By Avinash Prabhakar
New Delhi, Oct 24 (IANS): Globally, cancer has emerged as an important contributor to human health and the burden is growing with each passing year. Cancer has multifactorial causation theory and presents with different signs and symptoms as per the organ of origin. In India, 1.4 million people are diagnosed with cancer annually and 8,50,000 cancer patients die of it every year. Carcinoma of breast, lung, mouth, cervix, stomach and head & neck are major cancer types which are preventable but the majority of cases are diagnosed at advanced stages.
Gynaecological cancers are among the most common cancers in women and hence an important health issue. Due to the lack of cancer awareness, variable pathology, and dearth of proper screening facilities in developing countries such as India, most women report at advanced stages, adversely affecting the prognosis and clinical outcomes, says Dr Abhishek Shankar, Associate Professor, Department of Radiation Oncology, AIIMS Patna. This is an important agenda to focus more on cancer prevention and screening to make sure that cancer patients should reach the hospital, he adds.
Screening plays a significant role in detecting cancers at an early stage before appearance of the symptoms. In the situation, where most of the cancer cases in low and middle income countries (LMICs) are presenting to hospitals at an advanced stage, cancer prevention and screening will be a cost effective exercise to reduce cancer incidence and related mortality by detection of precancerous lesions and invasive cancer at early stages.
Health Promotion Approaches for Cancer Prevention
Dr Abhishek says that the health promotion interventions can help to decrease the incidence, prevalence of Non-communicable Diseases (NCDs) including cancer. Health promotion activities as a preventive measure for cancer are focused on underlying risk factors like physical inactivity, overweight and obesity, dietary factors including fruit and vegetable intake, tobacco and alcohol use, infections, and environmental and occupational exposure.
"Physical inactivity contributes to nearly 5 per cent of all cancer deaths. Many studies have reported that physical activity decreases the development of endometrial cancer and few studies. It is also estimated that 41 per cent of uterine carcinoma is due to obesity and overweight and there will be an increase in cancer incidence by nearly 3800 cases with every 1 unit increase in BMI," said AIIMS Patna Doctor.
Human Papilloma viruses (HPV) infection is associated with cancer of cervix, vagina, vulva, head and neck cancer, and anal canal in females. In case of cervical cancer, nearly 90 per cent cases have the presence of HPV and the two most commonly found strains are HPV 16 and 18.
Chemoprevention of Cancer
Oncologist Dr Shankar says that there are many substances, medicines, compounds and agents which are used to delay or inhibit the progression of disease, known as chemoprevention, in cancer. In recent years, advancement and improvement of research has given more insight about cancer biology. Many of the therapeutic agents for chemoprevention, currently under trials, are debatable.
HPV vaccines are proven to be clinically beneficial to lower the burden of cervical carcinoma. Diet rich in vitamin C reduces the risk of cervical cancer. Other trials were conducted using supplements like beta carotene and folic acid but none of them were found to be clinically beneficial.
Evidence-Based Cancer Prevention & Screening
Prevention and screening of cancer focus on reducing the cancer incidence and mortality. It is an important step to make the general population more aware about signs and symptoms of different cancers. The prevention of cancer includes change in lifestyle and eating habits, behaviour change and reduction in environmental and occupational carcinogen exposure, while screening aims at detecting the pre-malignant lesions or cancer at an early stage where chances of cure are much higher.
The burden of cervical cancer is high in the developing world and HPV infection is the major cause of cervical carcinoma. Cytology based screening of cervical cancer has been found to be beneficial in reducing cervical cancer risk among women in the developed world. Cytological examination also known as pap test or smear is highly effective in screening of cervical cancer. Cytology based screening is challenging for developing world in view of lack of trained human resources, infrastructure and finance. Other low cost modalities were developed which can be performed by healthcare workers at community level.
"Oncologists have limited their role in diagnosis and treatment of cancer, but there is a need to extend the role of oncologists' in cancer prevention and screening. Oncologists can play a crucial role in cancer prevention and control by risk assessment of high risk group people," said Dr Shankar.
Dr. Abhishek advises a multipronged strategy to tackle the growing burden of cancer and striking the preventable cancer burden which could be the best long term approach. Lack of nationwide screening guidelines and vaccination strategies are further hurdles in inciting an attack on these preventable cancers. Apart from government initiatives, advocacy by civil society and efforts of non-government organizations also needs to be promoted in this regard.
In summary, the unique challenges of preventable cancer burden may be dealt with indigenous and country-specific approaches which may result in a sustainable long term control of cancer.