Indian Journal of Medical and Paediatric Oncology

ORIGINAL ARTICLE
Year
: 2019  |  Volume : 40  |  Issue : 1  |  Page : 90--93

Trends in gallbladder cancer incidence in the high- and low-risk regions of India


Prachi Ravindra Phadke1, Sharayu Sitaram Mhatre2, Atul Madhukar Budukh2, Rajesh Prabhakar Dikshit1,  
1 Centre for Cancer Epidemiology, Tata Memorial Centre, Navi Mumbai; Homi Bhabha National Institute, Mumbai, Maharashtra, India
2 Centre for Cancer Epidemiology, Tata Memorial Centre, Navi Mumbai, Maharashtra, India

Correspondence Address:
Rajesh Prabhakar Dikshit
Centre for Cancer Epidemiology, Tata Memorial Centre, Kharghar, Navi Mumbai - 410 210, Maharashtra
India

Abstract

Background: Gallbladder cancer (GBC), a common cancer surrounding the Gangetic belt of India, accounts for 80%–90% of biliary tract cancers. GBC incidence shows striking geographical variation in India. Materials and Methods: We used the data from the National Cancer Registry Programme for the year 2001–2014 to study the time trends of GBC in the high- and low-risk geographical regions of India. Annual percentage change (APC) in age-adjusted incidence rates was computed by log-linear regression model. Results: Among females, a statistically significant increase in trend was observed in Cachar (APC: 7.0, P = 0.02), Delhi (APC: 4.0, P = 0.04), and Kamrup (APC: 4.3, P = 0.02) marked under high-risk region and in Bengaluru (APC: 5.7, P = 0.04) and Pune (APC: 3.4, P = 0.04) marked under low-risk region. Among males, increasing but statistically nonsignificant trends were observed in Cachar, Dibrugarh, Kamrup, Nagpur, and Sikkim, whereas decreasing trends were observed in Bengaluru, Barshi, Bhopal, and Kolkata. Aurangabad showed a statistically significant decrease in trend (APC: −14.5, P < 0.001) among males. Conclusion: The time trend and pattern of GBC have striking differences within the country as well as in state. Further large-scale region-wise studies are needed to find the risk factors of GBC.



How to cite this article:
Phadke PR, Mhatre SS, Budukh AM, Dikshit RP. Trends in gallbladder cancer incidence in the high- and low-risk regions of India.Indian J Med Paediatr Oncol 2019;40:90-93


How to cite this URL:
Phadke PR, Mhatre SS, Budukh AM, Dikshit RP. Trends in gallbladder cancer incidence in the high- and low-risk regions of India. Indian J Med Paediatr Oncol [serial online] 2019 [cited 2020 Jul 5 ];40:90-93
Available from: http://www.ijmpo.org/text.asp?2019/40/1/90/256159


Full Text

 Introduction



Gallbladder cancer (GBC) is less common in developed countries while its incidence is highest in some parts of India, Chile, and Mexico.[1] Within India, the states such as Assam (rate ratio [RR] [95% confidence interval [CI] – female: 7.18 [4.89–10.55] and male: 3.61 [2.44–5.36]) and Delhi (RR – female: 4.70 [3.93–5.61] and male: 2.04 [1.61–2.60]) showed highest rate compared to South India (RR – female: 0.39 [0.24–0.66] and male: 0.53 [0.33–0.85]).[2] To investigate secular trends in GBC over the past 14 years, we conducted this study to estimate the annual percentage change (APC) in the incidence rate within different regions of India and performed a comprehensive analysis to understand the time trends in different geographical regions of India.

 Materials and Methods



Incidence data

We retrieved age-adjusted incidence rate (AAR) per 100,000 of GBC from the National Cancer Registry Programme (NCRP) database,[3] for the period of 14 years (2001–2004 to 2012–2014). The NCRP database includes 30 population-based cancer registries (PBCRs), namely, Ahmedabad, Aurangabad, Bengaluru, Barshi, Bhopal, Cachar, Chennai, Delhi, Dibrugarh, Kamrup, Kolkata, Kollam, Manipur, Meghalaya, Mizoram, Mumbai, Nagaland, Nagpur, Naharlagun, Pasighat, Patiala, Pune, Sikkim, Thiruvananthapuram, Tripura, Wardha, Sangrur, Mansa, Chandigarh, and SAS Nagar. However, for trend analysis, we considered only 18 registries having AAR available for at least three time periods.

