今日の臨床サポート

乳がん検診

著者: 大貫幸二 宮城県立がんセンター 乳腺外科

監修: 中村清吾 昭和大学医学部外科学講座乳腺外科学部門

著者校正/監修レビュー済:2022/05/25
参考ガイドライン:
  1. 国立がん研究センター:有効性評価に基づく乳がん検診ガイドライン2013年度版
  1. 日本乳癌検診学会:乳癌診療ガイドライン2018年度版
  1. 日本医学放射線学会・日本放射線技術学会:マンモグラフィガイドライン第4版
  1. 日本乳腺甲状腺超音波医学会:乳房超音波検査診断ガイドライン改訂第4版
  1. 日本乳癌検診学会:マンモグラフィと超音波検査の総合判定マニュアル
患者向け説明資料

概要・推奨   

  1. 40歳以上の無症状の女性には、2年に1回のマンモグラフィによる乳がん検診が推奨される(推奨度2)
  1. 乳房にしこりなどの自覚症状がある場合は速やかに医療機関を受診することが推奨される(推奨度1)
  1. 女性自身が乳房の状態に日頃から関心をもち、乳房を意識して生活すること(Breast awareness)が推奨される(推奨度2)
薬剤監修について:
オーダー内の薬剤用量は日本医科大学付属病院 薬剤部 部長 伊勢雄也 以下、林太祐、渡邉裕次、井ノ口岳洋、梅田将光による疑義照会のプロセスを実施、疑義照会の対象については著者の方による再確認を実施しております。
※薬剤中分類、用法、同効薬、診療報酬は、エルゼビアが独自に作成した薬剤情報であり、 著者により作成された情報ではありません。
尚、用法は添付文書より、同効薬は、薬剤師監修のもとで作成しております。
※同効薬・小児・妊娠および授乳中の注意事項等は、海外の情報も掲載しており、日本の医療事情に適応しない場合があります。
※薬剤情報の(適外/適内/⽤量内/⽤量外/㊜)等の表記は、エルゼビアジャパン編集部によって記載日時にレセプトチェックソフトなどで確認し作成しております。ただし、これらの記載は、実際の保険適応の査定において保険適応及び保険適応外と判断されることを保証するものではありません。また、検査薬、輸液、血液製剤、全身麻酔薬、抗癌剤等の薬剤は保険適応の記載の一部を割愛させていただいています。
(詳細はこちらを参照)
著者のCOI(Conflicts of Interest)開示:
大貫幸二 : 特に申告事項無し[2022年]
監修:中村清吾 : 講演料(第一三共,中外製薬,メディコン),研究費・助成金など(アストラゼネカ,協和キリン,第一三共,島津製作所,大鵬薬品工業,日本化薬,持田製薬),奨学(奨励)寄付など(エーザイ,コニカミノルタ,中外製薬)[2022年]

改訂のポイント:
  1. 定期レビューを行い、いくつかの項目の修正とBreast awarenessに関する記述を加筆した。

まとめ

疾患情報(疫学・病態)  
  1. 日本人女性の乳癌罹患率は、30歳代後半から急増し40歳代後半から70歳代はほぼ同率で、80歳以降緩やかに減少する。
  1. 日本の対策型検診は、40歳以上に対して問診およびマンモグラフィによる隔年検診が推奨されている。欧米に比べて受診率が低いことが問題となっている。
  1. 40歳代もしくは乳腺組織が多い受診者に対して、マンモグラフィの精度はやや低い。
  1. 日本で、40歳代に対してマンモグラフィに超音波検査を上乗せするRCTが行われているが、まだ死亡率減少効果は証明されていない。
  1. 死亡率減少効果が証明されていない検診を任意型検診として行うに際しては、利益と不利益を受診者に十分説明する必要がある。
 
  1. マンモグラフィにおける乳房構成(J)(参考文献:[1]
  1. 乳房は個人差や経年変化により、乳腺組織(fibroglandular tissueと同義)および脂肪組織の量とその割合は多様であり、乳腺疾患の診断には、この多様性を考慮する必要がある。
  1. 日本のマンモグラフィガイドラインでは、米国のガイドライン(BI-RADS)に準じて、乳房構成を脂肪性(ほぼ脂肪組織)、乳腺散在(脂肪組織の中に乳腺組織が散在)、不均一高濃度(乳腺組織の中に脂肪組織が混在)、極めて高濃度(乳腺組織の中に脂肪組織はほとんどない)の4型に定義している。
 
