State of the Russian Oncology Service: esophageal cancer. Population-based study at the federal district level. Part II. Median survival, observed and relative survival of patients considering disease stage and histological structure of tumors

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ABBREVIATIONS:

EC – Esophageal cancer;

PCRD – Population-based Cancer Registry database;

NWFD RF – Northwestern Federal District of the Russian Federation;

NOS – Not Otherwise Specified;

Unk. – Unknown.

INTRODUCTION

Having at our disposal the new PCR database of the Northwestern Federal District of the Russian Federation with about a million of observations, the studies were conducted on the state of cancer care for patients with malignant tumors in Russia, including malignant melanoma of skin (C43), other malignant neoplasms of skin (C44), lip cancer (C00 ), tongue neoplasms (C01.02), malignant neoplasm of colon (C18), rectum (C19, 20), liver (C22), heart (C38), eye (C69), brain (C72), kidney (C64) and others [1–3].

Calculations of survival rates, subject to careful database maintenance, reflects the real effect of all anti-cancer measures taken. However, the process of improving survival rates is slow. The graph shows this process over the five-year periods [1, 2].

It is also important that the state reporting (Form No. 7) provide objective data on the cancer incidence and mortality rate in Russian population [4]. However, it does not include the data for calculating one-year and five-year observed and relative survival rates in the analytical indicators section. It specifies only the calculation of mortality in patients with cancer in the first year of observation, but these indicators are formed outside the PCR system created in Russia [5] and do not correspond to the real state.

A large number of studies have been devoted to the methodology for calculating the survival rates of cancer patients [1, 2, 6–13].

Unfortunately, in the Russian Federation, only a limited number of cancer registries calculate survival rates according to international standards. The first register was the PCR of Saint Petersburg, on the basis which three editions of the monograph “Survival of cancer patients” were prepared [1, 2, 7, 8, 14, 15].

Сalculation fragments were presented in the books of the PСR of St. Petersburg [7, 8, 14, 15]. Calculation of the survival rates for patients diagnosed with cancer were presented in the Express-information of the Northwestern Federal District of the Russian Federation [1, 2]. Calculations of the survival rate of patients with malignant neoplasms were also carried out by the PCR of the Arkhangelsk, Samara, Chelyabinsk regions and the Republic of Karelia [1, 2].

Express-Information 5th issue summarizes the data on the one-year and five-year survival rates of cancer patients in 16 administrative territories of the Russian Federation, which work on the basis of the programs developed by the Laboratory of Oncological Statistics staff of the N.N. Petrov National Medicine Research Center of Oncology and the Laboratory of Medical Cybernetics of the “Novel” LLC [1, 2].

The calculation of the survival rate of cancer patients is the most important indicator for assessing the activities of the oncological service, provided that doctors of cancer registries have access to the databases of the deceased. Median survival is necessary to control the level of observed and relative survival rates of cancer patients.

Median survival

Median survival is a variant that is in the middle of the variation series dividing it in half. In our case, it is the period during which 50% of the primary registered patients die [16].

For localizations with a high mortality rate, to which EC belongs, it is measured in months.

Table 1 shows the trends in median survival among esophageal cancer patients in the Northwestern Federal District of the Russian Federation for the period from 2000 to 2018.

 

Table 1. Trends in median survival among esophageal cancer (C15) patients in the Northwestern Federal District of the Russian Federation (NWFD RF) NWFD RF Population-based Cancer Registry database (PCRD) / Табл. 1. Динамика медианы выживаемости больных раком пищевода (С15) в СЗФО РФ БД ПРР СЗФО РФ

Sex	2000	2001	2002	2003	2004	2005	2006	2007	2008	2009	2010	2011	2012	2013	2014	2015	2016	2017	2018
Both	5,4	4,6	4,8	5,1	5,5	5,1	5,1	5,2	5,3	5,6	5,5	5,8	5,6	5,9	6,5	6	5,9	6,3	5,8
Male	5,1	4,5	4,9	4,8	5,3	5,1	5	5,1	4,8	5,5	5,1	5,7	5,2	5,8	6,6	5,5	5,9	5,9	5,8
Female	6,3	5,1	4,7	5,9	6,7	5,1	5,7	5,3	6,8	5,8	6,8	6	6,7	6,4	6,1	6,9	5,9	7,5	5,8

 

Annual fluctuations in the indicator may be explained by the difference in each observation year, the health status of the recorded contingents, the age difference of patients and other reasons. Large fluctuations in values among the female population may also be explained by the small number of observations.

