痴呆症和癌症是多因素引起的、广泛令人恐惧的、与年龄相关的临床综合征，且患病率不断增加。临床癌症研究取得了重大突破，带来了一些有效的治疗方法，而痴呆症领域在临床研究中取得的成功相对有限。癌症研究的经验教训可能会帮助痴呆症研究领域的人们面对临床护理方案不完全安全或有效时所面临的一些困境。癌症临床试验假设，未经治疗的癌症患者在初步诊断后发病和死亡的风险很高。因此，患者应该选择临床干预措施，无论是标准护理还是实验性干预措施，即使其益处不确定并且治疗的副作用可能很严重。对于许多有痴呆风险的个体来说，预后相应地具有较高的死亡率和严重发病风险，特别是如果一个人关注的是“健康寿命”而不是寿命。护理人员和患者可能会受到痴呆症和许多令人不安的相关症状的严重影响，这些症状往往远远超出健忘症的范围。民意调查、调查和有关“痴呆症担忧”的文献强烈强调公众对痴呆症的恐惧。尽管存在机构和行业障碍使随机试验的招募变得复杂，但痴呆症诊断中固有的未来发病率和死亡率的严重性可能需要重新考虑当前限制高危个体（无论是有症状还是无症状）自由的保护立场参与正在进行的临床研究并可能从中受益。癌症和痴呆症研究也有证据表明，参加临床试验安慰剂组的个体取得了意想不到的良好结果，这表明参与临床试验可以为参加者带来医疗益处。为了强调可能为当前和未来痴呆症临床研究提供信息的癌症临床研究的各个方面，本综述强调了三个主题：应权衡副作用的风险与不治疗通常带来的可怕后果；长期渐进（而不是“灵丹妙药”）临床进展的可取性；并且，联合疗法的最终重要性，反映出痴呆症临床综合征有许多潜在的生物学途径。© 2024。作者。

Dementia and cancer are multifactorial, widely-feared, age-associated clinical syndromes that are increasing in prevalence. There have been major breakthroughs in clinical cancer research leading to some effective treatments, whereas the field of dementia has achieved comparatively limited success in clinical research. The lessons of cancer research may help those in the dementia research field in confronting some of the dilemmas faced when the clinical care regimen is not entirely safe or efficacious. Cancer clinical trials have assumed that untreated individuals with cancer are at high risk for morbidity and mortality after primary diagnoses. Thus, patients deserve a choice of clinical interventions, either standard of care or experimental, even if the benefits are not certain and the therapy's side effects are potentially severe. The prognosis for many individuals at risk for dementia carries a correspondingly high level of risk for both mortality and severe morbidity, particularly if one focuses on "health-span" rather than lifespan. Caregivers and patients can be strongly impacted by dementia and the many troubling associated symptoms that often go well beyond amnesia. Polls, surveys, and a literature on "dementia worry" strongly underscore that the public fears dementia. While there are institutional and industry hurdles that complicate enrollment in randomized trials, the gravity of the future morbidity and mortality inherent in a dementia diagnosis may require reconsideration of the current protective stance that limits the freedom of at-risk individuals (either symptomatic or asymptomatic) to participate and potentially benefit from ongoing clinical research. There is also evidence from both cancer and dementia research that individuals enrolled in the placebo arms of clinical trials have unexpectedly good outcomes, indicating that participation in clinical trial can have medical benefits to enrollees. To highlight aspects of cancer clinical research that may inform present and future dementia clinical research, this review highlights three main themes: the risk of side effects should be weighed against the often dire consequences of non-treatment; the desirability of long-term incremental (rather than "magic bullet") clinical advances; and, the eventual importance of combination therapies, reflecting that the dementia clinical syndrome has many underlying biological pathways.© 2024. The Author(s).