강아지 개 림프종 CHOP 화학요법 증상과 원인, 진단·치료와 관리 포인트 총정리

Canine Lymphoma: Don't Wait — From CHOP Chemotherapy Symptoms to Treatment and Prognosis

Oncology/CancerDiseasesMeongsiljang Veterinary Advisory Board

Canine lymphoma is a common malignant tumor, and CHOP chemotherapy is the primary treatment. We’ll provide a comprehensive guide covering early symptoms, diagnosis, treatment stages, and key management points.

Canine Lymphoma Is a Common Malignant Tumor

Swollen lymph nodes in dogs, for lesion examination

Canine lymphoma is a cancer in which lymphocytes, a type of immune cell, become malignant. It is the most commonly diagnosed hematopoietic malignancy in dogs. The multicentric form is the most prevalent, often involving peripheral lymph nodes, the spleen, and the liver simultaneously. Consequently, enlargement of lymph nodes in areas such as under the jaw, in the neck, behind the shoulder blades, and on the inner thighs is often an early sign. - Key characteristics: Because lymphoma tends to spread throughout the body, early diagnosis is crucial for successful treatment. - Core treatment: Chemotherapy is the primary treatment, with CHOP-based protocols serving as the standard of care. - Improving survival: Appropriate treatment can induce remission and extend survival time. In particular, painless lymphomas, such as low-grade or small-cell types, often allow dogs to survive for several years. - Prognostic factors: Treatment response and prognosis vary depending not only on the stage but also on the anatomical location and immunophenotype, making accurate assessment essential.

The Main Causes of Lymphoma Are Not Yet Clear

The exact cause of canine lymphoma remains unclear. It is believed to result from a combination of factors, including genetic predisposition, immunosuppression, and environmental exposures such as herbicides, but no single factor has been definitively proven to cause the disease. - Breed Tendencies: While cases have been reported in certain breeds, no strong association with any specific breed has been established. However, breeds with the ABCB1 (MDR1) gene mutation, such as Collies, may experience increased toxicity from certain chemotherapy drugs, so genetic testing is recommended before treatment. - Risk Factor Management: Reduce environmental irritants and aim for early detection through regular health check-ups. - Prevention Potential: Although the cause is difficult to pinpoint, healthy lifestyle habits and regular veterinary exams can aid in early detection and management.

An image explaining the relationship between genetic factors and lymphoma

Main Symptoms Include Lymph Node Enlargement and Systemic Symptoms

The most common sign of lymphoma in dogs is enlarged lymph nodes. You may notice lumps under the jaw, in the neck, behind the shoulder blades, or on the inner thighs; these often feel firm and do not move when touched. - Systemic symptoms: Weight loss, decreased appetite, lethargy, difficulty breathing, vomiting, and diarrhea may also occur. - Asymptomatic period: Early stages often show few or no symptoms, making regular check-ups essential. - Importance of early detection: Quickly noticing changes in the lymph nodes and seeking veterinary care is key to successful treatment. - Timing of diagnosis: Since the disease is usually asymptomatic until symptoms appear, we recommend regular check-ups every six months.

Photos to help identify symptoms of lymph node enlargement in dogs

Symptoms Requiring Immediate Veterinary Visit

If your pet experiences difficulty breathing, severe vomiting or diarrhea, complete loss of appetite, decreased consciousness, or persistent high fever, immediate veterinary care is essential. These symptoms may indicate that lymphoma has affected internal organs or the bloodstream, or that complications have developed. The timing of treatment and survival rates depend largely on how quickly these emergency situations are addressed.

Diagnosis Is Confirmed Through Biopsy and Imaging Tests

Lymphoma is definitively diagnosed through cytological examination of a lymph node biopsy. - Importance of Biopsy: Directly sampling tissue allows for an accurate determination of malignancy. - Supportive Tests: Blood tests, abdominal ultrasound, and chest X-rays are used to assess the pet’s overall condition and disease stage. - Staging Classification: We check whether organs beyond the lymph nodes—such as the intestines, liver, and spleen—are affected, which is essential for developing a treatment plan. - Accurate Assessment: Because treatment strategies vary by stage, a comprehensive evaluation is crucial. - Foundation for Treatment: An accurate diagnosis is the starting point for effective therapy.

