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ORIGINAL ARTICLE
Year : 2015  |  Volume : 11  |  Issue : 6  |  Page : 155-160

Incidence and mortality of laryngeal cancer in Zhejiang cancer registry, 2000–2011


Zhejiang Provincial Cancer Center, Zhejiang Cancer Hospital, Hangzhou, Zhejiang, China

Date of Web Publication26-Oct-2015

Correspondence Address:
Lingbin Du
Zhejiang Provincial Cancer Center, Zhejiang Cancer Hospital, Hangzhou, Zhejiang
China
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/0973-1482.168177

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 > Abstract 

Background: Laryngeal cancer is the one of the most prevalent cancer of the upper respiratory tract. Aiming to get a better understanding of the epidemiological characteristics and trends of laryngeal cancer in Zhejiang cancer registry in China during 2000–2011, we used the standardized quality control and statistical methods to analyze the incidence and mortality that were vital for making decision about laryngeal cancer prevention and control.
Materials and Methods: Comparably high-quality data from eight population-based cancer registries in Zhejiang from 2000 to 2011 were qualified for analysis. The pooled data were stratified by area, sex, and age group. All incidence and mortality rates were age-standardized to the 2000 Chinese standard population and Segi's population, which were expressed per 100,000 populations. Average annual percent changes (AAPCs) and 95% confidence intervals of laryngeal cancer incidence and mortality were calculated for the temporal trends. The logarithmic trend line was also drawn to reflect the time trends of incidence and mortality.
Results: During the 12 years, the 8 cancer registries covered a total of 81,758,277 person-year population (65,500,842 in urban and 16,257,435 in rural areas) including 41,315,911 person-year males and 40,442,366 person-year females. The age-standardized incidence rates were 1.10/105 by Chinese population and 1.12/105 by world population, respectively. The incidence of laryngeal cancer was relatively low in subjects under 44 years old. Then, it increased sharply after 45 years old and finally reached the peak in subjects of 75–79 years old. The age-standardized mortality rates of the Chinese population and world population were 0.28/105 and 0.35/105, respectively. The mortality of laryngeal cancer was at a low level in subjects under 49 years old. The rate dramatically increased in subjects over 50 years old, and then peaked in the age group of 80–84 years. The crude incidence of laryngeal cancer in Zhejiang cancer registration areas in 2000 was approximately 1.39/105, and it reached 1.78/105 in 2011, with the AAPC of 2.47%; the temporal trend line indicates that the incidence remained steady during the 12 years. The crude mortality of laryngeal cancer in Zhejiang registration areas in 2000 was about 0.30/105 and increased to 0.66/105, with the AAPC of 4.24% which showed no statistical significance; the temporal trend line indicates that mortality was going up to a certain extent, but not evident.
Conclusions: Laryngeal cancer significantly influenced the quality of life for the patients. The comprehensive measures should be carried out to prevent the upward trend of laryngeal cancer.

Keywords: Cancer registry, epidemiology, incidence, laryngeal cancer, mortality, Zhejiang province


How to cite this article:
Li H, Wang Y, Zhu C, Wang X, Du L. Incidence and mortality of laryngeal cancer in Zhejiang cancer registry, 2000–2011. J Can Res Ther 2015;11, Suppl S2:155-60

How to cite this URL:
Li H, Wang Y, Zhu C, Wang X, Du L. Incidence and mortality of laryngeal cancer in Zhejiang cancer registry, 2000–2011. J Can Res Ther [serial online] 2015 [cited 2019 Aug 20];11:155-60. Available from: http://www.cancerjournal.net/text.asp?2015/11/6/155/168177


 > Introduction Top


Laryngeal cancer, which is a malignancy of the voice box, appears to be the one of the most prevalent cancer of the upper respiratory tract,[1] with over 130,000 cases occurring annually in the world.[2] As compared to the major types of cancer death, the contribution of laryngeal cancer is relatively modest. As is reported, laryngeal cancer is the 19th most common cause of cancer death worldwide, with around 83,376 deaths from laryngeal cancer in 2012 (1% of the total).[3] According to the figure released by the WHO and the International Agency for Research on Cancer (IARC) (GLOBOCAN 2012), there were an estimate of 20,014 new cases and 12,308 deaths in China, and the standardized incidence and mortality rates were 1.1/105 and 0.7/105, respectively, lower than the global incidence and mortality.[3] It is noted that larynx plays a significant role in sound generation and protecting function. The cancer of larynx could possibly metastasize to bone, brain, lung, and liver, causing a shorter survival, accordingly leading to the certain burden of disease on public health. Information on the overall effectiveness of laryngeal cancer management is, thus, increasingly important.

