Hi, Ahmed,

your question suggests that after resection there would be no recurrence. Is that really true? You would have to resect with quite a good distance to the borderline of the KOT. This would mean a tremendous loss of tissues, teeth, bone as well as soft tissues, depending on the localisation probably resulting in compromised facial aesthetics, need for reconstruction of the jaws (which method?), also in a loss of innervation of all these tissues, permanent numbness, whatsoever.

We prefer a marsupialisation, waiting for a reduction of the size of the KOT and then do a second surgery to remove the KOT, or even leave it.. We regularly see this reduction, we regularly see a complete fill of the radiolucent area with something which radiographically has the same appearance like bone (to be most careful in diagnosing from a radiograph) and we then and when see a radiolucency again after several years, which we interprete as recurrence. When diagnosed early (strict control protocol) this recurrence is quite small and can be either resected, or another marsupialisation can be done...

From my personal perspective, even if this approach would mean a recurrence every two years (which is not the case) I would prefer this minor surgery in local anaesthesia, and not the removal of a good portion of my jaws, teeth, nerves, and so on...

see also the discussion here:

https://www.researchgate.net/post/Is_marsupialization_still_the_treatment_of_choice_for_large_unicystic_lesions_of_the_jaws

Dear Yango, I totally agree with you. You have well explained my point of view. I don't need to explain more now, I have do decompression for large unicystic keratocystic Odontogenic tumours and I have good results. But how marsupialisation can work in multicytic lesion, have you already do enucleation for multicystic lesion?

Keratocystic Odontogenic Tumors (as they are now renamed) do not have very good results with marsupialization.

How did you measure 'good results' or 'success' ? Most commonly the recurrence of KCOTs are identified within 3-5 years but can occur at a later time too! So, do you have a series of cases with such a long term follow up to substantiate your claim that it is successful ?

I believe, a cautionary approach is advised and there is more discussion in the link presented above where I have added a few more issues related to treatment of benign cystic lesions of the jaws which could be one of a wide variety of pathologies.

Marsupialization in case of multicystic lesions should involve converting a multicystic lesion into a unicystic one. But enucleation with peripheral ostectomy combined with use of chemical cauterization (Carnoy's solution) or Liquid NItrogen cryotherapy can be advocated. But, both of these agents/methods have associated risks which must be taken into account -

A recent article on complications of Carnoy's solution is available in literature.

http://www.ncbi.nlm.nih.gov/pubmed/22360145

And for cryotherapy, there is a critical period initially during which the bone is more susceptible to fracture and it is of highest occurence at around 8 weeks post cryotherapy.

Only long term controlled study with well defined parameters can help us have more information in this regard.

Regards,

Akilesh. R

Dear Ramasamy, thank you for your response. When I say a good response to decompression in the case of large KOT, I talk about the reduction of the size of the lesion appreciated on radiography, for me decopression is not a definitive treatment, the goal of this approache is the reduction of the size to protect teeth, nerve... I agree with you that the reccurence can be observed a long time after surgery.

The probleme of the treatment of KOT is lack of well conducted study with hight level of evidence based. A systematic review was carried out (I think by Maurette et coll.) revealed that cryotherapy was associated with a hight risk of reccurence compared with enucleation along.

Best regard

Ahmed Chkoura

Dear Akilesh,

I totally agree with you that we need much more and better studies with much longer observation periods. And that we should be careful with expressions like "good results" etc. unless there are enough facts and data. But this is also true for "not good" - irrespective if that is a "rhetoric" reply or an answer which is meant to transport your opinion or conviction. I guess: it is both.

That of course forces the scientist in me to ask: could you please tell us what is your opinion/your protocol? Do you do marsupialisation, succeeded by enucleation, or enuclation alone (I can't guess it from your posts for sure)?

And - most important, as you request correctly - upon which "series of cases with such a long term follow up" it is based?

See, Ahmed and me, we wrote how we are doing in our departments, sharing our personal experiences (as I mentioned: we are just about to finish a long-term study).

You even "advocate" enucleation (maybe preceeded my marsupialisation?) - despite there are / may be some serious complications associated with this therapy (which you name, I appreciate that).

Judging something as *good* result does not mean that this treatment is the *best*. This leaves enough room for other approaches, which might give *very good* results. Of course it would be necessary to define what is "(very) good".

Advocating means, you must not only know which treatment is *good*, you must know all alternatives, and their value, if they are *not good* (like marsupialisation in your opinion, as I assume), or *very good* (like enucleation+Carnoy). In conclusion you must undoubtedly know which treatment is *best*. Such knowledge can only be based on comparative studies - at least. Or, better, on meta-analyses.