The improvement in the survival rate of EC patients is slow, but at the same time, we may note a clear pattern of growth in the median survival rate from five to six months, and even up to seven months among the female population.

Cumulative survival

Table 2 shows the dynamics of the observed survival rates of EC patients in the Northwestern Federal District of the Russian Federation for the period from 2000 to 2018. Over 19 years, the one-year survival rate of EC patients in both sexes increased from 29.2 to 29.6%, or by 1.7%.

 

Table 2. Cumulative observed survival of esophageal cancer (C15) patients in the NWFD RF. NWFD RF PCRD / Табл. 2. Кумулятивная наблюдаемая выживаемость больных раком пищевода (С15) в СЗФО РФ БД ПРР СЗФО РФ

both sexes
Year of diagnosis		2000	2001	2002	2003	2004	2005	2006	2007	2008	2009	2010	2011	2012	2013	2014	2015	2016	2017	2018
Absolute no. of patients		732	840	801	792	769	767	842	827	827	830	837	879	819	790	768	894	923	924	899
Median		"5,4 mos."	"4,6 mos."	"4,8 mos."	"5,1 mos."	"5,5 mos."	"5,1 mos."	"5,1 mos."	"5,2 mos."	"5,3 mos."	"5,6 mos."	"5,5 mos."	"5,8 mos."	"5,6 mos."	"5,9 mos."	"6,5 mos."	"6 mos."	"5,9 mos."	"6,3 mos."	"5,8 mos."
Observation period	1	29,2	24,4	24,9	27,6	27,4	26,8	27,2	26,7	27,9	28,6	28,5	31,4	30,0	28,5	31,9	32,5	33,6	31,8	29,6
	2	18,0	15,2	13,6	16,5	14,0	15,8	14,4	14,4	14,8	15,6	17,1	16,8	16,2	16,3	19,0	19,9	16,6	16,2
	3	14,2	10,9	11,3	12,2	11,8	10,4	10,8	10,6	11,6	13,0	13,4	12,6	12,1	12,8	13,8	14,3	9,7
	4	12,5	9,6	9,2	10,1	9,7	9,3	9,3	8,2	10,1	9,9	11,9	10,1	11,1	10,6	11,2	8,6
	5	12,2	8,4	9,2	9,4	8,8	8,6	7,8	7,6	9,6	9,1	11,2	8,9	9,9	9,4	7,8
males
Year of diagnosis		2000	2001	2002	2003	2004	2005	2006	2007	2008	2009	2010	2011	2012	2013	2014	2015	2016	2017	2018
Absolute no. of patients		530	620	590	586	562	574	609	613	614	587	622	633	598	602	573	619	669	662	666
Median		"5,1 mos."	"4,5 mos."	"4,9 mos."	"4,8 mos."	"5,3 mos."	"5,1 mos."	"5 mos."	"5,1 mos."	"4,8 mos."	"5,5 mos."	"5,1 mos."	"5,7 mos."	"5,2 mos."	"5,8 mos."	"6,6 mos."	"5,5 mos."	"5,9 mos."	"5,9 mos."	"5,8 mos."
Observation period	1	27,5	21,7	24,1	26,3	24,8	26,0	27,2	26,8	25,0	28,1	25,8	31,3	29,6	28,2	31,4	30,4	33,3	29,0	29,3
	2	15,7	13,6	11,8	15,3	13,2	14,6	13,8	14,7	12,5	15,5	14,0	15,6	15,5	15,9	18,9	17,5	15,3	13,5
	3	12,6	10,1	8,9	10,8	10,8	9,3	10,3	10,8	9,1	12,5	10,7	11,2	11,4	12,7	13,3	11,6	8,5
	4	11,2	9,2	7,4	9,4	8,6	8,2	9,0	8,5	8,2	9,4	8,8	8,7	10,4	9,8	10,7	7,0
	5	10,8	8,0	7,3	9,2	7,9	7,7	7,5	7,6	7,7	8,8	8,5	7,5	8,7	8,7	7,3
females
Year of diagnosis		2000	2001	2002	2003	2004	2005	2006	2007	2008	2009	2010	2011	2012	2013	2014	2015	2016	2017	2018
Absolute no. of patients		202	220	211	206	207	193	233	214	213	243	215	246	221	188	195	275	254	262	233
Median		"6,3 mos."	"5,1 mos."	"4,7 mos."	"5,9 mos."	"6,7 mos."	"5,1 mos."	"5,7 mos."	"5,3 mos."	"6,8 mos."	"5,8 mos."	"6,8 mos."	"6 mos."	"6,7 mos."	"6,4 mos."	"6,1 mos."	"6,9 mos."	"5,9 mos."	"7,5 mos."	"5,8 mos."
Observation period	1	33,8	32,4	27,1	31,5	34,3	29,6	27,3	26,5	36,4	29,9	36,4	31,7	31,3	29,6	33,4	37,5	34,5	39,2	30,4
	2	24,1	19,8	18,6	20,0	16,1	19,7	16,0	13,4	21,4	16,0	26,4	19,8	18,2	17,8	19,4	25,5	20,0	23,1
	3	18,6	13,2	18,2	16,2	14,5	14,1	12,3	9,9	19,1	14,0	21,6	16,2	14,0	13,2	15,2	20,8	13,3
	4	16,0	10,8	14,6	12,0	12,6	12,8	9,9	7,2	15,6	11,3	21,2	13,6	12,9	12,8	12,4	12,4
	5	16,0	9,3	14,7	10,0	11,2	11,4	8,4	7,5	15,1	9,9	19,3	12,4	12,8	11,6	9,3

