乳がん検診、ＡＩ導入で診断効率化に期待　スウェーデン研究

【パリＡＦＰ＝時事】乳がんの定期健診で行われる画像検査の分析に人工知能（ＡＩ）を導入することで、診断の大幅な効率化が期待できるとする研究結果が２日、スウェーデンで発表された。ただし、実際の乳がん健診でＡＩを広く活用するにはさらなる研究が必要だとしている。（写真はマンモグラフィー検査を受ける女性〈資料写真〉）
　ＡＩはその応用可能性が広く期待されているが、すでに有効性が示されている分野の一つが医療用画像の読影だ。放射線科医が不足する国が多い中、ＡＩの導入で時間のかかる画像診断が迅速かつ正確に行えるようになるのではないかと見込まれている。中でも注目されているのが、乳がん健診でのＡＩ活用だ。
　欧州では５０～６９歳の女性に２年に１回の乳房エックス線（マンモグラフィー）検査が推奨されており、現在は２人の放射線科医が画像を診断している。
　スウェーデンでは２０２１年４月～昨年７月、南西部の４か所でマンモグラフィーを受けた女性８万人の画像診断で、試験的にＡＩが導入された。
　撮影された画像は従来の放射線科医２人による診断か、ＡＩ支援システムによる診断に無作為に振り分けられた。後者ではＡＩのアルゴリズムが画像を読み取り、がんのリスクを１０段階で予測し、放射線科医１人がそれをチェックした。
　その結果、ＡＩ支援システムは２０％多くがんを発見。また画像診断に関わる放射線科医が２人から１人になったことで、全体の仕事量は４４％削減された。
　一方、ＡＩによる読影が、定期検診の合間で見つかる中間期がん（インターバルキャンサー）の抑制につながるかどうかをこの研究で判断できるまでにはあと２年かかるとチームは述べている。【翻訳編集ＡＦＰＢＢＮｅｗｓ】
〔ＡＦＰ＝時事〕（2023/08/03-17:13）

Artificial intelligence could help almost halve the workload of radiologists when it comes to searching routine scans for signs of breast cancer, a large Swedish study suggested on Wednesday.
The interim results of the trial were hailed as promising, but the authors cautioned that more research was needed before AI can be used to screen for breast cancer on a wider scale.
While increasingly convincing chatbots such as ChatGPT have driven speculation about the future potential applications of AI, one area in which the technology has already shown proficiency is in reading medical scans.
With many countries suffering from a shortage of radiologists, there are hopes that AI could make the time-consuming job of analysing routine scans quicker and more accurate.
This could have a particularly large impact for breast cancer. More than 2.3 million women were diagnosed with the cancer in 2020 alone, according to the World Health Organization, and it caused 685,000 deaths.
Regular screening is vital to identifying early signs of cancer. In Europe, women aged 50 to 69 are advised to get a mammogram every two years, with the resulting scan analysed by two radiologists.
The study in Sweden involved the scans of 80,000 women who had mammograms at four sites in southwest Sweden between April 2021 and July last year.
- 'Considerable importance' -
Their scans were randomly divided for analysis to either an AI-supported system or two human radiologists, who served as the control group.
The AI algorithm read the scans and predicted the risk of cancer out of 10. Its predictions were then checked by a radiologist.
The AI-supported system spotted 20 percent more cancers, the study said, which worked out to be an additional case for every thousand women screened.
When it came to false positives -- when a mammogram is first thought to look suspicious but is later cleared -- both the AI-supported system and the two humans spotted the same rate: 1.5 percent.
And the workload for radiologists was reduced by 44 percent for the AI group, because only one person was required to read the scans rather than the normal two.
The greatest potential of AI right now is that it could allow radiologists to be less burdened by the excessive amount of reading, said Kristina Lang, a radiologist at Sweden's Lund University and lead author of the study.
But Lang said the promising interim safety results were not enough on their own to confirm that AI is ready to be implemented in mammography screening, she said in a statement.
It will take two more years before the trial can say whether using AI leads to a reduction in what are called interval cancers, which are detected between routine screenings, the researchers cautioned.
Stephen Duffy, a professor of cancer screening at Queen Mary University of London who was not involved in the study, pointed out that the AI algorithm may have over-diagnosed certain forms of early breast cancer called ductal carcinoma in situ.
Nonetheless, he praised the high-quality study, saying that reducing the burden on radiologists' time was an issue of considerable importance in many breast screening programmes.