Can you please help us with these "long term controlled" studies "with well defined parameters"? Which are your criteria for "not good"? Is it just rate of recurrence? If yes: What does a somewhat higher rate of recurrence mean? Total desaster, complete failure? Or do you include also the costs and the risks and complications? Like local anesthesia versus general anesthesia (much higher risk for serious complications/death)? Like the aesthetic and functional problems of primary enucleation, resulting in the partial loss and reconstruction of the jaws, and the loss of numerous teeth? And some more aspects, see my first post in this discussion.

If you can't provide such studies: please consider to not blame other colleagues for something that you can't fulfil yourself, while you are the one who is to be criticized first since it is you who has the most ulterior opinion (recommendation vs information).

Hope you understand. Unfortunately my English is acceptable for scientifc content, but very bad for human interaction. So, sorry if the text sounds too harsh...

Nevertheless, I strongly support your strict demand for studies.

Kind regards

Yango

I do not find your English harsh at all. It is well written ... Sorry, if I was not very clear in my earlier posts.

Quoting from my earlier post (towards the end of the post where we usually start summarizing): -

" .................. But enucleation with peripheral ostectomy combined with use of chemical cauterization (Carnoy's solution) or Liquid NItrogen cryotherapy can be advocated. But, both of these agents/methods have associated risks which must be taken into account - ..."

.......

I just assumed I was clear when I wrote that .... but I guess, I was not!

So, I am just going to restate myself clearly and more precisely :-

We follow enucleation + peripheral ostectomy + chemical cauterization (if possible .... we do not use it in cases of maxillary lesions or in cases with very thin residual bone on the lingual aspect .. )

I also wish to clarify few other misinterpretation of my earlier posts :-

1.To clarify, it is NOT enucleation that has serious complications... it was the use of carnoy's solution or Liquid nitrogen for cryotherapy that has certain complications.

2. Enucleation is never used alone by us.

3. We do not use marsupialization for KCOT at all - not as a first stage procedure before enucleation or as an isolated treatment modality ... We enucleate at the first opportunity with adjunctive procedures like peripheral ostectomy + chemical cauterization to minimize the chances of residual linings / cells.

4. In cases of recurrences, we resect with continuity defect ....

.....................

Regarding literature ... I know there are lots for literature which support conservative treatment modalities but I just wish to take a cautionary stand in interpretation of those studies - Pogrel's partial retraction being a glaring example in this regard (read more below!)

1. Int J Oral Maxillofac Surg. 2001 Feb;30(1):14-25. Long-term follow-up on keratocysts treated according to a defined protocol. Stoelinga PJ.

Excellent study with an attempt to define the parameters ... and long term follow up!

2. J Oral Maxillofac Surg. 2007 Feb;65(2):362-3. Decompression and marsupialization as definitive treatment for keratocysts--a partial retraction. Pogrel MA.

Pogrel was one of the very strong advocates of a very conservative treatment modality for Keratocysts. This partially retracts his earlier his publication of 2004 and 2005.

[a-> 2004!(J Oral Maxillofac Surg. 2004 Jun;62(6):651-5; discussion 655-6. )

b -> 2005 J Oral Maxillofac Surg. 2005 Nov;63(11):1667-73. ]

3. Cochrane Database Syst Rev. 2010 Sep 8;(9):CD008464. doi: 10.1002/14651858.CD008464.pub2. Interventions for the treatment of keratocystic odontogenic tumours (KCOT, odontogenic keratocysts (OKC)). Sharif FNj, Oliver R, Sweet C, Sharif MO.

One of the first attempts at summarising the treatment modalities for KCOT. Inconclusive but recommended adjunctive procedures with enucleation for KCOT.

4. Int J Oral Maxillofac Surg. 2012 Jun;41(6):756-67. doi: 10.1016/j.ijom.2012.02.008. Epub 2012 Mar 23. A systematic review of the recurrence rate for keratocystic odontogenic tumour in relation to treatment modalities. Kaczmarzyk T, Mojsa I, Stypulkowska J.

Systematic review that dealt with the treatment modalities in relation to KCOT and its implications on recurrence ... one of the very few available on this subject.

5. Oral Surg Oral Med Oral Pathol Oral Radiol. 2012 Jul 6. [Epub ahead of print]

Management and recurrence of keratocystic odontogenic tumor: a systematic review. Johnson NR, Batstone MD, Savage NW.

Another systematic review ....

