MCT chemo

Re: MCT chemo

Martin Atkinson — Fri, 17 Feb 2012 13:19:18 GMT

[quote user="Laurence Webb"]

For those currently graded as intermediate I'd advise Ki67 staining which also seems to correlate fairly will with clinical behaviour. If it's low I'd probably be content to examine periodocally for recurrence and LN involvement. If high then full staging and consider chemo/TKI.

[/quote]

Agreed. I had one MCT graded as intermediate with not all margins clear and requested Ki67, this was low so the lab re-evaluated their original interpretation and downgraded it to low grade but not until after I'd gone back in with wider margins because the Ki67 took ages. Although the second bite of the cherry produced clear margins, the wound broke down because I'd had to pull it up tight and it was in an axilla, the client wasn't happy and jumped ship despite it all being covered by insurance. Must be a moral there somewhere.

Re: MCT chemo

Laurence Webb — Thu, 16 Feb 2012 23:26:18 GMT

Firstly it depends on which histopathologist examined the samples. In the past I've noted some labs grade most MCTs as intermediate (hedging their bets?) where as others tend to give a wider spread of low, intermediate or high grades.

TDDS (mentioned above) were recommended to me and are now grading MCTs using both the older Patnaik grading and the newer Kiupel system, which is still being assessed. Basically it seems that MCTs either behave in a benign (low grade) or malignant (high grade manner) so the criteria used for putting them into the intermediate grade is being questioned. The newer system uses different histo criteria and puts them in low or high grade although I gather it is too early to be completely confident in the grading.

Obviously enlarged Lns need to be aspirated although I've just had a high grade MCT which has been completely resected and no LN enlargement although aspirates show poorly differentiated MCs in the LN, which just goes to show that it doesn't have to be enlarged to have metastesis. If Ki67 isn't done then LN aspirates would be sensible.

Purely anecdotally, I've found that most intermediate MCTs completely removed do not recur.

Re: MCT chemo

Jillian Hall — Thu, 16 Feb 2012 21:28:41 GMT

What do people generally do for intermed grade MCTs removed with clear margins at surgery? Give a cautiously optimistic prognosis and just keep an eye on the local LNs, or FNA/remove local LNs, or give a cycle of chemo? Personally I go with the former, unless there's an enlarged LN.

Re: MCT chemo

Kate Richardson — Thu, 16 Feb 2012 20:56:48 GMT

Hi Julian, my info came direct from speaking to Josephine Howell, who was very helpful. I hadn't read the data, but useful to know.

She also said that testing Kit status was not necessary.

Re: MCT chemo

Julian Earl — Thu, 16 Feb 2012 18:17:37 GMT

[quote user="Kate Richardson"]

"Surgery still the best option if resectable, but if not or other reasons why ga not advisable, then worth trying Masivet. 85% chance of success, either complete remisison or reduction in size of MCT, generally see this within 2 months, if no change after 2months of treatment, no point in continuing. If there is a response then continue tx for 6months if complete remission, or long term if only achieved a reduction in size of MCT. Also if incomplete margins after resection or high grade tumour then also worth tx w masivet.

[/quote]

I think if you look at the Masivet data that the six-month status is the indicator for long-term prognosis; it specifically states that six weeks is not an appropriate indicator.

Here ya go:

"Control of the tumour at 6 months is predictive of long term survival

However, survival probability is strongly related with the assessment of controlled disease or progressive

disease at 6 months. As shown in the table below, a survival prognosis can be set at 6 months regardless of the

mutation c-Kit status.

...In conclusion, a 6-week short term response to TKI treatment is not predictive of long term survival, whereas a

dog with controlled tumour at 6 months can survive for a long period of time."

Re: MCT chemo

Kate Richardson — Thu, 16 Feb 2012 15:48:23 GMT

Hi, I have copy and pasted this from another thread http://www.vetsurgeon.org/forums/t/10243.aspx?PageIndex=1 (titled "Masivet" if you do a search on here). I researched Masivet for a case about 1-2 months ago.

Dose 12.5mg/kg, comes in 50mg and 150mg tablets. Tablets shouldn't be split. Approx £28 for pot of 30 x 50mg, £64 for 30 x 150mg, + £24 shipping fee per shipment regardless of how many pots ordered. Can be obtained via one of the wholesalers (NVS) or directly via website; they will email details including an access number and can be ordered via website and paid by credit card.

