State of the Russian Oncology Service: esophageal cancer. Population-based study at the federal district level. Part I. Morbidity and mortality rates, accuracy index, annual mortality

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ABBREVIATIONS:

MNO – Malignant neoplasms;

EC – esophageal cancer;

NWFD RF – Northwestern Federal District of the Russian Federation;

IARC – International Agency for Research on Cancer;

IA – index accuracy;

PCRD – Population-based Cancer Registry database.

INTRODUCTION

More than 8000 (8327–2019) primary EC cases are registered in Russia annually and more than 7000 (7024–2019) deaths from this cause [1].

A huge number of publications are devoted to cancer of the esophagus, among which it is necessary to highlight the fundamental work of Academician of the Russian Academy of Sciences M.I. Davydov [2].

A large number of publications are also devoted to the methodological problems of studying the patterns of dynamics of morbidity, mortality and the effectiveness of timely care for patients with esophageal cancer [3–11].

For 20 years, we have had the opportunity to deepen the development of effective anticancer measures only using the database of the population of St. Petersburg cancer registry [12-14]. Now this opportunity has expanded to the level of the federal district [15, 16].

Rough incidence among males is 3.9 times higher than among females (9.43 and 2.42 0/0000 respectively), and standardized (world standard), 5.7 times - 6.29 and 1.1 0/0000 respectively. The share of EC among all malignant neoplasms in males is 2.2%, in females 0.6% [1, 17].

In the world the highest standardized incidence rates of EC population were recorded among Africans in Zimbabwe (Harare) – 15.5 0/0000 determined by extremely difficult living conditions (poverty, dirt, dust storms). The high level of EC incidence was recorded in Japan (Miyagi) – 14.30/0000 and in the Arkhangelsk region of Russia – 12.8 0/0000. Average of 5-7 0/0000 was registered in many countries (Fig. 1, 2). Minimum levels in male population (less than 2.0 0/0000) were reported in Colombia, Israel and Algeria [18].

 

Fig. 1. Cancer incidence in Five Continents. Esophageal cancer. C15. Males. 2008–2012 [1, 18] / Рис. 1. Злокачественные новообразования в некоторых странах мира. Рак пищевода. С15. Мужчины. 2008–2012 [1, 18]

 

Fig. 2. Cancer incidence in Five Continents. Esophageal cancer. C15. Females. 2008–2012 [1, 18] / Рис. 2. Злокачественные новообразования в некоторых странах мира. Рак пищевода. С15. Женщины. 2008–2012 [9, 31].

 

Among female population, the first one is Zimbabwe with a sharp separation from the rest – 12.5 0/0000. The average level is in the range of 1.5-2.0 0/0000. Less than 0,5 0/0000 are registered in Korea, Spain and Belarus [eighteen].

Table 1 shows the dynamics of standardized EC indicators in Russia and the NWFD of the Russian Federation. For both sexes and among the male population, the greatest decrease in the indicator is observed, among the female population – a slight increase [1, 19].

 

Table 1. Trends in esophageal cancer incidence rate (С15) of the population of Russia and the Northwestern Federal District of the Russian Federation (NWFD RF) (standardized indicators) [1, 20–25] / Табл. 1. Динамика заболеваемости населения раком пищевода (С15) в России и СЗФО РФ (стандартизованные показатели) [1, 20–25]

both sexes
	2000	2005	2010	2015	2016	2017	2018	2019
Russia	3,44	3,17	3,22	3,18	3,17	3,21	3,18	3,19
NWFD	-	-	4,13	4,23	4,02	3,96	3,95	4,11
males
	2000	2005	2010	2015	2016	2017	2018	2019
Russia	6,98	6,52	6,62	6,47	6,39	6,45	6,35	6,29
NWFD	-	-	8,40	8,07	7,72	7,49	7,66	7,45
females
	2000	2005	2010	2015	2016	2017	2018	2019
Russia	1,14	1,03	1,01	1,00	1,02	1,04	1,04	1,10
NWFD	-	-	1,46	1,72	1,65	1,68	1,49	1,95

 

Figure 3 shows comparative data on the age-specific incidence rates of the population of Russia and the United States for a period close to 2010, according to the IARC Vol. XI “Cancer incidence in Five Continents” [18] and the Guide by P. A. Herzen Moscow State Medical Research Institute [20]. We do not see any sharp differences between the levels of age-specific indicators.

 

Fig. 3. Age-specific esophageal cancer (C15) morbidity rates of the population of Russia and the USA [18, 20] / Рис. 3. Возрастные показатели заболеваемости населения России и США раком пищевода (С15) [18, 20]

 

Index accuracy

The quality of the estimation of cancer patients is determined by the index accuracy (IA) [26, 27], that is, the ratio of the number of deaths to the number of initially registered patients. Its value should not exceed not only 1, but also 0.7 for cancer with a high mortality rate, such as EC [26-29].