Regards,

Akilesh. R

Dear Ramasamy,

Why you don't do decompression in case of large KCOT, if this first stage procedure will allow us to enucleate the lesion with less agressive approache. I give you an example when decopression -enucleation can be indicated : when KCOT are associated with Gorlin-Goldz syndrom, in this case lesions are multiple and with considerable size, resection or enucleation with carnoy solution can present a great risk for teeth, nerve, sinus.... In this case decompression allow us to have a reduction of the size of KCOT and then we can do enucleation with carnoy solution or other complementary techniques.

Best regards.

Dear Akilesh,

thank you very much for the articles.

According to our experiences (study in progress): We got a clear reduction of the size of the lesion. There was no resection of the jaws, there was no reconstruction necessary. There was not any irritation of the nerve.

We merely lost a single tooth. there was no need to change prosthetics. All treatments were done in local anesthesia.

You seem to set the rate of recurrence as the most important parameter - or as the single one.

You did not say why. However, that would be of highest interest, because this could explain your attitude.

From the latest review (Johnson et all 2012)

>>>

1 Simple enucleation of the KCOT is not endorsed because of the high recurrence rate.

2 A small KCOT where the margins can be accessed may be enucleated with adjunctive measures, such as Carnoy's solution.

3 A large, expanding KCOT is *best treated with a 2-stage approach*. Marsupialization first, followed by enucleation and adjunctive measures to decrease the surgical injury to the patient. If patient compliance with irrigating the cyst orifice is doubtful, then enucleation with the use of adjunctive measures as the primary operation is proposed.

4 Marginal or segmental resection offers the lowest recurrence rate. It is not advocated as a primary treatment modality for most tumors because of its morbidity and the benign nature of the disease. It may be considered in certain clinical scenarios, such as multiple tumor recurrence.

"Why you don't do decompression in case of large KCOT, if this first stage procedure will allow us to enucleate the lesion with less agressive approache....."

In the other discussion on unicystlc lesions and marsupialization, I posted a reply after yours. My stand on marsupialization is there.

https://www.researchgate.net/post/Is_marsupialization_still_the_treatment_of_choice_for_large_unicystic_lesions_of_the_jaws

To just summarise:-

1. Marsupialization needs a 2nd stage enucleation definitely else its a problem.

2. Full tissue is not avaiable for histopathologist opinion in the first stage.

3. The lesion changes characteristics after first stage .... and the 2nd stage sample might give a very different picture - may be!

I am not one minded about the 'recurrence' issue. If so, I would have said "resection is to be done": ... I did NOT say so. Why ? Because, recurrence alone is not my concern and I am also valuating other patient related and surgeon related aspects as well as the pathology related concepts.

I am just more comfortable doing enucleation even in the first stage. You can do marsupialization followed by enucleation + adjunctive procedures to just ensure that the peripheral cells/extensions of lesions are removed ...

But marsupialization alone or enucleation alone is not a procedure of choice is what literature seems to suggest at present.

The problem with GG syndrome is not just about this lesion. They mostly present with multiple lesions... but we must also remember that if a patient with features suggestive of GG syndrome and if he has single lesion that doesnt rule out the syndrome. In GG multiple presentation refers to many lesions but not necessarily at the same point of time. He may get another lesion in another region of jaw later. So the patient should have life long follow up apart from appropriate medical consultations for other issues.

The management here must be tailored to the lesions and presentation. But luckily they come in a bit early in their age (usually < 20 years of age) when their regenerating capacity is great. So, enucleation of the lesion still causes a good bone fill in the defect ... And since they have once been diagnosed with GG, we do a meticulous follow up and educate the patient. So next lesion when it occurs will be caught early!

It is the very large presentation at the first instance that can be a problem and for those cases, the procedure msut be tailored to achieve best results with least morbidity and less surgical trauma.

I prefer enucleation even there, but marsupialization followed by enucleation as you suggest is also an option.(but why I dont favour marsupialiation for reasons I mentioned above and when enucleation is also conservative enough ... but gives us complete tissue for analysis and so on!) Anyway it's a personal choice as we are not having particular guidelines in this regard anyway .. except that these procedures should not be used alone!

In reply to the other post:-

It's my personal view, which I would NOT even classify as expert opinion. It's just a view. All clinicians here would agree to the fact that they do not adopt any surgical idea blindly. They analyse and then apply it as they deem fit based on many other characteristics!

I just feel that the question should be asked for each patient as to what would be best for THAT patient when universally acceptable treatment approaches are lacking / proper guidelines are lacking in this regard. I believe adherence to the sound surgical principles and acheiving "removing all of the lesion with little morbidity and least recurrence" should be our goal and how we achieve it is upto us.

Regards,

Akilesh. R

Dear Ramasamy.

