The term cancer is often accompanied by fear, painful memories, and many questionsAlmost everyone knows someone close to them who has gone through this disease, and yet there is still quite a bit of confusion about what it is exactly, what its symptoms are, and what we can do to reduce the risk.
From modern medicine we know that cancer is not a single pathology, but a large group of diseases that share the same basic mechanismA group of cells undergoes changes in its DNA, ceases to follow normal growth patterns, and begins to multiply uncontrollably, with the capacity to invade neighboring tissues and spread to distant sites. Understanding the most common types of cancer, their warning signs, and how to prevent them is key to early detection and significantly improving the chances of a cure.
What is cancer and why does it occur?
Under normal conditions, the body's cells follow certain patterns. very precise genetic instructions that control their growth, division, and deathWhen a cell's DNA undergoes certain mutations, these instructions are altered and the cell can begin to multiply uncontrollably, ignoring the signals that should stop its division or induce its programmed death.
These genetic alterations can affect several types of genes: those that drive cell division (oncogenes), those that they act as brakes on growth (tumor suppressor genes) or those responsible for repairing errors in DNA. When enough mutations accumulate in any of these systems, cells stop behaving normally and become cancerous.
Most mutations responsible for cancer are acquired during life through the action of external factors (such as tobacco, solar radiation, or certain viruses) or through errors that occur spontaneously during cell division. Only a small percentage, around 5-10%, are due to Inherited mutations from the parents, which is known as hereditary cancer syndromes.
A very important characteristic of cancer is its ability to invade nearby tissues and spread to other organs through the blood or lymphatic system, a phenomenon known as metastasis. This spread, more than the primary tumor itself, is usually the main cause of serious complications and death.
Major cancer groups according to cell type
In addition to classifying tumors by the organ in which they originate (breast, lung, colon, etc.), doctors also group them according to the type of cell from which they arise, because this greatly influences their behavior and the most appropriate treatment. One of the most frequent groups is that of carcinomas, malignant tumors originating in epithelial cells that cover the surface of organs and tissues.
Most solid cancers in adults are carcinomas, and although a colon carcinoma and a lung carcinoma share certain characteristics, Each organ requires specific therapeutic strategiesThis group includes many of the most common tumors: breast, lung, prostate, colon and rectum, stomach, liver, or cervix, among others.
Another large group consists of the sarcomasThese originate in supporting tissues such as bone, muscle, or fat, although they are less frequent. In addition, there are groups with particular behavior, such as hematological cancers and tumors of the central nervous system.
Hematological cancers: leukemias, lymphomas, and myelomas
The so-called blood cancers include a group of diseases that affect the blood cells, bone marrow, and the lymphatic systemUnlike solid tumors, they often do not form a localized mass, but rather manifest as abnormal cells that circulate in the blood or colonize bone marrow and lymph nodes.
Leukemias are neoplasms of blood cells (mainly white blood cells) and bone marrow. In these diseases, a specific cell line is affected. It multiplies uncontrollably in the spinal cord.This displaces the normal cells that should produce healthy red blood cells, platelets, and antibodies. This results in anemia, frequent infections, extreme fatigue, and often, easy bruising or bleeding.
Lymphomas are cancers of the lymphatic system, the network of vessels and nodes that plays an essential role in the body's defenses. Lymph nodes are located throughout the body (neck, armpits, groin, mediastinum, etc.) and act as filters that trap germs and foreign substancesWhen they become malignant, they usually increase in size, may become palpable, and are accompanied by general symptoms such as fever, weight loss, or night sweats.
There are two main types of lymphoma: Hodgkin lymphoma, which has a very high cure rate if detected early, and non-Hodgkin lymphomas, which encompass more than 60 subtypes with highly varied behaviors, ranging from very slow-growing forms to very aggressive variants that require immediate intensive treatment.
Multiple myeloma is a cancer of plasma cells, a subtype of white blood cell that lives in the bone marrow and is responsible for producing antibodies. In myeloma, these cells become malignant, multiply, and generate large quantities of antibodies. abnormal antibodies that damage bone and kidneyThey cause anemia, predispose to infections, and lead to bone pain, fractures, and other complications. Treatment combines chemotherapy, corticosteroids, immunomodulatory drugs, and even bone marrow transplantation in selected patients.
