Mast Cell tumour - masivet?

RE: Mast Cell tumour - masivet?

Gerry Polton — Mon, 19 Oct 2015 14:58:23 GMT

No I don't. But many people do it. I don't find it changes my perception of the gravity of the tumour but I have the benefit of a) a lot of experience and b) extraordinary arrogance and over-confidence

Gerry

RE: Mast Cell tumour - masivet?

Rebecca MacMillan — Mon, 19 Oct 2015 14:56:25 GMT

Gerry, do you recommend Ki67 testing as well as normal histopath to grade these tumours?

RE: Mast Cell tumour - masivet?

Gerry Polton — Mon, 19 Oct 2015 08:13:53 GMT

Good morning

It is hard to clarify my position on the role of diet as I am not entirely clear what that role is. However, I have seen a small number of cases which have a medical history that smacks of immunological disturbance (chronic intermittent GI signs/food intolerance, adverse reaction to vaccinations/wormers, atopy) which also have multiple mast cell tumours. These tumours will wax and wane in size but are typically defined histologically as Patnaik intermediate grade. In some of these cases I appear to have achieved stabilisation of the disease process by exploring an exclusion diet principle in the same way as we would if we suspected pruritic skin disease due to food sensitivity.

I do not think that the diet treats the neoplastic mast cells.

Gerry

RE: Mast Cell tumour - masivet?

Aine Seavers — Sat, 17 Oct 2015 05:39:59 GMT

The whole issue of mast cell disorder is very confusing and of conflicting advise- on one hand one reads that the 3cm rule is not the holy grail it once was and the that cells on the edge are actually lower grade than the center and may be more responsive to medical therapy if not 3cm clear margins.

That reappearance is not re-occurrence per se but may be a de novo appearance.

Not to judge on nodes or WHO grades

Kevin Hahn's lecture classifies mast cell as a hamepoeitic stem cell immunological condition/disease presenting as skin lesions-
body wide immune system disruption/dysregulation that encourages those cells to be activated and clump together and cause this disorder.
My question is if If mast cell tumours are an immunoproliferative disorder then should we be looking at the immunoregulation more? Have you in the past suggested low allergen diets as part of the regime?

Preds alone overlooked as an option?

Should we not be surprised that many mast cell patients were atopic/allergic pre mast cell disorder appearing?

I have had either as my own patients or those of fellow vets with histology read as high mitotic index and or/often inoperable mast cells re the 3cm margin survive many years on low allergen esp z/d diets and preds/ranitidine either with or without removal of the mass- esp and despite it being in black labradors in caudal third so worse breed, worst site yet survival way beyond 77 day survival quoted- several years.

No doubt I will get shot down in flames by some for raising these heresies but when owner cant afford expensive meds or surgery or will agree to amputation we need to be discussing options that prolong quality and quantity of life.

I would very much appreciate your opinion on the diet as I thought I may have read of your success with some cases also with diet but I could be confusing specialists on this topic.

many thanks

Aine

RE: Mast Cell tumour - masivet?

Martin Atkinson — Fri, 16 Oct 2015 17:02:56 GMT

[quote user="KathW"]Are we always going for control in these cases rather than a cure?[/quote]Cure is a pie in the sky even in humans. I don't think Gerry would suggest TKI's are going to 'cure' anything. We are always looking for control and the best we achieve is long term remission even after total surgical excision with no evidence of metastasis.

RE: Mast Cell tumour - masivet?

KathW — Fri, 16 Oct 2015 16:48:35 GMT

" So in cases which in my hands meet the description you have given, these patients would be most likely to receive the combination of vinblastine and prednisolone in an effort to balance cost, risk and probability of a durable response. "

Is there any reason that you would use this combination rather than masivet in a case like this? Are we always going for control in these cases rather than a cure?

RE: Mast Cell tumour - masivet?

Gerry Polton — Fri, 16 Oct 2015 08:12:34 GMT

It's still an amazing drug but you have to use it in the right cases. Those are generally fast-growing very bad looking tumours. From my position, there appears to be a huge appetite to use Masivet and Palladia among practitioners, and that ought not be surprising because when these drugs work well they are amazing, but if used indiscriminately (not suggesting anyone would) one would find a high proportion of all mast cell tumours that are non- or minimally-responsive. Without looking back over cases that have been discussed on this forum, I have a feeling that the general tone of a query is often: moderately large tumour, owner cannot afford referral, therefore should I use Masivet. Cost was certainly an issue cited in the case we are discussing. As indicated, continued therapy is likely to be much more expensive than curative surgery. I know I am stating the obvious here but, the drugs should be used in cases which are best treated by these drugs, not in cases which would be best managed by a different means.

Perhaps the cases which are obvious candidates are given treatment without it being brought to this sort of forum. By contrast, when colleagues find the decision-making more tricky, often due to non-medical factors such as cost, willingness to travel, etc, the question is then asked.

Who knows...?

Gerry

RE: Mast Cell tumour - masivet?