1. Marsupialization needs a 2nd stage enucleation definitely else its a problem : yes but with enucleation that is more agreesive with a hight risk of morbidity. Why do not give time to decompression/marsupialisation to reduce the volume of the lesion, in this case the time is not the more important factor.

2. Full tissue is not avaiable for histopathologist opinion in the first stage : I totaly agree with you, but it's rare to have another lesion associated to the keratocyst, otherwise, we do a clinical and radiological follow-up and if the lesion seem to have a bade response to our approche we can do the enucleation, and then we can have the total specimen.

3. The lesion changes characteristics after first stage .... and the 2nd stage sample might give a very different picture - may be! Yes, that's was reported by Forssell et al. But in the positive sense, they reported that the lesions become less agressive, the evolution from the para to the orthokeratinesed form.

It is the very large presentation at the first instance that can be a problem and for those cases, the procedure msut be tailored to achieve best results with least morbidity and less surgical trauma. I have treated two young patient with Gorlin sundrome, one has 4 massive lesions and the other 5 massive lesions, in this situation the enucleation was very agressive, but with decompression + enucleation the surgical morbidity was less important.

Best regard

I think I have misunderstood some concept here ... earlier! I thought there is a definite metaplasia ... but after further reading it appears that after marsupialization there have been changes noted histologically but it is not clear whether it is the 'ingrowth' of the oral epithelium' or 'metaplasia' of the lesion. So the change in lesion is not sure either. The lining is thicker and easier to remove but in that case, may be it's just the ingrowth of the epithelium that causes it to become more thicker!(Please correct me if I am wrong or if there is new evidence that suggests my understanding wrong on this)

Pogrel in his letter to editor where he partially retracted his previous statement on "marsupialization" has mentioned that it is possible that some remnants get left behind and may be the cause of recurrence. They reported a recurrence rate of abut 12% on further follow up. Their initial study consisted of around 10 patients (when they published this in 2004).

So, if there is a risk of some cells being left behind, do you think these cells can get engulfed / embedded in the new bone that is regenerating and decreasing the size of the lesion ?

Can this be a source of recurrence ?

I agree about trying to be conservative with larger lesions. But, lesions which have come closer than 1 cm to the lower border of the lesion have a very high risk of undergoing fracture ... Is marsupialization going to prevent that fracture that might occur during the second stage enucleation ? I am not talking about just convenience, but I am trying to assess the real benefits of a seemingly less invasive procedure only to do a similar procedure again. Is it cost effective ? Is it effective, is all my doubt is. And if there is benefit, is it really fool proof against recurrence ? How much decrease in size do I expect ? Some 20% in about 3 months ? And some say upto 75% in 6-9 months? In that case, it means there is a rapid fill of bone. But if there are going to be cells trapped in that newly formed bone and can potentially cause recurrence, is it worth the risk ? That is my doubt.

I am not recommending mindless and radical resection for all lesions. I am not trying to prove any procedure as inferior, but I am just trying to understand what are the risk:benefit ratio of this procedure. I am interested in hearing about the disadvantages of doing marsupialization from those who perform it for marsupialization for KCOT. They must be experienced in it and what kind of issues they faced would be something I'd be interested in knowing as it can add to my knowledge as well as I do not have much experience with that procedure as applied to KCOT.

We may have to define what is the size of "large" lesion. I am also interested in knowing what may be your criteria for choosing two stage marsupialization + 2nd stage surgery over single stage aggressive enucleation + curettage + adjuvant procedures...

I am aware of the morbidity these lesions cause in Gorlin Goltz Syndromes but it is also hypothesized that the lesions are more aggressive in GG syndromes showing characteristic features of neoplasia.

Now my question is, do we follow the dictum followed for neoplasia that the "original extent or the extended present extent of the lesion" should dictate the surgical limit and not the 'reduced size'. I am aware this is a concept that is used in malignancies, but do you think this dictum should be used even in benign aggressive tumors ? I

I am not against doing marsupialization followed by enucleation. I mentioned it clearly in my earlier posts as well. My only doubt is whether is the risk vs benefit justify it's routine use from surgical point of view? (Le's assume the patient is co operative and will maintain oral hygiene and follow instructions / follow up etc; ... )

I am learning a lot of new things in this discussion and I am thoroughly enjoying the learning experience. I thank all contributors of this discussion for their critical opinions and evidences as it adds to all of our current understanding of the lesion and its management.

Regards,

Dr. Akilesh. R

India

My preference goes to marsupialization and decompression after biopsy which is mandatory so that we can be sure of the diagnosis.. very good results were reported and even from my personal experience.