Burden of Cancer & Cancer Screening in India

Cancer is the second leading cause of death globally after heart disease. India has a population of 1.3 billion across 29 states and 7 union territories, with many of the states being as large as other countries, with varying degrees of development, population genetics, environments and lifestyles, leading to a heterogeneous distribution of disease burden and health loss.

INCIDENCE OF CANCERS IN INDIA

Incidence is a measure of the probability of occurrence of a given medical condition in a population within a specified period of time. Incidence conveys information about the risk of contracting the cancer.

The top 15 cancers ranked by crude incidence and mortality rates in India (both sexes combined) are depicted in figure 1. As can be seen from the figure, breast cancer, cervical cancer and cancer of the lips/oral cavity make up the top three in terms of both incidence and mortality rates.

Figure 1 – Estimated crude incidence and mortality rates in 2018, India, both sexes, all ages. Source: GLOBOCAN 2018

The top 15 cancers ranked by crude incidence and mortality rates in India, for males, are depicted in figure 2. As can be seen, cancer of the lips/oral cavity, lung cancer and stomach cancer make up the top three in terms of both incidence and mortality rates. The biggest discrepancy between incidence and mortality rates of cancer in males is seen in cancer of lips/oral cavity. A similar discrepancy when comparing proportions of incidence to mortality can be seen in cancer of the hypopharynx where mortality is approximately a third of the incidence.

Figure 2 – Estimated crude incidence and mortality rates in 2018, India, males, all ages. Source: GLOBOCAN 2018

The top 15 cancers ranked by crude incidence and mortality rates in India, for females, are depicted in figure 3. As can be seen, breast cancer, cervical cancer and ovarian cancer make up the top three in terms of both incidence and mortality rates. The advances in screening and treatment of breast cancer can also be discerned by the fact there is a huge disparity between incidence and mortality. A similar discrepancy when comparing proportions of incidence to mortality can be seen in cancers of the uterine corpus and thyroid, where mortality is approximately a third and a fifth of the incidence respectively.

Figure 3 – Estimated crude incidence and mortality rates in 2018, India, females, all ages. Source: GLOBOCAN 2018

BURDEN OF CANCER

The burden of disability associated with a disease or disorder can be measured in units called disability-adjusted life years (DALYs). DALYs represent the total number of years lost to illness, disability, or premature death within a given population.(2)
DALYs are calculated by adding the number of years of life lost to the number of years lived with disability (YLDs) for a certain disease or disorder.(2)
Percentage of total cancer DALYs due to different types of cancers by sex in India are depicted in Figure 4. Surprisingly, the highest proportion of cancer DALYs, when taking both sexes into account, is due to stomach cancer. When comparing the percentages in males alone, it is lung cancer and in females alone, it is breast cancer.

Figure 4 – Percentage of total cancer DALYs due to different types of cancers by sex in India

GROWING BURDEN OF CANCER IN INDIA

The various reasons for the growing burden of cancer in India are:

• Increasing population
• India’s population is growing and is predicted to be greater than China’s in two decades. As the population grows, so will the number of people with cancer.
• Aging population
• India’s population is aging with a decreasing proportion of youngsters and increasing proportion of elders.
• As the predominant cancer incidence is in the middle-aged to elderly population, cancer burden will keep increasing with the increasing number of elders in India.
• Improved access to less invasive diagnostic tests
• More access to CT–guided biopsy and flexible endoscopy–guided biopsy will result in many more deep-seated cancers being diagnosed, which at times could occur just before death.
• Elderly Indians are seeking better health care
• Retired and elderly Indians who used to shy away from Western medicine have started to visit the clinics and are willing to undergo diagnostic procedures, leading to the detection of more cancers.
• Changing social and cultural practices
• India’s family planning program and right to education are empowering Indian women. An increasing number of women are getting higher education and taking up office work, resulting in later marriages and fewer children.
• These social changes could increase the risk of breast and ovarian cancer.
• Indian states with the most successful family planning programs (eg, Kerala) have the highest breast cancer incidence. However, the incidence of cervical cancer continues to be high among the women of less developed states, who marry early and have high birth rates.
• Increasing risk due socioeconomic prosperity
• Increasing economic prosperity and affordability of conveniences among India’s middle class have increased the per-capita calorie intake and reduced physical activity. This is exposing children, youth, and middle-aged Indians to excess fat gain and obesity.
• Cancer screening
• Casual use of cancer screening tests will diagnose many indolent cancers, particularly, breast, prostate, and low-grade neuroendocrine tumours in the upper and lower GI tract.

