Cancer in French Bulldogs: The Two Tumors Every Frenchie Owner Should Know

French Bulldogs are predisposed to two cancers in particular: mast cell tumors of the skin and gliomas of the brain. Frenchies have been overrepresented among dogs with mast cell tumors in studies from Italy, Sweden, and Germany (Engdahl et al., 2025; Pierini et al., 2019; Schwinn et al., 2026), and brachycephalic breeds, including the French Bulldog, are strongly overrepresented among dogs with gliomas (José-López et al., 2021; Miller et al., 2019).

What the research does not yet answer well is how often French Bulldogs die of cancer overall. The breed's popularity grew so quickly that large UK primary care studies have found very young populations, with a median age of 1.3 years in 2013 data (O'Neill et al., 2018) and 1.51 years in a later analysis (O'Neill et al., 2021). Many Frenchies have not yet reached the ages when cancer becomes common, and we did not find a published study that follows a French Bulldog population through to cause of death and reports how much of it is cancer.

The practical message is narrower and more useful: any new lump on a Frenchie deserves a needle sample, and a first seizure in a middle-aged Frenchie deserves a conversation about brain imaging rather than an assumption of epilepsy.

Key Points

• French Bulldogs have repeatedly been found at increased risk of mast cell tumors, and in an Italian hospital population their odds of being in the mast cell tumor group were more than four times those of the general hospital population (Pierini et al., 2019).
• Most mast cell tumors in Frenchies appear to be well differentiated, but not all of them are, and tumors on the toes were more often high grade in one small German study (Conrad et al., 2023).
• Mast cell tumors occur in young Frenchies too: French Bulldogs made up 11.5% of 849 dogs aged three years or younger with these tumors in a 2026 analysis (Schwinn et al., 2026).
• Gliomas are the brain tumor of concern, and seizures are the most common reason affected dogs are brought in (José-López et al., 2021; Pons-Sorolla et al., 2022).
• In one Spanish series of suspected gliomas, 40 of 60 dogs were French Bulldogs, and for 42% of all the dogs, cluster seizures or prolonged seizures were the very first sign of illness (Pons-Sorolla et al., 2022).
• Brachycephalic dogs face higher anesthetic risk (Gruenheid et al., 2018), which matters because MRI and most cancer surgery require anesthesia, so planning ahead with your veterinary team is part of good cancer care in this breed.

Detailed Explanation

Why the Data on Frenchies Is Thinner Than You Would Expect

In UK primary care practices, French Bulldog puppies rose from 0.02% of all puppies born in 2003 to 1.46% in 2013 (O'Neill et al., 2018). The same study found that the median age of Frenchies under veterinary care was 1.3 years, and the authors expected the breed's disease profile to shift as that young population aged.

That has a direct consequence for anyone looking up cancer statistics. Cancer is largely a disease of middle and older age, and until recently there were not many middle-aged and older Frenchies to study. So the research on this breed is built from tumor-specific studies, pathology laboratory records, and specialist case series rather than from lifetime cohort studies that follow a whole population to the end. Those studies still tell a consistent story, but it is a story about specific tumors rather than an overall cancer rate. A later UK analysis of 2,781 French Bulldogs found the breed still very young, with a median age of 1.51 years, and at increased odds of 20 of 43 common disorders compared with other dogs, most of them tied to the breed's conformation (O'Neill et al., 2021).

Mast Cell Tumors: The Best-Documented Frenchie Cancer Risk

Mast cell tumors are cancers of mast cells, immune cells that live in the skin and help drive allergic and inflammatory responses. They are the most common skin cancer in dogs (Engdahl et al., 2025).

French Bulldogs show up again and again in the risk data. In an Italian veterinary teaching hospital, French Bulldogs were overrepresented among dogs with mast cell tumors compared with the hospital's general population, with an odds ratio of 4.4 (Pierini et al., 2019). In a Swedish insurance study covering just over 600,000 dogs, French Bulldogs had an increased risk of being diagnosed with a mast cell tumor, although not an increased risk of dying from one (Engdahl et al., 2025). That second half of the Swedish finding matters, and it is covered below.

Young Dogs Are Not Exempt

Owners often assume cancer is something to worry about later. With mast cell tumors in Frenchies, that assumption does not hold.

A 2026 German analysis of cutaneous mast cell tumors in dogs three years old and younger found that French Bulldogs were the second most common pure breed in the group, making up 98 of 849 dogs, or 11.5%. French Bulldogs showed significantly higher odds of these tumors compared with crossbreeds, and in this young group Frenchies developed more tumors on the scrotum and fewer on the trunk than crossbreeds did (Schwinn et al., 2026).