  1. 高濃度乳房問題(O)(参考文献:[2]
  1. マンモグラフィの乳房の構成のうち、不均一高濃度と極めて高濃度は合わせて高濃度乳房(dense breast)と定義される。高濃度乳房は検診の精度が低いとともに、乳癌のハイリスクであることもわかっており、米国の多くの州において検診機関はマンモグラフィ検診受診者に乳房構成を通知することが義務づけられている。現在、全米で乳房構成を通知することが検討されている。法制化には「Are you dense?」というNPO法人の活動が大きく寄与している。
  1. 2016年10月に、日本でも患者団体から厚生労働省に乳房の構成を通知する要望書が提出され、日本乳癌学会、日本乳癌検診学会、日本乳がん検診精度管理中央機構(精中機構)が中心となってワーキンググループが設置され日本における対応について検討したところ、対象者への対応が明示できる体制にないことから、2017年3月に「対策型検診において乳房の構成を一律に通知することは現時点では時期尚早である」という提言をまとめた。その後、厚生労働省研究班(笠原班)でマンモグラフィ検診における乳房構成の通知方法についての検討が行われ、検診従事者が受診者に説明する際の助けとなるQ&A集が作成された[3]
  1. 任意型検診においては、可能な限り乳房構成を受診者に伝えて、高濃度乳房の場合には超音波検査の上乗せなどの情報を提供するべきであろう。
  1. ただし、マンモグラフィの乳房構成は目視による定性的評価であり精度管理が難しいこと、日本人の乳高濃度乳房は脂肪組織が少ないために相対的に高濃度に見えているなど、いくつかの検討すべき課題がある。
  1. 笠原班と精中機構で検討が重ねられ、乳房構成の評価方法がより細かく定義された[4]。その基準はマンモグラフィガイドライン第4版にも取り入れられている。
 
  1. マンモグラフィ検診の年代別・乳房の構成別に検討した感度(O)(参考文献:[5]
  1. 日本におけるマンモグラフィ検診(視触診併用)の年代別の感度は、40歳代71%、50歳代86%、60歳代88%であった。そのなかで、マンモグラフィ単独の感度を乳房の構成別に検討したところ、脂肪性91%、乳腺散在79%、不均一高濃度68%、極めて高濃度51%であった。不均一高濃度ないし極めて高濃度乳房の割合は40歳代76%、60歳代24%であり、年代別の感度はその乳房の構成に依存していた。
 
  1. 50歳以上に対するマンモグラフィ検診の死亡率減少効果(推奨度1SJG)(参考文献:[6]
  1. 欧米では50歳以上のマンモグラフィを用いたランダム化比較試験が7試験行われており、いくつかのSystematic reviewがある。
  1. 米国予防医療専門委員会の報告書では、50~59歳の相対危険度は0.86(95%信頼区間:0.75-0.99)、60~69歳は0.68(95%信頼区間:0.68-0.87)であった。つまり、マンモグラフィ検診を受診することによって50歳代では14%、60歳代では32%乳癌死亡を回避できることになる。また、1人の乳癌死亡を防ぐのに何人の検診が必要かを示すNNI(Number Needed to Invite for screening)は、50~59歳で1,339人、60~69歳で377人であり、利益が不利益を確実に上回ることからこの年代の隔年のマンモグラフィ検診を推奨している。
 
  1. 40歳代に対するマンモグラフィ検診の死亡率減少効果(推奨度1SJG(2SG)(参考文献:[6]
  1. 欧米では40歳代のマンモグラフィを用いたランダム化比較試験が8試験行われており、いくつかのSystematic reviewがある。
  1. 米国予防医療専門委員会の報告書では、40~49歳の相対危険度は0.85(95%信頼区間:0.75-0.96)、NNIは1,904人であったことから、この年代は利益と不利益が近接しており、定期的なマンモグラフィ検診を推奨しないと結論づけた。これに対して多くの団体がコメントを寄せている。日本乳癌検診学会は当面40歳代のマンモグラフィ検診を推奨するとしている(http://www.jabcs.jp/pages/uspfts.html)。
問診・診察のポイント  
 
