I started this blog a year ago. I am very happy to see that it has been well received by the readers and I hope it will continue to be helpful to people with suspected or diagnosed pheo and to colleagues.
The clinical research on pheo is growing at an amazing speed. Almost every month, interesting reports appear in reputable journals. In this month's Journal of Clinical Endocrinology and Metabolism, a paper written by Dr. Young at Mayo Clinic (he is on Dr. Pheo's pheo doctor list) and associates provide pretty definitive evidence that another old test for pheo diagnosis, adrenal venous sampling (AVS), should not be used any more. It remains a great test for some other adrenal disorders.
AVS had been invented way before the modern tests and imaging methods were used; it probably has seen its best times. Most younger endocrinologists are not even aware of this test, for a good reason, as it is seldom used for diagnosing pheo in the last 20 years. AVS is invasive and requires significant experience to do it right. A radiologist would insert a cannula into each of the main veins in the patient's groin and advance it into the adrenal veins. Catecholamines are then measured in the adrenal veins and in a peripheral vein. If one side shows much higher levels of catecholamines than the other side, it is then concluded that this side may have a pheo, at least so believed by the proponents of this test.
I missed the heydays of AVS. I never ordered it myself because I never felt it was needed in my own practice. I have taken care of patients who had this test done to them. It is invariably ordered by an endocrinologist who completed training many years ago, and the indications are not clear. The situation is usually like this: a patient would have some pheo symptoms and pheo markers are elevated but CT/MRI and MIBG scan do not clearly show any adrenal tumors. Someone would then suggest AVS. In my limited experience, AVS does not help in any tangible ways. On the other hand, it often reinforces a misconception that the patient has a pheo. In spite of my strong belief, it is not easy to convince my colleagues not to use it because there have not been studies to show the fallacy of AVS, until this paper appears.
This paper is not a typical study of diagnostic test. It does not address sensitivity or specificity. Rather, it shows the results of AVS in patients without pheo. The major observations are: 1) catecholamine levels are much higher in the adrenal veins than in peripheral veins (no surprise as they are supposed to be); 2) the catecholamine levels vary tremendously between individuals (300-fold difference); 3) catecholamines in the right adrenal veins tend to be higher than in the left one (can be as high as 83-fold). All the above are considered by some as evidence of pheo but remember all those patients do NOT have pheo. The data from this paper thus cast a large doubt on the value of AVS.
Regardless of what criteria are used for interpreting AVS results, the most important fact on AVS is that it has no clear indications in modern medicine and should not be ordered in the first place for diagnosing pheo. I cannot think of a clinical situation where AVS will aid in the diagnosis or localization of pheo.
I’d like to hear your experience on AVS.
Dr. Pheo
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In response to your questions on March 20 under your previous post, I do not know the answer to my heart function, but will ask at my doctor's appointment this week. I have no vomiting, but do have nausea for at least a week after chemo. I take Emend, Decadron, Zofron, Compazine, Ativan. I also have an Rx for medicinal marijuana, which helps with headache, nausea and sleep. Constipation is also an issue, and I have to use Miralax for the week after chemo, but after that, it's not really a problem.
ReplyDeleteWould you suggest phenoxybenzamine to replace the Linsinopril, or take in addition to? With my heart rate so high, my nurse told me this week that my dr. wants me to start with the phenoxy. Although I am his only pheo patient, he seems to be doing his homework. I get another PET scan in a few weeks.
Phenoxybenzamine is better than lisinopril for you.
ReplyDeleteDr. Pheo
Hi Dr Pheo -- Thank you for creating this blog. I've spent many an hour reading your posts since my Pheo diagnosis last month (I'm scheduled for surgery in mid April). One question for you: I've read conflicting reports regarding whether or not hemorrhage and necrosis in a Pheochromocytoma is common, and/or whether it might suggest a greater chance of malignancy. Thanks in advance!
ReplyDeleteDear Electronic,
ReplyDeleteHemorrhage or necrosis is not uncommon in pheo, especially in larger ones. They alone do not suggest malignant pheo. Indeed, there has been no consensus on how to predict a pheo's malignant potential.