An image explaining the lymph node biopsy procedure

CHOP Chemotherapy Is the Standard Treatment

CHOP chemotherapy is a combination of cyclophosphamide, doxorubicin (hydroxydaunorubicin), vincristine, and prednisolone, and it is a widely used standard treatment for canine lymphoma. - Treatment cycles: Multiple drugs are administered in alternating cycles, and many patients show a remission response with tumor reduction. - Side effect monitoring: During treatment, blood tests and regular check-ups are used to detect early signs of leukopenia, vomiting, and decreased appetite. In particular, doxorubicin and vincristine are P-glycoprotein substrates, so breeds suspected of having ABCB1 (MDR1) mutations, such as Collies, should consider genetic testing before treatment. - Treatment response evaluation: The size of lesions and overall condition are monitored throughout the treatment course, and the treatment plan is adjusted accordingly. - Survival period: With appropriate treatment, the remission period can be extended, and in particular, painless lymphomas such as low-grade and small-cell types often allow for survival over several years.

Home Care Focuses on Diet, Activity, and Regular Check-ups

- Dietary Management: Proper nutritional balance is essential, so we recommend using a specialized diet prescribed by your veterinarian. - Activity Management: During treatment, avoid excessive exercise and ensure your pet gets plenty of rest. - Regular Check-ups: Monthly blood tests and physical examinations are necessary throughout the treatment period. - Infection Prevention: Since the immune system may be weakened, maintain strict hygiene when going outdoors. - Emotional Support: Providing comfort in a calm and stable environment is important.

Home care environment during your dog’s treatment

Continuous Management Is Necessary Due to the Risk of Relapse

Even if your pet achieves remission with chemotherapy, the cancer may return over time. This happens because tumors naturally contain some cells that are resistant to chemotherapy drugs (as described by the Goldie-Coldman hypothesis), and as the tumor grows, the proportion of these resistant cells can increase, leading to treatment failure. It’s important to catch any early signs of recurrence through regular check-ups, blood tests, and close monitoring of symptoms. If the cancer does come back, you can discuss with your veterinarian the possibility of trying a different chemotherapy regimen or combination of medications.

Reviewed by a veterinarian

Dr. Tony — Punnawat Phongkittirak

Veterinarian

A veterinarian who majored in veterinary medicine at Khon Kaen University, Thailand, and completed the IVSA program at North Carolina State University in the United States. Drawing on clinical experience at animal hospitals, he works in the pet healthcare field and is dedicated to building a digital care environment that connects pet parents with veterinarians.

Frequently Asked Questions

How long does CHOP chemotherapy take?

Typically, multiple medications are administered in a rotating schedule, with the overall treatment period spanning several months. The schedule may be adjusted based on the patient's condition.

What are the side effects of chemotherapy?

Vomiting, diarrhea, loss of appetite, lethargy, and decreased white blood cell count are common. These symptoms are usually temporary and can be managed by a veterinarian through medication adjustments or supportive supplements.

Can my dog maintain a normal life expectancy even after treatment?

When treatment is successful and the disease goes into remission, it can significantly extend your pet’s lifespan. In particular, low-grade or small-cell lymphomas, which are often painless, can allow pets to live for several years. Early diagnosis and appropriate management are key.

Are there any other treatment options besides CHOP therapy?

Yes, in cases of recurrence or depending on the situation, other chemotherapy combinations including prednisone and lomustine may be considered. The specific protocol should be determined in consultation with your veterinarian (oncologist).

Do I need to make any special changes to my pet’s diet?

A veterinarian-recommended prescription diet is the best choice. It’s important to use a product that takes into account both nutritional balance and digestive absorption.

Comparison of CHOP Chemotherapy and Other Treatments

Item	Efficacy	Side effects	Treatment duration
CHOP-based chemotherapy	High remission-induction rate; indolent (low-grade) forms reported to survive several years	Vomiting, diarrhea, leukopenia	Cyclic administration over several months
Other combinations (e.g., prednisone, lomustine, etc.)	Tends to have a lower response rate and shorter remission duration than CHOP-based	Mild gastrointestinal symptoms	Varies by protocol
Immunotherapy	Adjunctive/long-term management purpose; immediate effect is limited	Mild fever, fatigue	Requires ongoing management

The choice of treatment is decided after consulting your veterinarian based on the patient's condition, stage, and the family's circumstances.

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References

[1] Clinical Medicine of the Dog and Cat, 4th Ed, 2023

[2] The Cat, Clinical Medicine and Management, 2nd Edition, 2021

[3] 100 Top Consultations in Small Animal General Practice, 2022