 

Among the male population, an increase in the survival rate of patients in the first year of observation was established from 27.5 to 29.3%, among the female population – a decrease from 33.8 to 30.4%. The relative survival rate in the first year of follow-up was 1.0% higher. The five-year observed survival rate of EC patients in the Northwestern Federal District had small annual fluctuations, especially among the female population. The relative survival rate compared to many other cancer sites for EC was also only 1.0% higher.

Thus, we may state that the five-year observed and relative survival rate of patients with EC in the Northwestern Federal District of the Russian Federation is actually 7–9%.

The high level of five-year survival in 2000 may be associated with the development of the methodology for the formation of the database and the difference in the age composition of the compared groups.

It is important to note that the five-year survival rate of EC patients in the Northwestern Federal District of the Russian Federation for patients under 60 years of age exceeded 10%.

Trends in the observed five-year survival rate of esophageal cancer patients, taking into account the stage of the disease

Figures 1–3 show the time series of survival rates of EC patients in the Northwestern Federal District of the Russian Federation, structured by five-year calendar periods from 2000 to 2014, which increases the reliability of the compared indicators. To estimate the five-year survival rate, we need to deviate from the analyzed date by at least seven years. The data at our disposal for 2020 for calculating the five-year survival rate will be available no earlier than 2027-2028.