Dr. Pheo
I had AVS done in 2002 at Greater Baltimore Medical Center. Result: hyperaldosteronism
ReplyDeleteRight adrenal removed 1 month later causing massive release of catecholamines which stunned my heart. FAST FORWARD to 2010: left adrenal KAPUT, probable pheo! Testing NOW!
I was positive in 24 hr urine metanephrine test, the ct scan showed prominent apical portion of the left adrenal gland with areas punctate calcifications. my doctor ordered an AVS, do i need to undergo such a procedure? we do not have mibg and plasma metanephrine test here in the philippines, thanks
ReplyDeleteI contacted you April 27, 2010 and sent my picture for a possible Pheo. At that time my
ReplyDeleteMIBG study showed uptake activity in the projection primarily anteriorly. Nothing has shown on MRI's or CT scans. Bio chemical (24 hour urine test) testing has shown on 3/10/2010 normetanephrine at 328 and metanephrine at 167. (nor+met) 495. 24 hour urine on 12/28/2010 normetanephrine was 347, metanephrine was 170. (nor+met) was 517.
Also increased was immunoglobulin m was 340.
As my picture showed back in April, 2010 my face is still burning, hot, red and in constant agony. Also have been tested for carcinoid. All results are normal. I have been to over 30 Dr's with NO diagnoses. I need help and don't know where else to turn. Please, any advise would be appreciated.
Jennie
If these numbers are normal, pheo is very unlikely. This is a frustrating disease. You need to find an interested physician who will look into the disease in great details.
ReplyDeleteHi Dr Pheo -- I posted a question in this thread a while back, (under the name "electronic") asking whether necrosis might be a risk factor for malignancy in Pheochromocytoma. At the time, you said not necessarily, but I've recently read a new article by Dr Pacak that seems to suggest that necrosis is a concern. The article, "Malignant pheochromocytoma: does the size and age matter?" (published in April of 2011 in the European Journal of Clinical Investigation) states that among the benign tumors in the study, 0% had necrosis, while 28% of the study's malignant tumors showed necrosis. As a layman, this suggests to me that (at least according to this study), necrosis would put a Pheo patient at a much greater risk of malignancy, but maybe I'm missing something? In any case, I'd love to know whether your thoughts on this topic have changed. Thanks again for maintaining this great blog!
ReplyDeleteDear Jed,
ReplyDeleteMy thoughts are essentially unchanged. As you see, 72% of malignant pheo do not have necrosis. The prediction of malignancy for pheo has been tried for many years without a good solution. Necrosis is one of the features used to predict malignancy but it should not be used alone. The best thing is to measure metanephrines every year after pheo surgery, whether you have necrosis or not. Chances are that you won't have metastasis or recurrence; but if it does happen, you will catch it early.
Dr. Pheo
Hi Dr Pheo – I’m grateful for your time with my (continued) questions. I realize this isn’t the best forum for issues like mine, but I'm finding it hard to otherwise get straight answers from a doctor who’s seen more than just a handful of Pheos.
ReplyDeleteYou mention in your response that there are a good percentage of malignant Pheos that do not present with necrosis, which is clear from Dr Pacak’s study and others. What I’m struggling with (as someone who had hemorrhage and necrosis on their Pheo) is the fact that necrosis was *not* found on any of the study’s apparently benign Pheos. I’m hoping you might be willing to share your personal experience on this topic: have you seen necrosis in Pheos that didn’t ultimately end up malignant?
Also perplexing: I’d previously understood that necrosis was fairly common in Pheos (one doc told me most Pheos have some intra-tumoral necrosis), yet in this study it was found in only 8 of a total 150 cases. I’d love to hear your thoughts on this topic as well. Does 8 out of 150 cases sound typical to you? If not, is it possible that they’re using the word “necrosis” to describe a very specific type of necrosis? (At least one earlier study drew a distinction between hemorrhagic necrosis and coagulative necrosis. Pacak’s article makes no mention of such a thing, so I can only assume they counted all types of necrosis.)
Thank you again,
Jed
Dear Jed,
ReplyDeleteYou are right. Necrosis means different things depending on who use the term. To pathologists, necrosis has specific definition and is actually not common in pheo. To the radiologists or surgeons, if they see a cystic component, they refer it to necrosis sometimes.
In the study, necrosis was the pathologists's necrosis. In doctor-patient talk, necrosis probably means "degeneration" or "cystic changes".
Dr. Pheo