What kind of disease is cancer? Part 4

Screening and early diagnosis

Atlas company blog, Geektimes

We have already told you what cancer is, what factors reduce and increase the risk of developing this disease. In this article, the experts of the Solo project of the Atlas biomedical holding share information about screening and diagnosis, as well as the types of malignant tumors that can be detected at an early stage.

What is the difference between screening, checkup and early diagnosis

Screening or medical examination is a series of examinations that allows you to detect a tumor in the absence of symptoms in a person. 
Screening programs are considered effective if they reduce mortality from the disease. Mortality is the ratio of the number of deceased patients to the average population. If the examination reveals a tumor at an early stage, but does not reduce the risk of mortality, then it is not considered effective.
The simplest example of screening is fluorography, which all adults need to undergo every year to detect tuberculosis.
Screening should be carried out in cases where it is safe to say that a person will receive more benefit than harm from further tests, treatment and related stress. 

Therefore, when developing screening programs, the following factors are taken into account:

• The disease should be well studied and widespread in the population;
• There must be effective treatment and affordable equipment;
• The diagnostic test must be safe, accurate and reliable;
• The cost of screening should not exceed the cost of diagnosing and treating the disease when it is detected at a later date;
• Availability of sufficient equipment and specialists to conduct tests.

Tests for cancer markers are not always suitable as a screening, since many of them are insufficiently sensitive and specific. Cancer markers are substances whose content increases in the blood in the presence of malignant tumors. But their number can increase with inflammation, infections and benign tumors.

Screening programs differ in different countries and regions, because surveys are selected based on statistics on morbidity and mortality, as well as economic feasibility for the state. In the USA and Europe, colonoscopy after the age of 50 is included in the list of free and recommended examinations, and in Russia is prescribed by a doctor.  In 1985, during a colonoscopy, Ronald Reagan was diagnosed with a large polyp (an excrescence on the mucous membrane) in the intestine, which could not be removed during the procedure. The next day, the tumor was removed, and the news about colorectal cancer, examinations and surgery was published in the newspapers. 

You can take care of your health not only with the help of government programs. A checkup is a series of health checkups that a person pays for independently. The main purpose of this service is to help a specific person, and not only to reduce the overall mortality rates of the population. Therefore, a checkup on the recommendation of a doctor may include additional examinations that the state does not finance.

Early diagnosis is a case when a patient comes to a specialist with any complaints, after which the doctor prescribes certain tests and examinations for diagnosis.

For some diseases, early detection in the absence of human complaints is difficult. For example, there is no mass screening for Alzheimer's or Parkinson's disease yet. This diagnosis can be established only by symptoms and research results.

What types of cancer can be detected at an early stage

Breast cancer

Mammography is considered an effective screening for breast cancer, which the National Cancer Institute (USA) recommends to all women aged 40 to 74 years.  X-rays of the mammary glands allow you to detect tumors in the early stages, when they cannot yet be probed. Also in the pictures, the specialist can see small accumulations of calcium. In some cases, they indicate the presence of breast cancer.

Individual screening programs may vary depending on risk factors. People with a genetic predisposition are recommended to start screening earlier and more often than others. Breast MRI is used as an additional research method.

Colon and rectal cancer

To reduce the risk of mortality from colorectal cancer, it is recommended to undergo colonoscopy, sigmoidoscopy and highly sensitive stool analysis for hidden blood.
Colonoscopy is a diagnostic method that allows you to examine and assess the condition of the rectum and colon. During a colonoscopy, the doctor may perform a biopsy or remove potentially dangerous polyps. This is an unpleasant and rather complicated procedure, so you need to do it only with a highly qualified specialist. If there are no contraindications, you can undergo a colonoscopy under anesthesia, for example, in the Atlas clinic. The National Cancer Institute recommends having a colonoscopy every 10 years between the ages of 50 and 75.

Sigmoidoscopy is a simplified version of colonoscopy. With this method of diagnosis, the doctor examines the rectum and the lower parts of the colon. During a randomized clinical trial, it was found that even one sigmoidoscopy procedure at the age of 55 to 64 years can significantly reduce the incidence and mortality from colorectal cancer. The National Cancer Institute recommends doing a sigmoidoscopy every 5 years from the age of 50.

Immunochemical analysis of feces for hidden blood is a highly sensitive method for diagnosing hidden bleeding in the lower gastrointestinal tract. Polyps and small cancerous tumors in the rectum and colon can bleed, so the analysis allows you to identify a tumor at an early stage and reduces the risk of mortality from colorectal cancer. Fecal analysis for hidden blood is recommended to be taken every 1-2 years from 50 to 80 years.

