Cancer Screening After 11: Weight, Ultrasound, FNA

After 11, cancer moves up the list of reasons a cat gets thin. Lymphoma is the most common cancer in cats, and squamous cell carcinoma is the most common oral tumor, with a second cluster on white ears and noses that see sun. Both are far easier to treat at 1 cm than at 4 cm, and both announce themselves through numbers you can collect at home: weight, appetite, and how many times a week the cat vomits. The screening rule is simple: 10 percent of body weight lost in 6 months buys a workup, not a wait.

The one number that matters: 10 percent in 6 months

A cat at 11 that drops from 4.5 kg to 4.0 kg has lost 11 percent, and that is a finding even if it looks bright and eats well. Weigh monthly on the same scale to the nearest 10 g, and compute the percentage against the highest weight in the last 12 months, not against last month. 5 percent in 3 months is faster than aging explains and deserves an examination within 2 weeks. 10 percent in 6 months deserves bloodwork, a urine test, blood pressure, and a thyroid level in the same visit, because hyperthyroidism and CKD produce the same curve as cancer and are far more common.

Why lymphoma hides in the gut

The alimentary form is the most common lymphoma in cats, and it does not produce a lump you can feel from outside. It produces a bowel wall that thickens from a normal 2 to 3 mm to 5 mm or more, plus vomiting 2 or more times a week, softer stool, and a slow weight slide over 2 to 4 months. Low-grade alimentary lymphoma can look identical to inflammatory bowel disease on ultrasound, which is why the sample matters: a 15 minute fine needle aspirate or a surgical biopsy is what separates the two. Many cats with low-grade disease do well for 12 months or more on oral chemotherapy, and the earlier the diagnosis, the more options stay open.

Squamous cell carcinoma: mouth, ears, nose

In the mouth, squamous cell carcinoma often starts under the tongue or along the lower gum, and the first sign is usually not a lump. It is 1 sided chewing, drooling that started 2 to 4 weeks ago, foul breath that dental cleaning did not fix, or a tooth that loosened without trauma. On the skin it favours the ear tips and the nose of white cats, starting as a crust that does not heal in 3 to 4 weeks. Any oral lesion that has not healed in 2 weeks needs a look, and any skin crust that persists past 4 weeks needs a sample rather than another ointment.

When abdominal ultrasound is the right test

Ultrasound is the cheapest way to see the inside of a cat without cutting. Book it when 1 or more of these is true: weight loss of 10 percent in 6 months, vomiting 2 or more times a week for 3 weeks, diarrhea for 3 weeks, a mass the vet can feel, jaundice, or drinking more than 60 ml per kg per day. A full abdominal scan takes 20 to 30 minutes, needs a 12 hour fast, and usually needs no sedation. Most vets will also take a chest X-ray in 2 views if lymphoma is on the list, because the chest decides the stage and the stage decides the plan.

The 15 minute fine needle aspirate

A fine needle aspirate is the highest yield test per minute in veterinary medicine. A 22 to 25 gauge needle, 3 to 5 quick passes into the mass or the thickened bowel, cells sprayed onto 2 or 3 slides, and the cat is done in 15 minutes with no sedation in most cases. Cytology comes back in 1 to 3 days at most labs. It answers the question that matters: round cells (lymphoma, mast cell), epithelial cells (carcinoma), or inflammation. If the sample is not diagnostic, the next step is a tissue biopsy, which is a 30 to 45 minute procedure under general anesthesia and 3 to 7 days for histology. Ask for the cytology first: it is faster, cheaper, and often enough to start treatment.

The annual numbers to collect from 11 on

Every 6 months: full examination, weight, body condition score, blood pressure, and a blood panel with a T4. Every 12 months: urine test with a urine protein to creatinine ratio, and a baseline abdominal ultrasound from 12 years. The examination should include a mouth check with the cat awake and, if tolerated, a look under the tongue, plus palpation of every lymph node and both kidneys. Write the results in 1 place: 4 numbers per visit over 3 years is a dataset, and a dataset catches a trend 6 months before a symptom does.

Finding	Threshold	Unit	First step	Days to an answer
Weight loss, slow	10	percent in 6 months	Bloodwork, urine, T4, blood pressure	2
Weight loss, fast	5	percent in 3 months	Examination within 2 weeks	14
Vomiting	2	times a week for 3 weeks	Abdominal ultrasound	3
Bowel wall	5	mm thick on scan	FNA of the wall	3
Oral lesion	10	mm, unhealed for 2 weeks	FNA plus dental examination	2
Lymph node	10	mm short axis	FNA of the node	2

What it costs, and what to ask for first

An examination, a blood panel, and a urine test usually land in the low band of the cost tables; an abdominal ultrasound and a cytology sit in the middle band, and a biopsy with anesthesia sits above both. If the budget only stretches to 1 test, spend it on the aspirate, not on a full panel of tumour markers, because the aspirate gives a diagnosis and the markers do not. Ask 3 questions at the visit: what is the cytology, what stage is it, and what does treatment buy in months. More on the disease is in lymphoma in cats and oral tumor signs.

Signs that skip the queue

Open-mouth breathing, a mass that doubled in 2 weeks, bleeding from the mouth or nose for more than 24 hours, sudden blindness, a leg that swells from the shoulder down, or not eating for 24 hours. Any of those means today. For everything else on this page, a 2 week window is reasonable: cancer screening is a schedule, not an emergency, and the cat that gets weighed every month is the cat that gets diagnosed at 1 cm.

Terms mentioned in this article

MMT4CKD

Frequently asked