Numbers of New Cases and Trends of Cancer 1993-2012 : Srinagarind Hospital Based Population , Khon Kaen , North-East Thailand

Cancer is a leading cause of death worldwide in both developed and developing countries, including Thailand (Siegel et al., 2012; Ferlay et al., 2010; Sriplung et al., 2005). In Thailand, the incidence of all cancers and the mortality rate resulting from malignant diseases gradually increase each year. In particular, incidences of colorectal cancer and breast cancer significantly increased during 1989-2000 (Sriplung et al., 2006). Lung cancer, in both males and females, is the most common cancer in many countries (Siegel et al., 2012). However, in Thailand, liver cancer is the most common cancer in males and breast cancer in many parts of the country is the commonest cancer in females (Sriplung et al., 2005), (Public Health Statistic, 2010, reported in Thai language). The number of patients diagnosed with cancer has noticeably increased in Srinagarind Hospital during the last 10 years (unpublished data, reported from Cancer Unit of Srinagarind hospital, 2000-2012). We therefore prepared this overview of all new cancer cases recorded in Srinagarind Hospital during 1993-2012, with an emphasis on changing trends in types of cancer in NE Thailand.


Introduction
Cancer is a leading cause of death worldwide in both developed and developing countries, including Thailand (Siegel et al., 2012;Ferlay et al., 2010;Sriplung et al., 2005).In Thailand, the incidence of all cancers and the mortality rate resulting from malignant diseases gradually increase each year.In particular, incidences of colorectal cancer and breast cancer significantly increased during 1989-2000(Sriplung et al., 2006)).Lung cancer, in both males and females, is the most common cancer in many countries (Siegel et al., 2012).However, in Thailand, liver cancer is the most common cancer in males and breast cancer in many parts of the country is the commonest cancer in females (Sriplung et al., 2005), (Public Health Statistic, 2010, reported in Thai language).The number of patients diagnosed with cancer has noticeably increased in Srinagarind Hospital during the last 10 years (unpublished data, reported from Cancer Unit of Srinagarind hospital, 2000Srinagarind hospital, -2012)).We therefore prepared this overview of all new cancer cases recorded in Srinagarind Hospital during 1993-2012, with an emphasis on changing trends in types of cancer in NE Thailand.
Kosin Wirasorn et al date of last visit, vital status at last follow-up and other necessary information.Deaths were not recorded but these data can be obtained from the civil registration database, if they are required.Only relevant data were presented in this study.

Overall numbers and trends of new cancer cases, 1993-2012
The numbers of new cancer cases recorded between 1993 and 2012 in Srinagarind Hospital are shown in Figure 1.For some analyses, the data were divided into 2 intervals; the first decade (1993)(1994)(1995)(1996)(1997)(1998)(1999)(2000)(2001)(2002) and the second decade (2003)(2004)(2005)(2006)(2007)(2008)(2009)(2010)(2011)(2012).The overall numbers of cancer cases were fairly constant from 1993 to 2005, but has shown an apparently accelerating increase since then.The numbers of male and female patients during the period surveyed were comparable, male patients being slightly more numerous than female.Both genders showed an increase in the last few years, and especially in the period 2010-2012.

Overview of the most common cancers in male and female, 1993-2012
The most common cancers in patients, both male and female, registered in Srinagarind Hospital for the period 1993 to 2012, are shown in Tables 1 and 2, respectively.The order of presentation in the tables is based on the numbers of cases of each type of cancer in the final year of the study.Additionally, data on the five or six most common cancers during 1993-2012 are presented graphically in Figures 2 and 3 for male and female, respectively.
Cancer of the liver and bile ducts was the most common cancer in both males and females (Tables 1 and  2; Figures 2 and 3).In males, this made up over 50% of all cancer cases (Table 1) and has shown a marked increase over the last few years.In females, the number of liver and bile duct cancer cases was approximately half of that in males, despite similar numbers of cancer patients of each gender.In females, cervical cancer was the most common cancer during the first decade of the study (Figure 3) but was subsequently surpassed by cancer of the liver and bile ducts and by breast cancer in the second decade (Table 2 and Figure 3).Nevertheless, in females numbers of cases of cervical cancer almost matched liver and bile duct cancer cases overall, despite very substantial reductions in numbers of cases of the former in recent years.
The second most common cancer in males was lung cancer (Table 1) while it was the sixth most common cancer overall in females (Table 2).The number of new lung cancer cases in males was reasonably constant at approximately 250 cases/year through the 20 year period reviewed (Figure 2) whereas it has gradually increased in females only in the last 10 years and markedly risen especially in the last few years (Figure 3).In 1993, the number of lung cancer cases in females was roughly 50 per year compared to 200/year in 2012.Consequently, lung cancer climbed up into the top five most common cancer in females during the recent 10 years observed.Breast cancer was the second most common cancer in females.Interestingly, the number of breast cancer cases was stable at approximately 200 cases/year during the first 10 years (Figure 3) then increased dramatically up to about 450 cases/year by the end of the second decade (Figure 3).
Colorectal cancer was the third and sixth most common cancer occurring in males and females, respectively (Tables 1 and 2), higher numbers of cases being reported from males (2,275 vs 1,846).The number of cases of colorectal cancer in males was stable at or below 100   1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008  cases/year during the first decade studied but increased considerably during the second decade (Figure 2).Similarly, the number of female patients with colorectal cancer has increased steadily during the last 20 years (Table 2).The fourth most common cancer in females was thyroid cancer with steadily increasing numbers of cases over the period surveyed.Approximately 70 cases/year were diagnosed in the early 1990s, rising to 300 cases/ year at the end of the period, with much of the increase occurring in the last three years (Figure 3).The commonest types of head and neck cancers in males and females differ: nasopharynx cancer was more common in males whereas females more commonly had mouth cancer (Tables 1 and 2).In males, nasopharynx cancer was the fifth most common cancer, with cases remaining stable in number during the last 20 years at approximately 100 cases/year (Figure 2).Cases of mouth cancer in females were likewise relatively stable in number, at between 50 and 75 in each year (Table 2).
Non-Hodgkin lymphoma, was approximately 4-fold more common in males than females.Additionally, it was the fifth most common cancer found in males with numbers of cases remaining stable during the period of study, at approximately 100 cases/year (Figure 2).

