專家表示，英國應考慮為 55 歲以下愛滋病毒感染者提供肺癌篩查

資料來源：基思·奧爾康 / 2022 年 10 月 11 日 /aidsmap

圖片來源：Peakstock/Shutterstock.com

美國 40 多歲的愛滋病毒感染者患肺癌的風險是其他人群的兩倍，而 60 多歲的愛滋病毒感染者的風險則高出 30%，這是一項在美國由2001 年到2016年癌症診斷的大型研究中已經發現。

本月發表在《刺胳針愛滋病毒》雜誌上的研究結果顯示，儘管幾十年來愛滋病毒感染者的肺癌發病率一直在下降，但肺癌仍然是愛滋病毒感染者中第二常見的癌症，到 2030 年，可能佔愛滋病毒感染者的所有癌症之 15%。

幾項研究報告稱，與其他人群相比，愛滋病毒感染者的肺癌發病比率更高，但美國愛滋病毒感染者老齡化人群中肺癌的最新信息一直缺乏。

為了調查愛滋病毒感染者罹患癌症的風險，美國國家癌症研究所的研究人員使用了愛滋病毒/愛滋病癌症匹配研究的數據，該研究將愛滋病毒數據與癌症登記數據聯繫起來，研究了 20-89 歲愛滋病毒感染者的癌症。 2001 年至 2016 年期間，美國有 11 個州。該研究將四個時期（2001-2004、2005-2008、2009-2012、2013-2016）愛滋病毒感染者的癌症發病比率與普通人群進行了比較，並觀察了年齡差異。

該研究還研究了非西班牙裔白人、非西班牙裔黑人和西班牙裔個體之間的癌症風險差異（其他種族的人數太少，無法進行有意義的比較，因此他們被排除在該分析之外）。

在研究期間，共進行了4,310,304人年的追蹤。隨著時間的推移，研究人群的變化反映了美國愛滋病毒感染者的老齡化。 50 歲以上的比例在 2001-2004 年和 2013-2016 年間翻了一番，達到 41%，到 2013-2016 年，一半的研究人群感染 HIV 至少十年。但是，在研究期間，隨著治療和診斷的改善，曾被診斷為愛滋病的人- 暗示有嚴重免疫抑制病史 – 的比例有所下降。

追蹤期間，3,426 名 HIV 感染者被診斷出肺癌（40% 為腺癌，25% 為鱗狀細胞癌，9% 為小細胞癌，3% 為大細胞癌，與一般人群的分佈相似）。肺癌的發病率在 2001-2004 年和 2013-2016 年期間減少了一半以上（從每 100,000 人年 124 例降至每 100,000 人年 58 例）。與 50-59 歲年齡組（每年-5%）相比，年輕人（20-39 歲，每年 -11%）的癌症發病率下降幅度更大。

然而，與普通人群相比，愛滋病毒感染者的肺癌發病率仍然較高，尤其是在較年輕的人群中。儘管愛滋病毒感染者的肺癌超標率隨著時間的推移而下降，但在 2013-2016 年仍比普通人群高出 48%。 2013-2016 年，40-49 歲 HIV 感染者的肺癌發病率是普通人群的兩倍，其中 50-59 歲高 61%，60-69 歲高 31%。 70 歲以上人群的比率沒有顯著差異。

研究人員還研究了愛滋病毒感染者與普通人群相比的絕對病例數——絕對超額風險——2013-2016 年追蹤，發現在 60-69 歲的愛滋病毒感染者中，每 100,000 人中大約有 50 例額外的肺癌病例發生。 

最後，他們計算了自 2011 年以來五年內 HIV 感染者中肺癌的累積發病率（病例總數），並將其與 HIV 感染者中其他癌症的累積發病率進行了比較。

在 20-39 歲的人群中，五年內肺癌的累積發病率為每 10,000 人 2 例。在50-59歲的愛滋病病毒感染者中，累計發病率為每萬人60例，70歲及以上人群累計發病率為每萬人160例。