A graphical representation (Fig. 5) shows a gradual, constant decrease in the value of the IA for Russia and less distinct - for the Northwestern Federal District of the Russian Federation, which indicates an improvement in the quality of registration of initially registered patients.

 

Fig. 5. Accuracy index for esophageal cancer patients [1, 20–27, 30] / Рис. 5. Достоверность учета (ИДУ) больных раком пищевода [1, 20–27, 30]

 

The trends of standardized morbidity indicators among the population of Russia and the Northwestern Federal District are shown in Figure 4.

 

Fig. 4. Trends in standardized indicators of esophageal cancer (C15) morbidity rates of the population of Russia and the Northwestern Federal District of the Russian Federation [1, 20–25] / Рис. 4. Динамика стандартизованных показателей заболеваемости населения России и СЗФО РФ раком пищевода (C15) [1, 20–25]

 

As for other administrative territories of Russia, IA in the amount of more than 1 is registered in 11 territories among the male population and 21 among the female population, i.e. the number of deaths exceeds the number of initially recorded patients. The data obtained indicate the severity of the pathology and the difficulties of intravital EC diagnosis.

Localization structure

PCRD allows one to study the particular feature about structural changes in malignant neoplasms for different localizations for different observation periods. 3971 EC cases have been selected for four observation periods from the PCRD of the Northwestern Federal District of the Russian Federation: 2000–2004, 2005–2009, 2010–2014, 2015–2018 (Table 2). For each period, the structure of the malignant neoplasm of esophagus was calculated according to the 4th sign of ICD-10 and the one-year survival rate of patients (which will be shown it in the second part of the article).

 

Table 2. Localization structure of esophageal cancer (C15) in the NWFD RF. NWFD RF Population-based Cancer Registry (PCR) database 2000–2018 (both sexes) / Табл. 2. Локализационная структура рака пищевода (С15) в СЗФО РФ. ПРР СЗФО 2000–2018 (оба пола)

ICD-10Б-10		2000–2004		2005–2009		2010–2014		2015–2018
		Abs. no.	%	Abs. no.	%	Abs. no.	%	Abs. no.	%
С15		3934		4093		4093		3640
Cervical esophagus	.0	31	0,8	321	7,8	352	8,6	128	3,5
Thoracic esophagus	.1	101	2,6	76	1,9	152	3,7	233	6,4
Abdominal esophagus	.2	31	0,8	26	0,6	33	0,8	58	1,6
Upper third of esophagus	.3	300	7,6	314	7,7	301	7,4	278	7,6
Middle third of esophagus	.4	1281	32,5	1178	28,8	1145	27,9	1004	27,7
Lower third of esophagus	.5	908	23,1	834	20,4	945	23,1	889	24,4
Overlapping lesion of esophagus	.8	128	3,3	173	4,2	240	5,9	329	9,0
Esophagus, NOS	.9	1154	29,3	1171	28,6	925	22,6	721	19,8

 

During four observation periods, the largest specific weight in the structure of the EC oncopathology has fallen on the middle third, lower third and upper third of esophagus. The proportion of the thoracic esophagus has doubled: from 2.6 to 6.4%. The proportion of Overlapping lesion of esophagus (C15.8) – a tumor extending beyond one or more other EC localizations has decreased [31].

Mortality

In Russia, more than 7000 (7024 – 2019) deaths from EC are registered annually: 5546 among the male population, 1478 among the female population. The ratio of EC mortality among males and females is as follows: in rough terms – 8.14 and 1.88 0/0000 (a difference of 4.3 times); in standardized – 5.4 and 0.83 0/0000 (6.5 times) [16, 20–25, 32].

The trends in the standardized mortality rates of the population of Russia and the Northwestern Federal District of the Russian Federation from EC is presented in Table 3 [17].

 

Table 3. Esophageal cancer (C15) morbidity rate of the population of Russia and the NWFD (standardized indicators) [1, 20–25, 32] / Табл. 3. Смертность населения России и СЗФО от рака пищевода (С15) (стандартизованные показатели) [1, 20–25, 32]

both sexes
	2000	2005	2010	2015	2016	2017	2018	2019
Russia	3,32	2,97	2,82	2,74	2,69	2,67	2,65	2,66
NWFD			3,82	3,66	3,49	3,43	3,39	3,55
males
	2000	2005	2010	2015	2016	2017	2018	2019
Russia	6,80	6,21	5,96	5,66	5,59	5,52	5,39	5,40
NWFD			8,09	7,34	6,8	6,82	6,69	6,81
females
	2000	2005	2010	2015	2016	2017	2018	2019
Russia	1,03	0,89	0,8	0,81	0,76	0,77	0,83	0,83
NWFD			1,15	1,34	1,33	1,30	1,29	1,45

 

In general, the process is the same as with morbidity: a decrease in rates among the male population and an increase among the female population in the Northwestern Federal District of the Russian Federation.