A cancer registry is an information system designed for the collection, storage, management, and analysis of data related to people with cancer.[4] In 2002, the National Central Cancer Registry (NCCR) of China was established by the Ministry of Health to enhance the systematic management of cancer surveillance and cancer research.[5] At present, with increasing acknowledgment of the importance of cancer surveillance, more and more cancer registries have been set up to collect the incidence, death, and follow-up information of cancer required by NCCR.

Zhejiang Province is located on the Eastern coastline of China, with a relatively developed economy, a high urbanization level, and a rapidly aging population. Aiming to get a better understanding of the epidemiological characteristics and trends of laryngeal cancer in Zhejiang cancer registry during 2000–2011, we used the standardized quality control and statistical methods to analyze the incidence and mortality that were vital for making decision about laryngeal cancer prevention and control.


 > Materials and Methods Top


Data source

The laryngeal cancer information was reported from eight cancer registries (comprising Jiashan, Jiaxing, Haining, Hangzhou, Shangyu, Xianju, Kaihua, and Cixi) in Zhejiang Province. The data were collected from hospitals and community health centers, including the new rural cooperative medical system, the basic medical insurances for urban residents, and other methods. The all death surveillance system was linked with the cancer incidence database for identifying the cases with death certificate only (DCO) and passive follow-up. Zhejiang Provincial Cancer Center (ZJCC) is responsible for cancer data collection, evaluation, and analysis from the local population-based cancer registries. The 8 cancer registries (3 urban areas and 5 rural areas) submitted data to the ZJCC for the year 2000–2011. Laryngeal cancer cases were classified according to the International Classification of Diseases for Oncology, 3rd edition and the International Statistical Classification of Diseases and Related Health Problems 10th Revision (ICD-10). The invasive cases of laryngeal cancer (ICD-10: C32) from 2000 to 2011 were extracted and analyzed from the overall cancer database.

Quality control

Data were checked and evaluated by ZJCC based on "Guideline for Chinese Cancer Registration" and referring to data quality criterion of "Cancer Incidence in Five Continents Volume IX" by IARC/International Association of Cancer Registries (IACR). MS-Excel and IARC-crg Tools (2.05, Ferly, IARC/IACR) were used for data collection, sorting, checking, and evaluation. The proportion of morphological verification (MV%), percentage of cancer cases identified with DCO%, mortality to incidence ratio (M/I), as well as percentage of uncertified cancer (unknown basis [UB%]), were used to evaluate the completeness, validity, and comparability of data quality.

Statistical analysis

Laryngeal cancer incidence and mortality were calculated as the annual number of new/death cases per million person-year and were further stratified by area (urban/rural), sex (male/female), and age groups (0, 1–4, 5–84 by 5 years, 85+ years). The Chinese population in 2000 and the World Segi's population were used for age-standardized rates. The cumulative risk of developing or dying from cancer before 75 years of age (in the absence of competing causes of death) was calculated and presented as a percentage. Average annual percent changes (AAPCs) and 95% confidence intervals (95% CIs) of laryngeal cancer incidence and mortality were calculated for temporal trends from 2000 to 2011. The logarithmic trend line was also drawn to reflect the time trends of incidence and mortality in MS-Excel. SAS version 9.2 (SAS Institute Inc., Cary, USA) was used to calculate the incidence and mortality rates. Joinpoint Regression Program version 4.0.0 (Statistical Research and Applications Branch, National Cancer Institute) was used to calculate AAPC and 95% CI.