Cervical cancer

A cytology smear and an HPV test reduce the incidence and mortality from cervical cancer.

A cytology smear, or pap test, is a procedure for collecting cells from the surface of the cervix and vagina. The smear evaluates the size, shape, number and nature of the location of cells, which makes it possible to diagnose background, precancerous and cancerous diseases of the cervix. The Pap test is recommended to be carried out every three years from the age of 21. In Russia, this analysis is prescribed once a year from the age of 18.

The HPV test is used to test DNA and RNA for the presence of oncogenic types of virus. With the help of a cytology smear and an HPV test, which is carried out every 5 years from 30, a specialist can detect more changes in the cervix leading to cancer than after only a pap test.

Lung cancer

Screening using low-dose spiral computed tomography reduces the risk of lung cancer mortality among active smokers.

Low–dose spiral CT is a procedure with low doses of radiation, during which an X-ray machine scans the body in a spiral. This is a sensitive screening test that displays both benign and malignant neoplasms, which often leads to overdiagnosis and unnecessary interventions. For this reason, this screening method is recommended only for heavy smokers who have a high risk of developing lung cancer.

A liquid biopsy can be an additional method for screening lung cancer. The FDA has already approved a new technology for early diagnosis and selection of optimal treatment for this type of tumor.

X-rays and sputum cytology are not considered effective screening examinations, as they do not reduce the risk of mortality. 

Other types of tumors

There are no effective screening programs for other types of malignant tumors yet. More research is needed to assess how surveys affect morbidity and mortality.

It is important to pay attention to changes in the body. For example, check moles regularly.

The exception to the rule is stomach cancer screening in Japan. This is the country with the highest incidence of stomach cancer. It is assumed that this is due to the increased salt content in food and the prevalence of Helicobacter pylori infection. The state screening program has significantly reduced the death rate from stomach cancer, but in other countries this effect has not been achieved.

In which cases screening and early diagnosis can be dangerous

Despite the advantages of early detection during screening programs, this approach has disadvantages.

Hyperdiagnostics. The detection of a tumor does not always improve and prolong the patient's life. Some types of malignant tumors may be asymptomatic and not disturb the patient in any way. In such cases, when a tumor is detected, a number of examinations and treatment are prescribed to the patient, which worsens the quality of life and the psychological state of the person. This explains the high percentage of suicides among adolescents and young people who have been diagnosed with cancer. For example, a prostate-specific antigen (PSA) test reduces the risk of prostate cancer mortality, but increases the risk of overdiagnosis and unnecessary treatment. Therefore, this test is not recommended as a screening for healthy people.

Screening examinations can give false results. 

A false positive result is obtained if the test demonstrates the presence of a tumor, but additional examinations refute this. Such mistakes lead to the fact that a person once again experiences, often undergoes expensive and difficult medical procedures. 

A false negative result is obtained if the test does not show the presence of a tumor when there is one. Therefore, the examinations necessary for the patient are postponed to a later date.

On the one hand, early detection allows you to cure the tumor until it has grown. On the other hand, the detection of a neoplasm can only worsen the patient's quality of life, without improving survival. Screening is a modern problem of oncology, which requires additional clinical studies, government support, an established system between the detection and treatment of malignant tumors, as well as the training of qualified specialists.

A doctor should make a plan of examinations and prescribe additional procedures – he knows what accuracy can be counted on and how to treat the screening results correctly.

Red flags

Often cancer does not manifest itself in any way in the early stages, so it is important to monitor your health in general and pay attention to the changes that occur with the body. 

We have compiled an approximate list of signals in which case it is better to contact a specialist to understand if everything is in order:

• Unexplained weight loss or gain;
• High fever and chills;
• Constant fatigue and weakness;
• Unexplained and prolonged pain that does not stop for more than four weeks;
• Changes in appetite and frequent discomfort after eating;
• Frequent constipation or diarrhea for no apparent reason;
• The appearance of new moles, the change of old ones, non-healing wounds and ulcers;
• Changing the size or shape of breasts or nipples;
• A cough that does not go away for a long time;
• Bleeding (blood in urine, stool, coughing, spotting from the vagina, nipples);
• Thickening or lump under the skin;
• Heavy sweating during sleep;
• Problems with urination.

To detect cancer at an early stage, it is important to listen to your body, respond to signals in time and generally monitor your health. However, no one is completely immune from the disease. In the next article Atlas will tell you what to do if cancer is diagnosed.

Portal "Eternal youth" http://vechnayamolodost.ru  01.09.2017