The American Cancer Society (ACS) has updated its clinical guidelines to include blood-based and advanced stool-based screening options for adults aged 45 to 75.

美國癌症協會 (ACS) 已更新其臨床指南，為 45 至 75 歲的成年人納入血液檢測及進階糞便篩檢選項。

The revision of screening protocols is predicated on a documented increase in colorectal cancer incidence among younger populations, specifically a 50% relative increase in adults aged 45 to 49 between 2021 and 2022. Consequently, the ACS reaffirms that screening should commence at age 45 for average-risk individuals. While the colonoscopy remains the gold standard due to its capacity for simultaneous detection and excision of precancerous polyps, institutional barriers—including preparatory requirements, sedation, and scheduling constraints—have contributed to a significant screening gap, with approximately one-third of eligible U.S. adults remaining untested.

篩檢方案的修訂是基於記錄到年輕族群中大腸直腸癌發病率的增加，特別是在 2021 年至 2022 年間，45 至 49 歲成年人的相對發病率增加了 50%。因此，ACS 再次確認，平均風險個體應從 45 歲開始進行篩檢。雖然大腸鏡檢查因能同時偵測並切除癌前息肉而仍維持金標準，但醫療體系的障礙——包括準備要求、鎮靜與排程限制——導致了顯著的篩檢缺口，約有三分之一的合格美國成年人尚未接受檢測。

To mitigate these barriers, the ACS has endorsed three additional diagnostic tools. The Shield blood test, approved by the FDA in 2024/2025, detects tumor-derived DNA fragments with an 83% efficacy rate for colorectal cancers. However, the ACS stipulates that blood-based testing should be reserved for patients who decline or cannot access visual or stool-based exams, as it is less effective at identifying precancerous polyps. Furthermore, the organization now recommends Cologuard Plus and ColoSense, advanced stool tests that demonstrate a detection rate exceeding 90% and require administration only every three years, surpassing the 80% detection rate of annual high-sensitivity fecal immunochemical tests (FIT).

為了緩解這些障礙，ACS 已認可三項額外的診斷工具。Shield 血液檢測於 2024/2025 年獲得 FDA 批准，能偵測腫瘤衍生 DNA 片段，對大腸直腸癌的有效率為 83%。然而，ACS 規定血液檢測應保留給拒絕或無法進行視覺或糞便檢查的患者，因為其識別癌前息肉的效果較差。此外，該組織目前推薦 Cologuard Plus 和 ColoSense，這兩種進階糞便檢測的偵測率超過 90%，且每三年僅需執行一次，優於每年一次的高靈敏度糞便免疫化學檢測 (FIT) 80% 的偵測率。

International responses to these developments vary. In Canada, while provincial guidelines differ, some jurisdictions, such as Prince Edward Island and Ontario, have lowered the screening age to 45. Canadian health officials have noted that the introduction of less invasive options, such as blood draws, may enhance program participation. Nevertheless, clinical concerns persist regarding the potential for 'screening substitution,' wherein patients may opt for less comprehensive tests, thereby forfeiting the preventative benefits of colonoscopies. It is established that any positive result from a blood or stool-based test necessitates a follow-up colonoscopy for definitive diagnosis and intervention.

國際社會對此發展的反應各異。在加拿大，雖然各省指南有所不同，但部分管轄區（如愛德華王子島和安大略省）已將篩檢年齡降至 45 歲。加拿大衛生官員指出，引入較低侵入性的選項（如抽血）可能會提高計畫的參與度。儘管如此，臨床上仍對潛在的「篩檢替代」感到擔憂，即患者可能會選擇較不全面的檢測，從而喪失大腸鏡檢查的預防效益。目前已明確，任何血液或糞便檢測的陽性結果都必須進行後續的大腸鏡檢查，以完成最終診斷並採取干預措施。

The ACS has diversified screening options to increase early detection rates, though colonoscopy remains the primary recommendation for comprehensive prevention.

ACS 多樣化了篩檢選項以提高早期偵測率，儘管大腸鏡檢查仍是全面預防的首要建議。