Discussion
Srinagarind Hospital is a major tertiary health care center for Northeast Thailand, receiving referrals from all over the region and thereby serving a population of around 22 million people.The hospital is served by many subspecialty physicians with expertise on malignancy, hence, most cancer cases in the NE are referred here to receive the proper management.The data reported here therefore likely reflect actual cancer trends within the broad region.
This study reveals that the overall numbers of cancer cases has increased, especially in the seconddecade of the study and the results are consistent with the incidence of cancer elsewhere in Thailand (Sriplung et al., 2005 andPublic Health Statistic, 2010, reported in Thai language).The three most common cancers in males in Thailand during 2004-2006 were colorectal cancer, lung cancer and liver and bile duct cancer, respectively (Khuhaprema et al., 2012).Additionally, breast cancer, cervix and uterus cancer and colorectal cancers are the three most common cancers occurring in females in Thailand (Sriplung, et al., 2003;Khuhaprema et al., 2007;2010;2012).Thus the results from Srinagarind Hospital during the past 20 Kosin Wirasorn et al years are quite similar to those of Thailand as a whole.A major point to note is that liver and bile duct cancer was the most commonly seen cancer in female patients studied in Srinagarind Hospital, whereas it occupies sixth position in the country as a whole.The proportion of liver and bile duct cancer recorded in Srinagarind hospital is noticeably higher than that of the other part of Thailand.The Northeast region has a high incidence of Opisthorchis viverrini (liver fluke) infection because members of the local population frequently consume uncooked cyprinoid fish, which are the intermediate hosts of this parasite (Sripa and Pairojkul, 2008).Opisthorchiasis is a significant risk factor for bile duct cancer (Sripa et al., 2011).The apparent increase in numbers of liver and bile duct cancers in the last 10 years is probably due to the increasing numbers of referred cases from primary health care centers, extensive health promotion about causes of cholangiocarcinoma (CCA) leading to increased patient awareness, and improved diagnostic technology.In addition, Srinagarind Hospital is famous for expertise on treatment of CCA and some other cancers, hence attracting patients from all over Thailand.
Since we only report numbers of recorded hospitalbased cases, we cannot say whether community incidences of these cancers have changed in the population at large in the period 1993-2012.As mentioned above, numbers of cases reaching Srinagarind Hospital will change according to changes in diagnostic methods and referral patterns, especially if increasing numbers of cases from outside NE Thailand are being referred to Khon Kaen.Changes in screening and early intervention methods might also have influenced the data, as is likely the case for cervical cancer.An effective campaign to promote cervical cancer scanning by Pap smear has been in place in Thailand since 2002 (Kasinpila et al., 2011).In addition, HPV vaccine has been promoted during the last few years in Thailand.These two interventions are expected to reduce the incidence of cervical cancer (Praditsitthikorn et al., 2011) and that is likely reflected in our data.
The increased overall number of cancer cases might be due to demographic factors, such as increasing population size and greater longevity of individuals.It may also reflect an increase in high risk behavior such as unsafe sex leading to HIV or HPV infection, and metabolic syndromes such as diabetes mellitus and obesity (Rattanamongkolgul et al., 2004;Phanuphak et al., 2013;Suthipintawong et al., 2011;Aekplakorn et al., 2004).
The increased numbers of lung cancer cases in females, which is similar to worldwide trends (Mathers et al., 2001;Greenlee et al., 2000), might be because of changing life styles leading, for example, to an increase in passive smoking in bars, pubs and night clubs (Kamsa-Ard et al., 2013).Anti-smoking campaigns are strongly promoted in Thailand; however, fewer females than males seem to be responding (Sagerup et al., 2011) and the numbers of new lung cancer cases in females is still gradually rising.In the last 10 years, the number of breast cancer cases in females has noticeably increased.This might result from the increase in obesity, and the adoption of fat-rich Western diets by the Thai population during recent decades (Sangrajrang et al., 2013).Other factors that may play a part include late child bearing, having fewer children and physical inactivity, all associated with increased westernization (Jemal et al., 2010).

Figure 3 .
Figure 1.Overall Numbers of New Cancer Cases Recorded Annually during 1993-2012 in Srinagarind Hospital