Tumors of the central nervous system
Tumors of the central nervous system include those that originate in the brain or spinal cordThey do not fit entirely into the classic categories of carcinomas or sarcomas, because nerve tissue is highly specialized and has its own characteristics.
These tumors can cause very different symptoms depending on their location: from persistent headaches, epileptic seizures or personality changes, to difficulty moving a part of the body, balance problems, or visual disturbancesBecause the brain and spinal cord are within rigid structures (skull and spine), any additional mass can increase pressure and generate striking neurological signs.
The 10 most common types of cancer and their symptoms
Globally, certain tumors account for a high percentage of diagnoses. Understanding their main symptoms is crucial for detecting warning signs and consulting a doctor promptly, since Early diagnosis can make all the difference between a curative treatment and a merely palliative one.
Breast cancer
Breast cancer is currently the most frequently diagnosed cancer worldwide. It accounts for approximately 12-13% of all cancer cases, and it is estimated that Approximately 1 in 8 women will experience it during their lifetime.Although it can also occur in men, it is much less common in them.
Among the most common symptoms is the appearance of a lump or nodule in the breast or armpit, which is not necessarily painful. Other possible symptoms include changes in the shape or size of the breastAreas of thickening, dimpling or retraction of the skin, persistent redness, abnormal nipple discharge or sudden nipple inversion.
Monthly breast self-examination helps women become familiar with the normal appearance and texture of their breasts, so any changes can be detected earlier. Even so, the key tool for early diagnosis is regular mammography, recommended for middle-aged and older women, usually every one or two years depending on guidelines and personal risk factors. When diagnosed in its early stages, The five-year survival rate is approaching 99%..
Lung cancer
Lung cancer is one of the deadliest cancers worldwide and is strongly linked to tobacco use. It is estimated that Up to 9 out of 10 deaths from this cancer are related to cigarette smoking. or other tobacco products, including secondhand smoke. The lifetime risk in smokers is several times higher than in those who have never smoked.
Its initial symptoms may go unnoticed, but a persistent cough that doesn't go away, changes, or is accompanied by blood in the sputum is a clear warning sign. Shortness of breath, chest pain, and hoarseness are also common. repeated respiratory infections, intense fatigue and unexplained weight loss.
In practice, the overall survival rate for lung cancer remains low, at around 20-25% at five years when all stages are considered. However, when the tumor is detected very early, localized, and small, The chances of a curative treatment increase significantly.This has prompted screening programs using low-dose computed tomography in high-risk groups (people with many years of tobacco use).
Colorectal cancer (colon and rectum)
Colorectal cancer encompasses tumors of the colon and rectum and is one of the most frequently diagnosed cancers in both men and women. It is estimated that approximately 1 in 23 men and 1 in 25 women They will develop it throughout their lives, and its frequency increases with age.
Risk factors include being overweight or obese, physical inactivity, high consumption of red and processed meats, alcohol, tobacco, and certain personal or family histories (such as adenomatous polyps, long-standing ulcerative colitis, or hereditary syndromes). A diet low in fiber and vegetables is also associated with a increased risk of developing this tumor.
The most typical symptoms include persistent changes in bowel habits (diarrhea, constipation, or alternating between both), blood in the stool (sometimes visible and other times only detectable in specific tests), abdominal pain or discomfort, a feeling of incomplete bowel movement, and unexplained weight loss. Occasionally, early polyps or tumors do not cause symptoms, hence the importance of screening.
When detected in its early stages, colorectal cancer has a five-year survival rate of over 90%. Early detection programs using fecal occult blood test or colonoscopy They allow the discovery of precancerous lesions and early tumors, resulting in a much more favorable prognosis.
Prostate cancer
Prostate cancer is one of the most common cancers among men, especially in older age groups. More than half of diagnoses occur in men over 65, and it is estimated that around 1 in 8 men He will develop this type of cancer if he lives long enough. The prostate is a gland exclusive to males, located below the bladder and responsible for producing part of the seminal fluid.
In its early stages, prostate cancer may not cause any symptoms. As it progresses, symptoms may include difficulty starting urination, a weak urine stream, frequent urination (especially at night), pain or burning during urination, blood in the urine or semen, and the feeling of not completely emptying the bladder. These symptoms, however, can also be caused by a benign enlargement of the prostate gland. Therefore, a medical evaluation is always necessary..
