thyroid carcinoma

Re: thyroid carcinoma

Alex Gough — Fri, 10 Aug 2012 17:29:08 GMT

[quote user="Andrew Kent"]Alex you are right[/quote]

Nice to know it happens occasionally!

[quote user="Andrew Kent"]Good thyroid revision for me today![/quote]

Me too!

Alex

Re: thyroid carcinoma

Andrew Kent — Fri, 10 Aug 2012 17:24:30 GMT

Alex you are right - it seems by understanding was out of date - reading that second paper it seems that the most important aspect of deciding re radioactive iodine is whether or not the tumour traps iodine and this is a feature of some but not all non-functional tumours. The conclusion is that if it highlights on scintigraphy then it will trap iodine and so would be a candidate for radioactive iodine. However in this case I guess this would now be difficult to ascertain if the tumour has already been excised. The other thing it seems with dogs is that due to the relative higher doses required the chance of side effects (bone marrow suppression) is greater. Good thyroid revision for me today!

Re: thyroid carcinoma

Alex Gough — Fri, 10 Aug 2012 17:06:20 GMT

[quote user="Andrew Kent"]My understanding is that radioactive iodine therapy is only appropriate in functional thyroid tumours (which are the minority) rather than all thyroid masses? Have you run thyroid blood tests?[/quote]

I dont have any experience with radio-iodine to disagree with you, but my reading is that it works better in functional tumours, but can also work in euthyroid dogs. Scintigraphy can be used to assess whether it is a suitable candidate apparently. However, paper I just came across suggests extended survival times were possible with surgery alone. Couple of abstracts below.

Alex

Abstract

Journal of the American Veterinary Medical Association

July 1, 2012, Vol. 241, No. 1, Pages 95-103

doi: 10.2460/javma.241.1.95

Outcome following simultaneous bilateral thyroid lobectomy for treatment of thyroid gland carcinoma in dogs: 15 cases (1994–2010)

Joanne L. Tuohy, DVM; Deanna R. Worley, DVM, DACVS; Stephen J. Withrow, DVM, DACVS, DACVIM

Department of Clinical Sciences, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, CO 80526. (Tuohy, Worley, Withrow)

Dr. Tuohy's present address is Department of Clinical Sciences, College of Veterinary Medicine, North Carolina State University, Raleigh, NC 27606.

Presented in abstract form at the American College of Veterinary Surgeons Veterinary Symposium, Seattle, October 2010; and the Veterinary Cancer Society Conference, San Diego, October 2010.

The authors thank Dr. Jens Eickhoff for assistance with statistical analyses.

Address correspondence to Dr. Worley (dworley@colostate.edu.

Objective—To evaluate the outcome of resection of simultaneous discrete bilateral mobile thyroid gland carcinomas (TGCs) in dogs.

Design—Retrospective case series.

Animals—15 dogs with resected simultaneous discrete bilateral mobile TGCs.

Procedures—Medical records (from 1994 to 2010) were searched for dogs with the appropriate diagnosis and treatment. Information collected included signalment, clinical signs, diagnostic test results, tumor mobility (mobile tumor identified by movement ≥ 1 cm in all planes during palpation), complications, adjuvant treatments, and outcome.

Results—Mobile, discrete, bilateral TGCs were removed in all dogs. Among the 15 dogs, complete parathyroidectomies were necessary in 9; parathyroid tissue was reimplanted in 4 and preserved in 2. Complications included hemorrhage and laryngeal nerve trauma, but without serious consequences. Thirteen dogs received calcitriol with or without supplemental calcium after surgery. In the immediate postoperative period, hypocalcemia developed and was corrected in 11 dogs. At the end of the study, 7 dogs continued to receive calcitriol with or without supplemental calcium, and 8 dogs required long-term thyroid hormone treatment. Six dogs received adjuvant chemotherapy. Local tumor recurrence or de novo distant metastasis was not detected at each dog's last follow-up examination. Median survival time was 38.3 months. Three dogs were lost to follow-up, 8 survived (4.3 to 77 months after surgery), and 4 died of unrelated causes.

Conclusions and Clinical Relevance—In dogs with TGCs undergoing bilateral thyroid lobectomies, a successful outcome can be expected, even when parathyroid gland tissue cannot be preserved. The role of adjuvant chemotherapy in treatment outcome was not clearly defined.

Aust Vet J. April 2005;83(4):208-14.

A J Worth¹; R M Zuber; M Hocking

¹Centre for Companion Animal Health, Massey University Veterinary Teaching Hospital, Private Bag 11-222, Palmerston North, New Zealand.

