James K. Rone, MD, FACP, FACE

Unilateral vs. Bilateral Surgery for Primary Hyperparathyroidism

August 26, 2012

Tags: Hyperparathyroidism

THIS ONE IS MORE FOR PHYSICIANS--IT IS MY COMMENTARY, AS REQUESTED BY A SURGEON COLLEAGUE, ON A SERIES OF LETTERS TO THE EDITOR IN THE JOURNAL OF THE AMERICAN COLLEGE OF SURGEONS ON THE BEST SURGERY FOR HYPERPARATHYROIDISM, THE MOST COMMON CAUSE OF HIGH CALCIUM LEVELS:

(1) Unilateral surgery misses 75% of incidental thyroid cancers
--IRRELEVANT
--PT surgery is not done to find thyroid cancer
--Not clear that finding occult PTC improves survival
--Many clinically significant thyroid cancers will be evident on exam or u/s and such findings should dictate a more extensive exploration
--Routine preop thyroid u/s with FNA as needed should identify most patients needing a bilateral operation for thyroid-related indications
(2) Unilateral surgery necessitates life-long f/u for recurrence
--INSIGNIFICANT
--Life-long f/u need consist of no more than an annual exam with an internist that includes a serum Ca++ level
(3) ioPTH is unreliable
--INTRIGUING (but not crippling, unless one is seeking 100% perfection, which is rarely achievable in medicine)
--PT adenomas are not autonomous, they retain negative feedback but simply have a higher set point for Ca++; that is, it takes a higher than normal Ca++ to suppress PTH release
--I can therefore easily imagine a “dominant” adenoma suppressing a smaller adenoma, leading to a “normal” post-resection ioPTH, which then rises in the future, manifesting as a recurrence or persistence of the pHPT
--Recurrent or persistent pHPT has always been to my thinking a possible outcome of a 1st surgery—not ideal, but if sufficiently infrequent, acceptable
--Thus I wouldn’t reject unilateral surgery solely on the basis of a low-level failure rate
--I don’t know the quantitative criteria you use to make intraoperative decisions based on ioPTH, but on the basis of the Tampa group’s findings, I might suggest that some very substantial drop be required (say, <75%) to head off extension of a planned unilateral surgery into a 4-gland exploration
--And if such a protocol led to an intraoperative shift from unilateral to bilateral procedures in an excessive # of cases, then I would interpret that as a reason to just do 4-gland explorations routinely
--The Tampa group cites some 2nd adenomas being missed even when postop PTHs dropped <90% compared to preop baseline
--20 patients, they state, out of their 18,000; that sounds like a low-level acceptable failure rate that would be picked up on follow up
(4) 1/3 of Tampa’s new patients had been denied operations because the tumor couldn’t be localized preoperatively
(5) Surgeons observe and rescan every 6-12 months, even in symptomatic pts
(6) Surgeons usually perform at least 2 localizing studies, and may decline to operate without 2 studies in concordance
--I consider the last 3 bullet points SHOCKING, DISTURBING, and representative of MISMANAGEMNT of pHPT
--pHPT is a biochemical diagnosis and the decision to operate is based on clinical and biochemical criteria
--imaging does not enter into that decision
--Positive imaging helps the surgeon but a negative scan DOES NOT alter the decision to do surgery
--The only time I would do more than one study would be prior to a reoperation after an initial failure
--Multiple preop studies would seem to me to be a disturbing waste of healthcare dollars
(7) The third letter states that unilateral surgery should not be abandoned, but that the striving for a unilateral operation may have gotten out of hand, especially considering time and cost factors
--AGREE
(8) Final thoughts:
--The decision to operate is a medical one
--After that, the selection of procedure—unilateral vs. bilateral—is a surgical one, which should not inordinately delay getting the pt to the OR
--Certainly putting off appropriate surgery simply in order to be able to do a unilateral procedure is wrong
--Also, unilateral surgery and associated imaging must not be used as a crutch to promote the performance of parathyroidectomies by less experienced surgeons
--I don’t know your protocol in this regard, but I would propose that one sestamibi scan be done preop and if positive, go unilateral, and if negative go bilateral
--Failure to drop the ioPTH to at or below (??) the lower limit of normal should lead to consideration of extending the surgery to bilateral
--To do multiple preop imagining studies is not cost effective
--Medical f/u to detect occasional recurrent or persistent disease is not onerous
--Having said that, I admit, I generally tell people they don’t need to see me again once they have their surgery—perhaps I need to rethink that in the case of unilateral procedures
--Lastly, as with anything there are pros and cons to be weighed in deciding between unilateral and bilateral operations—seems to me the unilateral procedure might fall short with respect to outcomes, cost, and OR efficiency. Are there enough pro’s to offset those con’s?

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