Cancer in German Shepherds: Hemangiosarcoma, Inherited Kidney Cancer, and Signs

The cancer German Shepherd owners most need to know about is hemangiosarcoma, an aggressive cancer of blood vessel cells that most often affects the spleen. In a UK study of more than two million dogs, German Shepherds had about six times the odds of being diagnosed with hemangiosarcoma compared with crossbred dogs, and they were the second most common breed among the hemangiosarcoma cases analyzed (Barry et al., 2025).

German Shepherds also carry a rare inherited cancer syndrome, renal cystadenocarcinoma and nodular dermatofibrosis, caused by a known gene mutation for which a DNA test exists (Lingaas et al., 2003; UC Davis Veterinary Genetics Laboratory, n.d.).

It is worth keeping this in proportion. In UK primary care data, cancer accounted for 14.5% of German Shepherd deaths with a recorded cause, behind musculoskeletal disorders and inability to stand (O'Neill et al., 2017). Cancer is an important risk in this breed, but it is not the dominant one it is in breeds like the Bernese Mountain Dog.

Key Points

• German Shepherds had 6.35 times the odds of a hemangiosarcoma diagnosis compared with crossbred dogs, and 5.18 times the odds when only biopsy-confirmed cases were counted (Barry et al., 2025).
• About 0.42% of German Shepherds were newly diagnosed with hemangiosarcoma each year in UK primary care, among the highest rates of any breed (Barry et al., 2025).
• Early signs of internal hemangiosarcoma are often vague and intermittent and easily attributed to other conditions (Barry et al., 2025).
• Many dogs with hemangiosarcoma are euthanized at diagnosis, and a UK study found this may be driving very short reported survival times, while surgery was associated with a lower hazard of death (Taylor et al., 2025).
• Renal cystadenocarcinoma and nodular dermatofibrosis is inherited in a dominant pattern, so a dog needs only one copy of the mutation to be affected, and a DNA test can identify it (UC Davis Veterinary Genetics Laboratory, n.d.).
• The first sign of that syndrome is usually firm nodules in the skin, typically by about 6 years of age (UC Davis Veterinary Genetics Laboratory, n.d.).

Detailed Explanation

Putting Cancer Risk in Context

A UK study of German Shepherds under primary veterinary care found a median lifespan of 10.3 years. Among deaths with a recorded cause, the most common categories were musculoskeletal disorders (16.3%), inability to stand (14.9%), cancer (14.5%), and spinal cord disorders (13.6%) (O'Neill et al., 2017).

That context matters for two reasons. First, it means a German Shepherd owner's worry list should not start and end with cancer. Second, it means that when a German Shepherd becomes weak in the hind end or struggles to rise, cancer is one possibility among several, and many of the others are more common.

Hemangiosarcoma: The Main Cancer Concern

Hemangiosarcoma is a cancer arising from cells that line or form blood vessels. It has been reported to account for 40% to 64% of primary splenic disease and nearly half of heart tumors in dogs, and except for the form that arises in the skin, it is typically biologically aggressive (Barry et al., 2025).

The largest study to date of hemangiosarcoma in general veterinary practice examined the records of 2,250,741 UK dogs seen in 2019. Among dogs aged five and older, German Shepherds had 6.35 times the odds of a hemangiosarcoma diagnosis compared with crossbred dogs, the third highest of any breed after the Dogue de Bordeaux and the Flat-Coated Retriever. When the analysis was restricted to cases confirmed by biopsy, German Shepherds still had 5.18 times the odds (Barry et al., 2025).

German Shepherds made up 84 of the 788 hemangiosarcoma cases in that analysis, or 10.7%, second only to Labrador Retrievers, a far more numerous breed (Barry et al., 2025). The annual rate of new diagnoses in German Shepherds of all ages was 0.42% (Barry et al., 2025).

The same study found that odds rose with body weight and with age, peaking between 11 and 13 years, and that the median age at diagnosis across all breeds was 10.5 years (Barry et al., 2025). Hemangiosarcoma was rare in dogs under five in this study.

Why It Is So Often Found Late

The authors of the UK study noted that early signs of internal hemangiosarcoma may be vague, intermittent, and easily attributed to other conditions, and that knowing a breed is at increased risk supports earlier suspicion and more targeted testing (Barry et al., 2025).

