Introduction

Cancer, as defined by Holland,1 is a disease characterized by the uncontrolled division of abnormal cells that invade surrounding tissues, potentially leading to death if left untreated.2 There are more than 200 distinct types of cancer, typically named after the organ or cell type of origin. A hallmark of cancer cells is their reduced adhesion compared with normal cells,34 which facilitates detachment and dissemination to other body parts via the blood or lymphatic system. This process, known as metastasis, results in the formation of new neoplasms called metastatic tumors.

Several behavioral factors are associated with cancer incidence, screening, recurrence, and mortality. For example, cigarette smoking significantly contributes to mortality rates of various cancers, including those of the lung, oral cavity, esophagus, larynx, bladder, stomach, pancreas, kidney, and cervix.1

Cancer is emerging as a significant public health concern in India, including in Himachal Pradesh. India ranks third globally in estimated new cancer cases, with 1.2 million diagnoses in 2018, and second in cancer-related deaths, with 785,000 mortalities that year. According to the Global Cancer Observatory (GLOBOCAN, 2018), the age-standardized rates per 100,000 people were 89.4 for cancer incidence and 61.4 for cancer mortality. Cancer can affect any part of the body and individuals of all ages, although the risk generally increases with age, particularly from middle age onwards. The incidence rates quadruple between ages 40 and 80 for all cancer types combined.56

Breast cancer is the most common form of cancer affecting both men and women. In India, the most prevalent cancers among men are oral cancer (age-standardized rate: 13.9), lung cancer (7.8), stomach cancer (6.2), colorectal cancer (5.8), and esophageal cancer (5.5%). Among women, the most prevalent types are breast cancer (24.77), cervical cancer (14.77), ovarian cancer (5.55), oral cancer (4.33), and colorectal cancer (3.11). The incidence rates of various cancers vary significantly across Indian regions, with a minimum fivefold difference for any cancer type.78 Approximately 18.1 million individuals worldwide live with cancer (National Cancer Institute, 2020). Lung, stomach, liver, colon, and breast cancer cases cause the most cancer deaths annually. Cancer is a major public health burden in both developed and developing countries, with approximately 70% of all cancer deaths in 2020 occurring in low- and middle-income countries (World Health Organization International Agency for Research on Cancer, 2020). In India, approximately 850,000 new cancer cases are diagnosed annually, with approximately 580,000 cancer-related deaths each year.9

There is an alarming increase in cancer cases in Himachal Pradesh, with approximately 8,500 cases detected annually, although many cases are unnoticed in remote areas (Times of India, 2023). Himachal Pradesh, with its rural charm, represents a unique context for studying cancer burden. Predominantly rural, 89.97% of its population lives in rural areas. Health indicators show that Himachal Pradesh performs better than other states, with a crude birth rate of 15.4, a crude death rate of 6.9, an infant mortality rate of 19, and a total fertility rate of 1.6.10

Despite these favorable indicators, the state's increasing incidence of cancer, attributed to tobacco use, lifestyle patterns, environmental risks, and genetic predispositions, presents significant public health challenges. In rural Himachal Pradesh, limited health care access exacerbates the cancer burden, complicating life for individuals, families, and communities. The state has 12 districts, each with a chief medical officer and divided into 75 health blocks, each led by a block medical officer. The health institutions included 3 zonal hospitals, 9 district/regional hospitals, 6 teaching hospitals, 79 civil hospitals, 93 community health centers, 585 primary health care centers, and 2,085 health subcenters.

Shimla district, with a population of 814,010 (2011 census), predominantly rural (75%), has a sex ratio of 916 females per 1,000 males and a literacy rate of 83.64%. Given the growing cancer burden, it is crucial to study cancer trends in Himachal Pradesh to inform advanced control measures. The present study aimed to examine the age and gender trends of cancer patients in rural Shimla district, Himachal Pradesh, India.

Methods

The present study employed a retrospective observational design to examine age and gender trends among cancer patients in rural Shimla, Himachal Pradesh, India. Cancer data were sourced from the Regional Cancer Hospital, Indira Gandhi Medical College, Shimla, for the period 2014 to 2022 as part of the Hospital-Based Cancer Registry. The inclusion criteria included confirmed cancer diagnoses in rural residents of Shimla district, excluding urban residents and nonresidents of Himachal Pradesh. The recorded demographic factors included age (below 11 years and 68 years and above), place of residence, gender, cancer type, and stage at diagnosis (classified as “early” for stages I and II or “advanced” for stages III and IV).

Results and Discussion

The present study addresses the following research questions:

• Research _{Question 1}: What is the age distribution of cancer patients in Shimla district's rural areas?

Age-Wise Trend of Cancer Patients in Each Block

The data are presented in Fig. 1 and the corresponding graph illustrates the distribution of cancer cases across various age groups in different regions. The analysis is as follows:

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Fig. 1: Age-wise trend of cancer patients in each block of the Shimla district.

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Fig. 1 shows that there is a clear trend toward increasing cancer incidence with advancing age. The number of cases was minimal in the youngest age groups and increased significantly from 28 years onwards, peaking in the 58 to 67 years age group. Theog consistently reported the greatest number of cases across all age groups, particularly those aged 38 years and older. Rampur and Jubbal and Kotkhai also had high incidences, especially in the middle to older age groups. Regions such as Chopal, Rohru, and Chirgaon exhibited a lower but still significant number of cases, particularly in older age groups.

• Research _{Question 3}: What are the specific age and gender distribution of patients with different types of cancer in Shimla district's rural areas?

Conclusion

The comprehensive analysis of cancer incidence in Himachal Pradesh reveals crucial insights into the distribution of cases across age groups, genders, and regions, informing public health strategies and resource allocation. The data indicate a significant increase in cancer incidence with age, peaking in the 58 to 67 years age group, and highlight a noticeable increase in cases starting from 28 years onwards. This underscores the necessity for targeted cancer screening and early detection programs, particularly for older adults.

The nearly equal distribution of cancer cases between males (50.1%) and females (49.9%) suggests that cancer affects both genders similarly, emphasizing the need for gender-neutral public health interventions. Significant regional disparities are evident, with Theog, Rampur, and Jubbal and Kotkhai reporting the highest number of cases, collectively accounting for nearly half of the total cancer burden. Conversely, blocks such as Kupvi exhibit the lowest incidence rates. The chi-square analysis confirmed a statistically significant difference in cancer incidence by age and gender, but not by regional distribution within genders.

Based on these findings, several strategic initiatives are recommended: prioritizing health care resources in high-incidence regions to ensure equitable access; implementing widespread and regular cancer screening for high-risk age groups (38 years and older); conducting region-specific educational campaigns focusing on lifestyle changes, early detection, and cancer prevention; involving technical experts to educate rural populations on safe pesticide and chemical use; and strengthening surveillance systems to monitor cancer trends and evaluate intervention effectiveness.

The present study underscores the need for age-specific, gender-neutral, and region-specific public health strategies to manage and mitigate the cancer burden in Himachal Pradesh effectively. By focusing on high-incidence regions and ensuring equitable health care access, public health systems can improve cancer outcomes and reduce mortality rates associated with the disease.