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

Waiting and watching — but for how long?

Updated: September 26th, 2018

Have you been told to “just watch” a lump or mass on your dog by a veterinarian? I wouldn’t be surprised if you have. I too have advised that to my pet Guardians.  But how long is ok? What size is too big?  Are there actual guidelines?

In my veterinary training, I was taught that if a mass is not growing or changing in appearance, it is likely ok to do nothing and leave it – “just continue to monitor.” It’s been ten plus years since I started my medical oncology residency, and from my experience treating dogs and cats with cancer, that is not always the best advice.

While many skin masses are benign, some of these masses may also be slow-growing malignant tumors and it is better to remove them early, when it is more likely that the tumor can be completely removed with wide margins with the FIRST surgery.  I feel we are waiting too long, for too many masses.

This week I saw two cases that really depressed and frustrated me. Both were cats. I know this is a blog about dog cancer, but these cases illustrate exactly why it can be problematic to wait too long to take action – no matter what species we’re talking about.

Earlier in the week, I met Tiger, a big 16 year old cat with a recurrent tumor on his lower jaw, up front by the incisors.  It was first removed exactly a year ago. And now, it was back, and 3 cm wide. Think about how big a cat’s head is, and you’ll see that is a big tumor.

The tumor was a low grade fibrosarcoma, which, as in in dogs, is a malignant connective tissue cancer with tentacle-like projections that extend out from the visible tumor. It is these tentacles that make recurrence after surgery common if the surgery does not also remove a large amount of tissue around the tumor. We need a wide, clean “margin” of tissue. How big a margin? That’s what can be tricky to figure out by “just monitoring” it.

This week, as I visually inspected Tiger’s mouth with our surgeon at our practice, I was cautiously optimistic that surgery was an option. But just looking at a tumor doesnt tell the whole story, so, to be sure, we did a CT scan. Unfortunately, based on the CT scan, the tumor and its tentacles extended too far back. Surgery was no longer an option, as there was no way to get wide enough margins, and (most importantly) leave a functional mouth so the kitty could eat once he recovered. The surgery last year did not get wide enough margins. We didn’t want to do another resection (surgery), because we would end up with a minimal margin, and that would lead to another recurrence.

The second kitty I saw this week was Tulip. She also had a low grade sarcoma, a peripheral nerve sheath tumor, on the right side of muzzle. Tulip’s Guardian first visited her vet five months ago, after she noticed a small mass on the side of her face. Her vet prescribed steroids and antibiotics, which did not help for long. A month later, the mass was biopsied. At that point, the mass was still small, about 1cm, and likely still a good candidate for surgical removal.  Unfortunately, I did not see the case until this week, four months after that biopsy. At this point, the mass is greater than 3 cm.

The point I’m making here is that for both of these cases, the cancers might have (essentially) been cured if they had been treated with more assertive methods early, while they were still small tumors. Tiger’s first surgery should have had much wider margins, to reduce the risk of recurrence. Tulip should have had a big surgery with wide margins on that small, 1 cm tumor, rather than taking a wait-and-see approach.

Big surgeries, early, on small tumors, can be really helpful for these sarcomas. As in dogs, the metastasis rate is low for sarcomas, and chemotherapy is typically not recommended once the surgery removes the tumor.

Instead, I had to deliver the frustrating news that we are now beyond surgery as an option, in both cases. We now have palliative radiation, palliative pain medications, and anti-inflammatories. Palliative techniques are not designed to remove the cancer, remember. They are meant to help the dog, or in this case, cat, feel better while the cancer continues to do what cancer does.

Understandably, both guardians wept when I explained the situation. My heart was heavy, as I outlined the lack of good therapeutic options to rid these cats of their once-treatable cancers.

Dr. Dressler and I write in our book that there’s always something you can do to help your dog with cancer – and there is. You can always improve quality of life, change the diet, start supplements, and, of course, take advantage of palliative and therapeutic treatments.

But please – if you’ve landed on this page because your dog (or cat, in honor of Tulip and Tiger) has a lump or a bump, and you have been told to wait and watch it … rethink that.

In my next post, I’ll give you some guidelines for how to handle a “wait and see” situation.


Dr. Sue

Leave a Comment

  1. Kathi Myers on February 15, 2019 at 5:31 am

    Thank you! We noticed a lump in my sweet dog nearly a year ago. It finally got to a point of concern that we took her to the vet. They poked at it, said it was nothing to worry about and to just monitor it. It grew and changed color. Took her back to vet. “It’s still ok”. Then it got bigger and purple so we took her to another vet last week. They poked it and also said it was nothing to worry about, but we asked for a biopsy anyway. Sure enough – malignant spindle cell. What is WRONG with these vets?!

