目次
Early Detection of Cancer in Dogs, Cats, and Pets
Pet owners likely think, “I want to find cancer as early as possible and start treatment as soon as I can.”
As you may know, the number of cancer cases in dogs and cats is increasing significantly in Japan, and many of them are losing their lives to cancer. Just like in humans, early detection and early treatment of cancer are crucial for pets. If you are aware of the symptoms of early cancer beforehand, you may be able to notice abnormalities quickly, and the earlier that treatment begins, the higher the chance of cure.
However, there are several reasons why early detection of cancer in dogs and cats is difficult:
- Many early cancers exhibit no symptoms.
- There are no good methods to detect early cancers.
In many cases, cancer is found at an advanced or terminal stage. Often, early cancer is discovered serendipitously during examinations for other purposes.
Symptoms of Early Cancer
Similar to humans, it is said that symptoms of cancer in dogs and cats do not appear until the cancer has progressed significantly. Changes in a pet’s health condition often occur only after the cancer has grown substantially or metastasized.
Therefore, it is difficult to detect cancer early based on changes in a pet’s health condition.
However, there are some cancers that can be detected from changes in appearance. For example:
| Type of Cancer | Early Symptoms/Changes |
|---|---|
| Mammary Tumors | Lymph nodes near the skin may swell, which can be detected by touch. Lymphomas growing in internal lymph nodes, spleen, or intestines are harder to notice until they progress. There are no subjective symptoms in pets. |
| Malignant Lymphoma | Lymph nodes near the skin may swell, which can be detected by touch. Lymphomas growing in internal lymph nodes, spleen, or intestines are harder to notice until they progress. There are no subjective symptoms in pets. |
Testing for Early Cancer in Dogs and Cats
As mentioned above, early cancers often exhibit few symptoms, making it difficult to notice cancer from changes in a dog’s or cat’s condition. If it is hard to detect early cancer based on symptoms, the only option left is to find it through testing.
Some tests can detect small tumors just a few millimeters deep within the body. However, various issues make it challenging to find a test that reliably identifies early cancers at this time.
Some tests that can detect internal cancers include:
| Type of Imaging Test | Effectiveness in Detecting Cancer |
|---|---|
| X-ray Examination | An X-ray captures a transmissive photograph of the body. Abnormalities are found based on the density shades in the photos. While there is radiation exposure during the imaging, the burden on the pet is relatively low. However,distinguishing millimeter-scale lesions is difficult, and early cancers are often missed. |
| Ultrasound Examination |
Things You Can Do to Prevent Early-Stage Cancer from Progressing
You may already know this, but there is a theory that cancer cells are generated within an animal’s body every day, and this idea is currently the most plausible. The number of cancer cells produced in a human body is estimated to be 3,000. Considering the size of the body, it is believed to be several hundred to several thousand in dogs and cats. Even with that number of cancer cells in the body, there are no particular health issues. Of course, there are no symptoms of cancer. Incidentally, the cancer cells that are produced are usually eliminated by the body’s innate immune system.
Let’s consider whether symptoms will appear in a dog that generates 500 cancer cells a day. If the number of cancer cells increases by 100 to become 600, will symptoms appear? No, they will not. What if it doubles to 1,000? Again, no symptoms will appear. What about 10,000, which is twenty times the original number? You might call this ultra-early-stage cancer, but symptoms are still unlikely to appear.
When the number of cancer cells exceeds 100,000, it is likely that cancer will eventually develop. However, it is still uncommon to be diagnosed with cancer at this stage because it is difficult to detect even with examinations.
When the number of cancer cells exceeds 100 million, abnormalities start becoming visible through tests or to the naked eye. If a lump forms, it might be about the size of a 1 cm ball.
However, dogs and cats rarely exhibit symptoms that they can be aware of.
If the cancer is in areas such as the skin or the mouth, you may notice swelling or other abnormalities. Lymph nodes just under the skin might be detectable through touch.
When it develops deep within the body, detecting abnormalities can be challenging. Pets that live outdoors might also not be easily monitored. If discovered at this stage, it is often considered early-stage cancer. On the other hand, if metastasis is found, it is classified as terminal cancer. The distinction between early-stage and terminal cancer is not determined by the number of cancer cells, but rather by factors like the extent of penetration through organ walls or metastasis to lymph nodes and other organs. Note that even if it is classified as early-stage cancer, there might already be invisible metastasis.
Currently, in Japan, the number of pets losing their lives to cancer has increased significantly. Malignant tumors, i.e., “cancer,” are among the top causes of death in dogs and cats. For elderly pets, cancer is the leading cause of death.
As written on this page, early detection of cancer is challenging even with repeated tests. Therefore, it might be more beneficial to focus on cancer prevention.
It can be said that having a strong immune system makes it less likely to develop cancer.
Cancer is a “lifestyle disease.” In other words, changing lifestyle habits could prevent cancer.
It is said that two-thirds of cancers can be prevented. Recent advancements in medical science have clarified that even if there are high-risk underlying conditions or genetic predispositions, improving diet and lifestyle can suppress the carcinogenesis process.
The immune system is surprisingly delicate and can fluctuate greatly due to mental factors and daily diet. This means that having a good time daily serves as cancer prevention and learning about proper diet also helps in prevention. Instead of focusing solely on early detection, why not prioritize daily prevention?
What You Can Do for Immune System Measures
At our laboratory, we believe that by using Cordy to regulate the immune system, reviewing diets, providing necessary nutrients, and improving the environment, the prognosis of pets suffering from cancer can be improved. We are conducting ongoing research in this area.
If you have any questions, please contact us.
監修獣医師：林美彩 所属クリニック：chicoどうぶつ診療所
代替療法と西洋医学、両方の動物病院での勤務経験と多数のコルディの臨床経験をもつ。 モノリス在籍時には、一般的な動物医療（西洋医学）だけでは対応が困難な症例に対して多くの相談を受け、免疫の大切さを痛烈に実感する。
ペットたちの健康維持・改善のためには薬に頼った対処療法だけではなく、「普段の生活環境や食事を見直し、自宅でさまざまなケアを取り入れることで免疫力を維持し、病気にならない体づくりを目指していくことが大切である」という考えを提唱し普及活動に従事している。
所属：
- Dog Cancer (Tumor) – Symptoms, Diagnosis, Surgery, Treatment, Diet, Tips for Improvement and Cure
- Cat Cancer (Tumor) – Symptoms, Diagnosis, Surgery, Treatment, Diet, Tips for Improvement and Cure
- Feline Infectious Peritonitis (FIP) – Coronavirus Infection, Symptoms, Tips for Improvement and Cure
- Feline AIDS (FIV) – Onset, Symptoms, Treatments, and Overcoming Methods
