SAN FRANCISCO – Patients with hyperparathyroidism due to multiple endocrine neoplasia type 1 (MEN-1) have a 4 in 10 chance of persistent hyperparathyroidism if they undergo surgery that leaves at least one gland in place, according to a retrospective cohort study presented at the annual clinical congress of the American College of Surgeons.
“Limited initial parathyroidectomy in patients with MEN-1–associated primary hyperparathyroidism results in a high failure rate. Additional enlarged contralateral parathyroid glands are frequently missed by preoperative localizing studies,” commented lead investigator Dr. Naris Nilubol, a staff clinician with the endocrine oncology branch of the Center for Cancer Research, National Cancer Institute, Bethesda, Md.
Dr. Naris Nilubol
“We conclude that limited parathyroidectomy in MEN-1 guided by preoperative localizing studies is associated with high failure rates and therefore should not be performed,” he maintained.
In an interview, session comoderator Dr. Marybeth S. Hughes, a staff clinician with the thoracic and gastrointestinal oncology branch, Center for Cancer Research, National Cancer Institute, commented, “In general, I would say that the data presented just reiterates the standard of care, that MEN-1 patients should have bilateral neck exploration with [removal of] three and half glands, or four glands with autotransplantation. So it just basically solidifies what is being done standardly. I don’t think there is a compelling argument to change the standard.”
Dr. Nilubol and colleagues reviewed the charts of 99 patients with MEN-1 who underwent at least one parathyroidectomy at the National Institutes of Health (NIH).
Of the 64 patients who had initial surgery at NIH and had preoperative localizing studies done, 32 had only a single enlarged gland identified by the tests, suggesting they would be good candidates for limited surgery, according to Dr. Nilubol. Bilateral neck dissection at the time of parathyroidectomy showed that in 22 (69%) of these 32 patients, the studies had correctly identified the largest gland; however, in 19 (87%) of those 22, it missed another enlarged gland on the contralateral side. Furthermore, in 5 (16%) of the 32, the largest gland was found on the contralateral side.
With a median follow-up of 23 months, the risk of persistent hyperparathyroidism was 41% for patients who had limited parathyroidectomy (three or fewer glands removed) at initial surgery, significantly and sharply higher than the 6% seen in patients who had subtotal parathyroidectomy or more extensive surgery (at least three and a half glands removed).
Dr. Marybeth S. Hughes
Looking at the cumulative number of glands removed during initial and subsequent surgeries, 57% of patients having two or fewer glands removed and 45% of those having two and a half to three glands removed had persistent hyperparathyroidism – both significantly higher than the 5% of patients having at least three and a half glands removed.
Regarding complications, 10% of the patients who had their initial surgery at NIH developed permanent hypoparathyroidism, reported Dr. Nilubol, who disclosed that he had no relevant conflicts of interest.
Session attendees asked about the use of parathyroid hormone levels intraoperatively to guide surgery and what strategy surgeons follow at his institution in this patient population.
Previous research has suggested that intraoperative parathyroid hormone levels do not add any information that would change the operative plan, Dr. Nilubol replied. “Everybody at NIH has preop localizing studies as part of the clinical investigation, but it doesn’t change the way we approach it. Everybody gets a bilateral neck exploration and three and a half–gland removal,” provided all glands can be found, he said.
Session attendee Dr. Michael J. Campbell, a surgeon at the University California, Davis, commented, “A 10% permanent hypoparathyroidism rate in these patients – and they have a tendency to be young, most of them in their late teens, early 20s – that’s a major complication. So could you take your data and make exactly the opposite argument, that maybe you should be doing less to these patients to limit that fairly life-altering complication?” Permanent hypothyroidism at that age is “a significant medical problem,” Dr. Nilubol agreed. However, “at the NIH, we don’t operate on everybody just because they have primary hyperparathyroidism. They have to fulfill metabolic complications before we choose to operate on them. We want to delay the surgeries and [time] between the surgeries because if they live long enough, it will recur, so we want to operate when we can make the most difference, meaning [addressing] kidney stone, bone loss, etc. The most common reason for young patients is they have kidney stones, which leads to surgery.”