 

Fig. 1. Trends in five-year observed survival of esophageal cancer (C15) patients considering disease stage (both sexes) NWFD RF PCRD / Рис. 1. Динамика наблюдаемой пятилетней выживаемости больных раком пищевода (С15) с учетом стадии заболевания в СЗФО РФ (оба пола) БД ПРР СЗФО РФ

 

Fig. 2. Trends in five-year observed survival of cancer patients under the age of 60 in the NWFD RF (both sexes) NWFD RF PCRD / Рис. 2. Динамика наблюдаемой пятилетней выживаемости больных ЗНО в возрасте до 60 лет в СЗФО РФ (оба пола) БД ПРР СЗФО РФ

 

Fig. 3. Trends in five-year observed survival of cancer patients under the age of 60 and older in the NWFD RF (both sexes) NWFD RF PCRD / Рис. 3. Динамика наблюдаемой пятилетней выживаемости больных ЗНО в возрасте 60 лет и старше в СЗФО РФ (оба пола) БД ПРР СЗФО РФ

 

The general rule: when sending materials to the publisher, it is necessary to submit illustrative or tabular material. In our case, both sets complement each other. There is one more nuance, which we will dwell on later. Figure 1 reflects the survival or death of EC patients, taking into account the stage of the disease. Naturally, the question arises: what is this first stage of the disease, in which from 80 (2005–2009) to 40% (2010–2014) of the primary registered patients die? The answer is simple: tabular data (even after clarification) reflect the results of data collection outside the database of cancer registries, and the figures – the real state of the problem already according to the actual results calculated on the basisof the PСR database. These data, of course, may differ due to errors of doctors when making a diagnosis. The five-year survival rate of patients with the first stage of the disease should theoretically be 100%. From this value, 10% of patients may die from other causes, that is, the survival rate of patients with stage I of the disease (if it is stage I) should not be less than 90%.

The discrepancy between the proportions of early stages and the real value of survival rates is determined by the strongest administrative pressure on the chief doctors of oncological dispensaries, heads of all levels: local and all-Russian. Since these indicators are formed manually, in a hurry, by January 20 (F. 7), and also on self-control, you can trust them with great care. The same problems can be traced when assessing the indicator of neglect (stage IV of the disease).

It is necessary to repeat once again that in order to obtain information about the real state of the oncological service, one-year and five-year survival rates should be calculated only on the basis of the PСR database available in all administrative territories of the country [17].

Malignant neoplasm is the most severe pathology. What do we see in the published reference books reflecting government reporting? The one-year mortality rate in EC patients is 56%, and in some territories it is much less (Moscow region - less than 40%, the Chechen Republic and the Republic of Ingushetia - 28%), while the actual death rate of patients is not less than 70%.

This also applies to many other localizations of cancer that create the illusion of well-being [5].

Figures 2 and 3 give an idea of the effectiveness of the performed anticancer measures in relation to EC for patients in younger age groups (up to 60 years old) and patients aged 60 years and older. Better survival rates are clearly seen among patients in younger age groups. If the five-year survival rate of EC patients with stage I of the disease among people under the age of 60 was 63.3%, then among those who have reached 60 years of age, this indicator in the first stage was only 29.3%, in the second - 13.4%. not to mention the third and fourth stages (Fig. 2, 3).

Localization structure of esophageal cancer and patient survival rate

For the first time in Russia, at the population level, a study was carried out to study changes in the detailed EC localization structure, taking into account the fourth character of ICD-10. 15760 primary cases for patients with a EC diagnosis were selected from the PCRD of the Northwestern Federal District of the Russian Federation, grouped by four five-year periods from 2000 to 2018. A stable EC structure distribution was noted for detailed groups of neoplasms.

The first place in the localization EC structure belongs to the middle third of esophagus (С15.4), the second - to the lower third of esophagus (С15.5). These two detailed localization groups account for more than 50.0% of all EC cases.

It is important to note that C15.9 subheading (Esophagus, NOS) decreased over the four observation periods from 29.3% to 19.8%, which indicates an improvement in the quality of diagnosis of this pathology.

