ARDMS NewsWire August 19, 2011

Thyroid Ultrasound Reporting System Helps Track Cancer Risk

Thyroid nodules can be risk stratified based on the number of suspicious features on ultrasound, allowing for an effective reporting and data system for thyroid imaging, according to researchers from Yonsei University in Seoul, South Korea.

In a study of more than 1,600 patients with thyroid nodules, the team found a significant association of malignancy with thyroid features detected by ultrasound, including solid component, hypoechogenicity, marked hypoechogenicity, microlobulated or irregular margins, microcalcifications, and taller-than-wide shape.

The group also found that the probability and risk of malignancy escalated as the number of suspicious features increased, allowing for these markers to serve as the basis for a thyroid imaging reporting and data system (TIRADS).

"Risk stratification of thyroid malignancy according to the number of suspicious ultrasound features allows for a practical and convenient TIRADS," the researchers wrote.

While widespread use of ultrasound has led to increased detection of thyroid nodules, it can be difficult to decide which nodules need further evaluation, according to senior author Dr. Eun-Kyung Kim, PhD.

"There have been some papers regarding risk evaluation of thyroid nodules based on ultrasound features, but they are complex [systems]” said Kim. "So we wanted to develop a practical approach to categorize thyroid nodules according to [their] malignant risk."

At their institution, 3,674 ultrasound-guided fine-needle aspiration biopsies were performed on 3,674 focal thyroid nodules in 3,414 consecutive patients between May and December 2008. Patients were included in the study if they had the following:

Maximal nodule diameter ≥ 1 cm
Benign or malignant results at cytology
Thyroid surgery after specimens from cytologic examination classified as suspicious for papillary thyroid carcinoma, indeterminate, or inadequate
In all, 1,658 thyroid nodules in 1,638 patients were included in the study (Radiology, 2011).

Patients ranged in age from 11 to 81 years, with a mean age of 50.6. Mean nodule size in the study was 19.9 mm, with a range of 10 to 80 mm. Thyroid ultrasound was performed using an iU22 ultrasound scanner, with a 5-12 MHz linear-array transducer; both compound and conventional imaging were performed in all patients.

One of seven radiologists, including three fellows and four radiologists with five to 13 years of experience, performed the exams and described the nodules according to their internal component, echogenicity, margins, evidence of calcifications, and shape at the time of biopsy. Ultrasound-guided biopsy was performed after ultrasound evaluation of the thyroid gland by the same radiologist, according to the authors.

Of the 1,658 nodules, 1,383 were benign and 275 were malignant. From univariate analysis, the researchers found that the ultrasound features of a solid component, hypoechogenicity, marked hypoechogenicity, microlobulated or irregular margins, microcalcifications, and taller-than-wide shape were significantly associated with malignancy.

Multivariate analysis then showed that the risk of malignancy increased with increasing numbers of suspicious ultrasound features.

"With these findings, we created TIRADS category 3 (no suspicious US features), 4a (one suspicious US feature), 4b (two suspicious US features), 4c (three or four suspicious US features), and 5 (five suspicious US features) using the risk of malignancy from the BI-RADS categorization," the authors wrote.

The low fitted probability of malignancy for thyroid nodules with no suspicious ultrasound may indicate that it is safe to follow up the mass rather than go to biopsy, according to the authors. However, nodules classified as TIRADS 4 or 5 (at least one suspicious ultrasound feature), are candidates for biopsy.

"This new TIRADS can be easily applied in the clinical field because it is not difficult for those who perform US to count the number of suspicious US features," the authors wrote.

Kim noted that the results were from a single institution, so more studies from other facilities will need to be performed to validate the thyroid imaging reporting and data system.

View the article online.

Article written by staff at auntminnie.com, and adapted for the purposes of this newsletter.

