|Year : 2020 | Volume
| Issue : 4 | Page : 678-682
Incidence and pattern of distribution of cancer in India: A secondary data analysis from six population-.based cancer registries
Rohan Shetty, Rohan Thomas Mathew, Manavalan Vijayakumar
Department of Surgical Oncology, Yenepoya Medical College Hospital, Mangalore, Karnataka, India
|Date of Submission||18-Sep-2020|
|Date of Decision||07-Nov-2020|
|Date of Acceptance||10-Dec-2020|
|Date of Web Publication||25-Dec-2020|
Rohan Thomas Mathew
Department of Surgical Oncology, Yenepoya Medical College Hospital, Mangalore - 575 018, Karnataka
Source of Support: None, Conflict of Interest: None
Background: The incidence of cancer is on the rise in India as well as around the globe. Earlier oral, breast, and cervical cancers constituted a major burden of cancer in India. However, the recent world statistics suggest that the proportion of lung, colorectal, breast, and prostate cancers is increasing. The Indian National Cancer Registry reports provide robust data regarding the cancer incidence in India.
Objectives: We aimed to analyze the Indian National Cancer Registry report of 2020 to determine whether there has been a change in the trend of cancer incidence.
Materials and Methods: Six population-based cancer registries (PBCR) with the highest number of patients were selected from each zone of the country. From these, a total of 1,87,891 patients were included in the study to ensure a pan-India representation. The relative proportion of oral, breast, cervical, lung, ovarian, endometrial, and prostate cancers was determined from these PBCRs. The mean of these values for each of these cancer types from the six PBCRs was considered the mean proportion of these cancer types across the country.
Results: According to data from the PBCRs, lung and oral cancers were found to be the leading cancer types among men, and breast and cervix uteri cancers among women. The mean relative proportions showed that oral, breast, and cervical cancers still constitute the major bulk of this disease in India. Moreover, it was observed that the incidence of lung cancer has significantly increased. Likewise, the incidence of the cancers of the prostate, ovary and endometrium is also on the rise. The highest age-adjusted incidence rates (AAR) for men were noted in the Aizawl district of Mizoram and the highest AAR for women was in Papumpare district of Arunachal Pradesh.
Conclusion: There continues to be a disproportionately high incidence of cancers in northeast India. Policymakers and healthcare professionals should focus on the emerging cancers along with oral, breast, and cervical cancers, which still constitute the major cancer burden in our country.
Keywords: AAR, registry, India, PBCR, cancer incidence
|How to cite this article:|
Shetty R, Mathew RT, Vijayakumar M. Incidence and pattern of distribution of cancer in India: A secondary data analysis from six population-.based cancer registries. Cancer Res Stat Treat 2020;3:678-82
|How to cite this URL:|
Shetty R, Mathew RT, Vijayakumar M. Incidence and pattern of distribution of cancer in India: A secondary data analysis from six population-.based cancer registries. Cancer Res Stat Treat [serial online] 2020 [cited 2021 Jan 21];3:678-82. Available from: https://www.crstonline.com/text.asp?2020/3/4/678/304968
| Introduction|| |
Cancer incidence is continuously increasing in India. Earlier studies have reported that oral, cervical, and breast cancers constitute the common malignancies in India, comprising about 34% of all the reported cases. Cancer treatment causes a significant burden on the healthcare delivery system as the majority of patients present at later stages. This also causes a significant economic strain on the patients, particularly those from the lower socio-economic strata. The incidence and pattern of distribution of cancers across the country can provide valuable insights to the policy makers and advocacy groups to improve the planning for the prevention and early diagnosis of cancer. Moreover, it can help to appropriately allocate resources towards cancer screening programs, based on the geographical distribution of specific cancers.
A cancer registry is defined as an organization for the systematic collection, storage, analysis, interpretation, and reporting of data on patients with cancer. The Indian Council of Medical Research (ICMR) and the National Centre for Disease Informatics and Research (NCDIR) have been collecting data pertaining to cancer since 1982. Recently, they published the report of the National Cancer Registry Programme 2012–2016. A population-based cancer registry (PBCR) is a systematic collection of information on reportable neoplasms from multiple sources in a geographically defined population residing in an area for a period of one year. On the other hand, hospital-based cancer registries (HBCRs) deal with the data on treatment, management, and outcomes of the patients reporting to a specific hospital.