Article Abstract

OBJECTIVE: To assess the efficacy of radioactive iodine treatment (131I) for canine thyroid carcinoma, as both the sole therapeutic modality and as an adjunct to surgery.

DESIGN: Retrospective analysis of case records from the Gladesville Veterinary Hospital Nuclear Medicine Service, Sydney, between August 1988 and December 2001.

CASE DETAILS: The records of 65 dogs with thyroid carcinoma were analysed according to therapy and outcome. Forty-three dogs received radioiodide therapy, either as the sole therapeutic modality (32) or as an adjunct to surgery (11). Radioisotope therapy consisted of one to three doses of 131I with a dose range of 555 to 1850 MBq. For analysis, dogs were divided into groups according to therapy: no treatment, surgery alone, surgery with radioiodide therapy or radioiodide therapy alone. Mode of therapy, dosage of 131I, clinical staging and age were all independently analysed according to survival to compare efficacy or predictive value respectively.

RESULTS: When radioiodide therapy was used as an adjunct to surgery, median survival was 34 months. Censored median survival time for dogs that received radioiodide alone was 30 months. Dogs that did not receive treatment had a median survival of only 3 months. Log rank statistical analysis indicated that mode of therapy was significantly correlated with survival but that clinical stage of disease was not.

CONCLUSION: The authors conclude that 131I therapy is effective at extending survival time, both as a sole therapeutic modality and as an adjunct to surgery, in dogs with invasive canine thyroid carcinoma. Incomplete surgical resection may not prolong survival in dogs also receiving 131I therapy, however surgical resection with curative intent should be recommended as the first line of therapy for mobile thyroid carcinomas. Radioisotope therapy can be recommended for cases where surgery alone is considered unlikely to be curative because of metastatic disease or local invasion, or for cases where surgery has been attempted but complete surgical removal has not been achieved.

Re: thyroid carcinoma

Andrew Kent — Fri, 10 Aug 2012 16:56:26 GMT

[quote user="Lorna McHardy"]

[quote user="robloxley"]

[quote user="Andrew Kent"]Have you ruled out surgery just based on the histo?[/quote]

Sounds like the histo was on the mass post excisional surgery, if my understanding is right?

[/quote]

Yes, that's right. The only question now is radiotherapy/chemotherapy... or not.

[/quote] Sorry I misunderstood - so the surgery was an attempted full excision rather than biopsy? If so then I would go for follow up radiation rather than chemo if worried about local recurrence. [quote user="alex gough"]

I understand that some centres that do iodine therapy are licensed to treat adenomas only, whereas others are licensed to treat adenocarcinomas because of the higher dose required. I think Langford might be licensed for adenocarcinomas - might be worth a ring. If it was my dog I would prob go for radioiodine therapy, although would be interested to know their figures for survival times. External radiotherapy also is not a terribly invasive procedure, although some centres like to give more lower dose treatments than others, which supposedly reduces side effects but is more difficult for the owner if they are travelling a long way.

Alex

[/quote] My understanding is that radioactive iodine therapy is only appropriate in functional thyroid tumours (which are the minority) rather than all thyroid masses? Have you run thyroid blood tests?

Re: thyroid carcinoma

Alex Gough — Fri, 10 Aug 2012 15:10:50 GMT

Alex

Re: thyroid carcinoma

Lorna McHardy — Fri, 10 Aug 2012 14:02:30 GMT

[quote user="robloxley"]

[quote user="Andrew Kent"]Have you ruled out surgery just based on the histo?[/quote]

Sounds like the histo was on the mass post excisional surgery, if my understanding is right?

[/quote]

Yes, that's right. The only question now is radiotherapy/chemotherapy... or not.

Re: thyroid carcinoma

Rob Loxley — Fri, 10 Aug 2012 13:41:28 GMT

[quote user="Andrew Kent"]Have you ruled out surgery just based on the histo?[/quote]

Sounds like the histo was on the mass post excisional surgery, if my understanding is right?

Re: thyroid carcinoma

Andrew Kent — Fri, 10 Aug 2012 11:21:59 GMT

Have you ruled out surgery just based on the histo? If so I would rethink this as surgery is likely to be the best solution if possible and can give good results - obviously the more mobile the mass the more likely it would work. This could be combined with radiotherapy if poor margins. If surgery is not an option then radiotherapy would be the better second choice as chemo is unlikely to give much benefit on its own and is more likely to give nasty side effects. Chemo is likely to be more important if metastatic disease is present. In tolerant dogs most of them are completely normal on radiation therapy and would recommend this without hesitation to any owner that is willing.

Re: thyroid carcinoma

Rajat — Fri, 10 Aug 2012 10:39:03 GMT

The dog is relatively young and sounds like in good shape otherwise.