CANCER SCREENING

Checking for cancer (or for abnormal cells that may become cancer) in asymptomatic people is called screening. Screening can help find several types of cancer early, before they become symptomatic. Early detection is important because when abnormal cells/cancer is found early, it may be easier to treat. By the time symptoms appear, the cancer may have begun to spread and be harder to treat.
But it is important to keep in mind that, as with any test, screening tests have both pros and cons:

1. Overdiagnosis: The screening test correctly shows that a person has cancer, but the cancer is slow-growing and would not have harmed that person in his or her lifetime, leading to unnecessary overtreatment.
2. False-positives: the test indicates that cancer may be present even though it is not. False-positive test results can cause anxiety and are usually followed by additional tests and procedures that also have potential side-effects.
3. False-negatives: the test indicates that cancer is not present even though it is. False-negative test results may provide false reassurance, leading to delays in diagnosis and possibly causing an individual to put off seeking medical care even if symptoms develop.

TYPES OF CANCER SCREENING TESTS

Not all cancers currently have screening tests, but those that do have specific tests.

Breast cancer:

1. Mammography
   
   Mammography is the most widely used screening modality for the detection of breast cancer. There is evidence that it decreases breast cancer mortality in women aged 50 to 69 years and that it is associated with harms, including the detection of clinically insignificant cancers that pose no threat to life.
2. Clinical breast examination
3. Breast self-examination

Technologies such as ultrasound, magnetic resonance imaging, and molecular breast imaging are being evaluated, usually as adjuncts to mammography, and are not primary screening tools in the average population. Another potential screening test is thermography in which a special camera that senses heat, is used to record the temperature of the overlying skin. Tumours can cause temperature changes that may show up on the thermogram. However, there have been no randomized clinical trials of thermography to find out how well it detects breast cancer.

The U.S. Preventive Services Task Force (USPSTF) recommends that women ages 50 to 74 have mammography every 2 years. They recommend that mammography be considered in women ages 40 to 49 after evaluating the risks and benefits of this test with a doctor.

Cervical cancer:

1. Human papillomavirus (HPV) testing
2. Pap test – Conventional or the recommended LBC testing (Liquid based cytology)

Visual inspection with acetic acid (VIA) is a screening test that can be done with few tools and the naked eye. This screening test is very useful in places where access to medical care is limited.

The ACS/ASCCP/ASCP recommend that women aged 21 to 29 years be screened every 3 years with cytology alone (cervical cytology or Pap testing). Women aged 30 to 65 years should be screened every 5 years with cytology and HPV testing (co-testing) or every 3 years with cytology alone. Women at increased risk of cervical cancer (i.e., women with a history of cervical cancer, a compromised immune system, or diethylstilbestrol exposure) may need to be screened more often. Women who have had CIN 2+ should continue screening for 20 years after the last abnormal test result, even if it extends screening beyond age 65 years.

The ASCCP and SGO issued interim guidance in 2015 that recommended primary HPV screening starting at age 25 years as an alternative to cytology alone or co-testing.

Colorectal cancer:

Five types of tests are used to screen for colorectal cancer:

1. Faecal occult blood test (guaiac faecal occult blood / faecal immunochemical test)
2. Sigmoidoscopy
3. Colonoscopy
4. Virtual colonoscopy
5. DNA stool test

Studies have shown that screening for colorectal cancer using digital rectal exam does not decrease the number of deaths from the disease.
The USPSTF recommends screening for colorectal cancer starting at age 50 years and continuing until age 75 years. The decision to screen for colorectal cancer in adults aged 76 to 85 years should be an individual one, taking into account the patient’s overall health and prior screening history.
In 2012, the National Comprehensive Cancer Network recommended colonoscopy every 10 years as the preferred screening strategy if available; otherwise, it recommended annual guaiac faecal occult blood test (gFOBT) or faecal immunochemical test (FIT), with or without flexible sigmoidoscopy, every 5 years or flexible sigmoidoscopy alone every 5 years as secondary approaches to screening.
In 2015, the American College of Physicians recommended that average-risk adults aged 50 to 75 years should be screened for colorectal cancer by 1 of 4 strategies:
i. annual high-sensitivity gFOBT or FIT
ii. flexible sigmoidoscopy every 5 years
iii. high-sensitivity gFOBT or FIT every 3 years plus flexible sigmoidoscopy every 5 years
iv. colonoscopy every 10 years.

