10/22/2024
Understanding Feline Mammary Cancer: What Every Cat Owner Should Know
While breast cancer in women is a well-known concern, many pet owners might be surprised to learn that our beloved feline companions are also at risk for this serious condition. With about one in eight women affected, awareness campaigns have been launched to encourage regular screenings. But what about our pets? Female cats, in particular, face a significant risk of mammary cancer, making it crucial for cat owners to be informed and vigilant.
The Reality of Mammary Cancer in Cats
Mammary cancer ranks as the third most prevalent cancer among cats, typically affecting senior female felines around the age of 10 to 12, especially those that remain unspayed or were spayed later in life. Unlike dogs, where only about 50% of mammary tumors are malignant, a staggering 90% of mammary tumors in cats are cancerous and can spread rapidly to nearby glands and lymph nodes.
Cats possess four pairs of mammary glands (thoracic, cranial abdominal, caudal abdominal, and inguinal), with the thoracic and inguinal glands being the most commonly affected. As a responsible pet owner, it’s essential to regularly check these areas for any unusual lumps, as cancerous cells can easily migrate across the glands.
Initially, tumors may feel small, resembling a pebble or dried pea. However, prompt removal is crucial. If left untreated, these tumors can grow larger, harden, and eventually burst through the skin, leading to painful, infected ulcers.
Survival Rates and Tumor Spread
The size of the tumor significantly influences survival rates. Tumors smaller than 0.8 inches (2 cm) have a median survival time of approximately 4.5 years post-removal, whereas larger tumors exceeding 1.2 inches (3 cm) drop to a median survival time of just six months. Tumors often spread from mammary glands to local lymph nodes and can reach vital organs like the lungs, brain, bones, and spleen. Pre-surgery chest X-rays and blood tests are essential for assessing the extent of the disease.
Identifying Risk Factors
Several factors can heighten the risk of mammary cancer in cats:
• Gender: Being female is the most significant risk factor.
• Breed: Siamese cats are particularly susceptible, often developing tumors at a younger age compared to other breeds.
• Hormonal Exposure: Historical exposure to progestin hormones, once used for behavioral issues, poses a risk.
Protective Measures
The most effective way to reduce the risk of mammary cancer is through early spaying. Spaying before six months of age leads to a remarkable 91% reduction in risk. Even spaying before one year still results in an 86% reduction. Interestingly, having given birth to kittens does not impact the risk of developing mammary cancer.
Understanding Tumor Types
Feline mammary tumors primarily fall into two categories: carcinomas and adenocarcinomas. Among these, papillary or tubular carcinomas are the least aggressive, while anaplastic carcinomas are the most dangerous, often leading to rapid decline.
Tumors are graded from I to III based on malignancy. Grade I tumors generally have a favorable one-year survival rate, whereas Grade III tumors treated surgically have no survivors after one year.
Treatment Options: Surgery and Beyond
Surgical intervention is the cornerstone of treatment, aiming to excise as much of the tumor as possible while minimizing the risk of spread. Ideally, both mammary chains should be removed, although this may require multiple surgeries due to limited skin availability.
Aggressive surgery can yield a disease-free interval of one year in about 50% of cats, with a two-year interval in 32% of cases. If lymph nodes are already affected or if tumors recur, the prognosis is less optimistic.
Chemotherapy often follows surgery to enhance disease-free intervals, with common drugs including adriamycin and cyclophosphamide. While not all cats will respond, those that do can experience significantly extended survival times.
Navigating Euthanasia Decisions
As the disease progresses, cat owners may face heart-wrenching decisions regarding quality of life. Symptoms such as infected, ulcerated tumors or tumor spread to the lungs can severely impact a cat's well-being. The average survival time for cats with advanced lung involvement is a mere month.
Quality of life assessments are deeply personal, and while it’s essential to consider your cat’s comfort and enjoyment, consulting with your veterinarian can provide valuable guidance.
Conclusion
Mammary cancer in cats is a serious condition that requires awareness and proactive care. By understanding the risks, recognizing early signs, and seeking timely veterinary intervention, you can play a vital role in your cat’s health and well-being.
Veterinarian for Cats and Dogs. Our goal is to practice the highest quality medicine and surgery with compassion and an emphasis on client education.
