BALTIMORE – In the treatment of primary hyperparathyroidism, clinical guidelines recommend using sestamibi scan for localizing adenoma, but increasingly endocrinologists are using sestamibi results to determine whether or not to refer a patient for parathyroidectomy surgery, while surgeons are using the scans as a factor in deciding whether to perform the operation.
That was the conclusion of a paper Dr. Susana Wu presented at the American Association of Endocrine Surgeons annual meeting. Dr. Wu reported on behalf of her colleagues at Kaiser Permanente Los Angeles Medical Center and at Scripps Clinic in San Diego.
Dr. Susana Wu
“This study suggests that negative sestamibi scan (SS) results influence management of patients with primary hyperparathyroidism,” Dr. Wu said. “Endocrinologists were less likely to refer to surgeons and surgeons were less likely to offer parathyroidectomy to a patient with a negative sestamibi scan.”
The study involved a retrospective chart review of all 539 patients with primary hyperparathyroidism in the Kaiser Permanente Southern California database from December 2011 to December 2013, 452 of whom were seen by 63 endocrinologists at 14 centers. Among these patients, 260 had SS – 120 negative and 140 positive. The study identified statistically significant variations in how both endocrinologists and surgeons managed patients depending on SS results. The researchers used Kaiser Permanente’s electronic referral system to track referrals.
“The most significant negative predictor for endocrinologists referring to surgeons was a negative sestamibi scan, with an odds ratio of 0.36,” Dr. Wu said.
Endocrinologists referred 86% of patients with positive SS to surgeons, but only 68% of those with negative SS. Surgeons exhibited a similar practice pattern. “Surgeons were less likely to recommend parathyroidectomy for patients with a negative sestamibi scan, with an odds ratio of 0.20,” Dr. Wu said. Surgeons operated on 87% of patients with a negative SS scan but 96% with a positive SS.
Dr. Philip Haigh
In an interview, study coauthor Dr. Philip Haigh explained that parathyroidectomy when the SS is negative is a more difficult operation for the surgeon, and that might make some physicians hesitate before going forward with surgery. “It has been previously shown by other studies that it is a more difficult operation when the sestamibi scan is negative because you have to look at four glands instead of removing just one, but if the surgeon is experienced, it should achieve a high success rate,” Dr. Haigh said. He said that parathyroidectomy in sestamibi-negative hyperparathyroidism had a cure rate as high as 98% in the study presented.
He offered two thoughts on how clinicians should use the study results. “To the endocrinologist, if you’re going to order a sestamibi scan, don’t change your referral practice depending on the result,” Dr. Haigh said. “To the surgeon, if you’re not comfortable operating on a patient with a negative sestamibi scan, then find someone who is.”
The study had a few limitations, Dr. Wu said. Along with its retrospective nature, the study also did not account for potential disparity in radiological vs. surgeon interpretation of the scans.
During the discussion, Dr. Samuel Snyder, of Baylor Scott & White Health, Temple, Tex., said he concurred with the results Dr. Wu reported. “It really worries me about what is happening to patients who have negative scans,” he said. “What I’ve seen in patients referred for surgery is a lot of variation in how the sestamibi scan is done.” He asked if the study accounted for the different types of sestamibi scans and how they were performed, but Dr. Wu said it did not.
Dr. Christopher McHenry of MetroHealth Medical Center, Cleveland, also concurred. “I think this is a phenomenon that occurs more often than we think or we’re aware of,” he said. “I continue to be amazed with how clinicians equate a negative sestamibi scan with not having primary hyperparathyroidism. I think it needs to reemphasized that the sestamibi scan is not diagnostic; it’s for localization.”
He asked Dr. Wu, “How do we change behavior to deal with this problem?”
Dr. Wu said her institution is developing a safety-net program that would aim to increase the identification and chart coding of patients with primary hyperparathyroidism, automate essential labs to be ordered in patients with high calcium, and automate referral to endocrinologists. The study and its findings will be disseminated to endocrinologists in the region.
The study authors had no disclosures.