  1. 乳がん検診は無症状者が対象である。症状がある場合は、検診には偽陰性が発生することを説明し医療機関で診察を受けるように指導する。

これより先の閲覧には個人契約のトライアルまたはお申込みが必要です。

最新のエビデンスに基づいた二次文献データベース「今日の臨床サポート」。
常時アップデートされており、最新のエビデンスを各分野のエキスパートが豊富な図表や処方・検査例を交えて分かりやすく解説。日常臨床で遭遇するほぼ全ての症状・疾患から薬剤・検査情報まで瞬時に検索可能です。

まずは15日間無料トライアル
本サイトの知的財産権は全てエルゼビアまたはコンテンツのライセンサーに帰属します。私的利用及び別途規定されている場合を除き、本サイトの利用はいかなる許諾を与えるものでもありません。 本サイト、そのコンテンツ、製品およびサービスのご利用は、お客様ご自身の責任において行ってください。本サイトの利用に基づくいかなる損害についても、エルゼビアは一切の責任及び賠償義務を負いません。 また、本サイトの利用を以て、本サイト利用者は、本サイトの利用に基づき第三者に生じるいかなる損害についても、エルゼビアを免責することに合意したことになります。  本サイトを利用される医学・医療提供者は、独自の臨床的判断を行使するべきです。本サイト利用者の判断においてリスクを正当なものとして受け入れる用意がない限り、コンテンツにおいて提案されている検査または処置がなされるべきではありません。 医学の急速な進歩に鑑み、エルゼビアは、本サイト利用者が診断方法および投与量について、独自に検証を行うことを推奨いたします。

文献 

Akihiko Suzuki, Shinichi Kuriyama, Masaaki Kawai, Masakazu Amari, Motohiro Takeda, Takanori Ishida, Koji Ohnuki, Yoshikazu Nishino, Ichiro Tsuji, Daisuke Shibuya, Noriaki Ohuchi
Age-specific interval breast cancers in Japan: estimation of the proper sensitivity of screening using a population-based cancer registry.
Cancer Sci. 2008 Nov;99(11):2264-7. doi: 10.1111/j.1349-7006.2008.00926.x. Epub 2008 Sep 15.
Abstract/Text The age-specific sensitivity of a screening program was investigated using a population-based cancer registry as a source of false-negative cancer cases. A population-based screening program for breast cancer was run using either clinical breast examinations (CBE) alone or mammography combined with CBE in the Miyagi Prefecture from 1997 to 2002. Interval cancers were newly identified by linking the screening records to the population-based cancer registry to estimate the number of false-negative cases of screening program. Among 112 071 women screened by mammography combined with CBE, the number of detected cancers, false-negative cases and the sensitivity were 289, 22 and 92.9%, respectively, based on the reports from participating municipalities. The number of newly found false-negative cases and corrected sensitivity when using the registry were 34 and 83.8%, respectively. In detected cancers, the sensitivity of screening by mammography combined with CBE in women ranging from 40 to 49 years of age based on a population-based cancer registry was much lower than that in women 50-59 and 60-69 years of age (40-49: 18, 71.4%, 50-59: 19, 85.8%, 60-69: 19, 87.2%). These data suggest that the accurate outcome of an evaluation of breast cancer screening must include the use of a population-based cancer registry for detecting false-negative cases. Screening by mammography combined with CBE may therefore not be sufficiently sensitive for women ranging from 40 to 49 years of age.

