Abstract
The article presents scientific evidence that confirms the new paradigm that “early” diagnosis is not always beneficial, and that screening and early diagnosis can do more harm than good. As a result, of screening, in a number of cases, lesions are diagnosed that, although have histological patterns of cancer, are often clinically insignificant, indolent i.e. overdiagnosis takes place. Such lesions primarily include latent cancers of the prostate and thyroid gland. An increase in the incidence of certain types of cancers in the United States and other developed countries, as a result, of the introduction of PSA screening, mammography, ultrasound examination of the neck and other highly sensitive diagnostic methods, with stable or decreasing mortality, is a sign of overdiagnosis. In Russia, there is also a marked increase in the incidence of cancer of the prostate, breast, thyroid, kidney and melanoma, while mortality from these forms of cancer is stable or decreasing. The increase in the incidence of all malignant formations in Russian, as in American men, is determined by the increase in the incidence of prostate cancer.
In randomized clinical trials of the efficacy of screening for prostate and breast cancer, an excess of the detected cases of cancer in the screening group compared with the control group indicates overdiagnosis. With an increase in follow-up (10-15 years), the number of excess cases in the screening group decreases. However, in some studies even after 10-15 years of follow-up, the excess of cancer cases in the screening group persisted, i.e. overdiagnosis was confirmed. Thus, the problem of overdiagnosis is also relevant to controlled clinical trials, despite a well-verified protocol and strict adherence to it. The danger of overdiagnosis in real life, daily practice, and especially with opportunistic screening, which, by definition, is carried out without quality control, is much higher. Overdiagnosis often leads to unnecessary, sometimes excessive treatment and a deterioration in the quality of life of patients who are not cancer patients.
Refusal of aggressive therapy and active follow-up should be the method of choice for the management of patients with asymptomatic neoplasms identified at the screening. Such tactics will avoid unnecessary and excessive interventions, which, in turn, will prevent a deterioration in the quality of life of patients and, in addition, will reduce the cost of treatment.
Key words: overdiagnosis, screening, early diagnosis, trends in incidence and mortality, prostate cancer, breast cancer, thyroid cancer
A new paradigm of screening and early diagnosis: assessment of benefits and harms