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New Screening Protocol Detects Early Pancreatic Cancer

A screening protocol that uses serum levels of CA 19-9 to guide the use of endoscopic ultrasound (EUS) can identify early-stage pancreatic cancer, and is more likely to do so than standard means of detection, according to research published in the July issue of Gastrointestinal Endoscopy.
"By adhering to this protocol, you are significantly more likely to detect early stage 1 pancreatic cancers than if you use normal means - that's the take-home message," lead author Richard Zubarik, MD, chief of endoscopy at Fletcher Allen Health Care, University of Vermont, Burlington said.

But other experts are not so sure.

"The authors rightly conclude that their study demonstrates the feasibility of such an approach, but we need to see validation in larger trials involving more patients," Wen Wee Ma, MD, from the Roswell Park Cancer Institute, Buffalo, New York stated.

Another expert, Randall E. Brand, MD, professor of medicine at the University of Pittsburgh Medical Center in Pennsylvania, agrees that the concept merits more study. "This was not the best-designed study," he said. "To me, the take-home message was more that this is very provocative, very suggestive, but needs a better study to really expand on the results. It's hard for me to take a lot out of this study."

Earlier Detection of Pancreatic Cancer Is Needed

In their study, Dr. Zubarik and colleagues performed a serum CA 19-9 test on 546 patients, aged 50 to 80 years, who had at least 1 first-degree relative with pancreatic adenocarcinoma.

"The sensitivity and specificity of this tumor marker ... are reported to range from 70% to 90% and 70% to 98%, respectively," Dr. Zubarik said. "This blood test has been used in the past to follow people with pancreatic cancer in mass screening, but has never been used in this high-risk population before."

If the CA 19-9 test was above 37 U/mL, the individual went on to have EUS. Any lesions that were detected in the pancreas were biopsied. "The pancreas lies right behind the stomach and the first part of the small intestine. You get a very fine look at it with that test, and with ultrasound guidance, you can biopsy as many lesions as you see," Dr. Zubarik explained. CA 19-9 serum levels were above 37 U/mL in 27 patients (4.9%). EUS was performed in 26 patients (1 patient refused to undergo the procedure). The EUS findings were normal in 14 patients.

Potentially premalignant or malignant findings were detected in 5 patients (0.9%). Of these, 1 patient was diagnosed with stage 1 adenocarcinoma. In addition to the adenocarcinoma, the screening protocol detected 1 neuroendocrine tumor, 1 intraductal papillary mucinous neoplasm, 1 mucinous neoplasm, and 1 pancreatic intraepithelial neoplasia-1. The patient with adenocarcinoma had surgery and is alive and well 3.5 years later, with a CA 19-9 level of 11 and no evidence of disease recurrence. All other patients with neoplasia are also alive and well, Dr. Zubarik noted. The patient diagnosed with stage 1 adenocarcinoma "is the longest survivor of pancreatic adenocarcinoma detected in a published screening protocol," he said. The cost to detect 1 pancreatic neoplastic lesion was $8,430.75. The cost to detect the single adenocarcinoma was $41,123.74.

"I am pleased with the results," Dr. Zubarik said. "The findings are preliminary. It's an exciting idea that I think needs to be further evaluated to see if it's cost effective."

Not Ready for Prime Time

However, Dr. Ma suggested that this screening protocol is problematic in several ways. Only 70% to 80% of pancreatic cancer patients express CA 19-9, so this approach will not pick up the other 30% who have pancreatic cancer but do not express this biomarker, he pointed out. "We need a better, more specific serum biomarker for pancreatic cancer screening than CA 19-9."

In addition, EUS fine-needle aspiration (FNA) is highly complex, operator-dependent, and requires specialized expertise. "The centers that can do good, safe EUS FNA of the pancreas are often confined to tertiary centers, posing a limitation to large-scale screening," he said. Dr. Ma also pointed out that, in the study, the detection rate in this high-risk population for pancreatic adenocarcinoma was 0.2%, with a false-positive rate of 0.9%.