The same researchers pointed out that benign histiocytomas are very common in young dogs, and that potentially malignant mast cell tumors are an important alternative diagnosis to rule out (Schwinn et al., 2026). A young Frenchie with a new skin lump may well have something harmless, but the only way to know is to sample it.

Are Frenchie Mast Cell Tumors Usually Low Grade?

Mostly, yes, but this is where the research gets genuinely mixed, and it is worth understanding why.

Mast cell tumors are graded by a pathologist, and histological grade remains one of the cornerstones of predicting how a tumor will behave (Conrad et al., 2023). Two grading systems are in use: an older three-tier system (grades I, II, and III) and a newer two-tier system (low grade and high grade). Your dog's report may use either or both.

German pathologists describe French Bulldogs as a breed that tends to form well-differentiated cutaneous mast cell tumors (Conrad et al., 2023), which is reassuring. The Swedish finding of more diagnoses without more mast cell tumor deaths in the breed (Engdahl et al., 2025) is consistent with that picture, although that study did not have grade information, so the connection is an interpretation rather than something it measured.

Two studies complicate it. A Portuguese study of 244 dogs with mast cell tumors found French Bulldogs at higher risk of grade III tumors, with an odds ratio of 7.9 in an unadjusted comparison (Martins et al., 2021). The confidence interval around that estimate was very wide, from about 2.4 to 26.1, which means the true effect could be much smaller or larger, and the study was small. And a German study of mast cell tumors on the toes found that 4 of 7 French Bulldogs had high-grade tumors, and 3 of 7 carried a particular mutation in the c-kit gene associated with more aggressive behavior, both proportions higher than in mixed-breed dogs (Conrad et al., 2023). Seven dogs is a very small number, and the authors could not follow survival, but they suggested that tumor location may matter especially in this breed.

The honest reading is this: many Frenchie mast cell tumors appear to be low grade, and the breed was not at increased risk of mast cell tumor death in the Swedish data (Engdahl et al., 2025), but a Frenchie's breed is not a guarantee of a benign tumor. Location, grade, and the full pathology report determine what happens next, not the breed average.

The c-kit Test and Why It Might Come Up

Some mast cell tumors carry mutations in the c-kit gene, which produces a receptor that tells mast cells to grow. In the toe tumor study, internal tandem duplications in exon 11 of c-kit were significantly associated with higher grade and faster-dividing tumors (Conrad et al., 2023). The same authors noted that certain targeted drugs act on this receptor and that, under European approval terms at the time they wrote, one of them required a confirmed c-kit mutation before use (Conrad et al., 2023).

If your Frenchie has a mast cell tumor, particularly on a toe or with a higher grade, asking whether c-kit testing would add useful information is a reasonable question. [INTERNAL LINK: mast cell tumor overview, when published]

Brain Tumors: Gliomas in French Bulldogs

Gliomas are tumors that arise from the supporting cells of the brain. They are strongly overrepresented in several brachycephalic breeds, including Boxers, Boston Terriers, Bullmastiffs, and English and French Bulldogs, and a genetic locus on canine chromosome 26 has been associated with glioma risk across multiple breeds (Miller et al., 2019).

French Bulldogs feature prominently in recent case series. In a multicenter study of 91 dogs with glioma, 78% belonged to brachycephalic breeds, and 23 were French Bulldogs (José-López et al., 2021). In a single-hospital study from Spain, 40 of 60 dogs with suspected glioma were French Bulldogs. These were presumptive diagnoses based on MRI and history rather than biopsy; the authors suggested this reflected both the breed's local popularity and a higher predisposition (Pons-Sorolla et al., 2022). A retrospective study of 343 French Bulldogs with neurological disorders at a French veterinary school found that brain tumors made up 36.8% of brain disorders, with glioma, confirmed or suspected, the most common type (Mayousse et al., 2017).

The Seizure That Should Not Be Dismissed

The most common way a glioma announces itself is a seizure.

Seizures were the main presenting complaint in 62% of dogs in the multicenter study (José-López et al., 2021) and in 77% of dogs in the Spanish series (Pons-Sorolla et al., 2022). The Spanish study found something especially important for owners: in 42% of dogs, cluster seizures or status epilepticus, meaning a prolonged seizure or several seizures without recovery in between, were the very first sign of disease. About half of the dogs had a normal neurological exam at presentation, or had changes attributed to the seizure itself (Pons-Sorolla et al., 2022). In other words, many of these dogs looked fine between episodes.

The median age of dogs in the Spanish series was 9 years, with a range of 4 to 15 (Pons-Sorolla et al., 2022). A first seizure in a middle-aged or older Frenchie is a different situation from a first seizure in a young dog, and it is worth asking your veterinarian directly whether MRI is warranted.