    • Dog Cancer Vet Team on February 15, 2019 at 7:19 am

      Hi Kathi,

      Thanks for writing, and for sharing your story. This is why Dr. Sue writes in this article, that if a lump is larger than 1cm, or has been there for over a month to get it checked by a vet ASAP. Your vet must perform a fine needle aspirate and/or a biopsy to make an accurate diagnosis. If your vet won’t do it, then she recommends finding a vet who will.

  2. carol jones on May 19, 2018 at 9:00 am

    25 lb. miniature pincher, 13-1/2 years old. Large spindle cell sarcoma on back right leg. Four surgeries for removal in the last year. March 5, 2018 Vet says he can do no more. Tumor around and under leg bone, tumor now size of baseball and beginning to look bumpy and red in spots with all hair coming off tumor. We are waiting. We just have no advice other than wait. Our vet did his best but he is done with us now. We are giving our dog 9 drops of cannabis oil from druggist. We think it helps. Our dog eats everything he can with this oil…we have been advised. We do NOT know what to expect. The cancer odor is very bad and this dog is our baby and sleep with us. We wash clothes a lot. Is there anything else we can do and what will eventually happen with the tumor. Thank you.

    • DogCancerBlog on May 21, 2018 at 9:59 am

      Hi Carol, thanks for writing. Do you have a copy of The Dog Cancer Survival Guide yet? It has lots of ideas on diet and supplements that might be supportive to your baby as you try to help fight that tumor. At this point, it sounds like you need more support, too. Perhaps a second opinion or another veterinarian might have some ideas about how to keep him comfortable? You might also take a look at this post, which will help you to know what “the end” looks like — and help you to know whether you are close to it or not. Many cuddles to you and your little boy from all of us.

  3. Susan Kazara Harper on June 1, 2015 at 4:07 pm

    Hi Marti,
    Please give a big HAPPY BIRTHDAY to Buddy. I’m sorry this response has been delayed, and I know you may not feel very happy with this diagnosis looming. But Buddy can celebrate his 10th birthday in your loving care! and that’s something not every dog, nor human can enjoy. Do you have a copy of the Dog Cancer Survival Guide book? If so, please check out pages 36, 37 and 48 where it talks about decompensation. We know our dogs have the natural instinct from their wild cousins to hide, or ‘compensate’ for any state that is not perfect helth. When they are no longer able to do this, we call it decompensation, and sometimes that’s when we humans actually realize there is a problem. You know Buddy better than anyone, and your vet will know his medical state. Basically, there is so much you can do to help Buddy, starting with a Dog Cancer Diet (free download at, or it’s presented in the book), and keeping yourself as upbeat and unstressed as possible. Disease feeds on stress, and Buddy knows your heart probably better than you do yourself. If you can infuse every day with joy at being together, fantastic nutrition, play, and vigilance with your vet, Buddy may surprise you both. Please do refer to the book and work closely with your onncologist. Buddy does not have a number engraved on him, a final date, or anything like that. A prognosis only relies on statistics and don’t take into account the individual spirit of the dog. As long as he’s happy, enjoys his appetite and can poo and pee in comfort, he’s doing well. Do check out Part IV of the Book, Making Confident Choices. Every day is a gift, with or without a cancer diagnosis. Enjoy that birthday cake (or bone) and hold him close. Good luck to you both!

  4. Marti Farber on May 12, 2015 at 10:39 am

    Dear Dr. Ettinger,
    My Buddy is a beagle he will be 10 on June 01,2015 on April 01 he was diagnos. by oncologist with a sarcoma tumor it’s location between the kidneys and adrenal gland and dangerously close to a major artery they told me if I di the surgery he would only have 6-8 months to live if he didn’t bleed out and die on the table which was a 60% plus chance. So if this were me I would not have the surgery and leave this in God’s hands. My question is what signs should I be looking for as this cancer progresses & any tips for caring for my baby as every day now is a gift.
    I look forward to your response.
    Sincerely yours,
    Marti Farber

