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Featuring Demian Dressler, DVM and Sue Ettinger, DVM, Dip. ACVIM (Oncology), authors of The Dog Cancer Survival Guide

The Oncologist’s Perspective on Statistics: Part One

Updated: April 15th, 2019

I know what you are thinking. Statistics … ick, boring. I agree. I was never a fan of learning about stats. In fact, statistics was one of my least favorite classes in undergrad.

But when you are dealing with the overwhelming diagnosis of cancer, there are a ton of statistics to learn. How long will my dog live without treatment? With treatment? What is the response rate to a protocol? What is the difference between median and mean survival times? What about disease free interval? Is your head spinning yet?!

I was also required to learn many stats during my residency and for my oncology boards.  By this time, I actually liked learning the stats … because while cancer can be unpredictable, statistics are practical. Statistics help me predict many things about cancer for my patients.

For example, osteosarcoma is the most common bone tumor. In fact, 85% of dogs with cancer in the bone will be diagnosed with osteosarcoma. Statistics tell us that three-quarters of these tumors develop in the limbs, with the front legs twice as likely develop this tumor.  The most common locations are towards the knee and away from the elbow – the top of the shoulder, the wrist, and the knee (bottom of femur or top of tibia). Osteosarcoma is typically seen in large and giant breeds including  Great Danes, St Bernards, Irish Setters, Rottweilers, German Shepherds, Golden Retrievers, and Doberman Pinschers.

So when last month, I met George, a middle aged St. Bernard with a lytic lesion in his radius bone at the wrist, I could predict to his Guardians with high likelihood that George’s diagnosis was osteosarcoma.

With many clinical studies and statistical analyses, we can predict that dogs treated with amputation alone have a median survival time of four to five months, with 90-100% dying at one year and only 2% are still alive after two years.  With statistics, we can predict that the median survival times for dogs treated with amputation and chemotherapy increase to 10 to 12 months, with 20-25% of dogs still alive after 2 years. That’s a good amount of information, thanks to statistics.

So, as you can see, statistics are helpful and something you will undoubtedly want to learn, because they give you expectations and will help you formulate your treatment plan.

In my next blog, I will discuss some of the limitations is statistics and see why they are not always helpful. For more information on osteosarcoma or cancer-related statistics, check out the Dog Cancer Survival Guide.


Leave a Comment

  1. Leslie on February 7, 2012 at 1:11 pm

    Hi, I wonder if you could give me statiscs on osteosarcoma of the mandible? I have a four and half year old female mixed breed who was diagnosed with osteosarcoma of the mandible. She has had the tumour removed. I have one vet telling me that osteosarcoma of the flat bones has less of a chance of metastizing to the lungs and a higher survival rate. I have another vet telling me there is not a whole lot of difference. Can you give me some stats similar to the ones you wrote of above? I’m trying to figure out it chemo would be a good idea….


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