缺乏意識和提供者的能力意味著 2019 年只有不到二十分之一的最高風險患者得到篩檢

基斯‧奧爾康 / 2024 年 5 月 28 日 / 愛滋病地圖

2019 年，在美國，肛門癌風險最高的愛滋病毒感染者中，不到二十分之一接受了這種疾病篩檢，約三分之一的人無法透過其照護機構進行篩檢（疾病管制與預防中心 (CDC)研究發現）。

然而，最近的另一項研究發現，肛門自我檢查或由伴侶篩檢可以發現早期肛門癌病變，與臨床醫生檢查高度一致，從而可以早期治療。自我檢查可以作為社區主導的有用工具，提高人們對肛門癌篩檢必要性的認識。

在美國，愛滋病毒感染者被診斷出患有肛門癌的可能性是一般人群的 19 至 28 倍。同性戀和雙性戀男性的發生率最高（每年每 10 萬人中約有 89 例）。

肛門癌篩檢的第一線是肛門細胞學檢查或抹片檢查。此測試用於從肛門區域收集細胞，這些細胞可以在顯微鏡下觀察，以尋找提示癌症的變化。肛門細胞的變化是分級的，從需要在未來再次檢查的低級別病變，到需要立即使用高解析度肛門鏡檢（HRA）進行檢查的高級別病變。在麻醉下採集病變組織樣本，並在高解析度顯微鏡下進行檢查，以檢測細胞的癌化。

由於直到最近還缺乏隨機研究的證據，癌症專家在制定關於肛門癌高風險族群應多久接受篩檢的指南方面進展緩慢。 2022 年的一項重大研究顯示，治療癌前病變可降低 HIV 感染者患肛門癌的風險。肛門癌專家於 2024 年發布的指南建議每年進行篩檢，但美國沒有國家建議。接受過高解析度肛門鏡檢查訓練的醫生也很短缺，因此獲得的機會並不均衡。

CDC 於2019 年收集了在美國16 個州和波多黎各接受照護的愛滋病毒感染者的數據，以及2021 年為他們提供照護的醫療機構的數據。 他們研究了接受照護的人的特徵、接受肛門癌篩查的比例以及如何進行照護。

該調查確定了3,136 名愛滋病毒感染者患肛門癌的風險最高，其中包括1,656 名年齡在35 歲或以上的同性戀和雙性戀男性和變性女性，以及1,480 名年齡在45 歲或以上的其他愛滋病毒感染者。調查樣本還包括 964 名未被視為高風險族群的愛滋病毒感染者。

研究族群中 41% 是黑人或非裔美國人，29% 是白人，22% 是西班牙裔，74% 是男性，2% 是跨性別女性。近三分之二 (63%) 的年齡在 45 歲或以上。

樣本中很大一部分人失業或無法工作(41%)，並且生活在聯邦貧困線以下(41%)，54% 的人依賴公共醫療保險，11% 的人依靠瑞安·懷特 (Ryan White) 的資金來支付生活費用照護費用或根本沒有健康保險。

三分之一的樣本在前一年曾有過可檢測到的病毒量測量，14% 的樣本在前一年曾出現過晚期HIV 相關症狀，57% 的樣本在過去曾出現過與HIV 相關的症狀。

「如果檢測到異常情況時無法進行後續 HRA 檢測，那麼服務提供者就不願意提供塗片檢測」。

在肛門癌風險最高的愛滋病毒感染者中，只有不到 5%（4.8%）在前一年接受過抹片檢查的篩檢。 35 歲以上的男同性戀和雙性戀男性以及跨性別女性接受篩檢的比例較高（盛行率差異為 3.8%，p=0.006）。但與樣本中的非西班牙裔白人相比，黑人/非裔美國人接受篩檢的可能性明顯較低（盛行率差異 -2.8%，p=0.027）。與高中以上教育程度的人相比，高中或以下教育程度的人的篩檢率顯著較低，與就業者相比，失業或無法工作的人的篩檢率顯著較低。在可檢測到病毒量的人群、異性戀人群和南方各州人群中，篩檢率也顯著降低。

研究發現，抹片檢查結果異常的樣本中有 22% 在提供高解析度肛門鏡 (HRA) 篩檢的機構接受照護，而 45% 在將患者轉介至另一家 HRA 提供者的機構接受照護。 32% 的人在沒有提供現場篩檢或建立轉診途徑的場所接受照護。愛滋病毒感染者在獲得 HRA 方面沒有因種族或族裔、性別、年齡或教育程度而有顯著差異。愛滋病毒感染者如果他們在過去一年中患有晚期 HIV 或 CD4 計數低於 200，則更有可能可以在可現場取得 HRA 的設施中接受照護。

研究人員表示，缺乏提供 HRA 篩檢的能力是篩檢的一個主要限制因素，因為如果服務提供者在發現異常情況時無法進行後續 HRA 檢測，則不願意提供塗片檢測。高解析度肛門鏡檢查在技術上具有挑戰性，臨床醫生需要接受如何以高標準進行檢查的培訓。