The cancer registries include data about the age group, cancer incidence, cancer mortality, crude incidence rate, age-specific rate, age adjusted, or age standardized rate.
The cancer registry report provides robust data on the incidence, pattern of distribution, and burden of cancer across the country. The aim of this study was to highlight the geographical distribution and type of cancers that we need to focus on to reduce the cancer incidence, and to eventually reduce the morbidity and mortality arising from the disease. We also aimed to determine the emerging cancer types in the country.
| Methodology|| |
General study details
This is a secondary data analysis study that was initiated after the publication of the report of the National Cancer Registry Programme (NCRP) in July 2020. This study was not funded by any agency. Approval from the Institutional Ethics Committee was not obtained for this study as the data were available in the public domain. There was no direct contact with the patients, and no patient identifiers were included in the study. Therefore, informed consent of the patients was not obtained. This study was conducted according to the ethical guidelines established by the Declaration of Helsinki and the Indian Council of Medical Research.
The data for this study were obtained from the published reports of 28 PBCRs and 58 HBCRs. The data were collated and published as a single report by the ICMR, and were available in the public domain. For this analysis, we selected only the PBCR data as we believed it would better represent the scenario across the country. The 28 PBCRs were geographically divided into the north, south, east, west, central, and northeast zones. One PBCR was identified from each of these six zones that had the highest number of reported cases. From these six PBCRs, a total of 1,87,891 patients were included in the study.
The primary endpoint of our study was to understand the trends of cancer incidence in India. Moreover, we aimed to determine if the incidence of other cancers in India was on the rise, and if so, which these emerging cancers were.
We chose the PBCRs with the highest number of reported patients from each region. These were the PBCRs of Delhi, Chennai, Mumbai, Kolkata, Nagpur, and the Tripura State. The mean relative proportions of cancers of the oral cavity (including mouth and tongue), breast, cervix uteri, lung, prostate, ovaries, and corpus uteri (endometrium) in these PBCRs were determined. These proportions were then further analyzed and compared to determine the emerging cancers in India.
We defined the various endpoints in our study as follows: Relative proportion: It is the proportion of a specific cancer type in relation to all the other cancer types in a particular cohort or population. Mean relative proportion: It is the arithmetic mean of the relative proportions of a specific cancer type in different populations. Age-adjusted incidence rate (AAR): It is used to reduce the age bias in cancer incidence, as the incidence of cancer increases with age. This makes the rates of cancer comparable between countries. A world standard population that takes into account the age structure is used to arrive at age-adjusted or age-standardized incidence rate.
A formal sample size calculation was not performed for this study. The relative proportion of cancers of the oral cavity (including mouth and tongue), breast, cervix uteri, lungs, prostate, ovaries, and corpus uteri (endometrium) were tabulated. From these, the mean relative proportions were calculated to arrive at a pan-India relative proportion. Microsoft Excel was used for data analysis. No other statistical tests were performed as the raw data were not available in the public domain. Additionally, the most common cancers in both the sexes for each PBCR were also tabulated. Likewise, the AAR for all cancers in all PBCRs were also tabulated.
| Results|| |
The details of the PBCRs and the data extracted are presented in [Figure 1]. Ten PBCRs reported lung cancer to be the most common cancer among men, whereas nine reported oral cavity cancer as the commonest cancer among men. This was followed by esophageal and stomach cancers. For women, 21 PBCRs reported breast cancer to be the most common cancer, followed by cancers of the cervix uteri [Table 1]. In majority of the PBCRs that reported breast cancer as the most common cancer, cervix uteri cancers were the second most common [Table 2].
|Table 2: Relative proportion of specific cancers in the selected population-based cancer registries (in percentage)|
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The crude rate, AAR, and truncated rates from the PBCRs of the northeast region are tabulated in [Table 3]. A comparison of the AARs per million population of all the PBCRs showed a high incidence of cancer in the northeast region of the country. The Aizawl district of Mizoram had the highest AAR for men at 269.4, while Papumpare district of Arunachal Pradesh had the highest AAR for women at 219.8. These were among the highest AARs in the country.
