Diagnostic Imaging's Weekly Scan: Nov. 13, 2020

November 13, 2020
Whitney J. Palmer

Diagnostic Imaging and Testicular Cancer Risk; Digital Breast Tomosynthesis/Synthetic Mammography Combination for Breast Cancer Screening; Efficacy of Low-Dose CT Lung Cancer Screening; and the Evolving Role of the Radiologic Technologist

Welcome to Diagnostic Imaging’s Weekly Scan. I’m senior editor, Whitney Palmer.

Before we get to our featured interview with Michael Odgren about the evolving role of the radiologic technologist in celebration not only of National Radiologic Technology Week, but also the centennial of the American Society of Radiologic Technologists, here are the top stories of the week.

There’s been a recent push lately to re-think the need for lead shielding during imaging on some patients. But, a study published this week in PLOS ONE showed us that reducing that protective measure might not be the best idea in some cases. It takes as little as three X-rays or CT scans to raise a man’s risk of testicular cancer by nearly 60 percent, according to researchers from Penn Medicine. Yes, testicular cancer is rare, but it is the most common form of cancer in men ages 15 to 45 – and the incidence seems to be growing. In 1975, only three in 100,000 men were diagnosed – it’s six in 100,000 now, and nearly 9,500 men are expected to get the diagnosis by this year’s end. To determine whether radiation exposure from diagnostic imaging is playing a role in that increase, the team conducted an observational study on 1,246 men who either did or did not have testicular cancer. After adjusting for known risk factors, such as cryptorchidism, family history, age, and race, they found that men who had at least three diagnostic scans, including colon X-ray or CT below the waist, saw a 59-percent spike in their testicular cancer risk over those who had never had a diagnostic exposure. The risk was also elevated among men who had exposure prior to age 10. These results, they said, underscore the need to control radiation dose and optimize shielding practices when appropriate.

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Pivoting to breast cancer, we received more evidence this week that radiologists pick up on more cancers when they use digital breast tomosynthesis with synthetic mammography rather than relying on digital mammography alone. In fact, this combo can detect potentially invasive cancers at an earlier stage. In Radiology, a team of researchers from the Veneto Institute of Oncology in Padua, Italy, examined the outcomes of using digital breast tomosynthesis for screening programs. To do this, they enrolled 34,638 women with an average age of 58 years in their study and had 32,870 of them undergo repeat breast screening – half who had digital breast tomosynthesis and synthetic mammography and half to had only digital mammography. In both rounds of screening, they saw that digital breast tomosynthesis detected a higher proportion of early-stage cancers than digital mammography – 322 to 153 on first screening, and 131 to 59 on second screening. And, the cancer detection rate was 8.1 per 1,000 for re-screening with the combined techniques and only 4.5 per 1,000 for mammography. In addition, for the combo, the proportion of tumors that were stage II and above at re-screening was 14.5 percent, and it was 8.5 percent with mammography by itself. Outside investigators validated the importance of these findings, confirming that they did, indeed, highlight that the improved outcomes from digital breast tomosynthesis extend beyond baseline screening.

And, now, on to lung cancer. Low-dose CT screening has been slow to catch on in the United States with some lack of clarity around whether it works in reducing mortality in high-risk patients. Results from a large study out this week in the Annals of Family Medicine confirms that it does. In fact, for every 250 at-risk adults scanned, providers can prevent one death. That’s a statistically and clinically significant drop in lung cancer-specific mortality of 0.4 percent, according to investigators from the University of Georgia. These findings can be critical because the Centers for Disease Control & Prevention found that only 4.5 percent of eligible patients are actually getting lung cancer screening now, and most are still relying on chest X-ray. To reach their conclusion, the providers examined eight studies that included health outcomes from 90,275 patients who have 20-to-30 pack year histories or who gave up smoking within the past 10-to-15 years, comparing those who underwent low-dose CT screening to those who had usual medical care or chest X-ray. Based on their analysis, the team found a significant reduction in the risk of death with low-dose screening compared to the control group, leading to that 0.4-percent absolute risk reduction for lung cancer-specific mortality. They also found the absolute risk for reduction for all-cause mortality was 0.34. Given the fears of over-diagnosis with low-dose CT screening, these results are reassuring, the team said, because they indicate that, even though over-diagnosis cannot be ruled out as an unintended harm of the screening, it does not appear to increase other causes of mortality. Overall, the team said, their findings fall in line with the U.S. Preventive Services Task Force recommendations for implementing CT-based lung cancer screenings in adults between ages 55 and 80 who have a smoking history.

And, finally, this week, Diagnostic Imaging spoke with Michael Odgren, president of the American Society of Radiologic Technologists, about the ever-evolving role of the technologist in practice. Not only did he touch on the biggest issues facing the profession currently, but he also talked about how the pandemic has impacted daily activities, as well as what the profession can anticipate going forward. Here’s what he had to say.