Signs and symptoms of cancer
Cancer symptoms are changes caused by the presence of cancer.
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When cancer develops, it often causes changes in the body. These changes, known as signs and symptoms, typically arise from the tumor’s effect on the area where it is growing, but some symptoms—like unexplained weight loss or fatigue—can be more general. Because there are over 100 distinct types of cancer, the possible signs and symptoms vary widely and can appear in many different ways.
A sign is an objective, measurable finding, such as a fever, rash, or bruise. A symptom, on the other hand, is a subjective experience reported by the person, like pain, dizziness, or tiredness. These categories can overlap: for instance, a person may feel feverish (a symptom), and a thermometer can confirm a high temperature (a sign). Many cancer symptoms start gradually and are vague, which is why regular screening—using lab tests, physical exams, tissue samples, or imaging—is a key public health measure. Screenings can catch cancer before symptoms appear or early in its course. Some cancers can even be prevented with vaccines targeting the viruses that cause them, such as HPV vaccines for cervical cancer. Educating people about persistent, unexplained, or multiple worrisome symptoms is also crucial, as these warrant a medical evaluation to reduce cancer-related illness and death.
Cancer produces symptoms through several mechanisms. A growing tumor can compress nearby structures, causing pain, inflammation, or loss of function—this is called mass effect. Not all cancers form solid tumors, and even non-spreading (benign) tumors can be dangerous if they occur in critical places like the brain or heart. Tumors can also deplete normal cells of oxygen and nutrients, disrupting organ function and potentially leading to organ failure. The Warburg effect describes how cancer cells alter their energy production to support growth, which may open treatment possibilities. Some cancers release ectopic hormones, causing paraneoplastic syndromes—for example, parathyroid tumors producing excess parathyroid hormone or carcinoid tumors releasing serotonin. These hormones act far from the tumor, so symptoms may appear in distant parts of the body. Certain cancers increase the risk of blood clots (venous thromboembolism) due to excess clotting factors, which can block circulation or travel to the heart, lungs, or brain. Cancer treatments can further raise this risk.
Quick Facts
- Field
- Oncology
- Deaths
- 8.8 million (2015)
Facts from the source article.
Lore & Background
Cancer is a group of diseases involving abnormal cell growth with the potential to invade or spread to other parts of the body. Cancer can be difficult to diagnose because its signs and symptoms are often nonspecific, meaning they may be general phenomena that do not point directly to a specific disease process. In medicine, a sign is an objective piece of data that can be measured or observed, such as a high body temperature, a rash, or a bruise. A symptom, by contrast, is the subjective experience that may signify a disease, such as pain, dizziness, or fatigue. Signs and symptoms are not mutually exclusive; for example, a subjective feeling of fever can be noted as a sign by using a thermometer that registers a high reading.
Cancer may produce symptoms through several mechanisms. Mass effect occurs when an abnormal growth of tissue compresses nearby structures, causing pain, inflammation, or disruption of function. Loss of function happens when tumor cells deplete normal cells of oxygen and nutrients, potentially leading to organ failure. The Warburg Effect describes how cancer cells in the presence of oxygen and glucose take a different path of energy production. Paraneoplastic syndromes occur when some cancers produce ectopic hormones, causing endocrine imbalances. Patients with certain cancers are at increased risk of venous thromboembolism due to excess production of clotting factors. Cancers may also stimulate fluid shifts, leading to effusions such as pleural effusions or abdominal fluid buildup.
Reader's Guide
The signs and symptoms of cancer are of central importance to public health and clinical practice. Because many symptoms of cancer are gradual in onset and general in nature, cancer screening is a key public health priority. Screenings can identify cancers before symptoms develop, or early in the disease course. Patient education about worrisome symptoms that require further evaluation is paramount to reduce morbidity and mortality from cancer. Symptoms that cause excess worry, symptoms that persist or are unexplained, and/or the appearance of several symptoms together particularly warrant evaluation by a health professional.
Modern approaches to cancer detection have evolved beyond traditional symptom recognition because of new technologies that can potentially identify cancers at earlier, more treatable stages. Cancer biomarkers provide crucial information about the different states of cells when transitioning from healthy to malignant cancer conditions. Liquid biopsies allow for minimally invasive molecular characterizations of cancers through the detection of circulating cells and their DNA. Artificial intelligence applications in cancer diagnosis could have a beneficial impact for cancer screening and diagnostic processes. These technologies aim to assist healthcare professionals in screening asymptomatic patients and investigating suspicious symptoms.
Did You Know?
- There are more than 100 different types of cancer with a wide range of signs and symptoms.
- Patients with certain types of cancers are at increased risk of blood clots due to excess production of clotting factors.
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