Hospital-based Population of Elderly Cancer Cases in Northeastern Thailand

A rapid decline in fertility and improved life expectancy result in the dramatic increase in older adults, both absolute numbers and as a ratio in Thailand (Knodel et al., 2011). The proportion of older individuals will increase from 13 percent in 2010 to 30 percent by 2030 (Office, 2014). Aging is a significant risk factor for developing cancer (Lichtman et al., 2014). As people get older, more will suffer from cancer. More than 60% of cancers are diagnosed in those age more than 65 years old (Yancik, 1997). Since Thailand is moving toward an ageing society, the number of cancer diagnoses in elderly patients is expected to increase. Dealing with elderly cancer is a challenge for oncologists. Not only the limitation in functional status, but also the problems with co-morbidity, frailty, polypharmacy, and treatment toxicity (Lichtman et al., 2014; Maggiore et al., 2014). Both the disease and its treatment affect overall life expectancy, quality of life, and burden for the caregivers (Chindaprasirt et al., 2014). Therefore, we conducted this overview of elderly cancer data derived from Srinagarind Hospital cancer registry to get a perspective of the trends of cancer type and its impact in Northeastern Thailand.


Introduction
A rapid decline in fertility and improved life expectancy result in the dramatic increase in older adults, both absolute numbers and as a ratio in Thailand (Knodel et al., 2011). The proportion of older individuals will increase from 13 percent in 2010 to 30 percent by 2030 (Office, 2014).
Aging is a significant risk factor for developing cancer (Lichtman et al., 2014). As people get older, more will suffer from cancer. More than 60% of cancers are diagnosed in those age more than 65 years old (Yancik, 1997). Since Thailand is moving toward an ageing society, the number of cancer diagnoses in elderly patients is expected to increase.
Dealing with elderly cancer is a challenge for oncologists. Not only the limitation in functional status, but also the problems with co-morbidity, frailty, polypharmacy, and treatment toxicity (Lichtman et al., 2014;Maggiore et al., 2014). Both the disease and its treatment affect overall life expectancy, quality of life, and burden for the caregivers (Chindaprasirt et al., 2014).
Therefore, we conducted this overview of elderly cancer data derived from Srinagarind Hospital cancer registry to get a perspective of the trends of cancer type and its impact in Northeastern Thailand.
if they are required. Only relevant data were presented in this study.

Results
During 1993-2012, a total of 73,218 new cancer cases were diagnosed in Srinagarind Hospital and elderly patients (≥65 years) accounted for 31.6% of all cancer patients. The number of older patients increased from the first to the second decade, but the mean age was comparable; 71.2 vs 71.9 years (Table 1). From from the first to the second, new elderly cancer cases increased by 46%. The absolute number of patients increased in all age groups but the number of the oldest old (≥80 years) doubled. The number of cancer cases had been rather stable from 1993-2005, but increased gradually since then ( Figure 1). Male patients outnumbered female patients in all age groups except those aged more than 80. Table 1. Gender and age distribution of cancer cases in patients age ≥65 years diagnosed during 1993-2012 (the first decade) and 2003-2012 (the second decade).
The top three cancers for overall population over the age of 65 years were liver and bile duct, head and neck, and lung cancer as shown in Figure 2. Most of the patients age 65-69 years. In male patients, the top five cancers were liver and bile duct, lung, colorectal, oral cavity, and prostate cancer ( Figure 3A). In female patients, the top five cancers were liver and bile duct, oral cavity, cervix uteri, colorectal, and lung cancer ( Figure 3B).
Liver and bile duct cancer was the most common cancer in both males and females. It has outnumbered other cancers and showed an accelerating increase during the last five years (Figure 3). Most of the patients aged 65-   Colorectal cancer was the third and the fourth most common cancer in males and females, respectively. New patients increased substantially in both sexes and rose to nearly four-fold from 33 cases in 1993 to 122 cases in 2012 (Figure 4).
Lung cancer was the second most common cancer in males and the fifth in females. The figure of new cases was rather constant during the two decades for male patients, approximately 100 cases per year. In females, however, the total number markedly rose especially in the last few years ( Figure 5).
Interestingly, thyroid cancer figures considerably increased in older women, with only 93 cases in the first decade to 266 cases in the second. Likewise, breast and ovarian cancer numbers also gradually increased in the last 10 years. The figures for both cancers nearly doubled from the first to the second decade.

Discussion
We found that the number of new elderly cancer cases increased substantially especially in the last five years. Liver and bile duct cancer was the most common in older men and women from Northeastern Thailand. Interestingly, prostate, thyroid, and colorectal cancer numbers had the highest percentage of increase of new cases from the first to the second decade.
The number of elderly cases rose in the last few years. The finding is consistent with other hospital-based registry in Thailand and data from the US and the UK (Attasara et al., 2014;Surveillance, 2015;UK, 2015). The increase of overall cancers in elderly could be due to an expanded population size, demographic shift toward aging society in Thailand, better diagnostic tools, and easier access to healthcare system from the policy of universal coverage since 2001.
Liver and bile duct cancer have always been the burden of this region of the world. Despite the effort in promoting healthier and safer lifestyle to prevent opisthrochis viverrini infestation, new cases are still sky high. The same trend as the all age-group population was reported earlier (Wirasorn et al., 2014). Surgery is the most effective therapy for the disease (Friman, 2011) however, most of the older patients may not be able to tolerate major surgery like hepatectomy or wedge resectio. They could not tolerate chemotherapy either (Sookprasert et al., 2012). The mortality for older patients with cholangiocarcinoma is likely to be high and it is an urgent issue for healthcare workers in this region.
Although prostate cancer cases have doubled from from the first to the second decade, the total number of cases was fewer compared with the data from UK or Norway (Syse et al., 2012;UK, 2015). The number of thyroid cases surprisingly rose in older women in the second decade. We do not have the mortality data, but we assume that it must be low, inferred from the data from other parts of the world (Pellegriti et al., 2013). The experience of overdiagnosis of thyroid cancer from South Korea made us to consider more about screening or even operating in thyroid cancer especially in older age group (Ahn et al., 2014).
Our data could not refer to community incidences which was the major limitation of this study. Since we reported only hospital-based cases and there was no data about mortality rate, we could not conclude entirely the real burden of elderly cancer.
In conclusion, elderly cancer cases have been increasing and liver and bile duct cancer is still the burden in this part of the world. Treatment modalities and palliative care for older populations are urgently needed.