In practice, hemangiosarcoma of the spleen often comes to attention when a tumor bleeds. Presentations of internal bleeding can include sudden collapse, weakness, lethargy, and a swollen belly (Allen, 2016). A dog may appear to stabilize after a bleed, but the underlying mass remains and can bleed again (Allen, 2016). To an owner, a smaller bleed can look like a brief "off day." For a middle-aged or older German Shepherd, a day of unexplained weakness and pale gums that seems to pass is worth a veterinary visit, not a wait-and-see approach. [INTERNAL LINK: can-dogs-survive-ruptured-spleen]

The Survival Numbers, and Why They Mislead

A companion UK study followed 788 dogs clinically diagnosed with hemangiosarcoma in general practice. Median survival from diagnosis across all cases was just 9 days, and only 4 days for splenic hemangiosarcoma (Taylor et al., 2025).

Those figures need careful reading. Among dogs whose diagnosis was confirmed by biopsy, median survival was 105 days. Surgery was associated with a reduced hazard of death, and the authors warned that a widely held belief that hemangiosarcoma is hopeless may be promoting euthanasia at the time of diagnosis, creating a self-fulfilling prophecy of short survival (Taylor et al., 2025).

This does not make hemangiosarcoma a good-prognosis cancer. It means that the shortest survival figures largely reflect decisions made at diagnosis, not what happens when a dog is treated. It also matters because not every bleeding splenic mass is cancer. In one surgical study, about 40% of dogs with a bleeding splenic mass did not have a splenic malignancy (Ziogaite et al., 2024), and without a biopsy there is no way to know which kind your dog has. The library's article on ruptured spleens covers that decision in detail. [INTERNAL LINK: can-dogs-survive-ruptured-spleen]

Cutaneous hemangiosarcoma, the form that arises in the skin, behaved very differently, with a median survival of 119 days even in the full clinically diagnosed group (Taylor et al., 2025). A new skin lump on a German Shepherd deserves a needle sample, because hemangiosarcoma in the skin behaves very differently from the internal form.

Renal Cystadenocarcinoma and Nodular Dermatofibrosis

This is the German Shepherd's own hereditary cancer syndrome. It was originally described in the breed and is characterized by tumors in both kidneys, benign smooth muscle tumors of the uterus in females, and firm nodules in the skin made of dense collagen (Lingaas et al., 2003).

In 2003, researchers identified the cause: a mutation in the canine BHD gene, also known as FLCN, the canine counterpart of the gene behind a hereditary kidney cancer syndrome in people (Lingaas et al., 2003).

What owners need to know:

• The syndrome is inherited in a dominant pattern. A dog with one copy of the mutation will develop the disease, and each of its puppies has a 50% chance of inheriting it from a mating with an unaffected dog (UC Davis Veterinary Genetics Laboratory, n.d.).
• The disease appears later in life and is progressive. Affected dogs typically develop multiple firm skin nodules by about 6 years of age, and tumors develop in both kidneys, with variable timing and growth (UC Davis Veterinary Genetics Laboratory, n.d.).
• A DNA test is available, and dogs that test clear of the mutation will not develop this syndrome from it and cannot pass it on (UC Davis Veterinary Genetics Laboratory, n.d.).

The skin nodules are the practical early clue. If your German Shepherd develops several firm lumps in the skin, mention this specific syndrome to your veterinarian. The nodules themselves may seem harmless, but their significance is what they can signal about the kidneys.

If you are buying a German Shepherd puppy, it is reasonable to ask whether the parents have been tested for this mutation.

Other Cancers in German Shepherds

German Shepherds are also listed among breeds at increased risk of osteosarcoma, the aggressive bone cancer most common in large and giant breeds (Polton et al., 2025). Osteoarthritis was among the most common disorders recorded in UK German Shepherds (O'Neill et al., 2017), so a limp is usually orthopedic, but a limp that persists, recurs, or comes with a firm swelling near a joint deserves X-rays. [INTERNAL LINK: cancer-in-great-danes, osteosarcoma section]

This article focuses on hemangiosarcoma and the inherited kidney cancer syndrome because that is where the German Shepherd-specific evidence is strongest. German Shepherds can develop any cancer that affects dogs.

Living With the Risk

The UK research did not identify anything an individual owner can do to prevent hemangiosarcoma. Its authors suggested that changes in breeding practices, such as outcrossing, might reduce its frequency in future generations (Barry et al., 2025). What owners can control is how quickly they act on vague signs in a middle-aged or older dog, and whether they seek a definitive diagnosis rather than assuming the worst.

