September 21, 2012 (Quebec City, Quebec) — Some papillary thyroid cancer (PTC) patients with limited, even regional, disease can expect excellent outcomes after complete tumor resection without radioactive iodine (RAI), new research shows.
Iain Nixon, MD, from the Memorial Sloan-Kettering Cancer Center in New York City, and colleagues found that at a median follow-up of 63 months, select patients with early primary disease (pT1/T2) and low-volume metastatic disease in the neck (PT1/T2 N1) managed without RAI had excellent outcomes.
Even in patients with advanced local disease (pT3/T4), some with pT3 N0 disease were safely managed without RAI, as were some with more aggressive local disease in the absence of nodal metastasis, the researchers note.
Dr. Nixon presented findings here at the American Thyroid Association (ATA) 82nd Annual Meeting.
Balancing Risks and Benefits
"It's been shown that RAI has a role in reducing recurrence and improving survival in thyroid cancer, but it's not clear which patients will benefit the most and, since there are side effects with RAI, balancing those risks and benefits is difficult," Dr. Nixon told Medscape Medical News.
"Our findings suggest that most patients with pT1/pT2 disease limited to the thyroid can be managed without RAI and that even selected patients with low-risk local disease and limited nodal disease have good outcomes following management without RAI. In an era of individualized medicine, we all need to understand the risks, the benefits, and the alternatives when deciding on the management of this disease," he said.
As Dr. Nixon pointed out, the ATA guidelines on the management of well-differentiated thyroid cancer recommend the routine use of RAI in T3 or greater primary tumors and selective use in patients with intrathyroidal disease smaller than 1 cm.
RAI is also recommended in patients with evidence of nodal metastases.
In this study, Dr. Nixon and colleagues set out to analyze their experience with the selective use of RAI in PTC patients, placing particular focus on patients who did not receive it.
They conducted a retrospective review of 1129 PTC patients who were considered to be free of distant disease after having undergone total extra capsular thyroidectomy. The median age of the patients was 46, 39% had T3/T4 disease, and more than 40% had nodal disease.
"These patients did well," Dr. Nixon observed. "Disease-specific mortality was only 1% and our recurrence rate at 5 years was 8%," he said.
RAI Not Without Adverse Effects
One of the subgroup analyses the researchers performed was on the 490 patients who had disease limited to the thyroid. Of these, 36% received RAI and 64% did not.
"None of these patients died during follow-up," Dr. Nixon noted. "When we look at results stratified by RIA, there was no statistical significance in outcomes — with a 5-year regional recurrence rate of only 2% and a distant recurrence rate of 1% in patients selected not to have RAI," he said.
Another 193 patients had limited local disease with evidence of nodal metastasis. Of these, 74% received RAI and 26% did not.
Again, there were no deaths during follow-up. In those who did not receive RAI, none of the patients had a recurrence in the neck and no patient had distal recurrence after 5 years of follow-up, "so again, they had excellent outcomes," Dr. Nixon reported.
The majority of the 444 patients with more aggressive local disease (T3/T4) received RAI. Of the 16% that did not, there were no deaths at 5 years, the regional recurrence rate was 2%, and the distant recurrence rate was 7%.
Dr. Nixon noted that RAI is not without adverse effects, including salivary and lacrimal dysfunction and an increased rate of dysphagia, all of which have been shown to decrease in quality of life.
"There is also an association with an increased risk of secondary malignancy," Dr. Nixon added.
Tendency to Overtreat
Older men with larger tumors and patients with evidence of extra thyroid extension or nodal or distant metastasis are more likely to require RAI, according to international guidelines.
However, it is not clear whether these guidelines are being followed, said Dr. Nixon.
"I think as a community, we've tended to overtreat patients to reduce the chance of recurrence and death, but, as we recognize the side effects [of RAI] more, selecting patients who will benefit the most has become more important," he explained.
Steven Sherman, MD, from the University of Texas M.D. Anderson Cancer Center in Houston, "applauded" the effort of the researchers to counsel physicians about their overuse of RAI. However, he believes that the orientation of the presentation was not really about the efficacy of RAI but about the efficacy of expert initial surgery.
"The surgical approach that the group is describing here is one that is less likely to be safe in the hands of surgeons who do a lot less surgery — and a lot less expert surgery — than this group might do," Dr. Sherman said.
Any discussion "about what the risk of RAI might be in an aggressively treated surgical population also has to consider what the relative toxicity of aggressive surgical intervention might be outside of tertiary referral centers that would replace the use of RAI."
Dr. Nixon has disclosed no relevant financial relationships.
American Thyroid Association (ATA) 82nd Annual Meeting: Oral abstract 4. Presented September 20, 2012.
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Cite this: Surgery Offers Excellent Outcomes in Select PTC Cases - Medscape - Sep 21, 2012.