Cancer Incidence and Survival Rates
Cancer is a disease caused by an abnormal and uncontrolled division of body cells. The growths affect nearby tissues and can also spread to other parts of the body. At present, cancer is the second-leading cause of death globally. In 2018, cancer alone was responsible for an estimated 9.6 million deaths globally. Cancers of the lung, the female breast and colorectum are the top three cancers in terms of mortality. The three cancers are solely responsible for one-third of cancer incidences across the globe as well as the high mortality burden globally. Although most cancers are caused by exposure to cancer-causing substances, age, gender, race, and social class influence cancer incidence and survival rate.
Cancer statistics
According to a World Health Report, one in 5 men and one in 6 women worldwide develop cancer during their lifetime, and one in 8 men and one in 11 women die from the disease (1). By 2018, new cases of cancer had risen by up to 18.1 million. Furthermore, the total number of people who are alive five years of a cancer diagnosis, the five-year prevalence, is an estimated 48.3 million (WHO, 2).
Cancer deaths in Asia and Africa are higher than those of America and Europe. The high cases in Asia and Africa are attributed to poor prognosis and limited access to timely diagnosis and treatment.
Among women, breast cancer is the leading cause of cancer death (WHO, 2). Besides, breast cancer is the most commonly diagnosed cancer in women. Cervical cancer is the fourth cause of cancer death among women, with a mortality rate of 7.5% (WHO, 2). Among men, lung cancer is the most commonly diagnosed cancer as well as the leading cause of cancer death (WHO, 2). Evident from the statistics, cancer is claiming the lives of many people globally. Thus, apart from looking for long-term prevention and cure, it is crucial to understand the factors that increase cancer risk or affect the survival rate.
Age
According to the National Cancer Institute (NCI), the risk of cancer increases with age since the median patient age at the time of a cancer diagnosis is 66. Cancer is sometimes considered an age-related disease because the occurrence of most cancers increases with age with a rapid rise after the midlife period. In line with White et al. (3), as a marker of time, age captures the duration of exposures and the accumulation of cancer risk. Thus, as people grow older, they tend to have more potential exposures to cancer-causing agents as well as develop unhealthy habits.
Midlife and older age is a time of increased vulnerability to cancer (White et al. 4). Midlife is when the prevalence of multiple cancers risk factors increases, and incidence rates start to increase for many types of cancer. For instance, hormone replacement therapy in menopause can lead to the development of breast cancer later in life. Furthermore, a recent study revealed that exposures which cause molecular and cellular changes in mammary tissues during puberty could influence the breast cancer development later in life (White et al. 3). Therefore, when the body is weak and starts developing other chronic conditions, it is when the cancerous cells start multiplying and affecting people in their old age.
Healthy midlife can prevent a cancer-ridden old age. According to White et al., people should strive to live in healthy environments, manage their chronic conditions as well as promote healthy behaviors (4). Besides, since radiation exposure increases cancer risk, people should minimize radiation exposure to decrease their vulnerability to cancer during old age.
Gender
Gender is an important factor in the pathogenesis, diagnosis and prognosis of many diseases. In line with Cook et al., the risk of cancer malignancy is much higher in males compared to females (2). Such differences were triggered by difference in hormones, body mass index as well as viral infections. Lung cancer is the leading cause of cancer deaths among men. The leading cause of lung cancer is tobacco smoking. Statistics prove that men smoke tobacco more than women. Thus, men are more exposed to lung cancer because of excessive tobacco usage. As such, in lung cancer, men are more exposed than women because of tobacco. Prostate cancer is the second leading cause of cancer deaths among men. Prostate cancer, as per the name, occurs in the prostate glands. Therefore, although cancer of the prostate glands is common and a leading cause of cancer deaths among men, the cancer is rare among women. Although women can also suffer prostate cancer since the Skene glands also produce prostate hormone, the incidences are rare among women. Thus, there are some types of cancer which can cause severe death rates among men and remain rare in women.
Women are affected by cancer of the breast. About one in 4 of all new cancer cases diagnosed in women worldwide are breast cancer. While breast cancer is a leading cause of cancer deaths among women, the same cancer is rare among men. Men breasts and tissues can also develop breast cancer, although the cases are very rare among men. Cervical cancer is also a leading cause of cancer deaths among women. Cervical cancer is a sexually transmitted disease caused by the Human papillomavirus (HPV)infection. Men are the carriers and transmitters of the HPV virus although the men do not get cancer. Most men who develop HPV never show any signs of the disease and the virus goes away by itself. Unfortunately for women, the HPV virus causes the deadly cervical cancer.
It is evident that some types of cancers affect some genders. Whereas prostate cancer claims the lives of many men, the disease is a rare among women. Breast and cervical cancers mostly affect women compared to males. Although lung cancer is a leading cause of cancer death in both men and women, lung cancer is more prevalent among men because of the high smoking rates among men.
Race
Racial differences determine cancer susceptibility and survival. According to Ozdemir, in US registries recording cancer incidence and survival by race, individuals of African ancestry have a globally increased risk of malignancies compared to Caucasians and Asian Americans (1). Although one can point out the difference in socioeconomic status and healthcare facilities, Hispanics have a lesser susceptibility to the disease with the same socioeconomic status as Africans. Therefore, variation in racial genetic makeup can raise or lower one’s susceptibility to cancer.
Initially, the difference in incidence and survival rate between Africans and other races were attributed to historic confounding socioeconomic status and lifestyles. There existed a wide gap between the diet, alcohol, and tobacco usage as well as access to cancer screening and treatment. However, Hispanics have lower incidences and high survival rates despite having comparable socioeconomic backgrounds as Africans. Therefore, cancer incidence and survival difference between Africans and other races are mostly genetic.
