Dog Lymphoma: Survival Rates, CHOP, and What Comes Next

Lymphoma is one of the most common cancers in dogs, and it's frequently the diagnosis that arrives without warning — a swollen lymph node found at a routine check-up, or a dog that seems off for a few days before the bloodwork comes back changed.

Positively, it responds to treatment better than almost any other canine cancer. The harder truth is what happens after that first remission.

What lymphoma is — and why surgery isn't the answer

A systemic cancer of the lymphatic system: lymphoma is present throughout the body, not concentrated in a single mass. Surgery isn't the primary treatment for this reason — there's no discrete tumour to remove. The disease is addressed with chemotherapy.

This also means the usual measure of success — "did we get it all?" — doesn't apply. With lymphoma, success means remission: reducing the cancer burden to undetectable levels, and keeping it there.

CHOP: what the treatment involves

Canine lymphoma is treated with CHOP — cyclophosphamide, doxorubicin, vincristine, and prednisone. These four drugs are given in rotating sequences over roughly six months, typically in weekly or bi-weekly sessions at a veterinary oncology practice.

About 80–90% of dogs treated with CHOP achieve remission. That's a high response rate by any oncological standard.

Dogs also tolerate the protocol far better than most owners expect. Veterinary oncologists dose to quality of life, not to maximum tumour kill — calibrated differently from human oncology. Severe side effects such as hospitalisation, significant nausea, or hair loss affect fewer than 5% of dogs in most CHOP protocols. Many dogs continue their normal routines throughout treatment. It's not the experience most owners picture when they hear the word "chemotherapy."

The honest picture on survival

With CHOP, median survival is 12–14 months. Most dogs achieve remission, but most also relapse — typically within a year of starting treatment. When that happens, rescue protocols exist, but response rates fall with each subsequent line of therapy.

Twelve to fourteen months is not nothing. For many families, a year of good-quality life with their dog matters enormously — time for walks, for routines, for the ordinary things that make up life together. But it's worth going into CHOP with a clear understanding of what it can and can't deliver. It buys time, and often good time — it doesn't cure.

What happens in the window between remission and relapse is the gap that current treatment options don't fully address. The dog looks well, feels well, and is functionally cancer-free. But without something targeted at keeping the disease suppressed, relapse remains likely.

The post-remission problem — and where the science is heading

In human oncology, this same challenge has driven significant research into adjuvant therapy — treatment given after primary treatment has achieved remission, designed to prevent relapse. This is precisely where personalised cancer vaccines have shown their strongest results.

Moderna's personalised mRNA vaccine reduced the risk of recurrence or death by 49% at five years in high-risk melanoma patients — given after surgery had already cleared visible disease. BioNTech's pancreatic cancer vaccine generated measurable T-cell responses in 50% of patients. Those who responded had dramatically better outcomes: only 2 of 8 responders had relapsed at 3.2 years, compared to a median recurrence-free survival of 13.4 months in non-responders.

Consistently across these trials, personalised vaccines perform best when the immune system only needs to find and destroy small amounts of residual disease — not when it's fighting a large, established tumour actively suppressing immune activity.

More than 150 human trials of personalised mRNA cancer vaccines are currently underway across 20+ cancer types. At Novectis, we're building the infrastructure to make this approach accessible for dogs in Switzerland — coordinating sequencing, neoantigen selection, mRNA synthesis, and administration under Switzerland's Formula magistralis exemption. How that process works is covered in our post on personalised cancer vaccines for dogs.

What to do now

Standard of care remains CHOP, and starting quickly after diagnosis matters. The protocol works within its limits, and giving it the best chance means not delaying.

After that, the decision about what to pursue post-remission is worth a detailed conversation with a board-certified veterinary oncologist. They can assess your dog's specific situation — lymphoma type and stage, degree of response to treatment, overall health — and advise on whether additional approaches make sense.

If you want to explore what personalised vaccine approaches might look like alongside or after standard treatment, our Founding Patient Programme is accepting a limited number of dogs. We work alongside the treating oncologist throughout. Each case contributes anonymised data that builds the evidence base for every dog that follows.