The prognosis is usually very good, especially when the tumor is localized. In these situations, the five-year survival rate approaches 100%. In fact, in some selected low-risk cases, active surveillance (periodic check-ups without immediate treatment) is chosen to avoid side effects of aggressive therapies that may not be necessary.
Stomach cancer
Gastric cancer, although less common than the aforementioned cancers in some high-income countries, remains responsible for a significant number of cases and deaths worldwide. Its incidence is higher in men and has been linked to factors such as tobacco use, diets rich in salted or smoked foods, and chronic infection with the bacteria *Gypsies*. Helicobacter pylori, a significant risk factor for this tumor.
The symptoms can easily be confused with other digestive disorders: loss of appetite, unexplained weight loss, pain or discomfort in the upper abdomen, persistent heartburn, indigestion, nausea, or feeling full quickly after eating. Often These signs appear when the disease is already in an advanced stagewhich explains his more reserved prognosis.
The five-year survival rate varies greatly depending on the stage. In very early stages it can approach 70%, but when the tumor is diagnosed with widespread regional involvement or metastasis, The curative options are considerably reducedTherefore, in people at high risk or with persistent symptoms, it is recommended to consider performing an upper digestive endoscopy.
Liver cancer
Primary liver cancer (mainly hepatocellular carcinoma) is among the most common and deadly tumors worldwide. It must be distinguished from liver metastases, which are tumors that originate in other organs (colon, breast, lung, etc.) and spread to the liver, but which They are not considered liver cancer in the strict sense..
Most hepatocellular carcinomas They appear on a liver that is already chronically damaged.liver disease is usually caused by cirrhosis. The main causes of cirrhosis include prolonged and heavy alcohol consumption, chronic hepatitis B and C, fatty liver disease, and other metabolic disorders. The risk increases significantly when the liver is scarred and loses its normal structure.
Symptoms include weight loss, pain or discomfort in the upper right abdomen, a feeling of a mass, tiredness, jaundice (yellowing of the skin and eyes), changes in the color of stools and urine, abdominal swelling due to fluid buildup (ascites), and often, progressive deterioration of general conditionThe prognosis, unfortunately, is usually unfavorable, and the overall five-year survival rate is around 30% for all stages combined.
Cervical cancer
Cervical cancer affects only women with female reproductive organs and is among the most common gynecological cancers. Most cases are closely linked to persistent infection with [unspecified pathogen]. high-risk human papillomavirus (HPV)especially types 16 and 18, which are responsible for a large proportion of precancerous lesions and invasive cancers.
In its early stages, it may not produce noticeable symptoms. As it progresses, symptoms may appear. abnormal vaginal bleeding (between periods, after sexual intercourse, or in postmenopausal women), unusual vaginal discharge, pelvic pain, and discomfort during intercourse. These are signs that should not be normalized and require evaluation by a healthcare professional.
The good news is that this cancer is largely preventable. HPV vaccination in girls, boys, and adolescents, along with screening programs (Pap smears, HPV detection tests, and colposcopies when indicated), allow to identify precancerous lesions and treat them before they progress to an invasive tumor. In fact, most deaths from this cancer are concentrated in countries where these resources are not yet well implemented.
Esophagus cancer
Esophageal cancer is less well-known to the general public, but it is among the most common digestive tumors. It most frequently affects middle-aged and older men and is linked to tobacco and alcohol use, obesity, chronic reflux, and certain unhealthy diets. In some cases, Barrett's esophagus (a precancerous condition associated with gastroesophageal reflux) clearly increases the risk of this tumor.
In its early stages, it is usually silent. As the tumor grows and narrows the esophageal lumen, the person You may notice difficulty swallowingFirst with solid foods and later even with liquids. Other common symptoms include retrosternal or chest pain, unintentional weight loss, persistent cough, hoarseness, and, in some cases, vomiting blood.
Survival depends largely on the stage at which the disease is diagnosed. Even in localized tumors, the chances of living five years after diagnosis do not exceed 50% in many studies, and when there is metastasis, The prognosis is clearly becoming unfavorable.Hence the importance of consulting a doctor for prolonged dysphagia or digestive alarm symptoms.