PMID 18795941
US Preventive Services Task Force
Screening for breast cancer: U.S. Preventive Services Task Force recommendation statement.
Ann Intern Med. 2009 Nov 17;151(10):716-26, W-236. doi: 10.7326/0003-4819-151-10-200911170-00008.
Abstract/Text DESCRIPTION: Update of the 2002 U.S. Preventive Services Task Force (USPSTF) recommendation statement on screening for breast cancer in the general population.
METHODS: The USPSTF examined the evidence on the efficacy of 5 screening modalities in reducing mortality from breast cancer: film mammography, clinical breast examination, breast self-examination, digital mammography, and magnetic resonance imaging in order to update the 2002 recommendation. To accomplish this update, the USPSTF commissioned 2 studies: 1) a targeted systematic evidence review of 6 selected questions relating to benefits and harms of screening, and 2) a decision analysis that used population modeling techniques to compare the expected health outcomes and resource requirements of starting and ending mammography screening at different ages and using annual versus biennial screening intervals.
RECOMMENDATIONS: The USPSTF recommends against routine screening mammography in women aged 40 to 49 years. The decision to start regular, biennial screening mammography before the age of 50 years should be an individual one and take into account patient context, including the patient's values regarding specific benefits and harms. (Grade C recommendation) The USPSTF recommends biennial screening mammography for women between the ages of 50 and 74 years. (Grade B recommendation) The USPSTF concludes that the current evidence is insufficient to assess the additional benefits and harms of screening mammography in women 75 years or older. (I statement) The USPSTF concludes that the current evidence is insufficient to assess the additional benefits and harms of clinical breast examination beyond screening mammography in women 40 years or older. (I statement) The USPSTF recommends against clinicians teaching women how to perform breast self-examination. (Grade D recommendation) The USPSTF concludes that the current evidence is insufficient to assess additional benefits and harms of either digital mammography or magnetic resonance imaging instead of film mammography as screening modalities for breast cancer. (I statement).

PMID 19920272
Abstract/Text PURPOSE: To determine how many cases of breast cancer might be found if women not known to have the disease were thoroughly examined (the disease "reservoir").
DATA SOURCES: MEDLINE search from 1966 to the present.
STUDY SELECTION: Hospital-based and forensic autopsy series examining women not known to have had breast cancer during life.
DATA EXTRACTION: Observed prevalence of occult invasive breast cancer or ductal carcinoma in situ (DCIS) in which the number of women who were given a diagnosis was the numerator and the number of women examined was the denominator. For each autopsy series, we attempted to ascertain the level of scrutiny (sampling method, number of slides examined) given to the pathologic specimens.
DATA SYNTHESIS: Among seven autopsy series of women not known to have had breast cancer during life, the median prevalence of invasive breast cancer was 1.3% (range, 0% to 1.8%) and the median prevalence of DCIS was 8.9% (range, 0% to 14.7%). Prevalences were higher among women likely to have been screened (that is, women 40 to 70 years of age). The mean number of slides examined per breast ranged from 9 to 275; series that reported higher levels of scrutiny tended to discover more cases of cancer.
CONCLUSIONS: A substantial reservoir of DCIS is undetected during life. How hard pathologists look for the disease and, perhaps, their threshold for making the diagnosis are potentially important factors in determining how many cases of DCIS are diagnosed. The latter has important implications for what it means to have the disease.

PMID 9412284
Sue Moss
Overdiagnosis and overtreatment of breast cancer: overdiagnosis in randomised controlled trials of breast cancer screening.
Breast Cancer Res. 2005;7(5):230-4. doi: 10.1186/bcr1314. Epub 2005 Aug 25.
Abstract/Text Data from randomised controlled trials of mammographic screening can be used to determine the extent of any overdiagnosis, as soon as either a time equivalent to the lead-time has elapsed after the final screen, or the control arm has been offered screening. This paper reviews those randomised trials for which breast cancer incidence data are available. In recent trials in which the control group has not been offered screening, an excess incidence of breast cancer remains after many years of follow-up. In those trials in which the control arm has been offered screening, although there is a possible shift from invasive to in situ disease, there is no evidence of overdiagnosis as a result of incident screens.

