Lies, big lies or statistics? Why is the debate about the methodology of the formation of cancer registers – the collection and interpretation of medical data on morbidity and mortality from cancer among domestic specialists not the first year, explains Anton Barchuk, candidate of medical sciences, oncoepidemiologist, executive director of the Association of Oncologists of the Northwestern Federal District.
Yesterday, “Doctor Peter” published a letter addressed to colleagues from oncology clinics, Professor Vakhtang Merabishvili, Chairman of the Scientific and Methodological Council for the Development of Information Systems of the Oncology Service of the North-West Region of Russia and Head of the Scientific Department of the Organization of Anticancer Control of the Nizhny Novgorod Cancer Research Center named after N.N. Petrova. Anton Barchuk, a researcher at the same Research Center for Oncology named after N.N. Petrova and Tampere University (Finland).
Oncological statistics has been conducted in Russia since 1953, orders of the Ministry of Health No. 420 and No. 135 of 04/19/1999 regulate the registration of cancer patients in accordance with international standards approved by the WHO for cancer registries and relevant at that time. Today, the cancer registry in Russia is one of the largest in terms of population coverage; local registries cover 85-95% of cancer patients. These figures are unattainable for many countries, but coverage is not the only indicator, data quality is important.
In Western Europe, they are processed before publication for two years. For example, data for 2018 will be released only in 2020 – 2021. During this time, primary information is verified. We have reports on cancer statistics appear at the end of January of the year following the reporting. However, we must not forget that, unlike other countries, Russia has a centralized system of cancer care: in most regions, all patients are concentrated in one medical institution – an oncology clinic. This allows you to receive information about new cases of cancer quickly.
Therefore, Anton Barchuk explains, allegations of inaccurate data and insufficiently verified statistical information are an exaggeration that does not reflect the real state of the cancer registration system: “Nevertheless, it is indeed necessary to gradually move away from this practice. Because it contains objective shortcomings that are procedural in nature, they must be and it is important to eliminate them, but this does not greatly affect the overall picture of morbidity and mortality rates. ”
An objective comparison of current Russian data on one-year mortality (the number of patients who die from cancer in the first year after diagnosis) with European is possible only on the basis of “fresh” numbers. In Europe, this is now Eurocare-5, which reflects statistics for 1999-2007. And the “fresh” statistics show that there the one-year mortality rate of men was 31%, women – 25%, in England and Wales this figure was 35-40%. In Russia, this figure is about 20%. Why?
– In domestic practice, it is customary to consider this indicator, including skin tumors – basal cell carcinomas, which, along with a high specific gravity in oncological morbidity, are characterized by high detectability at the first stage and practically no mortality. Abroad, data on these malignant neoplasms are not included in the statistics at all, says Anton Barchuk. – Nobody hides these features of the technique. For a correct comparison of foreign and domestic data, it makes sense to analyze the indicators of one-year mortality by localization of malignant diseases, comparing mortality from lung cancer, breast cancer, prostate cancer, and so on separately. In this case, European and Russian statistics do not contradict each other.
Why do Russian statistics show that cancer detection is increasing in the early stages? This is due to the emergence in the country of medical examination and routing programs. In some regions, there is indeed a surge in incidence due to the detection of early stages of breast cancer, prostate cancer, as well as malignant neoplasms of other localizations, Barchuk believes.
“We can confirm the increase in the diagnosis of malignant neoplasms in the early stages based on the increase in the proportion of patients admitted to the hospital with early forms of cancer, which we observe,” he says.
In order to objectively assess the level of survival and mortality, in the world practice the index of reliability of accounting is used – the IMU, it is calculated as the ratio of mortality to morbidity with reference to survival. It is very different for different types of tumors, can approach and exceed 1 for pancreatic cancer and lung cancer, which indicates a high mortality rate from these diseases, which is characteristic of the whole world. However, it does not reflect the quality of cancer registration, since with an increase in the proportion of early stages, it will in any case decrease. The only way to compare morbidity and mortality over time between different periods and regions is through age-standardized indicators. Now they are available and are in the public domain, we use them in scientific work.
– Yes, there are questions regarding the quality of statistics and our task is to analyze the data of each region of Russia in order to take into account local bottlenecks in the collection and processing of information. This work is yet to be done. As well as work on the regulatory framework, the orders by which the industry works do not keep pace with modern realities. All of this is part of the national concept of oncology, ”says Anton Barchuk. – Last year we translated into Russian the international classification of oncological diseases, and since this year the Ministry of Health has recommended its use in all cancer registries of the country. But the process of introducing a new classification for registers also takes time.
The basis for the modernization of cancer registries can be the creation of a system that will take into account in real time all patients with cancer, as well as the types of medical care provided to them – surgical, radiation, drug treatment, rehabilitation, palliative care.
There are difficulties with the “tracking” of patients to death. Without this information, survival statistics will always be incomplete. But this problem needs to be solved within each individual region, since it includes the issue of the interaction of cancer registries and registry offices.
An information space is needed from which both clinicians and oncoepidemiologists can draw the necessary data. On the basis of the NMIC Oncology. N.N. Petrova is already integrating the registers of the subjects of the North-West Federal District, which are being transferred to unified software. This is essentially a pilot project that will take the collection and presentation of data to a new, “digital” level. Nevertheless, the main problem for oncoepidemiology remains the problem of their interpretation, which will help to evaluate, among other things, the quality of medical care. Using a limited set of indicators that today falls into cancer registries, we are depriving ourselves of the unique opportunity to fully reveal their potential and realize their value.