Vakhtang Merabishvili: We reached a confusing situation with cancer statistics

Russian version

We were promised a National Strategy in fight against cancer, but its finalisation is being delayed all the time. We can understand why. It is hard to find a black cat in a dark room. It is difficult to identify national priorities in the fight against cancer, if you have several times more of those dying of it than those being ill, and in some cases cancer patients live eternally. False figures and concepts do not let us move forward.

Vakhtang Merabishvili, in charge of cancer control at NN Petrov Cancer Research Institute, head of the only Russian Cancer Registry which contributed to the series of publications by the International Agency for Research on Cancer “Cancer Incidence in five continents» (CI5), addressed some of them at his seminar “Modern demography” in the Higher School of Economics.

1. The Russian State Statistics in the field of oncology are true and correct. 

Statistics in this area is carried out in our country since 1953. The first issue, classified as “For Official Use Only”, presented data on cancer morbidity and mortality in this country and was published in 1962 – almost simultaneously with the first volume of the series CI5, “Cancer Incidence in Five Continents “ .

But there is an important detail. Merabishvili said: “I do not recommend using either our data at the time, or the data of the first two “Cancer Incidence in Five Continents” volumes. It was a preliminary practice run of collecting the information. Since then, the International Agency for Research on Cancer has developed important international criteria to make sure the numbers are objective”. Our government cancer statistics, lead by the PA Herzen Moscow Research Institute of Oncology, often does not follow this criteria. “The Herzen Institute formulates an official report on the state of oncology services in the country. All information is compiled on the basis of data provided by the regional administrative districts. But which task do the regional health authorities have? To improve things all the time – if not in reality, then on paper. To reduce the one-year mortality rate, increase the proportion of early stage cancer detection, and so on. There is such high administrative burden that we reached a confusing situation with cancer statistics in the country. “

There is yet another problem – the system of data acquisition. “All regional administrative districts should compile by January 20th a state report for the previous year. Naturally, this report is not for the 12 months of the previous year, but for the 10-11 plus “leftovers” from the previous year. Even theoretically, to collect data on all deaths in the last three calendar months of the year is impossible. This leads to a dramatic under-reporting of the one-year mortality. One must compile the malignancy report at least one year after, following a thorough reanalysis of all data from January to December, as do cancer registers worldwide. And most importantly – one must ban the meaningless quarter-year data collection. It is necessary to reduce significantly the number of criteria on the analysis of  oncologic service performance and to rely only on verified cancer registry databases”.

2. More than 50 percent of all cases of cancer in Russia are detected in early stages.

“There is a distortion of the real picture – some areas indicate not even 50, and 65 percent of cancer early stage detection”, — says Merabishvili. Meanwhile, the data collected in accordance with international standards shows quite different figures. For example, on the basis of data from cancer registries in St. Petersburg and other regional administrative areas of the North-Western District there are no more than 30-35 percent early cancer detection, if accounted to the survival statistics. With men, it is even 23-25 ​​percent. “There are such localised events where cancer is almost not being detected in its 1-2 stages. For example, cancer of liver, pancreas. But if you take the state report, we will see in it amazing numbers – some regions show that the detection rate of liver cancer in the early stages is up to 30-33 percent. It is not true. It just cannot be. Survival statistics according to international criteria do not confirm this. Almost all patients die in the first year”.

3. In Russia nearly 600 thousand new cases of cancer are detected every year. The incidence of malignant tumours is 409 cases per 100 000 population in Russia. 

In reality, these figures should be higher. In international statistics, there is a reliability index in statistics – a special indicator that takes into account the ratio of the number of deaths from the disease and the number of disease sufferers. Merabishvili said: “This figure depends on many things –  for example, which tumour type is the most common. In malignant skin cancer, the index should be close to zero – there is a good survival ratio. The average for the various countries is 0.5. It is obvious that the reliability index of the statistics can not be greater than one: the number of people who died from the disease should not exceed the number of registered patients.” What do the Russian official figures show? “With liver cancer, the number of deaths exceeds the number of patient cases in 52 regions. The same situation for lung cancer, in 7 regions, including in Moscow. And in some cases the difference is multifold. Like, in 2015 in Sevastopol the number of liver cancer patients among men was 3 times smaller than the number of deaths from it.” But it can also be the other way around.

4. The number of cancer survivors has reached 3 million 400 thousand people in Russia. 

This figure gives serious doubts. Merabishvili said: “It appears that a third of them are dead souls, even though it is presented as a great success in oncology. In the 20 Russian regions, oncologists do not have access to the deaths databases due to protection of personal information.” Those who have overcome this barrier, accrued from 2011 to 2015-2016 quite a number of dead souls. As a result, the number of “undead” cancer patients is growing, distorting the statistics and causing wrong organisational decisions.

What is the way out? Merabishvili said: “We need to do at least once every ten years a census of cancer patients with the review of primary document archives. We carried out such work in Leningrad in the mid-80s. Exactly then we established a significant, in the range of 50 percent, under-reporting of detected neoplastic malignancies in children”.

5. Cancer survival rates in Russia are significantly lower than in civilized countries. 

Wrong. Standardized mortality rates from malignant tumours for the whole of Russia and for almost all administrative areas were sinking in the last 30 years. But the statistics for the survival of cancer patients in eight regions where the registers are maintained in accordance to international standards, are close to the European average.

6. The stated aim by the Ministry of Health to reduce by 2020 the cancer mortality in the country to 190 cases per 100,000 population – a clear and realistic benchmark.

No, not at all. Merabishvili said: “We have a unique development – the number of cancer cases versus the age of patients. What do we see on this line? Till the age of 35 the line runs almost horizontally. Starting from 35 years of age, the incidence of cancer starts to grow. Each year, by 10 percent. Over the five-year period at 50-70. By the end of your life it shoots up”. It is easy to guess: if a society has higher ratio of the elderly, the cancer mortality it will certainly be higher. That is why in order to compare the situation in different countries, one must use only standardized mortality rates – in terms of a standard age structure of the population.

It is therefore futile to reduce the “raw” cancer mortality in Russia, where the proportion of the elderly population is growing and in the near future should continue to grow. So, it’s time to face the reality – stop the rigging of statistics and try to prepare the health system to the real challenges ahead. Without honest statistics it won’t work.

Translation: For Better Science

© Алла Астахова.Ru