Blood monitoring advised to check for neutropaenia, anaemia, increases in ALT and decreases in albumin ie liver parameters, every 2 weeks"

Depending on size of dog though it isn't cheap- worked out approx £3-400 per month if I recall for a 30-35kg lab.

Re: MCT chemo

argyro koukouseli — Thu, 16 Feb 2012 14:41:56 GMT

i ve found this for you,vincristine(alone) 0,75mg/m2,IV weekly for four weeks.study size 27 dogs.survival rates not reported.2/27 showed partial remission.

Re: MCT chemo

An On MRCVS — Thu, 16 Feb 2012 13:51:26 GMT

[quote user="Malcolm Ness"]

It seems that this surgery has achieved remarkably little except further impoverishing the owner.

[/quote]

Thank you for the words of advice, Mr Ness. As I already mentioned, we are going to help the owners out with further surgery, although the lump was so large that we're going to struggle to get wide margins, particularly deep, and the owners won't go for amputation - despite discussion. But we'll do what we can, in our own, basic, general practice way. Rest assured, if the dog is not for saving, it won't be for want of effort or amenability on our part. Stitches came out yesterday, so surgery is mooted for the start of next week, depending on finances. And what we have already achieved is a diagnosis, likely prognosis and a treatment plan, for a lot less than would make good business sense.

Chemo was discussed before surgery, mainly along the lines of masivet or vinblastine/pred. The spanner was slightly thrown into the works when the oncologist suggested vincristine as a treatment in isolation.

So I do thank you for your input - always appreciate hearing from somebody who is an undoubted expert. But the situation is not perhaps as badly managed as you have surmised. I think that's all from me on the subject - thanks to all who chipped in.

Re: MCT chemo

Laurence Webb — Thu, 16 Feb 2012 10:55:06 GMT

[quote user="An On MRCVS"]Masivet isn't necessarily the panacea it was launched as[/quote]No, it probably isn't! It is, however, licensed so you'd need to justify using other drugs on a clinical basis. Tom Cave suggested he was seeing a similar response rate to Masivet/Palladia as to conventional chemo and with a similar incidence of side effects.

[quote user="An On MRCVS"]We haven't done kit testing, and would probably need to put the money into chemo instead[/quote] From discussions I'm not convinced of it's necessity. Apparently there are lots (maybe 20) c-Kit mutations but commercial tests are only available for 2 of them. So a -ve result does not mean that a TKI will not work although it may be less likely to be effective.

The drug reps of course advise using TKIs in all cases. But they would!

Re: MCT chemo

Andrew Kent — Thu, 16 Feb 2012 09:04:06 GMT

[quote user="robloxley"]

[quote user="An On MRCVS"]What is surprising is the apparent lack of agreement on first line treatments, whether the kit mutation is present or not[/quote]

I guess that's due to lack of the data comparing different treatments. And given, for starters, the difficulty in categorising individual MCTs on a 'good to bad scale' (even given all the information from gross appearance, histo features, Patnaik and Kiupel grading, agNORs, Ki67, MI, ckit etc.) I can't see it being the easiest to study?

[/quote] And because I think the more we know about TKI's the more we realise we don't know. There is certainly more to them than C-kit mutations and so whether or not this is present doesn't really aid in decision making of whether to use them or not and as such is purely academic IMO. I am not aware of vincristine alone for Mcts and think one of the other options already discussed would be a better use of resources - the cost of vinblastine and pred will not be much different to vincristine alone.

Re: MCT chemo

Malcolm Ness — Thu, 16 Feb 2012 08:16:09 GMT

[quote user="An On MRCVS"] Clocked as a possible MCT prior to and during surgery[/quote]

[quote user="An On MRCVS"]Margins not great[/quote]

[quote user="An On MRCVS"]Owners keen but pretty impoverished.[/quote]

???? I am a surgeon and therefore biased but there is little doubt that appropriate surgery gives you the best chance of a cure in these cases. It seems that this surgery has achieved remarkably little except further impoverishing the owner. Had the surgery been done properly then the rest of this discussion might not have needed to take place. IMO, much of what is being discussed now certainly should have been discussed with the owner before a scalpel was wielded.