 > Results Top


Data quality

After data cleaning and assessment, laryngeal cancer information from eight population-based cancer registries (three in urban and five in rural areas) were included for analysis. During the 12 years, the eight cancer registries covered a total of 81,758,277 person-year population (65,500,842 in urban and 16,257,435 in rural areas) including 41,315,911 person-year males and 40,442,366 person-year females. In the year of 2011, the eight cancer registries covered a population of 11,060,990 including 5,542,816 males and 5,518,174 females and representing 23.21% of Zhejiang population. The data quality indicators of M/I ratio, MV%, DCO%, and UB% were presented in [Table 1].
Table 1: Quality control index of laryngeal cancer in Zhejiang cancer registry, 2000–2011

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Incidence

There were 1359 new cancer cases of larynx (1267 males and 92 females) diagnosed in Zhejiang registration areas from 2000 to 2011, accounting for 0.58% of all new cancer cases. The crude incidence was 1.66/105 (3.07/105 in male and 0.23/105 in female). The age-standardized incidence rates were 1.10/105 by Chinese population (ASIRC) and 1.12/105 by world population (ASIRW), respectively. Among the patients aged 0–74 years, the cumulative rate was 0.14%. The incidence in males was 13.8 times as high as that in females. And also, the incidence in urban areas was higher than that in rural areas. The incidence data are summarized in [Table 2].
Table 2: Laryngeal cancer incidence in Zhejiang cancer registry, 2000–2011

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From 2000 to 2011 in Zhejiang cancer registration areas, the incidence of laryngeal cancer was relatively low in subjects under 44 years old. Then it increased sharply after 45 years old and finally reached the peak in subjects of 75–79 years old. The patterns of age-specific incidence were quite similar between the urban and rural areas. The male incidence in urban areas was higher than that in rural areas for almost all the age groups except for the age group of 30–34 years, while the female incidence in rural areas was slightly higher than that in urban areas except for the age group of 60–69 years. The age-specific incidence of laryngeal cancer is shown in [Figure 1].
Figure 1: Age-specific incidence of laryngeal cancer in Zhejiang cancer registry, 2000–2011

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Mortality

There were 463 cases died from laryngeal cancer in Zhejiang cancer registration areas during 2000 to 2011, accounting for 0.34% of cancer death. The crude mortality was 0.57/105 (0.98/105 in males and 0.14/105 in females). The age-standardized mortality rates of Chinese population and world population were 0.28/105 and 0.35/105, respectively. Among the patients aged 0–74 years old, the cumulative rate was 0.04%. The mortality in males was 7.14 times as high as that in females. Meanwhile, the mortality in urban areas was relatively higher than that in rural areas. The mortality data are summarized in [Table 3].
Table 3: Laryngeal cancer mortality in Zhejiang cancer registry, 2000–2011

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The mortality of laryngeal cancer was at a low level in subjects under 49 years old. The rate dramatically increased in subjects over 50 years old, and then peaked in the age group of 80–84 years. The male age-specific mortality in urban areas was relatively higher than that in rural areas, except for the age group of 55–59 years. Meanwhile, the female age-specific mortality in urban areas was a bit higher than that in rural areas, except for the age group of 50–59 years and 65–69 years. The age-specific mortality of laryngeal cancer is shown in [Figure 2].
Figure 2: Age-specific mortality of laryngeal cancer in Zhejiang cancer registry, 2000–2011

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The time trends of incidence and mortality

The crude incidence of laryngeal cancer in Zhejiang cancer registration areas in 2000 was approximately 1.39/105 and it reached 1.78/105 in 2011, with the AAPC of 2.47% (95% CI: 0.56–4.42%) [Table 4]; the temporal trend line indicates that incidence remained steady during the 12 years [Figure 3]. Among the males, the crude incidence was about 2.38/105 in 2000, then it increased to approximately 3.33/105, with AAPC of 3.21% (95% CI: 1.26–5.20%); and it turns out that the incidence of laryngeal cancer in males had kind of upward trend. The AAPC of incidence in females had no statistical significance; meanwhile, its temporal trend line seemed a downtrend. In addition, the incidence in rural areas apparently increased greater than that in urban areas.
Table 4: Average annual percent changes of laryngeal cancer incidence and mortality in Zhejiang cancer registry, 2000–2011

