Cancer itself does not discriminate when it comes to prevalence across various populations. Secondary to the existing differences within populations, the burden of the disease is not uniform. These disparities facilitate the variations in metrics such as incidence, prevalence, morbidity, mortality, screening rates, and stage at diagnosis seen in statistical data regarding cancer in the United States [5, 13]. Individual populations that may experience such disparities can be grouped by race & ethnicity, gender identity, geographic location, socioeconomic status, and education level. While the overall mortality of cancer has reduced in the United States, this progress is not equally distributed, and trends do not remain consistent when broken down into these specific populations [13].

Cancer health disparities is a term becoming increasingly common in literature and can be defined as the measurable differences in cancer outcomes in various population groups [5, 13]. They create barriers to oncologic care which impacts the diagnosis, treatment, and proper delivery of care. The effects of cancer health disparities have been studied worldwide, and Rates of cancers including breast, colorectal, and prostate have been proven to vary greatly between high-income and low-income countries, geographic areas, and race/ethnic groups [14].

Cancer health disparities related to race and ethnicity tend to lead the discussion in literature, with endless accounts of minorities experiencing disproportionate cancer burden. African American/Black individuals, for example, have a higher mortality rate than any other race for most cancers, as depicted in Fig. 3. As of 2022 data from the American Cancer Society, Black men had a 6% higher incidence but 19% higher mortality than White men. Black women actually had an 8% lower incidence; however, mortality was still 12% higher than White women [5, 15]. Following closely behind for mortality are Asian American, Latin American, and American Indian populations [16]. The reasoning for such discrepancies is multifactorial, however, research suggests that factors such as decreased access to healthcare, limited screening, socioeconomic status, and exposure to risk factors within these groups play a role [17, 18].

Annual rates of cancer deaths by race and ethnicity per 100,000 people shows that though rates have decreased over the past 20 years, differences still exist across races. Black individuals continue to be the race with the highest rates of cancer deaths [17]

Men are at a 2x higher risk of dying from non-reproductive cancer than women. The reasoning is not yet understood; however, it is thought to be a combination of genetic influence as well as sex dependent response to therapy [14]. Behaviors related to gender identity can further this discussion. For example, the rate of tobacco and alcohol use has been found to be higher in LGBTQ youths than heterosexual youths, which is associated with increased risk of cancer [5]. This population has been found to be less likely to adhere to screening and have increased incidence of HIV and HPV associated cancers. Barriers for this specific population are furthered by discrimination and lack of sensitivity of health care professionals in both preventative care and treatment [19].

Geographic location can hinder appropriate oncologic care by means of poor healthcare access for screening [20] and exposure to conditions that increase risk of cancer [5]. Primary care practitioners employ screening tests for common treatable cancers, most notably colorectal, breast, cervical, and prostate. However, patients living in rural areas experience difficulty accessing such primary care services and therefore are not appropriately screened, leading to later stage at diagnosis [20,21,22]. Patients may live in communities lacking clean air or water which can lead to exposure to carcinogenic substances [5]. Poor work or housing conditions have specifically been found to cause exposure to asbestos and radon, both known carcinogens [20].

The concept of built environment has been identified to have influence on health outcomes, as the community in which one lives in can influence behaviors that increase risk of cancer. For example, lower income areas tend to lack affordable, nutritious food options and as well as safe areas for individuals to exercise. Subsequently, these populations boast high rates of obesity, which is a known risk factor for many cancers, with a 17% increased risk of cancer-specific mortality [23].

Area deprivation index (ADI) is a measure of overall deprivation in an area based on 17 social determinants of health, assigned by zip code. Higher ADI indicates greater deprivation. A study correlating ADI to screening rates for breast, cervical, and colorectal cancer showed an inverse association with higher ADI having decreased odds of completing screenings, shown in Fig. 4 [21].

Area Deprivation Index (ADI) is a metric to describe the overall disparity within a zip code. High ADI indicates greater disparity and can be categorized 1–5. As ADI increases, screening completion rates of the area’s residents fall across all cancer types with routine screening [20]

Those of low socioeconomic status struggle to attain adequate oncologic health care for many reasons. This burden begins with inadequate funds to afford preventative screening tests, leading to later diagnosis. Those who are uninsured or Medicaid-insured have been proven to receive advanced stage diagnosis of cancer compared to those who are privately insured as well as decreased quality and quantity of treatment options [20]. Furthermore, cancer is known to be one of the most expensive medical conditions. Figure 5 illustrates the average costs at initiation of treatment, continuation of care, and within the last year of life for some of the most common cancer types. There is not a detailed breakdown of the cost of bone and joint cancer as it is not one of the most common cancer types, however literature notes that it can easily be upward of $100,000 [24].

Cancer care is a tremendous financial burden. Acute Myeloid Leukemia is the most costly disease to treat, though all cancers depicted in this figure are costly and could be problematic for patients of lower socioeconomic status with poor financial stability and poor access to insurance [23]

The term “financial toxicity” has been coined to describe the negative impacts that the high out-of-pocket costs of cancer treatment can have on a patient’s life. Cancer is one of the most costly conditions in the United States due to expenses associated with treatments and hospitalizations. Various factors such as cancer type, financial status, and health insurance coverage impact the level of financial toxicity experienced by an individual patient. Additionally, cancer patients can experience difficulty maintaining the work schedule that they had prior to diagnosis as a result of both physical limitations and time limitations. This increased financial burden can leave patients with temptation to skip medication and treatment in order to maintain enough funds to afford their personal budget. Conversely, paying for the treatments can lead to lower quality of life, anxiety, depression, and disruption of personal finances in order to afford treatment [25].

Relationship between higher educational attainment and more favorable cancer related outcomes is evident in literature. There is a correlation between lower education level and lower health literacy. This can affect patients’ desire to seek appropriate cancer screening due to being unaware of the necessity, regardless of the patient’s ability to access or afford the testing. Lower educational achievement has also been linked to lower rates of appropriate therapies following diagnosis [20]. A study performed specifically on colorectal cancer patients showed that those with higher education are less likely to die before the age of 65 than those with less education, regardless of race or ethnicity [5].

Cancer disparities are impacted by lack of diversity in participants of clinical research. Publishing work based on diverse participant pools would be most effective in establishing inclusivity and personalization of advancements in oncologic care applicable to all populations [5]. Unfortunately, research participant recruitment for cancer trials has not historically placed value in establishing a diverse group representative of the general population. Variations in demographics and clinical factors such as race, gender identity, socioeconomic status, age, and stage at diagnosis could lead to differences in effectiveness, tolerance and outcomes [13].