"More pet owners are hearing about canine cancer than ever before, but the reasons behind this rise aren't always what people assume."— Julie Schwenzer
Episode summary
Why does canine cancer seem to come up so much more often now? Dr. LoSasso — quick to note he's an ER doctor, not an oncologist — points to a combination of factors rather than any single cause. Pets are living longer as veterinary medicine improves, which simply creates more time for age-related disease to surface. Diagnostics have advanced too, especially ultrasound, along with newer blood tests designed specifically to screen for certain cancers. And owners are paying closer attention than they used to — a shift he says accelerated during the COVID-19 period, when pets became an even more central part of the family than before.
Some breeds carry a clear predisposition. The Boxer is the breed most veterinarians think of first when cancer comes up, with Golden Retrievers close behind; he also sees a lot of hemangiosarcoma and lymphoma in Labradors, though he notes that's partly a numbers game — Labradors were the most popular breed in the country for decades before being recently overtaken by the French Bulldog. On environmental causes, he's candid that he hasn't seen evidence linking ordinary diet, exercise, or household conditions to higher cancer rates in his own experience — the clearest environmental link he points to is radiation exposure, citing places like Chernobyl and Fukushima.
"These dogs are happy, healthy — they get a clean bill of health, their blood work looks normal. Unless somebody's specifically doing an ultrasound of the abdomen, those masses go completely undetected until the day they actually break open and start to bleed."— Dr. Michael LoSasso, DVM
The bulk of the conversation centers on hemangiosarcoma, a cancer that frequently forms as a mass on the spleen and produces no clinical signs at all — no lump you'd feel, no change in blood work, nothing to flag on a routine exam. Because abdominal ultrasound isn't part of a standard annual physical, these masses go undetected until they rupture and begin bleeding internally. At that point the dog collapses, gums turn pale, and a family that thought they had a perfectly healthy eight-, nine-, or ten-year-old dog is suddenly deciding between emergency surgery and euthanasia — often the same day.
Dr. LoSasso doesn't think it's a bad idea at all. He describes abdominal ultrasound as quick, non-invasive, and usually less expensive than X-rays — a straightforward way to screen the liver, spleen, and kidneys for problems before they become emergencies. He's equally open to annual chest X-rays in older dogs, and especially recommends it for small breeds prone to heart disease, since imaging can catch changes in heart size before symptoms ever appear. As he puts it: there's nothing harmful about sound waves — it's the same technology used routinely on pregnant women.
His practical takeaway for owners: physically feel your dog for masses regularly. Since many cancers — hemangiosarcoma especially — give no external warning until very late, hands-on exams at home paired with routine veterinary checkups remain one of the few ways to catch something before it turns into a crisis.
Questions answered in this episode
The following questions are answered by Dr. LoSasso in this episode, drawn directly from the conversation. These are real clinical answers from a practicing emergency veterinarian with 30+ years of experience.