It advised that average-risk adults younger than 50 years, older than 75 years, or with an estimated life expectancy of less than 10 years should not be screened.

Prostate cancer:

Five types of tests are used to screen for colorectal cancer:

1. Digital rectal examination (DRE)
2. Prostate-specific antigen (PSA) test.

A prostate cancer gene 3 (PCA3) RNA test may be used for certain patients. The PCA3 gene assay was approved by the U.S. Food and Drug Administration in early 2012, with the intended use to aid in the decision for repeat biopsy in men with a previous negative biopsy for an elevated PSA and for whom a repeat biopsy is being considered for a persistently elevated PSA. This test is performed on a urine sample collected after an attentive DRE (several strokes applied firmly to the prostate to the right and left prostatic lobes). Using a threshold value of 60, this test enhances the detection of prostate cancer while reducing the number of biopsies in men who are expected to ultimately have a negative biopsy.
According to the USPSTF, for men aged 55 to 69 years, the decision to undergo periodic prostate-specific antigen (PSA)–based screening for prostate cancer should be an individual one. It also recommends against PSA-based screening for prostate cancer in men 70 years and older.
The Memorial Sloan Kettering prostate cancer screening guidelines state that men aged 45-70 should have their PSA levels checked. Testing for men between 71-75 years of age should be based on past PSA levels and the health of the man. These guidelines do not recommend testing for men ages 76 or older.

Lung cancer:

Five types of tests are used to screen for colorectal cancer:

1. Low-dose computed tomography (LDCT)

The USPSTF recommends annual screening for lung cancer with low-dose computed tomography (LDCT) in adults aged 55 to 80 years who have a 30 pack-year smoking history and currently smoke or have quit within the past 15 years. Screening should be discontinued once a person has not smoked for 15 years or develops a health problem that substantially limits life expectancy or the ability or willingness to have curative lung surgery.
In 2012, the American College of Chest Physicians, the American Society of Clinical Oncology, and the American Thoracic Society recommended screening for lung cancer with LDCT, for persons aged 55 to 74 years who have a ≥30 pack-year smoking history and currently smoke or have quit in the past 15 years.
The American Association for Thoracic Surgery recommends annual screening with LDCT in current and former smokers aged 55 to 79 years who have a 30 pack-year smoking history. It also recommends annual screening starting at age 50 to 79 years in patients who have a 20 pack-year smoking history and additional comorbid conditions that produce a cumulative risk for cancer of at least 5% over the next 5 years. Furthermore, it recommends annual screening in long-term cancer survivors aged 55 to 79 years.
In 2013, the American Cancer Society also began recommending screening for lung cancer with LDCT in high-risk patients who are in relatively good health and meet the following criteria – persons aged 55 to 74 years who have a ≥30 pack-year smoking history and currently smoke or have quit in the past 15 years.

CANCER SCREENING & DIAGNOSIS AT SUBURBAN DIAGNOSTICS

Suburban diagnostics offers a large menu of tests which can help screen for, diagnose and monitor treatment of cancer.
Our radiology services including chest x-rays, mammograms and ultrasound can help screen for breast cancer and help in the diagnosis of cancers of the lung, prostate and other pelvic or abdominal organs.
Suburban has a robust cervical cancer screening service with FDA approved liquid-based cytology PAP screening as well as HPV DNA detection and genotyping.
Apart from these, the Suburban Diagnostics test menu also includes numerous biomarkers which may be used for screening, as risk biomarkers, or as a tumour marker; eg: Total PSA, freePSA, AFP, Beta hCG, CA-125, HE4, CA-19.9, CA15.3, CA72.4, CEA etc. Gender-specific cancer panels and cancer specific panels (eg: ROMA index) are included in the test menu. For hematological malignancies, tests like Bence-Jones protein, serum protein electrophoresis, BCR-ABL detection, FLT3 mutation detection, JAK2 mutation, PML-RARA detection etc are available.
Suburban Diagnostics has an advanced histopathology and cytopathology department, with all kinds of special stains and IHC available to clinch cancer diagnosis. Tests required for targeted therapy, and for cancer prognosis (eg: BRAF mutation analysis, EGFR mutation testing, BRCA1+2 testing etc.), are performed at Suburban Diagnostics. The latest “liquid biopsy” i.e. – circulating tumour cells detection test is also available.

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