A seizure does not automatically mean a tumor. In the same French Bulldog study, inflammatory brain disease of unknown origin accounted for 25% of brain disorders and was more likely in females under about five and a half years old (Mayousse et al., 2017). Imaging is how the two are told apart.

Other signs in dogs with glioma included changes in awareness or mentation, walking abnormalities, visual problems, and behavior changes (José-López et al., 2021).

Treatment and Outlook for Gliomas

Gliomas are difficult tumors, and the numbers reflect that.

In the Spanish series of dogs treated palliatively, which in that study included steroids and anti-seizure medication, median survival after diagnosis was 61 days. Seizures were the main reason for death or euthanasia in half of the dogs where the cause was known (Pons-Sorolla et al., 2022). Dogs whose tumors enhanced with contrast dye on MRI had significantly shorter survival than those whose tumors did not.

In the multicenter study, among dogs that survived more than one day, those receiving what the authors called definitive treatment lived significantly longer than those treated palliatively, with median survival of 84 days versus 26 days (José-López et al., 2021). Other veterinary oncologists have questioned how that study defined "definitive" treatment (Rohrer Bley et al., 2022), so those figures are best read as a sign that treatment can change the outlook rather than as a precise prediction.

There is one breed-specific finding that owners considering clinical trials should know about. In a multi-institutional study of dogs with high-grade glioma, French Bulldogs treated with immunotherapy survived a median of 132 days, compared with 221 days for Boxers and Boston Terriers given the same approach. French Bulldogs on immunotherapy did no better than French Bulldogs given palliative care, while Frenchies treated with stereotactic radiation therapy or an experimental sonodynamic therapy survived significantly longer than those given palliative care (Arnold et al., 2025). This was a retrospective comparison rather than a randomized trial, and only seven French Bulldogs received immunotherapy, so the finding needs confirmation, but the authors concluded that Frenchie gliomas may differ at a molecular level from those in closely related breeds.

When survival is measured in weeks to months, quality of life becomes central to every decision. The Joys of Life Scale from the Drake Dog Cancer Foundation can help you notice how your dog's good days and hard days are balancing out.

Anesthesia: A Frenchie-Specific Planning Issue

Confirming a brain tumor usually requires MRI under general anesthesia, and removing a mast cell tumor means surgery. French Bulldogs carry extra risk here. In a matched study of 223 brachycephalic and 223 non-brachycephalic dogs undergoing routine surgery or imaging, brachycephalic dogs were at higher risk of complications during and after anesthesia (Gruenheid et al., 2018).

That is not a reason to skip diagnosis or treatment. It is a reason to ask your veterinary team how they manage brachycephalic patients, whether your dog's airway has been assessed, and what monitoring will be in place during recovery.

What About Other Cancers?

Published evidence specific to French Bulldogs for other cancer types is limited. As the young population of Frenchies ages, more data will emerge, and it would not be surprising if the picture broadens. For now, the absence of breed-specific data for a given cancer means only that it has not been well studied in this breed, not that Frenchies are protected from it.

Keeping a Record

Two of the most useful things you can bring to a veterinary appointment for a Frenchie are photographs of any lump over time and a written log of any seizure: the date, time, how long it lasted, what it looked like, and how your dog behaved afterward. The Dog Cancer Tracker (dogcancertracker.com) is one way to keep that information in one place.

When to Contact a Veterinarian

Seek emergency veterinary care immediately if your French Bulldog has a seizure lasting longer than five minutes, has two or more seizures without fully recovering in between, or has more than one seizure within 24 hours. These are the veterinary definitions of status epilepticus and cluster seizures (Pons-Sorolla et al., 2022), and in the Spanish glioma series they were the first sign of illness in 42% of dogs.

Also seek emergency care for any breathing difficulty after sedation or anesthesia, given the breed's higher anesthetic risk (Gruenheid et al., 2018).

Schedule a prompt appointment if your Frenchie shows:

• Any seizure, even a single one that stopped on its own, particularly in a dog that is middle-aged or older.
• Changes in behavior, awareness, vision, or balance that are new.
• Any new lump or bump on the skin, at any age.
• A lump on a toe, the scrotum, or the groin area.
• A known lump that changes in size, color, or texture.

