By Marilynn Larkin
NEW YORK (Reuters Health) - Compared with the less intensive practice in the Netherlands, cervical screening in the U.S. may result in "two- to three-fold higher harms," researchers say.
In an earlier study, Dr. Dik Habbema of Erasmus MC, University Medical Center in Rotterdam, The Netherlands and colleagues found similar cervical cancer mortality and incidence trends in the two countries despite much greater screening intensity in the U.S., with many more life-time screenings advised.
More recently, the same team assessed the harms related to cervical screening in both countries, and the management of women who screen positive. The U.S. data came from Screening Effectiveness and Research in Community-based Healthcare (SEARCH); the source for The Netherlands was the NL Pathological Anatomical National Automated Archive. Data were analyzed for 2007, the latest complete year available from SEARCH.
As reported online November 16 in the International Journal of Cancer, the researchers compared the number of Papanicolaou (Pap) smear tests, abnormal test results, punch biopsies, health problems - anxiety, pain, bleeding, and discharge - and preterm births associated with excisional treatments.
An estimated 36 million Pap tests were performed in 2007 for 91 million US women ages 21-65, resulting in 2.3 million abnormal Pap smears, 1.5 million punch biopsies, 0.3 million treatments for precancerous lesions, 5,000 preterm births, and more than 8 million various health problems.
Overall, according to the authors, "We found a higher rate of Pap tests (Risk Ratio=2.4) in the US. The difference in rates was about the same for abnormal test results (RR=2.8), higher for punch biopsy (RR=3.9), and smaller for (cervical dysplasia) treatment (RR=1.7).
Under The Netherlands' screening guidelines, 58% fewer Pap tests, 64% fewer abnormal test results, 75% fewer punch biopsies, 40% fewer treatment procedures, 60% fewer preterm births, and 63% fewer health problems would have occurred.
The authors note that the SEARCH data did not differ much from other U.S. data for 2007 or from more recent data up to 2013.
Taken together, they conclude, the data suggest that "although the benefits of cervical cancer screening are similar between the U.S. and The Netherlands, many more women in the US experience harms than would be the case under the less intensive Netherlands screening practice."
Dr. Habbema told Reuters Health, "These results suggests that the number of lifetime smears in the U.S. could probably be further reduced with only a small impact on mortality reduction, and a much larger impact on the harms of screening."
The findings also "underline the extremely difficult problem of trade-offs between a high chance of small unfavorable consequences against a small chance of a large favorable consequence, in this case, not dying from cervical cancer," he said by email.
"Harms of screening have been understudied," Dr. Habbema added. "Additional research, registration and monitoring are required for a better judgment of harms in future decision making, both for public health recommendations and for individual decision making by women and their physician. This conclusion is highly relevant for HPV testing and cytological and HPV co-testing, with their higher screen-test positivity rates than cytological screening."
Dr. Steve Vasilev, medical director of Integrative Gynecologic Oncology at Providence Saint John's Health Center and professor at John Wayne Cancer Institute in Santa Monica, California, told Reuters Health, "We have known for many decades that screening for cervical dysplasia and cancer could safely be performed at less frequent intervals and be far more cost-effective to boot. The advent of integrated HPV testing has enhanced this safety and we have now finally moved solidly towards reducing screening (frequency) in the U.S."
"There is also no question that the biggest impact on reducing cervical cancer mortality is from reaching the under-screened population," he noted. "However, the well screened proactive individual patient generally prefers to know what their health status is on all fronts."
"As far as harms from screening findings, it's not about the screening per se. It's about what you do with the results," Dr. Vasilev said. "Therefore, the main focus should be on reducing the number of inappropriate procedures rather than reducing an individual's knowledge of the state of their health. This would likely result in less iatrogenic harm in the pursuit of health."
Int J Cancer 2016.
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