The article also failed to discuss complications from blood draws and EUS FNA procedures. "Risks of bowel perforation, bleeding, need for anesthesia, etc., with EUS FNA need to be taken into account, since these are significant factors," he said. "I would say this approach is not ready for prime time and will need further research."

Dr. Brand added: "I think their approach is the right approach. You have to do something before doing an EUS to make that more cost effective. Although the study is very thought provoking, it is by no means a definitive study."
View the article online.
Article written by staff at medscape.com and adapted for the purposes of this newsletter.

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Ultrasound of Neck Predicts Who Will Have A Stroke

Two noninvasive imaging tests may help determine which people with a narrowing of arteries in the neck will need surgery to reduce their future risk of stroke, a study suggests. A narrowing of the carotid arteries in the neck is known as asymptomatic carotid stenosis (ACS). "Asymptomatic" means the patient does not experience any symptoms. Carotid arteries in the neck deliver blood to the brain. They typically become narrowed when plaques build up in the inner lining of the arteries.

There is some uncertainty within the medical community on how to best identify people with ACS who are at high risk for stroke and need surgery or stenting to open their carotid arteries as opposed to treatment with medication.

In a two-year study of 435 people with severe ACS, researchers used ultrasound to assess the quality and composition of the plaque in the carotid arteries and a Doppler ultrasound test to look for the presence of tiny blood clots or particles called microemboli that may break off from the arteries and travel to the brain, causing stroke. The study is published in Neurology.
Determining Stroke Risk

During the study, 10 people had strokes and 20 people had transient ischemic attacks or mini-strokes.

People with fatty plaque in their carotid artery were more than six times more likely to have a stroke than those people without this type of plaque. Plaques that are rich in fat are considered more dangerous.

People with both fatty plaque and signs of microemboli were more than 10 times more likely to have a stroke than those without these two markers, the study shows.

According to the new study, the risk of future stroke is 8% per year for people who test positive on both screening tests. By contrast, future risk of stroke is lower than 1% per year for those with negative results on both imaging tests. The findings held regardless of other stroke risk factors such as high blood pressure, diabetes, smoking, and vascular disease.

"Most patients will stay asymptomatic [without symptoms] and not suffer a stroke, but it's hard to identify the patients who are at highest risk and should undergo surgery," said study researcher Raffi Topakian, MD, a neurologist at Academic Teaching Hospital Wagner-Jauregg in Linz, Austria. "If you are at high risk for future stroke, medication is not enough for you."

If these findings are reproduced by other researchers, they could change the way ACS is evaluated and treated, he said. As it stands, using ultrasound to look at plaque composition is common. The Doppler ultrasound test, however, is time consuming and the results can vary based on the technician performing the test.

Tatjana Rundek, MD, professor of neurology at the University of Miami Miller School of Medicine in Florida, routinely evaluates ACS patients using these two screening tools.

"These individuals have a disease but don't have symptoms yet, so this field is sort of divided," she said. "We would love to select patients at the highest risk for stroke for surgery."

"It is not enough to know the percent of [narrowing]. We need to know the composition of the plaque and what it looks like and the potential for embolization," she said. Itzhak Kronzon, a cardiologist at Lenox Hill Hospital in New York, says evaluation for patients with ACS starts with taking a thorough medical history including neurological exam. "If you have ACS, the likelihood of a stroke is small, but if you do have a stroke, it is devastating."

The Doppler test is not a standard part of assessing stroke risk in people with ACS, and Kronzon doesn't think it should be widely recommended based on these study results. More study is needed before this becomes common practice, he said.

In an accompanying editorial, Lars Marquardt, MD, the University of Erlangen-Nuremberg in Germany, writes that overall risk of stroke among people with ACS is relatively low and has decreased due to better management through cholesterol and high blood pressure drugs in recent years.

"If techniques like the one presented by [study researcher] Topekian are confirmed to be able to detect patients that have a higher than normal risk of stroke, screening of patients with this technique seems necessary," he said.