Africans have reduced susceptibility to sun-induced cancer because of their skin pigmentation. Melanin, the color pigmentation in Africans is protective against UV-induced cancers of the skin. However, in a recent South African study, Africans also suffer from skin cancer, although the tumors are different from those of other races (Ozdemir 3). Thus, Africans at a higher risk of cancer, seeing that even cancer can naturally prevent mutates to a different form of the disease.
Apart from genetic reasons, Africans also have the highest cancer incidence and lowest survival cases because of the lack of cancer awareness. Early detection of cancer increases the survival rate. Early diagnosis and screening play a significant role in the early detection of cancer (World Health Organization). For instance, cervical cancer has a high curable rate if detected early. However, African countries do not carry out enough awareness to encourage women to get regular cervical cancer screening. Breast cancer, the leading cause of cancer deaths among women, also has a high survival rate if detected and treated early.
Cultural factors also influence the high incidence and low survival rates among Africans. Africans are deeply rooted in people with a secure attachment to their culture. Some of the customs, such as mistrust in the health system prevent Africans from getting an early diagnosis or cancer screening. Tissue composition differs between races, which makes it crucial for Africans to screen cancer regularly. It is advisable for Africans to start cancer screening at the age of 45, rather than the recommended age of 50, to increase chances of early detection (Ozdemir 9). However, the belief that a healthy person should not visit the hospital hinders many Africans from early detection of curable cancers. Therefore, the incidence of cases remains high, and mortality increases among Africans compared to other races.
Socio-economic class
Cancer survival and mortality rate vary by socio-economic groups. The difference in social class is attributed to the lifestyle rather than genetic composition. For instance, men in the low socio-economic level are more likely to smoke more and eat less, a factor which attributes to the high mortality due to lung cancer. Men of more upper socio-economic classes are more likely to indulge in refines tobacco and eat at the required time. The lifestyle difference caused by socio-economic background influences the difference between survival and mortality rate between people of different socio-economic backgrounds.
Many cancers are treatable if detected at an early stage. However, people from low socio-economic backgrounds do not have the resources to screen cancer. In line with Wood, cancer diagnosis stage is the primary cause of variation in cancer mortality rate between people of different socio-economic classes (9). The cost of healthcare is high, especially to people without medical insurance covers. Whereas people from the top socio-economic class enjoy all ranges of medical services covered by their medical insurance; people from low socio-economic level do not have medical insurance covers. Cancer screening is costly, which makes it hard for poor people to receive regular testing. Therefore, among people from the low socio-economic class, cancer is detected at a late stage, decreasing their survival rate and increased mortality rates among poor people.
Care-giving to a cancer patient can also affect the mortality rate. Different cancer treatments are given cancer patients of different socio-economic classes. Cancer treatment is costly, and even more expensive if one does not have a medical insurance cover. Any medical insurance does not cover most people in the low socio-economic level. Therefore, the quality of cancer treatment received is more economical than those people with medical insurance covers. Also, the patient care given to a patient can affect the mortality of the person. In a low socio-economic setting, care-giving to cancer patients is weak due to lack of resources. Although care-giving cannot affect cancer survival, it can increase the mortality of a cancer patient.
Third-world countries also witness a high incidence and low survival rate due to socio-economic reasons. Cancer awareness plays a significant role in the early detection of the disease. However, cancer awareness is costly, and it calls for complete coverage to increase effectiveness. The cost burden of cancer awareness hinders awareness programs in developing countries. Also, the high cost of cancer screening makes it impossible to offer free screening tests. Thus, a majority of the population in developing countries miss out on cancer screening, which reduces the chances of early detection.
Conclusion
Despite the prevention and awareness campaigns in many parts of the world, cases of cancer remain high globally. Developing countries are worse hit by the disease because of inadequate resources. People require regular cancer screening to increase the chances of early detection and treatment. However, cancer screening is an expensive exercise which hinders many people from developing nations to get screened regularly. Also, cancer treatment is costly, a factor that lowers survival rates in developing countries. Cancer survival rates are also affected by age, whereby older people are more vulnerable to cancer. Race influences cancer susceptibility and mortality rate because of genetic composition. Africans are more susceptible to cancer compared to other races. Besides, some cancers are gender-specific, although generally, the risk of cancer is higher in males than females. The best way to reduce cancer mortality rates is by offering affordable screening tests, which increase the rate of early detection and treatment. Cancer is a worldwide burden which calls for global intervention.
Works Cited
Cook, Michael B., et al. “Sex disparities in cancer mortality and survival.” Cancer Epidemiology and Prevention Biomarkers 20.8 (2011): 1629-1637.
National Cancer Institute . Cancer Statistics . 27 April 2018. 1 August 2019 <https://www.cancer.gov/about-cancer/understanding/statistics>.
Özdemir, Berna C., and Gian-Paolo Dotto. “Racial differences in cancer susceptibility and survival: more than the color of the skin?.” Trends in cancer3.3 (2017): 181-197.
White, Mary C., et al. “Age and cancer risk: a potentially modifiable relationship.” American journal of preventive medicine 46.3 (2014): S7-S15.
Woods, L. M., B. Rachet, and M. P. Coleman. “Origins of socio-economic inequalities in cancer survival: a review.” Annals of oncology 17.1 (2005): 5-19.
World Health Organization . Latest global cancer data: Cancer burden rises to 18.1 million new cases and 9.6 million cancer deaths in 2018. Geneva, 12 September 2018.
World Health Organization. Early detection of cancer . 2019. 1 August 2019 < https://www.who.int/cancer/detection/en/>.