他們總結道：「迫切需要加強患者和醫療服務提供者對肛門癌危險因素和預防的教育和認識」。

參考文獻：

Rim SH et al. 「愛滋病毒感染者中肛門細胞學篩檢的普遍性以及愛滋病毒照護機構缺乏高解析度肛門鏡檢查的機會」。美國國家癌症研究所雜誌 djae094，2024 年。

Limited access to anal cancer screening among people with HIV in the US

Lack of awareness and provider capacity mean less than 1 in 20 at highest risk were screened in 2019

Keith Alcorn / 28 May 2024 / aidsmap

Less than one in twenty people with HIV at highest risk of anal cancer received screening for the condition in 2019 in the United States and around one-third had no access to screening through their care facility, a Centers for Disease Control and Prevention (CDC) study has found.

However, another recent study has found that anal self-examination or examination by a partner enabled detection of early-stage anal cancer lesions with a high degree of agreement with clinician exams, allowing earlier treatment. Self-examination may serve as a useful community-led tool for raising awareness of the need for anal cancer screening.

People with HIV are between 19 and 28 times more likely to be diagnosed with anal cancer than the general population in the United States. Incidence is highest among gay and bisexual men (about 89 cases per 100,000 per year).

The first line of anal cancer screening is the anal cytology test, or Pap smear. This test is used to collect cells from the anal area that can be viewed under a microscope to look for changes suggestive of cancer. Changes in anal cells are graded, from low-grade lesions that need to be reviewed again in the future, to high-grade lesions that need immediate examination using high-resolution anoscopy (HRA). A tissue sample from the lesion is taken under anaesthetic and examined under a high-resolution microscope to detect cancerous changes in cells.

Cancer specialists have been slow to develop guidelines on how often people at higher risk of anal cancer should undergo screening, due to a lack of evidence from randomised studies until recently. In 2022 a major study showed that treating precancerous lesions reduced the risk of anal cancer in people with HIV. Guidelines issued by anal cancer specialists in 2024 recommended annual screening but there is no US national recommendation. There is also a shortage of doctors trained to carry out high-resolution anoscopy, so access is uneven.

The CDC collected data in 2019 from people with HIV receiving care in 16 US states and Puerto Rico, and from the health facilities providing their care in 2021. They looked at the characteristics of people in care, the proportion who underwent anal cancer screening and how screening was accessed, whether onsite or by referral to another provider.

The survey identified 3136 people with HIV at highest risk for anal cancer, including 1656 gay and bisexual men and transgender women aged 35 or over, and 1480 other people with HIV aged 45 or over. The survey sample also included people 964 people with HIV not considered at higher risk.

The study population was 41% Black or African-American, 29% White and 22% Hispanic, 74% male and 2% transgender female. Almost two-thirds (63%) were aged 45 or over.

A high proportion of the sample were unemployed or unable to work (41%) and living at or below the federal poverty level (41%), 54% were reliant on public health insurance and 11% either relied on Ryan White funding to cover the cost of care or had no health insurance coverage at all.

One-third of the sample had had detectable viral load measurements in the previous year, 14% had advanced HIV-related symptoms in the previous year and 57% had had symptoms related to HIV in the past.

“Providers are reluctant to offer smear testing if they cannot carry out follow-up HRA testing if abnormalities are detected.”

Just under 5% of people with HIV at highest risk of anal cancer (4.8%) had received screening in the form of a smear test in the previous year. A higher proportion of gay and bisexual men and transgender women over 35 had received screening (a prevalence difference of 3.8%, p=0.006)). But compared to Non-Hispanic Whites in the sample, Black/African-Americans were significantly less likely to have undergone screening (prevalence difference -2.8%, p=0.027). Screening prevalence was significantly lower in people with high school education or less compared to those with post-high school education, and in the unemployed or those unable to work compared to those in employment. Screening prevalence was also significantly lower in people with detectable viral load, in heterosexual people and in people in Southern states.

The study found that 22% of the sample who had abnormal smear test results received care at sites which provided high-resolution anoscopy (HRA) screening, while 45% received care at sites which referred patients to another provider for HRA. Thirty-two percent received care at sites which provided no on-site screening or established referral pathway. There were no significant differences in access to HRA by race or ethnicity, by gender, age or education among people with HIV. People with HIV were more likely to be receiving care at facilities with onsite access to HRA if they had advanced HIV or a CD4 count below 200 in the past year.

The study investigators say that the lack of capacity to provide HRA screening is a major constraint on screening, because providers are reluctant to offer smear testing if they cannot carry out follow-up HRA testing in cases where abnormalities are detected. High resolution anoscopy is technically challenging and clinicians need training in how to carry it out to a high standard.

“There is a critical need for greater patient and provider education and awareness about risk factors for anal cancer and about prevention,” they conclude.

References Rim SH et al. Prevalence of anal cytology screening among persons with HIV and lack of access to high-resolution anoscopy at HIV care facilities. Journal of the National Cancer Institute djae094, 2024.