Questions to Ask Your Veterinarian

• Can we do a fine needle aspirate of this lump today rather than watching it?
• If this is a mast cell tumor, what grade is it under each grading system, and what is the mitotic count?
• Would c-kit mutation testing help guide treatment for this tumor?
• Were the surgical margins clean, and what is our recheck schedule?
• My dog had a seizure. Given the breed and age, do you recommend an MRI?
• If a glioma is suspected, what are the realistic options, including radiation therapy, and what would each involve?
• How do you manage anesthesia for brachycephalic dogs, and has my dog's airway been assessed?
• Is a referral to a board-certified veterinary oncologist or neurologist appropriate?

Sources

Arnold, S. A., Taylor, A. R., Hansen, K., Agarwal, V., Low, W. C., & Pluhar, G. E. (2025). Immunotherapy yields breed-specific worst survival outcomes among three investigated therapies in French bulldogs with high-grade glioma. Frontiers in Veterinary Science, 12, Article 1532439. 

Conrad, D., Kehl, A., Müller, T., Klopfleisch, R., & Aupperle-Lellbach, H. (2023). Immunohistochemical and molecular genetic analysis of canine digital mast cell tumours. Animals, 13(10), Article 1694. 

Engdahl, K., Saellström, S., Hedhammar, Å., Dimopoulou, M., & Rönnberg, H. (2025). The epidemiology of mast cell tumours in insured dogs in Sweden. Preventive Veterinary Medicine, 242, Article 106589. 

Gruenheid, M., Aarnes, T. K., McLoughlin, M. A., Simpson, E. M., Mathys, D. A., Mollenkopf, D. F., & Wittum, T. E. (2018). Risk of anesthesia-related complications in brachycephalic dogs. Journal of the American Veterinary Medical Association, 253(3), 301-306. 

José-López, R., Gutierrez-Quintana, R., de la Fuente, C., Manzanilla, E. G., Suñol, A., Pi Castro, D., Añor, S., Sánchez-Masian, D., Fernández-Flores, F., Ricci, E., Marioni-Henry, K., Mascort, J., Matiasek, L. A., Matiasek, K., Brennan, P. M., & Pumarola, M. (2021). Clinical features, diagnosis, and survival analysis of dogs with glioma. Journal of Veterinary Internal Medicine, 35(4), 1902-1917. 

Martins, A. L., Carvalho, F. F., Mesquita, J. R., Gärtner, F., & Amorim, I. (2021). Analysis of risk factors for canine mast cell tumors based on the Kiupel and Patnaik grading system among dogs with skin tumors. Open Veterinary Journal, 11(4), 619-634. 

Mayousse, V., Desquilbet, L., Jeandel, A., & Blot, S. (2017). Prevalence of neurological disorders in French bulldog: A retrospective study of 343 cases (2002-2016). BMC Veterinary Research, 13, Article 212. 

Miller, A. D., Miller, C. R., & Rossmeisl, J. H. (2019). Canine primary intracranial cancer: A clinicopathologic and comparative review of glioma, meningioma, and choroid plexus tumors. Frontiers in Oncology, 9, Article 1151.

O'Neill, D. G., Baral, L., Church, D. B., Brodbelt, D. C., & Packer, R. M. A. (2018). Demography and disorders of the French Bulldog population under primary veterinary care in the UK in 2013. Canine Genetics and Epidemiology, 5, Article 3. 

O'Neill, D. G., Packer, R. M. A., Francis, P., Church, D. B., Brodbelt, D. C., & Pegram, C. (2021). French Bulldogs differ to other dogs in the UK in propensity for many common disorders: A VetCompass study. Canine Medicine and Genetics, 8, Article 13. 

Pierini, A., Lubas, G., Gori, E., Binanti, D., Millanta, F., & Marchetti, V. (2019). Epidemiology of breed-related mast cell tumour occurrence and prognostic significance of clinical features in a defined population of dogs in west-central Italy. Veterinary Sciences, 6(2), Article 53. 

Pons-Sorolla, M., Dominguez, E., Czopowicz, M., Suñol, A., Maeso Ordás, C., Morales Moliner, C., Pérez Soteras, M., & Montoliu, P. (2022). Clinical and magnetic resonance imaging (MRI) features, tumour localisation, and survival of dogs with presumptive brain gliomas. Veterinary Sciences, 9(6), Article 257. 

Rohrer Bley, C., Meier, V., Beckmann, K., & Steffen, F. (2022). Letter regarding "Clinical features, diagnosis, and survival analysis of dogs with glioma." Journal of Veterinary Internal Medicine, 36(5), 1566-1567. 

Schwinn, J., Törner, K., Beitzinger, C., Klopfleisch, R., & Aupperle-Lellbach, H. (2026). The characteristics of 924 cutaneous mast cell tumours in dogs ≤ 3 years of age: With a short literature review of feline, equine, and human proliferative mast cell disorders. Veterinary Sciences, 13(5), Article 500.