50歲以後，肺癌的累積發病率等於或大於兩種定義愛滋病的癌症，卡波西肉瘤和非霍奇金淋巴瘤的發病率。

該研究小組得出結論，60歲以上的愛滋病毒感染者患肺癌的風險最高。雖然老年人風險增加的大部分原因是愛滋病毒感染者吸煙率較高，但在較年輕群體（20-39 歲和 40-49 歲）中觀察到的風險增加不能完全解釋為研究人員所說，吸煙。由 HIV 引起的免疫抑制也可能起作用。

隨著時間的推移，愛滋病毒診斷和治療的改進有望降低免疫抑制對肺癌風險的影響，並且仍然需要針對愛滋病毒感染者的戒菸計畫來解決更高水平的吸煙問題。但研究人員表示，仍需要進一步的研究來調查 HIV 如何成為肺癌的協同危險因素。

篩查的意義

透過使用低劑量 CT 掃描，在肺癌擴散之前及早發現肺癌，可以提高生存前景。除北愛爾蘭外，英國的一些國家的五年肺癌存活率在歐洲是最低的，尤其是男性。缺乏全面篩查和晚期診斷是重要的促成因素。在吸煙者中，非小細胞肺癌的 10 年生存率（當它是一種小的局部腫瘤時）可能接近 90%，但如果癌症已經擴散到肺部以外，預後就不那麼令人鼓舞了。

在美國，美國預防服務工作組已經建議對 50-80 歲有吸煙史的成年人進行篩查。然而，美國最近的一項研究發現，這些指南未能確定愛滋病毒感染者的許多病例，並且篩查需要從更年輕的年齡開始以提高檢測率。

英國國家篩查委員會上個月建議，應邀請所有有吸煙史的 55 至 74 歲的人進行肺癌篩查。在伴隨美國國家癌症研究所研究的一篇社論中，兩名英國癌症專家表示，愛滋病毒狀況應被視為納入英國肺癌篩查計畫的附加標準。

參考文獻：

Haas CB et al.  美國愛滋病毒感染者的肺癌趨勢和風險：一項基於人口登的記關聯研究。刺胳針愛滋病毒，9：e700-e708，2022。

Januszewski AP, Bower M. 愛滋病毒感染者的肺癌。刺胳針愛滋病毒，9：e670-e671，2022。

Risk of lung cancer is higher for people with HIV

UK should consider offering lung cancer screening to people with HIV under 55, say experts

Keith Alcorn / 11 October 2022 / aidsmap

Peakstock/Shutterstock.com

People in their 40s living with HIV in the United States were at twice the risk of developing lung cancer compared to the rest of the population, while people with HIV in their 60s were at 30% higher risk, a large study of cancer diagnoses between 2001 and 2016 in the United States has found.

The findings, published this month in the journal Lancet HIV, showed that although lung cancer rates in people with HIV have been declining for several decades, lung cancer remains the second most common cancer in people with HIV and is likely to account for 15% of all cancers in people with HIV by 2030.

Several studies have reported higher rates of lung cancer in people with HIV compared to the rest of the population but up-to-date information on lung cancer in the ageing population of people living with HIV in the United States has been lacking.

To investigate the risk of cancer in people with HIV, researchers from the US National Cancer Institute used data from the HIV/AIDS Cancer Match study, which links HIV data to cancer registry data, on cancers in people with HIV aged 20-89 years in eleven US states between 2001 and 2016. The study compared cancer incidence in people with HIV in four periods (2001-2004, 2005-2008, 2009-2012, 2013-2016) to the general population, and looked at differences by age.

The study also looked at differences in cancer risk between non-Hispanic White, non-Hispanic Black and Hispanic individuals (the numbers of people in other ethnic groups were too small to allow meaningful comparison and they were excluded from this analysis).

