Though it is a fairly non-aggressive form of the disease, papillary thyroid cancer (PTC) occasionally reappears in the lymph nodes of the neck following a thyroidectomy, which is why a team of Korean researchers recently assessed the viability of reoperating for persistent PTC.
The team, which hails from the University of Ulsan's College of Medicine in Seoul, found that following a thyroidectomy and radioactive iodine (I-131) treatment, the first reoperation to remove recurrent PTC achieves a remission rate of 51 percent.
Papillary carcinomas are the most common type of thyroid cancer. They account for at least 70 percent of all thyroid tumors in the U.S., according to the Columbia University Department of Surgery (CUDS).
PTC is also one of the mildest forms of the disease. With treatment, early and even advanced forms of papillary carcinomas have a relatively low rate of reappearance.
The Mayo Clinic estimates that between 15 and 30 percent of people with PTC who are treated with a thyroidectomy and I-131 ablation will experience a recurrence of the disease. It adds that in nearly 90 percent of these cases, the disease reappears locally, usually in the lymph nodes of the neck.
The new study is one of the first to address what to do about this recurrence. Researchers searched through patient records and identified 83 individuals who had been diagnosed with PTC, been given surgery and I-131 treatment to remove the cancer, experienced a recurrence and had a reoperation.
The team then tabulated how many of these patients were given a clean bill of health after the follow-up surgery. They found that more than one-half of all patients had blood levels of stimulated thyroglobulin low enough to indicate full remission.
Thyroglobulin is a protein that the body uses to produce thyroid hormones. The American Cancer Society says that, following a thyroidectomy, any detectable level of thyroglobulin is a reasonable indicator of the presence of thyroid cancer recurrence.
Why? With the gland removed, no thyroid tissue remains to produce the protein, meaning that any remaining thyroglobulin is likely being produced by recurrent thyroid cancer cells.
In the study, the five-year survival rate of participants with thyroglobulin levels under 5 ng/mL was 94 percent, compared to 74 percent with levels any higher than that, the group said.
Overall, just 13 out of 83 participants experienced a second recurrence of PTC. Korean researchers determined that patients who had thyroglobulin levels greater than 5 nanograms per milliliter of blood (ng/mL) were the most likely to experience a second recurrence.
The team concluded that, following thyroid removal and I-131 treatment, a subsequent reoperation to remove cancerous lymph nodes is a reasonably effective way to eliminate PTC.
CUDS estimates that papillary carcinomas account for 10,000 of the approximately 45,000 new cases of thyroid cancer diagnosed each year in the U.S. Fortunately, PTC is the most survivable form of thyroid cancer.
The National Institutes of Health states that more than 95 percent of adults diagnosed with PTC survive for at least a decade.