Discover the main tests for early detection of Cancer

Early diagnosis of cancer is a crucial factor in saving lives and reducing the costs of treating the disease, according to health authorities.

Understanding how this diagnosis is achieved is essential now that the incidence of cancer has increasingly increased at young ages, according to a report published in January by American Cancer Society.

Among U.S. adults ages 65 and older, adults ages 50 to 64, and those under age 50, “those under age 50 were the only ones of these three age groups who experienced an increase in overall cancer incidence” of 1995 to 2020, states the report published in the magazine HERE: A Cancer Journal for Clinicians.

Although the overall U.S. population is aging, “we are seeing a movement in cancer diagnoses toward younger people, despite there being more people in older populations,” said William Dahut, chief scientist at the American Cancer Society.

Therefore, early detection of cancer is becoming increasingly necessary, accompanied by primary prevention recommended by medical experts: actions such as exercise and healthy eating, involving reducing the consumption of processed foods, red meat and sugary drinks, and eliminating of alcohol consumption, according to the American Cancer Society.

The World Health Organization (WHO) explains that early identification of cancer consists of early diagnosis and screening.

Early diagnosis is effective for symptomatic cancers and involves awareness of symptoms, medical consultation, access to assessment and diagnostic services, and transition to a subsequent treatment service.

Screening seeks to identify signs of cancer or precancerous lesions in people who do not have symptoms, according to the WHO. Tests such as cytology and mammography are part of this group.

Tests for early detection of cancer

Elmer Huerta, oncologist, Public Health specialist and CNN contributor, highlights that early detection is a form of “secondary prevention”.

Secondary prevention, or early diagnosis, is useful for cancers that have tests to identify them when they are just starting. This prevention covers “a handful of cancers”, says the doctor.

“The difference with primary prevention is that, in it, I am avoiding coming into contact with the risk factor or the cause of the cancer, so that it does not occur, while in secondary prevention the cancer has already started, has already occurred, the cancer has already It’s growing, but it’s growing so slowly that, if there is evidence, I will find it to prevent it from getting worse,” said the oncologist and Public Health specialist.

These are the main early detection tests according to the United States National Cancer Institute:

Cytology to detect cervical cancer

For cervical cancer screening, American Cancer Society recommends human papillomavirus (HPV) testing and a Pap smear. These tests prevent diseases by identifying abnormal cells that can be treated before they become cancer.

Experts recommend carrying out these tests between the ages of 21 and 65, if women have already undergone adequate screening and are not at high risk of cervical cancer. The recommendation for the Pap smear is to start at age 21, and be repeated every three years until age 29. From the age of 30, cervical cancer screening should be done in the same way or can be done with HPV tests or a combined HPV and Pap test every five years until age 65.

Mammogram to detect breast cancer

Mammograms are performed from the age of 40, once a year, until the age of 75. “What it does is identify a cancer that is already growing, but finds it, as we oncologists say, the size of a grain of sugar, small, in time to operate on it and cure it,” said Huerta.

Occult blood test to detect colon cancer

This is a test for occult blood or invisible blood in the stool. “This test is carried out on men and women aged 50 and over. And, if it is positive, a test called colonoscopy can be carried out, which must be carried out every 5 or 10 years from the age of 50 onwards in men and women”, explains Huerta.

Colonoscopy

To reduce the risk of death from colorectal cancer, several tests are necessary, such as colonoscopy, sigmoidoscopy and highly sensitive tests that analyze feces (such as occult blood tests and DNA tests), according to the National Cancer Institute. These same tests prevent the disease from the beginning, because they sometimes find polyps (abnormal nodules in the colon) that can be removed before they turn into cancer.

Experts recommend that people at average risk for colorectal cancer have one of these screening tests from age 45 or 50 until age 75.

Low-Dose CT Scan to Detect Lung Cancer

For lung cancer, a test called low-dose computed tomography is performed, which must be done every five years. However, it is not suitable for everyone, according to Huerta, but for “smokers who have consumed one pack of cigarettes a day for 30 years or two packs of cigarettes a day for 15 years. In other words, heavy smokers.”

In addition American Cancer Society recently expanded its screening recommendations: anyone between the ages of 50 and 80 should be screened for lung cancer if they currently smoke or have ever smoked (regardless of how long ago) at a rate of 20 pack-years. A pack-year is defined as smoking an average of one pack of cigarettes per day for one year.

In addition to these exams, the United States National Cancer Institute highlights:

• Alpha fetoprotein test for people at higher risk of certain types of cancer, which is a blood test to detect liver cancer;
• Resonance magnetic to identify genetic changes that increase the risk of breast cancer;
• Cancer Antigen 125 (CA-125) Examination to detect early ovarian cancer;
• Clinical breast examination and breast self-examination ;
• Tests to detect multiple types of cancer , which measures the biological signals (biomarkers or tumor markers) that cancer cells release into body fluids. This screening test is not completely effective, but is sometimes offered to people at higher risk.

Why early detection is crucial

Dr. Huera says that in some of these types of cancer, the patient may not show any warning signs, which shows the importance of early diagnosis.

The World Health Organization notes that “advanced cancer detection and lack of access to diagnostic tools are common, especially in low- and middle-income countries.”

“Less than 30% of low-income countries have generally accessible diagnostic and treatment services and often lack referral systems for suspected cases of cancer, delaying and fragmenting care,” says the WHO.

Despite this, Huerta highlighted that the message and practical advice that must be clear is that anyone who has access “should go to the doctor before feeling symptoms”: regular exams are recommended.

“Cancer screenings save lives,” explains CNN wellness expert Dr. Leana Wen, an emergency physician and professor of Health Policy and Management at the Milken Institute School of Public Health in George Washington University.

“This is the case for both lung cancer and other types of cancer. Cancers are easier to treat when they are localized, before they spread to lymph nodes and other organs,” Wen said.

Cancer numbers around the world

Cancer remains one of the biggest public health concerns in the world. According to the World Health Organization, in its most recent compilation of consolidated figures, the disease was among the main causes of death in 2020, causing almost 10 million deaths.

The WHO points out that the most deadly cancers this year were lung (1.8 million deaths), colorectal (916 thousand), liver (830 thousand), gastric (769 thousand) and breast (685 thousand deaths).

In terms of cases, according to the WHO, the most frequent in 2020 were breast (2.26 million cases), lung (2.21 million), colorectal (1.93 million), prostate (1.41 million ), skin (1.20 million) and stomach (1.09 million).

*With input from CNN's Jacqueline Howard, Uriel Blanco, Cara Hassan, Jen Christensen and Madeline Holcombe