There are Public Health programmes which could prevent cancers developing or increase the probability that a cancer may be cured Early detection is an important factor in reducing the death rate from cancer, whether it is achieved by personal actions or through participation in organised public health programmes. Awareness of different visual body signs or symptoms that could easily be observed by anyone and that are possibly related to cancer is important. It is unequivocally established that cancer survival is better for early, localised disease than for the later stage, advanced forms of the disease. Thus, the earlier in the process that a cancer can be diagnosed and treated then the better this is for the patient. Potential symptoms of cancer should not be ignored, but should serve as a clear warning for the individual to consult his or her doctor for advice. The signs and symptoms described in Table 10 are not specific for cancer. When any one is present, the individual should see a doctor. Much effort has gone into cancer screening and the development of methods for finding cancers at an earlier stage in their development and increasing the prospects of a cure. It is possible to make recommendations based on the available evidence.
:: Women from 25 years of age should participate in cervical screening. This should be within programmes with quality control procedures in compliance with European Guidelines for Quality Assurance in Cervical Screening.
In many developing countries, the uterine cervix is one of the most prevalent sites for cancer, comprising about 25% of all female cancers. In industrialised populations, the disease is less common. In eastern and central European populations, the annual age-adjusted (using the World Standard Population as reference) incidence rates for invasive disease are 15–25 per 100.000 women. In the Nordic countries, the annual incidence was 15–30 per 100.000 women before the start of large-scale mass screening programmes.
The effectiveness of screening for cervical cancer has never been demonstrated in a randomised trial. There is, however, sufficient non-experimental evidence showing the efficacy of screening using a cervical smear (Pap) test performed every 3–5 years. This is based on case–control and cohort studies and on time trends and geographical differences associated within screening. The largest of these is the collaborative study co-ordinated by the International Agency for Research on Cancer (IARC) which showed that eradication of the disease is an unrealistic goal and that maximal protection after a negative smear is about 90%, which remains roughly the same during several years after the test. This conclusion is in agreement with the results of studies on the natural history of the disease, which have shown that most preinvasive lesions progress to frankly invasive cancer only over several years.
The effects are somewhat smaller at a population level. In some of the Nordic countries, the reduction was about 80% in women in the age groups exposed most intensively to screening. In the mid-1980s, after several years of organised screening, the overall incidence was 5–15 per 100.000 woman-years.
Cervix cancer screening should be offered to all women over 25 years. There is limited evidence of benefit from screening in women aged over 60 years, though the likely yield of screening is low in women over age 60 since the incidence of high-grade cervical lesions declines after middle age. Screening this age group is associated with potential harms from false-positive results and subsequent invasive procedures. Stopping screening in older women is probably appropriate among women who have had three or more consecutive previous (recent) normal Pap smear results. Yield is also low after hysterectomy, which leaves some cervical tissue, and there is scant evidence to suggest that screening produces improved health outcomes.
An organised programme consists of several essential elements. Defining the population to be screened is important. Personal invitation is the single most important means of attaining high attendance, especially when it is combined with effective information through the mass media. Free service has also been shown to improve attendance. Quality assurance of all steps of the process, monitoring and constant evaluation of the proportion of cancer detected, false positives and false negative readings, are mandatory. Near maximal effectiveness is achieved by an organised programme with high coverage, in which screening is initiated at the age of 25 years and is repeated at three- or five-year intervals until the age of 60. Extension of this approach should be considered only if maximal coverage has been attained, the resources are available and the marginal cost-effectiveness of the recommended changes has been evaluated.European Guidelines for Quality Control in Cervix Cancer Screening have been developed and are widely followed in Europe.
Infection with certain strains of HPV, generally acquired sexually, is the most important risk factor for cervical cancer. With the use of (modern) HPV detection methods over 90% of squamous cell cervical cancer and 75–85% of high-grade cervical intraepithelial neoplasia (CIN) lesions have detectable HPV DNA. Given the implication of HPV infection in cervical cancer, detecting HPV could represent an appealing screening method. A study of 2009 women having routine screening in England and Wales, showed that 44% of CIN lesions of grade 2/3 detected had negative cytology and were found only by HPV testing (for types 16, 18, 31 and 33): a further 22% were positive for HPV but demonstrated only borderline or mild cytological changes. However, 25% of CIN grade 2/3 lesions were not detected by the four HPV tests.
Routine HPV testing for cervical cancer screening is an important research topic at present as HPV infection is very common in women less than 30 years old, and what matters are those women over the age of 30 with a HPV infection that persists over a long period of time. HPV testing is still to be evaluated to find the role it could play in cervical cancer screening. It has the potential to become an important test in detecting cervix lesions in future and should be a current research priority.