Annual mortality

Annual mortality is the mortality of patients in each year of follow-up [28, 29]. To study the order of death of EC patients, 2959 people were selected from the PCRD of the Northwestern Federal District of the Russian Federation for the period 1995–1999 (Table 4). Out of the registered patients, 74.1% of men and 70.0% of women died in the first year of observation. Out of those who survived the first year (512 men and 247 women), 45.8% of men and 40.4% of women died in the second year of observation. In the third year, the mortality rate for men decreased to 21.0%, women – to 12.8%. By the tenth year, 3.2% of men and 6.1% of women remained alive. In subsequent years, a slight decrease in annual mortality rates has been noted.

 

Table 4. Annual esophageal cancer mortality rate in the NWFD RF (males, females, both sexes). NWFD RF PCR database (1995-1999) / Табл. 4. Погодичная летальность больных раком пищевода в СЗФО РФ с учетом пола. БД ПРР СЗФО РФ (1995-1999)

Observation period	males		females		both sexes
	Abs. no.	Mortality	Abs. no.	Mortality	Abs. no.	Mortality
1	2078	74,1	881	70,0	2959	72,8
2	512	45,8	247	40,7	759	44,1
3	266	21,0	144	12,8	410	18,2
4	202	19,5	119	18,0	321	19,0
5	158	18,1	93	12,0	251	15,8
6	124	21,5	79	13,0	203	18,2
7	92	8,8	65	4,7	157	7,1
8	82	9,8	61	6,6	143	8,5
9	73	5,6	56	0,0	129	3,1
10	67	10,5	54	11,3	121	10,9

 

In 2000–2004, 2005–2009, 2010–2014, the mortality rate of patients in the first year has remained within 70% with a slight decrease among the female population by the last observation period to 68.9%.

The death of patients develops mainly according to the classical type. Its level has been decreasing every year. There were only a few minor spikes in mortality: in the sixth year for men and in the fourth year for women. The spike in mortality in the tenth year of follow-up may be attributed to the cancer registry database cleanup (Fig. 6).

 

Fig. 6. Annual esophageal cancer mortality rate in the NWFD RF (1995–1999). NWFD RF PCR database [15, 16, 28, 29] / Рис. 6. Погодичная летальность больных раком пищевода в СЗФО РФ (1995–1999) БД ПРР СЗФО РФ [15, 16, 28, 29]

 

It should be noted that according to the official data of the annual reporting, formed outside the system of Population-based Cancer Registries developed in the country, in the first year of observation (Form No. 7) in Russia, not 70%, but 57.5% of patients die, in the Northwestern Federal District of the Russian Federation – 55.8%. There are territories that report the deaths in the first year of observation of less than 30% of the primary registered EC patients (Rostov Oblast, Chechen Republic) or from 30 to 39% (Moscow Oblast, Chukotka, Kamchatka). However, there is a sufficient number of administrative territories showing real statistics (70 and more %): Bryansk, Kaluga, Kostroma, Pskov, Kirov, Omsk, Magadan regions, Sevastopol [15, 16, 33].

Thus, the study of the the morbidity and mortality rates patterns of the most severe pathology – esophageal cancer – has led to the establishment of a slight decrease in the morbidity and mortality of the population of Russia and the Northwestern Federal District of the Russian Federation, an increase in the reliability of estimation (hence, an increase in the quality of estimation). It has become possible to identify the peculiarities in death of patients during each of the ten years of dispensary observation, the preservation of the highest (more than 70%) death of patients during the first year of observation.

Part II of this study will be devoted entirely to the estimation of survival rates: median survival, observed and relative survival of the EC patients, taking into account the stage of the disease and the histological structure of tumors.

The end of the article on P. 40

About the authors

Vakhtang M. Merabishvili

N. N. Petrov National Medical Research Center of Oncology of the Ministry of Health of the Russian Federation

Author for correspondence.
Email: MVM@niioncologii.ru
ORCID iD: 0000-0002-1521-455X
SPIN-code: 5705-6327

Doctor of Medicine (MD), Professor, Chief of the the Oncological Statistics Scientific Laboratory, Chairman of the Scientific-Methodological Council on Development of Information Systems of Cancer Control of the Northwestern Federal District, Head of the Population-based Cancer Registry of the Northwestern Federal District of the Russian Federation

Russian Federation, 68 Leningradskaya street, St. Petersburg, 197758

References

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