NASHVILLE, TENN. – Patients with stage I or II differentiated thyroid cancers do not need radioactive iodine treatment if their nonsuppressed thyroglobulin level is less than 2 ng/mL 2 weeks after surgery, according to Dr. Kathleen Hands.
When that’s the case, “I know the patient had an excellent surgery and will have an excellent prognosis with an extremely low likelihood of recurrence over the next 10 years without radioactive iodine. These patients can be managed safely and effectively without radioactive iodine in a community setting,” said Dr. Hands, a thyroidologist who practices in San Antonio.
Dr. Kathleen Hands
It’s common for patients in the United States to receive iodine-131 (I-131) after surgery for low-risk thyroid cancers “despite the abundance of evidence” showing that it does them no good and may cause harm and despite guidelines calling for conservative use of I-131, she said (World. J. Surg. 2002;26:879-85).
“It’s a habit,” a holdover from decades ago “when we didn’t actually have good surgical technique. We need to [heed recent data] and step away from what we did in the 60s, 70s, and 80s and get into the 21st century. We should stop using radioactive iodine in these low-risk patients,” Dr. Hands said at the American Association of Clinical Endocrinologists annual meeting.
Among radioactive iodine’s drawbacks are its expense and sometimes salivary and lacrimal problems associated with its use. Earlier in her career, “I personally had two of my cases” – 19 and 22 years old – “develop acute myelogenous leukemia [shortly] after I-131, one of whom succumbed. I took that very seriously. I’ve become very conservative in the use of this drug. Ablation should be restricted to patients with incomplete surgical excision or poor prognostic factors for recurrence or death,” she said.
This advice is backed up by findings from her review of 378 patients who underwent surgery for differentiated thyroid cancer, with MACIS (metastasis, age, completeness of resection, invasion, and size) scores below 7, meaning low-intermediate-risk disease. Patients ranged from 18 to 79 years old. The majority were women, and about a third had multifocal disease. Tumor sizes ranged from 0.8 mm to 4.0 cm. Twenty-one patients under 45 years old had lymph node metastases of less than 5 mm.
The patients had nonsuppressed thyroglobulin levels below 2 ng/mL 2 weeks after surgery. They opted against I-131, and were started on levothyroxine. There’s been no recurrence of disease in the group after 8 years’ follow-up; thyroglobulin was undetectable in 72% by 2 years. Those in whom thyroglobulin remained detectable had thyroglobulin velocities below 10% over a period of 5 years.
“Nonsuppressed thyroglobulin” means that the patients were not put on thyroxine right after surgery, so that Dr. Hands could get an idea if any tumor was left 2 weeks later. They also weren’t put on low-iodine diets in the interim, she said, because she had no intention of giving them I-131.
To get the most out of the approach, patients need excellent and complete surgeries. That means that endocrinologists should learn to perform preoperative neck ultrasounds – or refer to someone who can – to give surgeons a heads-up about tumor location, size, shape, and invasiveness, as well as lymph node involvement, calcifications, and other issues. “This is the kind of information your surgeon needs” to do a good job, Dr. Hands said.
She said she doesn’t worry about hypothyroidism when patients don’t get thyroxine right after surgery. Manipulation of the thyroid during surgery releases hormone into the system, and “I think that tides them over; It’s a long-acting hormone. Patients tolerate not having replacement immediately [after surgery],” Dr. Hands said.
There was no funding for the project, and Dr. Hands said she had no relevant financial disclosures.