We also have the opportunity to assess the effectiveness of the ongoing complex of anticancer measures at the federal district level and note a significant improvement in the one-year survival rate for cervical esophagus (C15.0), which increased from 23.3 to 35.0%. The same applies to patients with a diagnosis of the thoracic esophagus (15.1): an increase in indicators from 29.6 to 35.8%. The survival rate of patients in the upper, middle and lower third of esophagus increased to varying degrees. There was a decrease in the survival rate of EC patients of the abdominal esophagus (C15.2) [18–20].

Histological structure of esophageal cancer and patient survival

Out of 15760 cases, the EC histotype was indicated in registration cards only in 71.5%. The survival calculations for the group of patients who did not have a histological report were significantly worse than for those who underwent a complete examination.

The histological EC structure was presented by Squamous cell carcinoma, NOS – M-8070/3; Squamous cell carcinoma, large cell, non-keratinizing – M-8072/3; Squamous cell carcinoma, keratinizing – M-8071/3, as well as Adenocarcinoma, NOS – M-8140/3 (Table 3). It is important to note that the Neoplasm, malignant M-8000/3 cases (in fact, the absence of a histological conclusion) has decreased from 4.0 to 2.4%.

 

Table 3. Trends in localization structure and survival of esophageal cancer patients in the NWFD RF (both sexes) NWFD RF PCRD / Табл. 3. Динамика локализационной структуры и выживаемости больных раком пищевода в СЗФО РФ (оба пола) БД ПРР СЗФО РФ

ICD		2000–2004					2005–2009				2010–2014				2015–2018
		Abs. No	%	Survival			Abs. No	%	Survival		Abs. No	%	Survival		Abs. No	%	Surv.
				1- year	5- years	10- years			1- year	5- years			1- year	5- years			1- year
С15		3934		25,3	7,3	4,5	4093		26,2	6,8	4093		29,0	8,1	3640		30,8
Cervical esophagus	.0	31	0,8	23,3	3,9	3,9	321	7,8	19,2	4,6	352	8,6	27,3	5,3	128	3,5	35,0
Thoracic esophagus	.1	101	2,6	29,6	11,4	10,2	76	1,9	35,6	7,7	152	3,7	36,8	15,3	233	6,4	35,8
Abdominal esophagus	.2	31	0,8	35,5	12,9	9,7	26	0,6	48,0	14,9	33	0,8	48,4	14,0	58	1,6	28,2
Upper third of esophagus	.3	300	7,6	18,2	5,9	3,5	314	7,7	19,4	5,0	301	7,4	23,5	7,4	278	7,6	34,0
Middle third of esophagus	.4	1281	32,5	28,3	7,4	5,1	1178	28,8	30,8	7,2	1145	27,9	31,6	8,4	1004	27,7	32,4
Lower third of esophagus	.5	908	23,1	29,5	7,8	3,6	834	20,4	30,3	8,8	945	23,1	32,2	10,1	889	24,4	30,9
Overlapping lesion of esophagus	.8	128	3,3	16,9	5,4	4,1	173	4,2	16,2	5,8	240	5,9	20,1	4,8	329	9,0	24,2
Esophagus, NOS	.9	1154	29,3	20,8	7,0	4,2	1171	28,6	22,8	6,0	925	22,6	26,3	7,5	721	19,8	28,1

 

The entire observation period has been characterized by the constancy of the distribution of histotypes according to the marked headings. The highest one-year survival rate was in the M-8140/3 (Adenocarcinoma, NOS) – 38.1%. For other histotypes, the survival rate of EC patients in the first year of follow-up exceeded 30%.

CONCLUSION

Thus, the study has shown some success in the organization of cancer care for EC patients. The quality of the initial registration of patients has improved. The median survival rate of EC patients has increased from five to six months. The observed one-year survival rate has increased from 27.6% to 28.6%, or 3.6%; The five-year one has hardly changed.

The study showed that the five-year survival rate of EC patients at the age of up to 60 years is almost two times higher than among patients aged 60 and older.

The work shows the specificity of the survival rate of patients taking into account the histotype of the neoplasms.

Care should be taken to use government reporting data generated outside of the PCR database.

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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