This presentation is on priorities in terms of cancer screening and early detection in low and medium income countries. This slide shows the incidence and mortality from the most common cancers in less developed countries. In men, the most common are lung, stomach, liver, prostate, and colorectal cancers. In women, they are breast, cervical, lung, colorectal, and stomach cancers. Some cancers are preventable from primary prevention. Lung cancer through tobacco control, liver cancer from hepatitis vaccination, stomach cancer possibly through Helicobacter pylori infection eradication. Other cancers such are oral, cervical, and colorectal cancers, can be avoided through detection and treatment of precancerous lesions. And mortality from breast cancer can be reduced by effective early diagnosis. This graph plots magnitude of differences in survival between developed and developing countries against the three major elements of cancer control: primary prevention, early detection, and treatment. For tumor associated with poor diagnoses and prognoses such as, esophagus, liver, lung, and pancreatic cancer, the difference in survival between developed and developing countries is very low. There are no effective screening test or early detection procedures, and treatment is generally not effective. Primary prevention is, therefore, the only available strategy to reduce mortality from these cancers. Greater differences in survival are observed in cancer sites such as head and neck, breast, cervix, ovarian, and bladder cancer, which have a moderate to good prognosis if detected early, and treated appropriately. The differences in survival are likely to be reduced by linking early detection with adequate treatment facilities. Some of these cancers, of course, are amenable through primary prevention. Differences are more striking for cancers such as testis, lymphoma, and leukemia, in which improved multi-modality treatment has increased long survival. With appropriate logistics, the available resources can be used to deliver such treatment in developing countries, which is likely to reduce the difference observed in survival. This slide shows the suitable cancers for early detection in low and middle income countries. Breast cancer incidence is increasing in almost all low and middle income countries, and effective control measures are urgently required to reduce mortality. Method for early detection of breast cancer include screening mammography, clinical breast examination, breast self-examination. Mammography screening is expensive. It involved substantial, financial, and manpower resources. And thus, it is not feasible in most low and medium income countries. Breast awareness seems to be a clinically useful strategy, in which women are made aware of what is normal for them, what changes to report to their family doctor, and to seek for prompt referral for appropriate care. Along with creating breast awareness, sufficient capacity should be developed in health services for diagnoses and treatment of detected cases. Unknown responsive and inefficient health services with poor infrastructure and poor accessibility in the light of increasing demand due to awareness counteracts the potential benefit of a program of early clinical diagnosis. More than 80 percent of cervical cancers are diagnosed in low and medium income countries. Yet, there is no effective screening programs in these regions. There are several options such as cytology, HPV testing, visual testing for cervical screening. For screening to be successful, the screening tests for diagnoses and treatment should be provided onsite in one or two visits, and test must be affordable. The program requires constant monitoring and frequent retraining of test providers. HPV testing has clearly higher sensitivity and a lower specificity than cytology. The current available HPV tests are expensive and cumbersome. And there is a need to develop a simple, rapid, affordable, reliable, and valid biochemical test to be used in low and medium income countries. In recent years, new paradigms have been proposed to maximize participation to women from screening to treatment, and to improve cost effectiveness and efficiency. While vaccination provides the hope of the future, screening provides the current means of cervical cancer prevention, screening for colorectal cancer with fecal occult blood test, FOBT, has shown a 16 percent decrease in colorectal cancer mortality. Organized colorectal cancer screening programs are still in the early stage of development in most of high income countries. The feasibility of introducing and scaling up colorectal cancer screening with immunology FOBT was successfully demonstrated in Thailand recently, as a prelude to a national scale. Oral cancer has a long pre-clinical detection phase. Precancerous lesions can be clinically detected through careful visual inspection, and palpation of oral mucosa. Overall, visual screening was followed by a 34 percent reduction in mortality among users of tobacco, or alcohol, or both. This slide shows most of the cancer sites not suitable for early detection, because of lack of scientific evidence or absence of valid, or affordable screening test. This is a case for lung, gastric, liver, and prostate cancers. This slide shows a training course of cervical cancer screening for the treatment of low grade precancerous lesions in India. This slide shows fieldwork on visual inspection for oral cancer among high-risk population. This slide shows awareness brochures and FOBT testing for colorectal cancer screening, that is using them in a demonstration project in North Thailand. Thank you for your attention.
