Cancer
What is cancer? What types of tumors are most common? Everything about the causes, symptoms, and treatments used in oncology.
Symptoms and Causes
The word cancer refers to diseases caused by abnormal and uncontrolled cell growth in an organ or tissue of the body. When these cells continue growing and multiplying, they can destroy and replace normal tissue, causing the body to stop functioning properly. Although cancer is currently one of the leading causes of death worldwide, medical and scientific advances have allowed more and more patients to overcome the disease.
The characteristics of cancer and its response to treatments vary depending on the cells and the part of the body where it originates. In most cases, each type of cancer is named after the organ where it forms (e.g., breast cancer, lung cancer, or prostate cancer) and continues to be called the same even if it spreads to other areas as metastasis.
Cancer is divided into two major groups, which are further classified into different categories depending on the affected cells:
- Hematologic or blood cancers: occur in blood cells.
- Leukemia: originates in the red bone marrow, the tissue responsible for producing blood cells. As a result, an excess of white blood cells is produced, preventing the development of other components and potentially causing anemia, bleeding, thrombosis, or infections.
- Lymphomas: develop from lymphatic tissue, where lymphocytes grow abnormally and accumulate in lymph vessels and nodes, affecting the immune system. They can lead to Hodgkin lymphoma (B cells) or non-Hodgkin lymphoma (B or T cells).
- Multiple myeloma: results from the abnormal development of plasma cells, which accumulate in the bone marrow.
- Solid tumor cancers: occur in cells that form a tissue or organ.
- Carcinoma: the most common type. It originates in epithelial cells, which line the inside and outside of organs. They include adenocarcinomas, which form in glandular tissue (prostate or breast cancer), squamous cell carcinomas (lung or stomach cancer), basal cell carcinomas, which affect the epidermis and cause the most common type of skin cancer, and transitional cell carcinomas, which impact the urothelium (bladder or kidney cancer).
- Melanoma: affects melanocytes, the cells that produce melanin.
- Sarcoma: forms in bones and soft tissues (muscles, tendons, ligaments, or blood and lymphatic vessels). The most well-known is osteosarcoma, which is the most common bone cancer.
- Neuroendocrine tumors: may be benign or malignant and cause excessive hormone production. Carcinoid tumors and astrocytomas belong to this group.
- Brain or spinal cord tumors: affect nervous system cells.
- Germ cell tumors: originate in the cells that form eggs or sperm (ovarian or testicular cancer).
Symptoms
Symptoms vary depending on the type of cancer, the organs affected, and its growth rate. A medical evaluation is necessary to diagnose or rule out cancer. Some of the most common signs caused by cancerous tumors include:
- Fever.
- Easy bruising.
- Fatigue (shortness of breath).
- Persistent cough.
- Lumps under the skin.
- Indigestion.
- Difficulty swallowing.
- Weight loss.
- Fatigue.
Causes
Cancer occurs when a cell's DNA mutates and develops abnormally. These changes may be due to genetic predisposition, exposure to carcinogens, or lifestyle factors.
Risk Factors
Cancer can affect anyone, but some factors increase the risk of developing it, such as:
- Advanced age: the percentage of people with cancer increases after age 60.
- Smoking.
- Alcohol consumption.
- Obesity.
- Exposure to radiation, including sunlight.
- Weakened immune system.
- Chronic inflammation.
- Genetic predisposition.
- Infections: Human papillomavirus, hepatitis B...
Complications
Each type of cancer has its own complications. In general, metastasis, which is the spread of cancer cells to other organs, is one of the main complications. Additionally, many cancer survivors have an increased risk of recurrence.
Prevention
Early detection, while it does not prevent cancer, is essential to reducing mortality rates.
Therefore, it is important to attend recommended medical check-ups based on age and gender. Additionally, adopting healthy habits can help prevent certain types of cancer. Some recommendations include:
- Avoiding tobacco and alcohol consumption.
- Following a healthy diet.
- Maintaining a healthy weight.
- Exercising regularly.
- Practicing safe sex.
- Protecting oneself from ultraviolet rays.
- Undergoing regular medical check-ups.
What Doctor Treats Cancer?
The diagnosis and treatment of cancer require a multidisciplinary team typically involving specialists in Medical oncology, Radiation oncology, Surgery (depending on tumor location), Preventive medicine and Public health, Smoking cessation unit, Palliative care, Clinical psychology, and Endocrinology and Nutrition.
Diagnosis
Diagnostic tests for cancer also vary depending on the patient’s symptoms and, ultimately, on the type of tumor and the organs involved. Nevertheless, some are commonly used across most cases, including:
- "Medical history": physician-led questioning of the patient regarding symptoms and the progression of their condition.
- Physical examination: inspection and, particularly, palpation allow specialists to detect lumps or changes in the appearance and color of the skin.
- Blood tests: enable the detection of tumor markers and other abnormalities.
- Imaging studies: X-rays, ultrasound, magnetic resonance imaging (MRI), computed tomography (CT), and nuclear medicine tests (scintigraphy, PET-CT) provide representations of internal organs that help identify inflammation, enlargement, or tumors.
- Biopsies: a sample of tumor tissue is obtained by needle aspiration or biopsy, either in the outpatient setting or in the operating room, and subsequently analyzed in the laboratory. Through microscopic examination, characteristics such as cell size, shape, and organization are assessed, allowing differentiation between normal and malignant cells. In addition, microscopic analysis can define cancer subtypes. More recently, comprehensive molecular biology studies are performed to identify genetic alterations. This helps the physician better understand the tumor and determine potential treatment options for the patient.
Treatment
There are many ways to approach cancer. In fact, the most effective therapies are those that are individualized for each patient and combine different modalities. Three main types of treatment can be distinguished based on their objective:
- Surgery: procedures are performed to completely remove the tumor or, alternatively, to excise as many cancerous cells as possible.
- Adjuvant therapy: the aim of this approach is to eliminate malignant cells that may remain in the body after surgical intervention. The most common modalities include:
- Radiotherapy: a local treatment that uses high doses of ionizing radiation to destroy cancer cells. It is painless during administration. It may be used to achieve complete tumor control or as an adjunct to surgery or other oncologic treatments. Up to 70% of patients benefit from some form of radiotherapy.
- Immunotherapy: enhances the patient’s immune system to help it fight cancer. There are two approaches: stimulating natural defenses or administering biologically engineered substances. It is commonly effective in bladder cancer, melanoma, lymphoma, and leukemia.
- Chemotherapy: involves the use of pharmacological agents to destroy malignant tumors by inhibiting their growth. It is commonly used for brain, colorectal, or lung tumors.
- Hormone therapy: removes certain hormones when tumors depend on them for growth, or, in other cases, adds hormones to help the body eliminate cancer cells. It is typically used in breast and prostate cancer.
- Palliative care: provides significant benefit in alleviating the adverse effects of both the cancer itself and the treatments used to manage it. It helps reduce pain, improve mood, and support acceptance of the disease or the dying process as a natural course. It should be noted that palliative care can be introduced from the beginning of treatment to improve quality of life and is not limited to patients in the terminal stages of illness.