During the study period, a total of 4,310,304 person-years of follow-up occurred. Changes in the study population over time reflected the ageing of people with HIV in the United States. The proportion of over-50s doubled between 2001-2004 and 2013-2016, to 41%, and by 2013-2016, half the study population had been living with HIV for at least ten years. But the proportion of people who had a previous AIDS diagnosis – and by implication, a history of severe immunosuppression – declined as treatment and diagnosis improved during the study period.

During the follow-up period, 3,426 lung cancers were diagnosed in people with HIV (40% adenocarcinoma, 25% squamous cell, 9% small cell and 3% large cell carcinomas, similar to the distribution in the general population). The incidence of lung cancer more than halved between 2001-2004 and 2013-2016 (from 124 per 100,000 person-years to 58 per 100,000 person-years). Cancer rates fell more in younger people (aged 20-39, -11% a year) than in the 50-59 age group (-5% a year).

However, the incidence of lung cancer remained higher in people with HIV compared to the general population, especially in younger age groups. Although the excess rate of lung cancer in people with HIV declined over time, it remained 48% higher than the general population in 2013-2016. In people with HIV aged 40-49 years, lung cancer rates were twice as high as in the general population in 2013-2016, 61% higher in the 50-59 age group and 31% higher in the 60-69 age group. There was no significant difference in rates among the over-70s.

The researchers also looked at the absolute number of cases in people with HIV compared to the general population – the absolute excess risk – and found that in people with HIV aged 60-69 years, approximately 50 extra cases of lung cancer occurred per 100,000 person-years of follow-up in 2013-2016.

Finally, they calculated the cumulative incidence of lung cancer – the total number of cases – in people with HIV over five years from 2011 and compared this to the cumulative incidence of other cancers in people with HIV.

In people aged 20-39 years, the cumulative incidence of lung cancer was 2 cases per 10,000 people over five years. In people with HIV aged 50-59, the cumulative incidence was 60 cases per 10,000, and reached 160 cases per 10,000 in people aged 70 and over.

After the age of 50, the cumulative incidence of lung cancer was either equal to or greater than the incidence of two AIDS-defining cancers, Kaposi sarcoma and non-Hodgkin lymphoma.

The research group concludes that people with HIV over 60 are at highest risk of lung cancer. Although much of the increased risk in older people is explained by the higher prevalence of smoking in people with HIV, the increased risk observed in younger age groups (20-39 years-olds and 40-49 year-olds) cannot be fully explained by smoking, say the researchers. Immunosuppression caused by HIV probably plays a role too.

Improvements in diagnosis and treatment of HIV can be expected to reduce the contribution of immunosuppression to lung cancer risk over time, and smoking cessation programmes aimed at people with HIV are still needed to address the higher level of smoking. But further research is still needed to investigate how HIV acts as a synergistic risk factor for lung cancer, say the researchers.

Implications for screening

Spotting lung cancer early before it has spread, through the use of a low-dose CT scan, improves survival prospects. With the exception of Northern Ireland, the countries of the United Kingdom have some of the lowest five-year lung cancer survival rates in Europe, especially for men. Lack of comprehensive screening and late diagnosis are important contributory factors. In smokers, the 10-year survival rate for non-small cell lung cancer, caught when it is a small and localised tumour, can be close to 90%, but the prognosis is less encouraging if the cancer has spread beyond the lungs.

In the United States, screening of adults aged 50-80 with a history of smoking is already recommended by the US Preventative Services Task Force. However, a recent US study found that these guidelines fail  to identify many cases in people living with HIV and that screening needed to start at a younger age to improve detection rates.

The UK’s National Screening Committee recommended last month that everyone aged 55 to 74 with a history of smoking should be invited for lung cancer screening. In an editorial accompanying the US National Cancer Institute study, two British cancer specialists say that HIV status should be considered as an additional criterion for inclusion in the UK lung cancer screening programme.

References

Haas CB et al. Trends and risk of lung cancer among people living with HIV in the USA: a population-based registry linkage study. Lancet HIV, 9: e700-e708, 2022.

Januszewski AP, Bower M. Lung cancer in people living with HIV. Lancet HIV, 9: e670-e671, 2022.