Thyroid cancer
Thyroid cancer originates in the thyroid gland, located in the front of the neck. Most thyroid nodules are benign, and only about 5% are malignant tumors, but their detection can cause a great deal of anxiety. Even so, it is generally considered one of the cancers with best global forecast.
The most characteristic sign is the appearance of a lump or mass in the cervical region It can grow relatively quickly or remain stable for a while. Sometimes it is accompanied by pain in the front of the neck, changes in voice (hoarseness), difficulty swallowing, a feeling of local pressure, or swelling of nearby lymph nodes. Many of these findings, however, are discovered incidentally on imaging tests performed for other reasons.
When diagnosed in early stages and treated appropriately with surgery, radioactive iodine, and/or external beam radiation therapy, depending on the case, five-year survival rates approach 100% in the most common forms. This makes thyroid cancer a clear example of how Early detection and correct treatment can completely change the prognosis.
Bladder cancer
Bladder cancer originates in the tissue lining the bladder, the organ where urine is stored. It is more common in older people and men, and one of its main risk factors is smoking, in addition to some occupational exposures to chemicals (such as certain industrial dyes). Chronic bladder inflammation has also been linked to bladder cancer. higher risk in very specific situations.
The most striking symptom is usually the presence of blood in the urineSometimes visible to the naked eye (reddish or tea-colored urine) and other times only detectable through laboratory tests. Pain or burning during urination, frequent or urgent urination, and pain in the lower back or pelvic region may also occur.
Survival rates vary considerably depending on the depth to which the tumor invades the bladder wall and the presence or absence of metastasis. Superficial tumors, limited to the innermost layer, can be treated endoscopically and controlled with resections and medications instilled into the bladder, while invasive forms usually require more extensive intervention. more complex surgery and systemic treatments.
General symptoms that may suggest cancer
In addition to the specific signs of each tumor, there are general symptoms that, while not exclusive to cancer, should prompt a medical consultation if they persist. These include: intense fatigue without a clear cause, marked and involuntary weight changes, prolonged fever, profuse night sweats, palpable lumps under the skin, or pains that are not explained by apparent injuries.
Other warning signs include changes in moles (size, shape, color, irregular borders, itching or bleeding), skin wounds that do not heal, lasting changes in urinary or bowel habits, chronic cough or difficulty swallowing for no apparent reason. None of these symptoms alone confirms a cancer diagnosis.However, they do warrant a professional assessment to rule out serious problems or treat them in time.
Causes, risk factors, and genetic mutations
The development of cancer is usually the result of the interaction between a person's genetic predisposition and various external factors. Some of these factors are clearly modifiable, while others are completely beyond our control. Understanding this complex mix helps us accept that, although there are things we can do to reduce the risk, Zero risk can never be guaranteed..
Among the best-established risk factors are tobacco (the leading preventable cause of cancer), excessive alcohol consumption, obesity, sedentary lifestyle, a diet low in fruits and vegetables and high in processed meats, and excessive exposure to ultraviolet radiation from the sun. certain chemical substances (benzene, asbestos, aflatoxins, arsenic in the water, etc.) and some long-term infections caused by specific viruses or bacteria.
Regarding genetics, some people are born with inherited mutations that significantly increase the risk of certain tumors (for example, changes in genes). BRCA1/BRCA2 in breast and ovarian cancer(or mutations responsible for Lynch syndrome in colorectal cancer). Having this type of mutation does not mean that cancer is inevitable, but it does increase the probability if it is added to other environmental or lifestyle factors.
On the other hand, age plays a fundamental role: as the years go by, more mutations accumulate in cells and DNA repair mechanisms become less effective, which explains why Most cancers occur in older adultsHowever, this disease can also affect children, adolescents, and young adults, with somewhat different types of tumors and behaviors.
Prevention: how to reduce the risk of cancer
Experts estimate that between 30% and 50% of cancer cases could be prevented by adopting evidence-based measures. These are not magic formulas, but rather... daily habits sustained over time which also reduce the risk of many other chronic diseases.
Quitting smoking is probably the single most effective intervention for reducing the risk of multiple cancers (lung, larynx, bladder, pancreas, kidney, among others). Maintaining a healthy weight through a balanced diet and regular physical activity also contributes significantly. It is recommended to prioritize fruits, vegetables, legumes, whole grains, and lean proteins. limiting processed meats, excess salt, sugars and ultra-processed foodsIn addition, it is advisable to have the Community pharmacy as a driver of prevention in public health.