  5. Anna on July 10, 2014 at 8:31 pm

    Dr. Ettinger,

    Do you remember how long it was before Tiger’s tumor first started to return? My cat had a low grade fibrosarcoma removed from the top of his head approximately 7 months ago. It first appeared as a scar at the age of 9 months (summer of 2009) and grew very slowly until it was the size of a small pea, and was removed winter of 2013 while his teeth were being cleaned. It was around 2-3 mm in diameter and was removed with 1cm lateral margins, and as deep a margin as possible w/o removing skull (vet cut down to bone). The pathology report said that the tumor was well-differentiated and there was zero mitotic activity in the examined slices. Also, margins were reported to be clean. My vet discussed my cat’s case with the pathologist and he said that he had difficulty deciding if it was a fibroma or fibrosarcoma, but after consulting with another pathologist decided it was “just cellular enough” to classify as malignant. Due to the tumor’s low grade and clean margins, he thought my kitty might be cured. However, a second, more thorough margin check revealed a small focus of neoplastic cells. I consulted with a radiation oncologist and surgeon at the local vet school, and the surgeon said that in order to get the recommended margins, he would have to remove the top of my cat’s skull and replace it with a prosthesis; therefore, given the low grade of my cat’s tumor, he did not recommend re-resection. The radiation oncologist said that either radiation or a “wait and see” approach would be acceptable, given the lack of research on low grade fibrosarcoma in cats. However, she said if it were her cat she would do radiation. She is very confident in her team’s ability to spare his eyes and brain, and believes that the probability of radiation- induced cancer (I.e., osteosarcoma) is much lower than the probability of my cat’s tumor recurring w/o radiation, thanks to modern radiation techniques. The cost of treatment would be around $7000. I think it could be possible for me to come up with this money through a combination of donations and loans (unfortunately, I never purchased insurance…I didn’t even know pet insurance existed before his tumor was first documented by my vet in 2009, and buying it any time after that wouldn’t have been helpful because understandably, they don’t cover preexisting conditions). However, the limited research I’ve looked at suggests that for low grade fibrosarcoma, adjunctive radiotherapy does not reduce the rate of tumor recurrence in dogs and cats. Given how well-differentiated my kitty’s tumor cells are, I don’t even see how the radiation could “target” the residual cells. Radiation therapy is usually effective against cancer because it has a disproportionate effect on poorly differentiated cells (the healthy, well differentiated cells live and the cancerous, poorly differentiated cells die). It is difficult to pour so much money into a treatment that is unlikely to help, and will cause my kitty an enormous amount of stress (it would require 18 trips to the vet in one month, and my cat trembles and refuses to eat or drink while at the vet). Therefore, I’ve opted for the “wait and see” approach. That’s why I asked about Tiger. It’s been 7 months for my cat and there is no regrowth yet. I palpate once every two weeks. I found a small study which determined that the mean/median tumor free intervals for low grade fibrosarcomas in cats were between one and 1.5 years, so I’m definitely not breathing easily yet.

  6. xinch on June 22, 2014 at 5:29 am

    Hi Dr Sue, I live in Malaysia with my 5 year old American Cocker Spaniel, Shandy. Last August she had a mass grow on her upper lip and was removed and tested. The tests came back benign but just a month ago it regrew rapidly and aggressively. A 1cm margin was removed and the mass sent for testing. This time around, the mass is a malignant, Grade 2 soft tissue sarcoma! The pathology report states that while the excision margins are generally wide and the lesion fully excised, they’re also focally narrow (approximately 1mm). He has advised widening the margin to try and minimize the chances of regrowth, but even that he said may not be 100% effective. He’s also insisting that it probably has not metastasized and has declined to do an Xray to check so I’m not too sure what the next steps are in this case. She has an chronic case of malassezia which is currently being treated (it flared up again post-op). Could you please advise me on what the next best options are? 🙁

  7. Patty on April 8, 2014 at 5:12 pm

    Hi Dr. Sue, I spoke with you on your talk show about my dog Halo. She has the Apocrine ductular adenocarcinoma. Surgery on the tumor on her back was in Dec 2013. Saw an oncologist after speaking with you in February. He said it was a grade 8. Recommend praxicam for a year. Chest xray normal.all blood test normal. Ok, now he also wanted to send biopsy back to see how clear the margins were. They forgot to do this in February. They just sent it, and the margins are good but the depth is not good. Only 1 mm he said 4 mm would have been good. I’m confused on that, but now they want to do another surgery to get deeper. Or radation or metronic therepy. Halo has had this going on for so many months that I think the cancer cells are already elsewhere ready to spread, I’m concerned that since December s surgery an April surgery will be to late. I really am so sad and I don’t know what to do. She just turned 3. I wish they wouild have done all this sooner. I just wanted to know your thoughts on this. Is it really to late to do another surgery? Thank you

    • Susan Kazara Harper on April 11, 2014 at 10:17 am

      Patty, I can hear how distressed you are, of course you are. How is Halo in herself? At 3 she is very young and if she’s doing well with her appetite and her quality of every day life, she has a lot going for her. You say you’re worried the cancer has spread, but ‘worry is a prayer for what we don’t want’. I fall into worry about things too, and I know it doesn’t do a bit of good. I suspect the vet would not be recommending further surgery unless he felt that Halo was in good shape and that the surgery (or radio and metronomic chemo as you said) is worth trying. Yet ultimately all of this is your decision. And sometimes that stinks. Dr. Sue is off line for about a week, but you could email into again and perhaps get on the show again when she returns. I know this feels like it doesn’t help right now. Talk frankly with your vet, ask what he thinks is the best option for Halo at this point. Does he have any reason to believe the cancer has spread? Take a few deep breaths with Halo and talk to her about it all. You will know the best decision in your heart. Are you using any nutraceuticals to help support her? Is she on the Dog Cancer Diet? It all helps. I’ve had two dogs who surpassed both the odds and their prognosis when they had cancer. Good luck Patty. Give Halo a cuddle from me please.

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