, forever. And about dogs like Benjamin (http://www.everythinggolden.com/new_page_131.htm
)who saw 16. It does happen that goldens from familiar lines to thrive into the oldest of old age.
BISS GCHS AM CH Tamarack Billions Of Stars Over Poeticgold CD RN TDI CGCA CGCU CGC BPIS Top 20 2015 "Mystic"
Goldiva Raleigh Tangled Up In Blue CD RAE TDI TT CGCA CGCU " Tally"
GCH AM CH Harborview Sweeter Than 'Shine At PoeticGold CGC " Lush"
AM CH Pebwin Reverie SoothSayer CGC BPISS "Sayer"
PoeticGold I Named A Star For You CGC BISS "Cambridge"
AM CH RainyDay PoeticGold Secret Society BPIS "HipHop"