|Table 3: Crude rate, age-adjusted rate, and truncated rate of population-based cancer registries in Northeast region|
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The relative proportions of the selected cancer types from the selected PBCRs were tabulated [Table 2], and their mean relative proportions (in percentage) have also been presented in [Figure 2] and [Figure 3].
| Discussion|| |
The calculated mean relative proportions indicated that oral, breast, and cervical cancers continued to be the major contributors to the burden of cancer in India. The incidence of lung cancer is increasing in India. Trends in the geographical distribution indicate a high incidence of cancers in the northeast region of the country. In most of the PBCRs, lung and oral cavity cancers were the most common cancers among men. Among women, breast and cervix uteri cancers were the most common cancer sites. To determine the emerging cancers in India, we analyzed the relative proportion of the prostate, ovarian, and corpus uteri (endometrium) cancers along with lung, oral cavity, and breast cancers. For men, the mean relative proportions of the oral, lung, and prostate cancers were 15.6%, 12.15%, and 6.04%, respectively. For women, the mean relative proportions of the breast, cervical, ovarian, endometrial, oral, and lung cancers were 26.3%, 11.23%, 6.38%, 3.86%, 4.55%, and 4.74%, respectively.
A similar trend has been reported in the previous cancer registry report, as well as in other published data. Earlier, oral, breast, and cervical cancers constituted the major burden of cancer in India. The current report suggests the continuation of this trend, but also suggests an increase in the incidence of lung cancer. Global statistics indicate high incidences of lung, prostate, and colorectal cancers among men. Among women, the incidence is highest for breast, colorectal, and lung cancers. The emerging cancer profile of our country correlates with the global statistics where the incidence of lung, breast, and prostate cancers is expected to rise. Nevertheless, oral, breast, and cervical cancers still are the commonest cancers in India. Together they constitute more than 50% of all cancers reported in India. Global statistics identify colorectal cancer as the leading cancer type in both men and women, and a few PBCRs in India indeed show an increased incidence of colorectal cancers. Therefore, colorectal cancer should also be prioritized to keep a check on its increasing incidence.
The registry also highlights the high incidence of cancer in the northeast region of the country. The stark contrast seen in the incidence is worrying and needs to be addressed. The pattern of incidence is also different in northeast region. In men, the common cancers are esophagus, stomach, hypopharynx, and lung cancers, whereas in women it is cervix uteri, breast, and stomach cancers. Nasopharyngeal cancers, that are uncommon in other parts of the country, are also very common in this region. Different studies have reported this phenomenon, and various hypotheses have been put forward to explain this high incidence. Dietary factors, increased use of tobacco, changes in the genetic make-up, etc. are some of the suggested reasons.,Therefore, an urgent intervention from the regulatory authorities is required to correctly identify the risk factors and plan for early interventions to reduce the cancer-related mortality. The northeast region of our country requires organized population-based screening.
Out study had its limitations. We could not perform a detailed statistical analysis on the data as the absolute numbers were not available. Moreover, the data available from the PBCRs do not cover the length and breadth of the country, and hence may not be representative of the ground reality.
Our study emphasizes the trends of cancer in India based on the data from the National Cancer Registry program. It also highlights the importance of the cancer registry programs and their role in understanding the trends of cancer incidence. Oral, breast, and cervical cancers, that still contribute the major bulk of cancer cases in India are relatively easy to treat and have a better outcome if treated early. As much as there is a need to continue focusing on these cancer types, other emerging cancers such as lung, prostate, ovarian, and endometrial cancers should also be made part of the screening and early diagnosis programs.
Cancer being a multifactorial disease with multiple treatment modalities, there cannot be a one-size-fits-all solution, be it in treatment or screening. National screening and early detection programs can prove to be effective in identifying and treating all cancers. A country like India requires decentralized planning with local factors considered. Cultural and regional nuances must be negotiated to implement a successful program to reduce and control cancer incidence. The role of community oncology is important in these circumstances where a holistic approach to cancer control is essential.
Our study shows that there is a considerably high burden of cancer in northeast India. Although, oral, breast, and cervical cancers constitute the major cancer burden in India, equal importance should be given to other emerging cancer types in the country to ensure early detection through screening.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3]
[Table 1], [Table 2], [Table 3]