Definition of high- and low-risk regions

We divided Indian states and territories into high- and low-risk regions using incidence rates extracted from the PBCRs. States were considered to be in the high-risk region if PBCR existing in the state observed average AARs of >5.0 per 100,000 persons.[2] Others were considered as low-risk regions. According to the definition, Cachar, Delhi, Kamrup, Dibrugarh, Kolkata, and Sikkim were in the high-risk region, and the rest of the registries were considered to be in the low-risk region. For comparison, average AARs of all registries from high- and low-risk regions were taken for four time periods (2001–2004 to 2012–2014).

Estimation of annual percentage change

APC is a summary measure of the trend over a prespecified fixed interval. APC was estimated independently for both the genders for the selected 18 registries, namely, Aurangabad, Bengaluru, Barshi, Bhopal, Cachar, Chennai, Delhi, Dibrugarh, Kamrup, Kolkata, Kollam, Manipur, Mizoram, Mumbai, Nagpur, Pune, Sikkim, and Thiruvananthapuram for the time period of 2001–2004 to 2012–2014.

Trend was estimated using Joinpoint trend analysis software by the National Cancer Institute.[4],[5] APC was considered statistically significant if P value at 95% CI was ≤0.05.

 Results



[Table 1] and [Table 2] show gender-wise AAR for four time periods (2001–2004 to 2012–2014) in the 18 registries. There are substantial differences in the rates for both the genders, with high rates in Delhi, Cachar, Dibrugarh, and Kamrup and with lowest rates in Bengaluru, Barshi, Chennai, and Aurangabad. Among females, statistically significant increasing trends were observed in Bengaluru, Cachar, Delhi, Kamrup, and Pune, whereas the rates were decreasing in Aurangabad, Barshi, and Manipur. Among males, increasing but statistically nonsignificant trends were observed in Cachar, Dibrugarh, Kamrup, Nagpur, and Sikkim, whereas decreasing trends were observed in Bengaluru, Barshi, Bhopal, and Kolkata. Aurangabad showed a statistically significant decrease in trend (APC: −14.5, P < 0.001) among males.{Table 1}{Table 2}

As shown in [Figure 1] [Supplementary Table 1], in the high-risk region, there was a statistically significant increase in AAR among females (APC: 5.4, P < 0.001), whereas the trend was increasing but statistically nonsignificant among females (APC: 6.3, P = 0.2). No significant increase in AAR was observed in the low-risk region (male – APC: −1.1, P = 0.8 and females – APC: −1, P = 0.5).{Figure 1}[INLINE:1]

[Table 3] shows the within-state variation of AAR (2004–2014) in Maharashtra, northeast region, and south region. In Maharashtra, Mumbai showed slightly higher rates than other three regions, for both genders. There was no variation observed in rates within the four regions in South India. Variability in rates was observed in northeast region, with Cachar, Kamrup, and Dibrugarh registries in Assam showing high rates.{Table 3}

 Discussion



This trend analysis has shown that the rates of GBC incidence in the high-risk region are significantly increasing among females, whereas increasing but statistically nonsignificant trend was observed among males. Several factors such as diagnosis and completeness of reporting can affect the reported incidence of cancer.

In states with low risk of GBC, the rates of GBC were higher only in metro cities (Mumbai, Pune, and Bengaluru), whereas the rates were lower in small towns. This indicates the role of migration from high-risk areas to the metro cities. The role of migration in GBC was previously investigated.[2] It would be interesting to explore if the rising trend is because of high rates of migration from Northern states in India or there is a shift in lifestyle factors such as increase in obesity; consumption of fatty, spicy food; and reproductive factors for females which are contributing to develop GBC.

The time trend and pattern of GBC have striking differences even within state. For example, the rates are rising and are high only in Mumbai, Maharashtra, while among northeastern states, only Assam has high rates whereas Manipur, Mizoram, and Sikkim show low-to-medium rates of GBC. A detailed study about lifestyle patterns in Assam would thus be helpful to understand the reasons for high rates of GBC.

The risk factors of GBC are not widely studied. It has been estimated that the disease has high heritability component and risk loci surrounding ABCB4 and ABCB1 region on chromosome 7 has been identified.[6],[7] The lifestyle factors which are generally considered to increase the risk of GBC are gallstone, obesity, and infection.[8],[9],[10] In addition, among females, high parity is a possible contributing factor for the increase in the risk of GBC.[9]

 Conclusion



The time trend and pattern of GBC have striking differences within the country as well as in state. It would be important to conduct a large-scale study in the high- and low-risk regions of GBC to understand its etiology and to inform government regarding prevention strategies of this fatal disease.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

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