Regarding alcohol, the less consumed, the better: even moderate amounts have been associated with an increased risk of several types of cancer. Excessive sun exposure should be avoided through shade, protective clothing, and high-SPF sunscreen, and by discouraging [unclear - possibly "hanging" or "sunburning"]. artificial tanning boothsIt is also advisable to reduce contact with occupational and environmental carcinogens whenever possible, respecting safety and ventilation regulations.
Vaccines play a key role in preventing certain cancers: immunization against the hepatitis B virus reduces the risk of liver cancer, and vaccination against HPV... It reduces the likelihood of cervical cancer and other associated tumors. (such as some oropharyngeal or anal cancers). Participating in screening programs offered by health systems (mammograms, cytology, colonoscopies) is also a fundamental tool for secondary prevention, allowing for the detection of lesions in very early stages.
Early diagnosis, stage and grade of cancer
When cancer is suspected, the first step is to confirm the diagnosis through imaging tests (X-rays, ultrasounds, CT scans, MRIs, mammograms, endoscopies, etc.) and, above all, through microscopic analysis of tissue samples (biopsies). From there, it is essential to define the stage (how much disease there is and how far it has spread) and the degree (how aggressive the cells appear under the microscope).
The stage takes into account the size of the tumor, involvement of nearby lymph nodes, and the presence or absence of metastasis to distant organs. Roman numerals (I to IV) are usually used: stages I and II correspond to more localized tumors with a better prognosis, while Stage IV implies metastatic diseaseThis classification allows specialists from different centers to understand each other precisely when discussing specific cases (for example, stage IB cervical cancer or stage IIIA lung cancer).
The grade, meanwhile, refers to how "differentiated" the tumor cells are from the healthy tissue of origin. A tumor of Low grade is quite similar to normal tissue A low-grade tumor typically grows more slowly, while a high-grade tumor shows highly altered cells and tends to be more aggressive. The combination of stage and grade guides both treatment options and prognosis.
For example, a localized, low-grade, early-stage prostate carcinoma can be managed in some patients with active surveillance, postponing or avoiding invasive treatments. In contrast, a high-grade gastric cancer in stage II-III usually requires highly complex surgery combined with chemotherapy, due to the high risk of metastasis if only resection is performed.
Cancer treatment and complications
Cancer treatment is increasingly personalized and combines different therapeutic modalities depending on the type of tumor and the patient's condition. The most traditional are surgery (tumor removal when possible), radiotherapy, and systemic treatments such as chemotherapy, targeted therapies, immunotherapy, and, in some cases, immunotherapy. Hormone therapies for hormone-sensitive tumors (such as certain breast and prostate cancers).
The goal can be curative (to completely eliminate the disease), to significantly prolong life, or palliative, focused on relieving symptoms and improving quality of life when it is not possible to eradicate the tumor. Completing treatments within the recommended timeframe and manner is crucial to maximizing their effectivenessHowever, in practice complications may arise that require adaptation.
Complications related to cancer or its therapies include pain, fatigue, nausea, hair loss, digestive problems (diarrhea, constipation), blood disorders (anemia, infections, bleeding), chemical imbalances (such as hypercalcemia), respiratory problems, and neurological effects. In some cases, paraneoplastic syndromes may occur, in which the immune system reacts abnormally to the tumor. It ends up damaging healthy tissue.
When the disease is advanced or curative treatment is not feasible, palliative care becomes essential. Its aim is not to cure, but to alleviate physical, psychological, and spiritual suffering, with pain management being one of its priorities. Good palliative care, including the possibility of receiving care at home and adequate access to powerful analgesics such as morphine, It significantly improves the quality of life for patients and families..
Current knowledge about the most common types of cancer, their symptoms, risk factors, genetic mechanisms, and therapeutic options allows us to face this disease with more tools than ever before: from prevention and screening to precision medicine and palliative care (They decipher the black box of cancerUnderstanding how tumors behave and what options exist at each stage helps to make informed decisions, see a doctor sooner if you experience suspicious symptoms, and make better use of the treatment options offered by the healthcare system.