If she was mine I'd pursue Chemo and radiotherapy. Both are fairly well tolerated , and any s/e eg with doxo are easily mitigated by pre treatment. Not that it is without risks altogether!

I'd discuss TKIs with the companies that make them (masivel palladia) as some anti angiogenic effects may be beneficial and there are non published anecdotal reprots about various tumours being treated/studied at the time eg haemangiosarcoma with Masivet. Doesnt mean it will work but worth considering.

Re: thyroid carcinoma

Richard Fox — Fri, 10 Aug 2012 10:10:18 GMT

Not good prognosis and chemo prob wont really change things long term so if were mine I'd let nature take its course myself.

Re: thyroid carcinoma

Bob Russell — Fri, 10 Aug 2012 09:51:20 GMT

We had a springer with a thyroid carcinoma about 8 years ago. He was referred and enquiries were made about radioactive iodine treatment. Sadly nowhere in the UK was licenced to perform this but apparently somewhere in France was able to do this!

Things may have changed since but needless to say the dog was not treated this way!

Re: thyroid carcinoma

James Laidlaw — Fri, 10 Aug 2012 09:36:48 GMT

If money wasn't the issue and the side effects of the chemo relatively minimal I don't see why not to treat? You make it sound like the dog is pretty emotionally connected, and the bottom end of the mean survival time is double the absolute maximum with chemo, that's better than a lot of cancer treatments. In reality I'd want to discuss it as an owner, with a specialist, then make a fully informed choice.

Re: thyroid carcinoma

Utlendigur — Thu, 09 Aug 2012 23:05:27 GMT

Many years ago I used to have a collie, and one day noticed a lump in his neck (embarrassingly it was about the size of a small egg - but he was quite hairy). It was before we did many fnabs so I just removed it - it was obviously thyroid and histo came back as thyroid carcinoma. He was about 12, and a bit wimpy, and it was a good few years ago so radiotherapy and different chemo protocols weren't as common/available, so it never really occurred to me to refer him. I was very very lucky - no recurrence and he lived to about 16.

Re: thyroid carcinoma

KathW — Thu, 09 Aug 2012 22:55:40 GMT

I would do the same as Michael. Just my opinion and I appreciate some owners want to do "as much as possible"to gain more time with their pets, For me it stems from being a farmers grandaughter I think and the fact animals live in the present. Keep the dog dog happy and as pain free as possible but "quality of life" is more important than a few extra weeks or months.

Thats what I would do for my dog. For owners I present the options and discuss with them as appropriate.There's also the factors of cost and time to take the dog for regular treatments + assesment. SOme dogs would tolerate this more than others.

I have a collie cross nearly 14yr and she is a nightmare to treat. Even to clip her nails involves a strong other half to hold. She was unwell recently and I had to muzzle her for bloods - Pancreatitis diagnosed on Cpli. If she hadn;t improved I don't think I would have scanned her as it would have been very streesful for her without sedation. Plus shes elderly and quite arthritic - luckliy she improved but knowing my own dog there's a limit to how much I would treat her taking age and temprament into consideration.

Re: thyroid carcinoma

Lorna McHardy — Thu, 09 Aug 2012 22:44:09 GMT

Dogs don't come any better-natured than this one, and she will tolerate anything the owner asks her to tolerate; but is it fair? I repeat, if that were your dog, would you do it, or not? I'm asking for an owner point of view, not a vet one.

The radiotherapy is described as well tolerated by most dogs - whatever that may mean - and causing possible erythema and oozing of the skin, as well as possible oesophagitis and tracheitis. The chemo (doxyrubicin) comes with the usual potential for vomiting/diarrhoea etc.

Re: thyroid carcinoma

Michael Woodhouse — Thu, 09 Aug 2012 22:39:26 GMT

[quote user="Lorna McHardy"]Leaving aside the considerable cost of referral, if that were your dog, what would you do?[/quote]

I would make sure pain was controlled and make the rest of the dog's life as happy as I could.

I would not mess about with chemo and radiotherapy. Not if the dog was mine.

Re: thyroid carcinoma

Nicola Lawlor — Thu, 09 Aug 2012 22:27:37 GMT

What sort of nature does the dog have in terms of putting up with being in a clinic/having IV etc. If this dog is nervous and unsettled it would make me consider a lot harder against further treatment. I would want to know more about the treatment suggested and potential for side effects in a dog with these being carried out before making a decision. From an owner point of view make sure they don't have false hope if they go ahead with treatment as not every case is going to go as planned and they need to be ready to reconsider along each step of the treatment if there are unforseen issues with health or the ability of the dog to undergo this treatment. Ultimately it needs to be the decision of the owners when they have all the facts available to them.