PMID 16168145
Paola Pisani, D M Parkin, Corazon Ngelangel, Divina Esteban, Lorna Gibson, Marilou Munson, Mary Grace Reyes, Adriano Laudico
Outcome of screening by clinical examination of the breast in a trial in the Philippines.
Int J Cancer. 2006 Jan 1;118(1):149-54. doi: 10.1002/ijc.21343.
Abstract/Text The value of screening by Clinical Examination of the Breast (CBE) as a means of reducing mortality from breast cancer (BC) is not established. The issue is relevant, as CBE may be a suitable option for countries in economic transition, where incidence rates are on the increase but limited resources do not permit screening by mammography. Our aims were to assess whether mass screening by CBE carried out by trained para-medical personnel is feasible in an urban population of a low-income country, and its efficacy in reducing BC mortality. Our study was designed as a randomised controlled trial of the effect on BC mortality of 5 annual CBE carried out by trained nurses. The target population was women aged 35-64 years, resident in 12 municipalities of the National Capital Region of Manila, Philippines. The units of randomization were the 202 health centres (HC) within the selected municipalities. During 1995 nurses and midwives were recruited and trained in performing CBE. The first round of screening took place in 1996-1997. The intervention however showed a refractory attitude of the population with respect to clinical follow-up and was discontinued after the completion of the first screening round. Cases of breast cancer occurring in the study population during 1996-1999 were identified by the 2 local population-based registries. In the single screening round 151,168 women were interviewed and offered CBE, 92% accepted (138,392), 3,479 were detected positive for a lump and referred for diagnosis. Of these only 1220 women (35%) completed diagnostic follow-up, whereas 42.4% actively refused further investigation even with home visits, and 22.5% were not traced. Of 53 cases that occurred among screen-positive women in the 2 years after CBE only 34 were diagnosed through the intervention. Eighty cases occurred among screen-negative women. The test sensitivity for CBE repeated annually was 53.2%. The actual sensitivity of the programme was 25.6% and positive predictive value 1%. Screen-detected cases were non-significantly less advanced than the others. Previous studies have shown that most breast cancer cases in the Philippines present at advanced stages and have an unfavourable outcome. Although CBE undertaken by health workers seems to offer a cost-effective approach to reducing mortality, the sensitivity of the screening programme in the real context was low. Moreover, in this relatively well-educated population, cultural and logistic barriers to seeking diagnosis and treatment persist and need to be addressed before any screening programme is introduced.

Copyright 2005 Wiley-Liss, Inc.
PMID 16049976
Rengaswamy Sankaranarayanan, Kunnambath Ramadas, Somanathan Thara, Richard Muwonge, Jem Prabhakar, Paul Augustine, Muraleedharan Venugopal, Gopan Anju, Beela Sara Mathew
Clinical breast examination: preliminary results from a cluster randomized controlled trial in India.
J Natl Cancer Inst. 2011 Oct 5;103(19):1476-80. doi: 10.1093/jnci/djr304. Epub 2011 Aug 23.
Abstract/Text A cluster randomized controlled trial was initiated in the Trivandrum district (Kerala, India) on January 1, 2006, to evaluate whether three rounds of triennial clinical breast examination (CBE) can reduce the incidence rate of advanced disease incidence and breast cancer mortality. A total of 275 clusters that included 115,652 healthy women, aged 30-69 years, were randomly allocated to intervention (CBE; 133 clusters; 55,844 women) or control (no screening; 142 clusters; 59,808 women) groups. Performance characteristics (sensitivity, specificity, false-positive rate, and positive predictive value) of CBE were evaluated. An intention-to-treat analysis was performed for comparison of incidence rates between the intervention and control groups. Preliminary results for incidence are based on follow-up until May 31, 2009, when the first round of screening was completed. Of the 50,366 women who underwent CBE, 30 breast cancers were detected among 2880 women with suspicious findings in CBE screening that warranted further investigations. Sensitivity, specificity, false-positive rate, and positive predictive value of CBE were 51.7% (95% confidence interval [CI] = 38.2% to 65.0%), 94.3% (95% CI = 94.1% to 94.5%), 5.7% (95% CI = 5.5% to 5.9%), and 1.0% (95% CI = 0.7% to 1.5%), respectively. The age-standardized incidence rates for early-stage (stage IIA or lower) breast cancer were 18.8 and 8.1 per 100,000 women and for advanced-stage (stage IIB or higher) breast cancer were 19.6 and 21.7 per 100,000 women, in the intervention and control groups, respectively.