Re: MCT chemo

Rob Loxley — Wed, 15 Feb 2012 23:32:35 GMT

[quote user="An On MRCVS"]What is surprising is the apparent lack of agreement on first line treatments, whether the kit mutation is present or not[/quote]

Re: MCT chemo

An On MRCVS — Wed, 15 Feb 2012 22:15:23 GMT

[quote user="Martin Atkinson"]

[Masivet] Has to be the drug of choice but the OP hasn't answered yet why its not a choice for him.

[/quote]

Erm....... her?

Masivet isn't necessarily the panacea it was launched as . We haven't done kit testing, and would probably need to put the money into chemo instead. there are certain issues where it would be better to perform in-house chemo: slightly difficult circumstances. Sorry to be a bit enigmatic.

Basically I was always under the impression that vincristine in isolation was ineffective. vinblastine / pred is the most commonly used, although Tom Cave (someone suggested contacting him - already done) prefers lomustine as first line. What is surprising is the apparent lack of agreement on first line treatments, whether the kit mutation is present or not. Me, Ive always been impressed with Tom Cave and TDDS.

So, nobody out there using vincristine alone?

Re: MCT chemo

Rob Loxley — Wed, 15 Feb 2012 22:03:15 GMT

[quote user="Andrew Kent"]The traditional chemo approach would be vinblastine and prednisolone - reasonably cost effective but obviously haematologies can run up cost. Alternative would be a TKI[/quote]

How about chlorambucil and pred?

Re: MCT chemo

Martin Atkinson — Wed, 15 Feb 2012 19:19:30 GMT

[quote user="Laurence Webb"]

NVS keep Masivet in at around £70 for 30x 150mg tablets (1 per 12kg daily)

[/quote]

Useful to know Laurence as I thought you could still only get it direct from ab Science. Has to be the drug of choice but the OP hasn't answered yet why its not a choice for him. I have given preds and cyclophosphamide previously before TKI's appeared to a medium grade MCT (wasn't classified any better than that) that had metastasised to the local lymph node and it died of something else after 2 years - before any signs of MCT recurrence so if cost is the issue that would be the cheapest option. Gerry Polton at NDSR is the man to talk to about MCT's

Re: MCT chemo

Laurence Webb — Wed, 15 Feb 2012 18:59:49 GMT

[quote user="Andrew Kent"]Lotus time would be a third choice as well though doesn't really have any cost benefit over vinblastine/pred.[/quote]Lotus time? Must start measuring that in my chemo patients!

Lomustine comes in boxes of 20 tablets which is very expensive up-front (BNF price £455.62) so it is pretty prohibitive to buy in unless you're using it regularly, which we don't. You can get individual tablets from a local hospital but that's a bit of a pain. Vinblastine has less up-front cost and is easier to get hold of in sensible quantities.

If you're going to follow the cascade then you should be using Palladia or Masivet I suppose anyway. NVS keep Masivet in at around £70 for 30x 150mg tablets (1 per 12kg daily) so not cheap, plus regular bloods are required. For the dog I'm treating Palladia was more expensive although that may depend on body weight as they come in different tablet sizes.

Re: MCT chemo

Andrew Kent — Wed, 15 Feb 2012 17:36:54 GMT

The traditional chemo approach would be vinblastine and prednisolone - reasonably cost effective but obviously haematologies can run up cost. Alternative would be a TKI, masivet has recently come down a lot in cost and should be considered. Lotus time would be a third choice as well though doesn't really have any cost benefit over vinblastine/pred. Andy

Re: MCT chemo

Laurence Webb — Wed, 15 Feb 2012 17:02:05 GMT

Why isn't Masivet/Palladia a preferred option, apart from cost? Just interested as I've been investigating tyrosine kinase inhibitors instead of conventional chemo such as lomustine for a high grade MCT that was completely removed but has metastatic spread.

May be worth chatting to Tom Cave at Cave Specialists - he was helpful in advising me on my case.

Re: MCT chemo

An On MRCVS — Wed, 15 Feb 2012 15:43:15 GMT

Fairly sure the oncologist posts on here and didn't want to cause offence (!)

Re: MCT chemo

Michael Woodhouse — Wed, 15 Feb 2012 13:57:14 GMT

Why annon?