The Cancer Struggle in Asia
Smoking, alcohol consumption, and ambient particulate matter (PM) pollution continue to be prominent among the 34 identified risk factors for cancer. The study expressed concern about the escalating cancer burden in Asia attributed to the rising levels of ambient air pollution.
According to a recent study published in The Lancet Regional Health Southeast Asia journal, India recorded an approximate 1.2 million new cancer cases and 9,30,000 deaths in 2019, securing its position as the second-highest contributor to the disease burden in Asia for that year. The study, conducted by an international team of researchers, including experts from the National Institute of Technology Kurukshetra and All India Institute of Medical Sciences (AIIMS) in Jodhpur and Bathinda, highlighted India, along with China and Japan, as the primary countries in Asia witnessing a significant impact of cancer on public health. In total, Asia experienced 9.4 million new cases and 5.6 million deaths from cancer in 2019.
While China topped the charts with 48 lakh new cases and 27 lakh deaths, Japan recorded around 9 lakh new cases and 4.4 lakh deaths. The researchers examined the temporal patterns of 29 cancers in 49 Asian countries between 1990 and 2019, utilizing estimates from the Global Burden of Disease, Injuries, and Risk Factors 2019 Study (GBD 2019). In their study, they pointed out, “We examined the temporal patterns of 29 cancers in 49 Asian countries between 1990 and 2019 using estimates from the Global Burden of Disease, Injuries and Risk Factors 2019 Study (GBD 2019).”
Tracheal, bronchus, and lung (TBL) cancer emerged as the leading cancer in Asia, resulting in an estimated 13 lakh cases and 12 lakh deaths. This type of cancer was most prevalent in men and the third most frequent in women. Cervical cancer, specifically among women, ranked second or among the top-5 cancers in several Asian countries. The researchers emphasized the effectiveness of the human papillomavirus (HPV) vaccine, introduced in 2006, in preventing the disease and reducing HPV-related deaths.
In the continent and individual countries, TBL, breast, colon and rectum cancer (CRC), stomach, and non-melanoma skin cancer were among the top five most frequent cancers in 2019. Some countries also included leukemia, prostate, liver, and pancreatic cancers in their list. The researchers noted, “Overall, in the continent and individual countries, TBL, breast, colon and rectum cancer (CRC), stomach and non-melanoma skin cancer were among the top five most frequent cancers in 2019 with few countries having leukemia, prostate, liver and pancreatic cancers in the list, they said in their study.”
Smoking, alcohol consumption, and ambient particulate matter (PM) pollution remained dominant among the 34 risk factors for cancer. The researchers expressed concern, stating, “The rising cancer burden due to increasing ambient air pollution is concerning in Asia.” They highlighted that five of the top 10 countries with the highest population-weighted annual average of PM2.5 in 2019 were present in Asia – India, Nepal, Qatar, Bangladesh, and Pakistan, citing the State of Global Air Report produced annually in collaboration with the Institute for Health Metrics and Evaluation’s (IHME’s) GBD project.
The researchers attributed the primary reasons for increasing air pollution in Asia to industry-led economic growth, urbanization, rural-to-urban migration, and the growing usage of motor vehicles. Smokeless tobacco (SMT), such as khaini, gutkha, betel quid, and paan masala, posed a significant public health concern in South Asian countries like India, Bangladesh, and Nepal. India alone accounted for 32.9 per cent of global deaths and 28.1 per cent of new cases of lip and oral cavity cancer in 2019 due to the high prevalence of SMT. The researchers stressed, “More than 50 per cent of the oral cancer burden has been attributed to smokeless tobacco, whose prevalence has grown in recent times in South Asia, including India.”
SMT not only increased the risk of oral cancers but also heightened the risk of esophageal and pancreatic cancer, the researchers emphasized. They suggested that improved water and sanitation could help reduce the transmission of Helicobacter pylori (H. pylori) and, consequently, potentially lower the risk of stomach cancer.
The researchers observed a common pattern of reducing cancer burden in younger age groups and increasing cancer burden associated with increasing life expectancy as countries underwent development. Between 1990 and 2019, there was a reduced burden of cancers such as leukemia among those under 5 years of age. Simultaneously, there was a heightened burden of cancers associated with longer lifespans, including prostate, pancreatic, and breast cancer.
The team concluded that the mere availability of screening might not improve survival rates if cancer treatments were either unavailable or unaffordable. In low- and medium-income countries (LMICs) of Asia, oncologic infrastructure was either scarce or unaffordable, particularly in rural areas. Coupled with a weak referral system, patients often experienced delayed diagnosis and treatment, leading to lower survival rates. The researchers emphasized that, along with timely availability of cancer screening and treatment, the cost-effectiveness or coverage of treatment expenses must also be a policy priority.