SAN FRANCISCO — Thyroid nodules are very common after radiation exposure, and even though most are benign, some professional societies recommend periodic screening with ultrasound for individuals at high risk for thyroid cancer.
But a lower tech and less costly screening method appears to work just as well without leading to any overtly missed cancers, according to researchers from the Memorial Sloan Kettering Cancer Center in New New York City.
On the basis of their experience following a high-risk group — survivors who were treated for a childhood or young adult cancer with radiation that included the neck field — they recommend a step-wise approach, which begins with annual screening with manual palpation. Ultrasound is reserved for those with thyroid nodules identified on physical examination.
"No clinically advanced thyroid cancers have been missed using this approach," said lead researcher Dana Barnea, MD, from the Department of Medicine at Memorial Sloan Kettering.
"Screening routinely using ultrasound would likely detect more thyroid cancers," explained Dr Barnea, who presented the findings here at the Cancer Survivorship Symposium Advancing Care and Research. "However, these may be indolent and clinically insignificant cancers."
Ultrasound screening is not harmless, she cautioned, and could result in unnecessary biopsies and surgery, as well as significantly increased costs.
If routine ultrasound had been conducted on the 585 survivors, it would have cost $574,100, Dr Barnea reported. However, in their study, the researchers conducted only 106 thyroid ultrasounds, at an estimated cost of $26,726 (using Medicare cost).
The Children's Oncology Group (COG) recommends annual palpation of the thyroid. These "results support the COG guidelines and suggest that annual palpation of the thyroid is an adequate and safe means of screening this high-risk population," said Dr Barnea.
Thyroid cancer generally has a very good prognosis, with 5-year survival rates of about 98%. Although radiation does increase the risk of developing the disease, most radiation-induced thyroid cancers are papillary carcinomas, which have the most favorable prognosis.
Although the incidence of thyroid disease has tripled in the United States during the past 30 years, mortality rates have remained consistently low. "So is this simply an epidemic of overdiagnosis of thyroid cancer?" Dr Barnea asked.
No Missed Cancers and Cost Effective
In their retrospective study, Dr Barnea and colleagues evaluated the safety and efficacy of the COG recommendations. They reviewed the medical records of all adult survivors treated for a childhood or young adult cancer with radiation that included the neck field who were evaluated in the long-term follow-up program at Memorial Sloan Kettering from 2005 to 2015.
The 585 survivors who met the criteria were included in the analysis. During the study period, they made 2277 annual visits.
The median age at first evaluation was 30.2 years (range, 18.2 - 77.8). At a median of 21 years from radiation (range, 4.5 - 44.4), 40 survivors (6.8%) had a thyroid nodule identified on physical examination.
As part of the step-wise approach, ultrasound was performed on 39 survivors. The 24 individuals (62%) whose findings were deemed suspicious underwent fine-needle aspiration.
In this subgroup, there were seven papillary carcinomas, one of which was locally advanced. None of the patients had distant metastases. At a median of 2.2 years from the diagnosis of thyroid cancer (range, 1.0 to 7.4 years), six patients were reported to be doing well and were free of disease. One patient with a regional recurrence was being followed with active surveillance and was also doing well. No deaths were attributable to thyroid cancer.
The negative predictive value of all annual palpations was 100%; no thyroid cancers were detected in the year after a negative palpation, Dr Barnea reported.
Less Is More
This is a good model to explore because thyroid cancer tends to be very indolent, with extremely high cure rates, said Kevin C. Oeffinger, MD, director of the Cancer Survivorship Center at Memorial Sloan Kettering.
"This is a good example of how we may be diagnosing too many of these cancers, and therefore overtreating them," said Dr Oeffinger, a coauthor of the study who cochaired the session where the data were presented.
These patients will continue to be followed, he told Medscape Medical News, "but I think this is an important message."
What if a clinical examination wasn't done and the patient just presented if they felt a nodule. "Would the outcomes be any different? Maybe not," Dr Oeffinger said. "But most of these patients are being followed in large tertiary care centers like Memorial Sloan Kettering, so this is kind of a call back to our centers to back off a little bit on follow-up."
Merry-Jennifer Markham, MD, associate professor in the division of hematology and oncology at the University of Florida in Gainesville, agrees. "The development of secondary malignancies is one of the worrisome late effects that cancer survivors may be at risk for, depending on the type and amount of cancer treatment received," she told Medscape Medical News.
That said, physicians often rely on costly imaging studies for the detection of these second cancers, but physical examination can also detect them, she pointed out. "This study shows that an annual thyroid examination by a physician was able to detect all cases of thyroid cancer in a population of adult survivors of pediatric or young adult cancers at risk for secondary thyroid cancer."
"Not only does this study reaffirm a COG guideline that recommends annual thyroid palpation in those at risk, it reinforces that a simple physical examination technique has value — in more ways than one," Dr Markham said.
Dr Barnea, Dr Oeffinger, and Dr Markham have disclosed no relevant financial relationships. A few of the coauthors report relationships with industry, as noted in the abstract.
Cancer Survivorship Symposium (CSS) Advancing Care and Research: Abstract 254. Presented January 15, 2016.
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Cite this: Palpation for Thyroid Nodules in Cancer Survivors Saves $$ - Medscape - Jan 21, 2016.
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