Anyone noticing a new or unexplained change should discuss it with a healthcare professional rather than attempting to diagnose it through photographs or self-examination alone.
For eligible individuals, regular mammography is also an important screening method because it can detect certain breast abnormalities before they become noticeable.
7. A changing mole or unusual skin growth
The skin is the body's largest organ, and changes to its appearance can sometimes provide important health information.
Melanoma, a potentially serious form of skin cancer, may develop in an existing mole or appear as a new pigmented spot.
One useful approach to recognizing suspicious changes is the ABCDE method.
A β Asymmetry: One half of a mole looks different from the other.
B β Border: The edges are irregular, uneven, or poorly defined.
C β Color: The spot contains several different colors or develops an unusual color.
D β Diameter: The spot is often larger than approximately 6 millimeters, although melanomas can be smaller.
E β Evolving: The mole changes in size, shape, color, or appearance over time.
The evolving characteristic is especially important.
A mole that begins itching, bleeding, crusting, or changing should be examined.
Not every unusual mole is melanoma, but suspicious skin changes should not be ignored.
8. A sore that does not heal
Most minor cuts, scratches, and mouth sores gradually improve.
When a sore remains for an unusually long time, repeatedly bleeds, or continues to change, it may need professional evaluation.
Some skin cancers appear as persistent sores that do not heal normally.
They may develop a raised border, form a crust, bleed easily, or gradually increase in size.
Inside the mouth, persistent ulcers, white patches, red patches, or unexplained bleeding may sometimes be associated with oral cancer.
Other possible causes include irritation from dentures, dental problems, infections, nutritional deficiencies, and inflammatory conditions.
People who use tobacco or consume alcohol heavily may have additional risk factors for certain oral cancers.
A persistent mouth sore should be examined by a dentist or doctor, especially if it is accompanied by difficulty swallowing, pain, or a change in the appearance of the tongue.
Recognizing the difference between temporary and persistent changes
A common mistake is to assume that every unusual skin change is harmless.
Another mistake is to assume that every lump means cancer.
Neither conclusion is reliable.
The appropriate response is to observe the change and seek medical advice when it is new, unexplained, growing, bleeding, or refusing to heal.
Chapter 3: Digestive Problems That May Signal Something Is Wrong
The digestive system plays an essential role in maintaining overall health. It helps the body absorb nutrients, eliminate waste, and provide energy for everyday activities.
Because the digestive organs are connected, changes in one area can sometimes affect several others.
Persistent abdominal discomfort, unusual bowel movements, blood in the stool, and difficulty swallowing are among the symptoms that deserve attention.
The illustration at the beginning of this article shows a person experiencing abdominal discomfort alongside an image of the large intestine. These visual examples are particularly relevant because colorectal and other digestive cancers may produce symptoms involving bowel movements and abdominal function.
Here are four more warning signs.
9. Persistent changes in bowel habits
Everyone experiences occasional constipation or diarrhea.
Changes in diet, stress, travel, medication, infections, and dehydration can temporarily affect bowel movements.
However, a persistent change in normal bowel habits deserves medical attention.
A person may experience constipation that continues for several days or weeks, repeated episodes of diarrhea, or alternating periods of both.
Another possible change is a noticeable difference in stool shape or consistency.
Some people may also feel that they need to use the bathroom even after having a bowel movement.
These symptoms can occur with irritable bowel syndrome, inflammatory bowel disease, food intolerances, and infections.
However, they can also be associated with colorectal cancer.
When a tumor develops in the colon or rectum, it may affect the passage of stool and interfere with normal bowel function.
The symptoms depend on the location and size of the abnormal growth.
People should pay particular attention when bowel changes are new, persistent, or accompanied by abdominal pain, blood in the stool, or unexplained weight loss.
A doctor may recommend blood tests, stool tests, or a colonoscopy depending on the symptoms and the person's medical history.
10. Blood in the stool or rectal bleeding
Blood in the stool is a symptom that should never be casually dismissed.
It may appear as bright red blood on toilet paper, red streaks on the surface of stool, or darker stool that looks almost black.
Different appearances can suggest different sources of bleeding.
Bright red blood may come from hemorrhoids, anal fissures, or other conditions affecting the lower digestive tract.
Dark or black stool can sometimes indicate bleeding higher in the digestive system, although iron supplements and certain medications can also change stool color.
Colorectal cancer can cause bleeding when an abnormal growth damages nearby blood vessels.
Sometimes the amount of blood is too small to be visible.
In these situations, repeated blood loss may gradually contribute to iron-deficiency anemia.
A person may then experience fatigue, weakness, dizziness, or reduced exercise tolerance.
It is important to remember that hemorrhoids are common, but they should not automatically be assumed to explain every episode of rectal bleeding.
Medical evaluation helps identify the source.
Significant bleeding, black tarry stool accompanied by weakness, fainting, or severe abdominal pain requires urgent medical attention.
11. Persistent abdominal pain or bloating
Abdominal pain can develop for many reasons.
Digestive infections, constipation, food intolerances, gallstones, ulcers, and hormonal changes are all possible causes.
Occasional bloating after eating is also common.
However, persistent or progressively worsening abdominal discomfort should be evaluated.
Some people describe a dull ache that never completely disappears.
Others experience repeated cramps, pressure, swelling, or a sensation of fullness.
Depending on the location, abdominal symptoms may sometimes be associated with cancers involving the colon, stomach, pancreas, ovaries, or other abdominal organs.
For example, certain ovarian cancers may be associated with persistent bloating, abdominal enlargement, pelvic discomfort, and feeling full quickly.
These symptoms are nonspecific and are often caused by non-cancerous conditions.
Nevertheless, their persistence and combination can be important.
A doctor may ask when the symptoms began, whether they are related to meals, whether bowel habits have changed, and whether there has been unexplained weight loss.
Additional investigations may include blood tests, ultrasound, or other imaging studies.
12. Difficulty swallowing or persistent indigestion
Occasional heartburn after a heavy meal is not unusual.
However, repeated indigestion or difficulty swallowing should not become a normal part of everyday life.
Some people experience the sensation that food becomes stuck in the chest or throat.
Others notice pain when swallowing, repeated discomfort after eating, or persistent acid reflux.
These symptoms can be associated with gastroesophageal reflux disease, inflammation, narrowing of the esophagus, and other digestive conditions.
In some cases, they may indicate esophageal or stomach cancer.
Difficulty swallowing that progressively worsens is particularly important.
A person may initially struggle with solid food and later experience difficulty swallowing softer foods or liquids.
This requires medical assessment.
Persistent indigestion accompanied by unexplained weight loss, vomiting, loss of appetite, or abdominal pain also deserves attention.
Doctors may recommend an upper gastrointestinal endoscopy to examine the esophagus and stomach when clinically appropriate.