A written record helps. Note episodes of weakness, pale gums, reduced appetite, or a belly that looks fuller than usual, including ones that seem to resolve. The Dog Cancer Tracker (dogcancertracker.com) is one way to keep that history in one place. If your dog is diagnosed, the Joys of Life Scale from the Drake Dog Cancer Foundation can help you track how good days and hard days are balancing out.

When to Contact a Veterinarian

Seek emergency veterinary care immediately if your German Shepherd collapses, has pale or white gums, is suddenly very weak, or has a suddenly swollen abdomen. These can be signs of internal bleeding (Allen, 2016), which is how splenic hemangiosarcoma often first comes to attention.

Schedule a prompt appointment if your German Shepherd shows:

• An episode of weakness or lethargy that seemed to resolve on its own, especially if it happens again.
• Reduced appetite or weight loss without an obvious reason.
• A new dark red, purple, or bruise-like lump in the skin.
• Several firm nodules appearing in the skin.
• Increased thirst or urination, which can have many causes including kidney disease.
• A limp that persists, recurs, or comes with swelling near a joint.

Questions to Ask Your Veterinarian

• My German Shepherd had an episode of weakness that passed. Should we check for a splenic mass?
• If a splenic mass is found, how likely is it to be cancer, and can we know without surgery?
• If my dog needs surgery, will the spleen be sent for biopsy?
• Could these skin nodules be related to renal cystadenocarcinoma and nodular dermatofibrosis, and should we do the DNA test?
• If my dog carries that mutation, how should we monitor the kidneys?
• Is this new skin lump worth a needle sample today?
• For a limp, when should we move from pain medication to X-rays?
• Would a referral to a veterinary oncologist help us understand our options?

Sources

Allen, S. (2016). Blood, sweat and tears: Approach to the canine hemoabdomen. VetBloom. https://vetbloom.com/hemoabdomen/

Barry, G. J., O'Neill, D. G., Guillén, A., Taylor, C., Labadie, J., Pickard Price, P., [FLAG: verify whether additional authors appear here], & Brodbelt, D. C. (2025). Epidemiology of haemangiosarcoma diagnosed in dogs under primary veterinary care in the United Kingdom: Frequency and risk factors. Veterinary Oncology, 2, Article 26. 

Lingaas, F., Comstock, K. E., Kirkness, E. F., Sørensen, A., Aarskaug, T., Hitte, C., Nickerson, M. L., Moe, L., Schmidt, L. S., Thomas, R., Breen, M., Galibert, F., Zbar, B., & Ostrander, E. A. (2003). A mutation in the canine BHD gene is associated with hereditary multifocal renal cystadenocarcinoma and nodular dermatofibrosis in the German Shepherd dog. Human Molecular Genetics, 12(23), 3043-3053. 

O'Neill, D. G., Coulson, N. R., Church, D. B., & Brodbelt, D. C. (2017). Demography and disorders of German Shepherd Dogs under primary veterinary care in the UK. Canine Genetics and Epidemiology, 4, Article 7. 

Polton, G., Borrego, J. F., Clemente-Vicario, F., Clifford, C. A., Jagielski, D., Kessler, M., Kobayashi, T., Lanore, D., Queiroga, F. L., Rodrigues, L., Tranaeus Rowe, A., Vajdovich, P., [FLAG: four additional authors], & Bergman, P. J. (2025). Osteosarcoma of the appendicular skeleton in dogs: Consensus and guidelines. Frontiers in Veterinary Science, 12, Article 1633593. 

Taylor, C., Barry, G. J., O'Neill, D. G., Guillén, A., Price, P. P., Labadie, J., & Brodbelt, D. C. (2025). Survival time and prognostic factors in dogs clinically diagnosed with haemangiosarcoma in UK first opinion practice. PLOS ONE, 20(6), Article e0316066. 

UC Davis Veterinary Genetics Laboratory. (n.d.). Renal cystadenocarcinoma and nodular dermatofibrosis (RCND) of German Shepherd dogs. Retrieved September 24, 2026, from https://vgl.ucdavis.edu/test/rcnd-gs

Ziogaite, B., Contreras, E. T., & Horgan, J. E. (2024). Incidence of splenic malignancy and hemangiosarcoma in dogs undergoing splenectomy surgery at a surgical specialty clinic: 182 cases (2017-2021). PLOS ONE, 19(12), Article e0314737.