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Figure 3: Temporal trends of crude laryngeal cancer incidence in Zhejiang cancer registry, 2000–2011

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The crude mortality of laryngeal cancer in Zhejiang registration areas in 2000 was about 0.30/105 and increased to 0.66/105, with the AAPC of 4.24% (95% CI: −0.44%–9.14%) which showed no statistical significance [Table 4]; the temporal trend line indicates that mortality was going up to a certain extent, but not evident [Figure 4].
Figure 4: Temporal trends of crude laryngeal cancer mortality in Zhejiang cancer registry, 2000–2011

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 > Discussion Top


The present study demonstrated the numbers of new cases and deaths of laryngeal cancer as well as a preliminary overview of laryngeal incidence and mortality based on the pooled data from eight population-based cancer registries in Zhejiang during 2000–2011, in order to provide the scientific basis for making strategies on prevention and control of laryngeal cancer.

Laryngeal cancer comprises only a small part of overall mortality due to cancer, with wide variations among different countries. Laryngeal cancer mortality rates are the highest in Central and Eastern Europe and the lowest in Western Africa, but this partly reflects the varying data quality worldwide.[3] On a global scale, it accounts for 130,000 new cases per year in men and 21,000 in women, with significant differences in incidence across countries.[6] In the year of 2012, there were around 156,877 new cases (accounting for approximately 1% of all tumors) and 83,376 deaths (1% of total cancer deaths) from laryngeal cancer in the world; the highest world age-standardized incidence and mortality rates for laryngeal cancer are both in the Republic of Cuba. In 2011, China remained at a relatively low level of both incidence and mortality (1.14/105 and 0.61/105, respectively); China's laryngeal cancer incidence rates were estimated to be the 5th lowest in Asia, and mortality rates were the 6th lowest.[3] In addition, the incidence of laryngeal cancer in China was lower than that in Korea (1.5/105), but closed to that in Japan (1.1/105); the mortality of laryngeal cancer in China was higher than that in Korea (0.5/105) and Japan (0.2/105).[7] Recently, a report of cancer survival based on 21 cancer registries in 2003–2005 in China showed that the 5-year relative survival rates of laryngeal cancer for male and female were 52.9% and 44.4%, respectively.[5] However, the corresponding survival was in the range from 60% to 80% for males and exceeding 80% for females reported from six cancer registries within the Monitoring of Cancer Incidence in Japan project in 2000–2002.[8] The poorer survival rate of laryngeal cancer might in a way explain the reason why China had a similar incidence to Japan, but a higher mortality than that had.

Zhejiang is an Eastern coastal province of China, which belongs to comparatively, economically developed regions, and the per capita GDP exceeded $10000 for the 1st time in 2012.[9] During the period of 2000–2011 in Zhejiang cancer registration areas in China, the crude incidence rate was 1.66/105. Laryngeal cancer is much rarer in females than in males. The male to female sex ratio of incidence rate was 13.8. What's more, the mortality rate in males was 7.14 times as high as that in females. The incidence rate in urban areas was higher than that in rural areas while the difference in mortality rate between the urban and rural areas was quite modest. The ASIRC in Zhejiang cancer registration areas from 2000 to 2011 was 1.10/105, which is slightly higher than the figure from the NCCR in 2011, and its ASIRC was 1.13/105.[7] The incidence rate was 1.39/105 in 2000, and it increased to 1.78/105 in 2011, increased about 28.06%, with the AAPC of 2.47%. The crude mortality of laryngeal cancer in Zhejiang cancer registration areas in 2000 was about 0.30/105 and increased to 0.66/105 in 2011, with the AAPC of 4.24%. The increment of incidence was significantly higher than that of mortality. The temporal trend line indicates that the incidence and mortality remained steady during the 12 years. However, we observed the increasing incidence and mortality for men and decreasing incidence and mortality for women. The declining incidence for women were in agreement with earlier reports,[10],[11] although these decreases did not reach statistical significance.[11]

Age-specific incidence rates in the age group of 75–79 years achieved the highest point, which reached 7.68/105 in Zhejiang cancer registration areas. While in the national cancer registration areas, the incidence peaked in the age group of 80–84 years in urban areas and peaked in the age group of 85-year in rural areas.[7] The results reflected the aging population was an important cancer hazard. The data of Zhejiang cancer registration areas in China shows that the incidence of laryngeal cancer in males is rising up. Early, the laryngeal carcinoma is typically little and asymptomatic, and the higher mortality from laryngeal cancer in China could be mainly due to late presentation.[7] Therefore, we should effectively adopt the early detection and early treatment to reduce the mortality from laryngeal cancer.

