Editorial: Clinical cancer research in vulnerable populations

Vulnerable populations in cancer care include a wide array of possible conditions (see Table 1). Their vulnerabilities, whether medical, sociocultural, age- or socioeconomic-related, cause these cancer populations to be excluded from clinical trials. This introduces bias and a Matheus effect as clinical trial results are often not fully representative of the whole target population. This underrepresentation of the majority of cancer patients in clinical trials is a major drawback. The treatment of cancer patients with surgery, radiotherapy, and systemic anticancer drugs has reached an increasingly high level of effectiveness, sometimes shifting a cancer diagnosis towards the possibility of living a long life with a chronic cancer therapy treatment that takes place on a regular basis over a long period of time. Moreover, research is often so advanced that we may discuss “personalised cancer medicine” for different cancer types. Unfortunately, the progress that cancer research has made in cancer prevention, early detection, and treatment is not equitably accessible and applicable to vulnerable cancer patient populations. The main reason is that the patients included in clinical trials are not always representative of the whole target population. Indeed, the generalizability of trial results to all patients is usually hampered by the strict inclusion criteria of the clinical trials, leading potentially to overinflated reported benefits. In addition, the toxicity may be substantially higher in these vulnerable populations. Therefore, patients from the groups listed in Table 1 may not receive the best treatment option for their condition. Furthermore, the ethical implications of including vulnerable populations in clinical trials are often insurmountable for researchers attempting to gain approval for these studies.