Martin Atkinson — Thu, 15 Oct 2015 18:26:49 GMT

[quote user="Gerry Polton"]So in cases which in my hands meet the description you have given, these patients would be most likely to receive the combination of vinblastine and prednisolone in an effort to balance cost, risk and probability of a durable response. [/quote]Gerry, I was at the lecture you gave back in erm...well quite a long time ago*, when you had just finished trialling Masivet in the UK and it then seemed like the holy grail of treatment for MCT's. Your enthusiasm seems to have waned rather considerably since those heady days and you are rarely recommending it. Is that a true perception or have we just come across a lot of unsuitable cases on here recently?

*PS I've just dug out the notes and it was June 2010.

RE: Mast Cell tumour - masivet?

Gerry Polton — Thu, 15 Oct 2015 16:59:49 GMT

Regarding the pre-shrinking tumours question, I have pasted a response to a similar question on VetSurgeon.org from a couple of years ago:

"To get to the best bit though, what about treatment to pre-shrink the tumour? In my opinion, and this counts for mast cell tumours as well as other tumours, pre-treatment of a tumour is unlikely to result in a centripetal reduction in tumour diameter. There is no reason to believe that cancer cells at the furthest periphery of a tumour field would be particularly sensitive to the effects of your medical therapy or that if they were, they would curl up and retract into the body of the tumour thus enabling successful excision of a mass with a more conservative margin than would have been possible previously. Even if the tumour looks flatter or less angry following pre-operative medical therapy, this does not mean that the tumour no longer reaches as far into the surrounding tissues as it did before. My analogy for this is known as Gerry's Spider-Splat analogy. Like tumours, spiders can be scary. For people who don't regard spiders to be friends, they look a whole lot less scary when they have been flattened with a slipper or similar device before being slid onto a piece of card, covered with a suitably wide glass and taken outside. However, considering the width of the glass for the ultimate removal of that spider, even when flattened, the legs still extend just as far from the centre as they always did and therefore the glass should not be smaller. Use of a smaller glass inevitably leads to the tips of the legs projecting beyond the lip of the glass. When the spider has been splatted it is less threatening so we tend to proceed more happily even when the glass is not sufficiently large to completely cover it on the piece of paper or card... Reverting to the cancer management story, it is this proceeding more happily that gets us into trouble.

I hope that helps and maybe even amuses a little"

Obviously pre-treating did work to some extent with your previous case. I think it is important that everybody knows what they are actually achieiving though when they do this.

Regarding the pre-operative anti-histamines question, I use chlorphenamine prior to surgery and we tend to give NSAIDs after surgery just in case there is a disaster (never happened yet) which we think would be best managed with corticosteroids.

Gerry

RE: Mast Cell tumour - masivet?

Rebecca MacMillan — Thu, 15 Oct 2015 16:07:19 GMT

Thanks Gerry

Would you advise a course of antihistamines or an injectable antihistamine at the time of surgery for this sort of biopsy? Or would that have an effect on the results?

I don't think I was suggesting that medical therapy is in any way cheaper than surgery. More that if we were to do an incisional biopsy, then shrink the mass with masivet (or equiv) then a second later GA and remove the mass, that this would be more expensive than just treating with masivet and then removal of shrunken mass. I guess with the other example (the uninsured SBT), this is what we opted for, all the while telling him the masivet may not work, and we hadn't graded the tumour yet. It seemed to work out well for the staffie, so I guess I was wondering whether 'cutting corners' was all that bad or not.

I guess I need to present the options to the Labrador owner and will definitely suggest they do further work up first, then consider shrinking the mass so that we can try to remove it. Would you choose vinblastine and pred over masivet generally for this?

RE: Mast Cell tumour - masivet?

Gerry Polton — Thu, 15 Oct 2015 13:06:08 GMT

Not a lot to add. Surgery is definitely the treatment of choice when it is appropriate. The trick is knowing when it's appropriate. Hard to judge in these sorts of fora but I suspect from the description given that this would ultimately prove to be a high-grade intermediate-grade tumour (apologies if that doesn't make sense - I mean a bad intermediate rather than just making a vague reference to everything except the very low-grade ones). On that basis there is a definite risk of metastasis. If metastasis can be demonstrated then it is right to question whether surgery is appropriate (it's usually not). So step 1 has to be to get appropriate imaging performed and aspiration of regional lymph nodes if that is feasible. If the owner cannot afford clinical stage evaluations and surgery (and possibly medical therapy too after surgery), which, let's be honest, would all work out to be pretty expensive, then it is absolutely appropriate to propose medical therapy alone at this stage. That way you have not inflicted the morbidity associated with surgery which could prove, with the hindsight we don't yet have, to be really bad. I feel I should express the truth that I raise an eyebrow when presented with the suggestion that surgery might be too costly so therefore Masivet/Palladia might be appropriate. Medical therapy consistently works out more expensive than surgery, assuming that both were well-chosen and go on to work well. So in cases which in my hands meet the description you have given, these patients would be most likely to receive the combination of vinblastine and prednisolone in an effort to balance cost, risk and probability of a durable response.

Gerry

RE: Mast Cell tumour - masivet?

Anthony Dennison — Thu, 15 Oct 2015 11:58:13 GMT

I think you've answered your own question there - if cost isn't an issue, it's always worth doing survey imaging. I postedo n here about a MCT case recently where the primary mass disappeared, then the dog represented 3 days later collapsed with mets in the liver and spleen. I learnt a big lesson!