Previous studies have confirmed that the main risk factor for laryngeal cancer is smoking, including passive smoking;[12] Park et al. showed that 73.0% in males and 24.0% in females of laryngeal cancer were caused by tobacco smoking in Korea;[13] Wienecke et al. reported that 74.4% male and 65.7% female laryngeal cancer cases were caused by tobacco smoking among the patients aged over 35 years old in Germany.[14] The corresponding proportion of the laryngeal cancer patients who had the habit of smoking in China was 92.4%[7] while the percentage in Japan was a considerably high amount of 96.5%.[15] In addition, alcohol consumption is also a major risk factor of laryngeal cancer. From the research by Van Dijk et al., laryngeal cancer trends should be interpreted in terms of patterns and changes in the proportion of heavy drinkers.[16] Bosetti et al. concluded that elevated the laryngeal cancer mortality rates were found both in countries with high consumption of wine (such as France and Italy), hard drinks, and fruit-derived spirits (such as Hungary, the Russian Federation, and other Eastern European countries).[17] Particularly, the interactional combination of tobacco consumption and alcohol intake will possibly increase the risk of laryngeal cancer.[18] Alcohol intake is more closely related to cancer of the supraglottis when compared with cancers of the glottis and subglottis.[19] Diet may also have an impact on laryngeal cancer mortality, and particularly, the consumption of vegetables and fruits, which have been related to a reduced laryngeal cancer risk, may have had some effect in reducing the mortality from this neoplasm.[20],[21] Another risk factor may be human papilloma virus (HPV) infection. It is proved that Chinese laryngeal cancer patients have a relatively high level of HPV infection and the number of infected patients tend to increase over time.[7],[22] Sokic et al.[23] and Ramroth et al.[24] have concluded that environmental and occupational wood dust exposure will greatly increase the risk of laryngeal cancer; higher exposure to hardwood and softwood dust contribute to the evidence that wood dust, in particular from hardwood, is an independent risk factor.[24] We also observed that the gender influenced the incidence and mortality significantly. The rates of males were much higher than that of females. It is suggested that the expressions of androgen receptor and estrogen receptor may have the effects on the pathogenesis of laryngeal carcinoma.[25]


 > Conclusions Top


Laryngeal cancer significantly influenced the quality of life for the patients. Zhejiang Province has a relatively low level of laryngeal cancer burden during the recent 12 years in China, however, the increasing incidence and mortality in males, especially in the elderly is worrying. Anyway, the comprehensive strategies, including health education, health promotion, early detection, and cancer screening should be carried out to prevent the upward trend of laryngeal cancer. Our study will serve as a basis for laryngeal cancer prevention and control, public health policy implementation and evaluation, as well as scientific research.

Acknowledgments

We are grateful to all the population-based cancer registries for data collection, sorting, verification, and database creation.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

 
 > References Top

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Machii R, Saika K. Five-year relative survival rate of larynx cancer in the USA, Europe and Japan. Jpn J Clin Oncol 2014;44:1015-6.  Back to cited text no. 8
    
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Wienecke A, Barnes B, Lampert T, Kraywinkel K. Changes in cancer incidence attributable to tobacco smoking in Germany, 1999-2008. Int J Cancer 2014;134:682-91.  Back to cited text no. 14
    
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Van Dijk BA, Karim-Kos HE, Coebergh JW, Marres HA, de Vries E. Progress against laryngeal cancer in The Netherlands between 1989 and 2010. Int J Cancer 2014;134:674-81.  Back to cited text no. 16
    
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  [Table 1], [Table 2], [Table 3], [Table 4]



 

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