PMID 21862730
S Kanemura, I Tsuji, N Ohuchi, H Takei, T Yokoe, Y Koibuchi, K Ohnuki, A Fukao, S Satomi, S Hisamichi
A case control study on the effectiveness of breast cancer screening by clinical breast examination in Japan.
Jpn J Cancer Res. 1999 Jun;90(6):607-13.
Abstract/Text A case-control study was conducted in Miyagi and Gunma prefectures, Japan, to evaluate the effectiveness of breast cancer screening by clinical breast examination (CBE) alone in reducing breast cancer mortality. Case subjects, who were female and had died of breast cancer, were collected from residential registry files and medical records. Control subjects matched in sex, age and residence were randomly selected from residential registry files. The screening histories during 5 years prior to the cases having been diagnosed as breast cancer were surveyed using the examinee files of the screening facilities. Finally, the data of 93 cases and 375 controls were analyzed. The odds ratio (OR) of breast cancer death for participating in screening at least once during 5 years was 0.93 (95% confidence interval (95% CI) 0.48-1.79). The cases were more symptomatic than the controls when screened. If the participants who had had symptoms in their breasts were classified as not screened, the OR decreased to 0.56 (95% CI 0.27-1.18). The case control study suggests that the current screening modality (CBE) lacks effectiveness (OR = 0.93), although it might be effective for an asymptomatic population (OR = 0.56). The number of cases was small, and a larger case-control study is desirable to define whether CBE is effective or not. However, it is necessary to consider the introduction of mammographic screening to reduce breast cancer mortality in Japan.

PMID 10429651
Noriaki Ohuchi, Akihiko Suzuki, Tomotaka Sobue, Masaaki Kawai, Seiichiro Yamamoto, Ying-Fang Zheng, Yoko Narikawa Shiono, Hiroshi Saito, Shinichi Kuriyama, Eriko Tohno, Tokiko Endo, Akira Fukao, Ichiro Tsuji, Takuhiro Yamaguchi, Yasuo Ohashi, Mamoru Fukuda, Takanori Ishida, J-START investigator groups
Sensitivity and specificity of mammography and adjunctive ultrasonography to screen for breast cancer in the Japan Strategic Anti-cancer Randomized Trial (J-START): a randomised controlled trial.
Lancet. 2016 Jan 23;387(10016):341-8. doi: 10.1016/S0140-6736(15)00774-6. Epub 2015 Nov 5.
Abstract/Text BACKGROUND: Mammography is the only proven method for breast cancer screening that reduces mortality, although it is inaccurate in young women or women with dense breasts. We investigated the efficacy of adjunctive ultrasonography.
METHODS: Between July, 2007, and March, 2011, we enrolled asymptomatic women aged 40-49 years at 42 study sites in 23 prefectures into the Japan Strategic Anti-cancer Randomized Trial (J-START). Eligible women had no history of any cancer in the previous 5 years and were expected to live for more than 5 years. Randomisation was done centrally by the Japan Clinical Research Support Unit. Participants were randomly assigned in 1:1 ratio to undergo mammography and ultrasonography (intervention group) or mammography alone (control group) twice in 2 years. The primary outcome was sensitivity, specificity, cancer detection rate, and stage distribution at the first round of screening. Analysis was by intention to treat. This study is registered, number UMIN000000757.
FINDINGS: Of 72,998 women enrolled, 36,859 were assigned to the intervention group and 36,139 to the control group. Sensitivity was significantly higher in the intervention group than in the control group (91·1%, 95% CI 87·2-95·0 vs 77·0%, 70·3-83·7; p=0·0004), whereas specificity was significantly lower (87·7%, 87·3-88·0 vs 91·4%, 91·1-91·7; p<0·0001). More cancers were detected in the intervention group than in the control group (184 [0·50%] vs 117 [0·32%], p=0·0003) and were more frequently stage 0 and I (144 [71·3%] vs 79 [52·0%], p=0·0194). 18 (0·05%) interval cancers were detected in the intervention group compared with 35 (0·10%) in the control group (p=0·034).
INTERPRETATION: Adjunctive ultrasonography increases sensitivity and detection rate of early cancers.
FUNDING: Ministry of Health, Labour and Welfare of Japan.

Copyright © 2016 Elsevier Ltd. All rights reserved.
PMID 26547101

ページ上部に戻る

戻る

さらなるご利用にはご登録が必要です。

こちらよりご契約または優待日間無料トライアルお申込みをお願いします。

(※トライアルご登録は1名様につき、一度となります)


ご契約の場合はご招待された方だけのご優待特典があります。

以下の優待コードを入力いただくと、

契約期間が通常12ヵ月のところ、14ヵ月ご利用いただけます。

優待コード: (利用期限:まで)

ご契約はこちらから