Skin cancer can range from a slow-growing spot that only damages the skin around it to an aggressive disease that spreads to your organs, bones, and brain. What it does to you depends almost entirely on the type you have and how early it’s caught. When found early and still confined to the skin, melanoma has a 100% five-year survival rate. Once it spreads to distant organs, that number drops to 34%.
What You Notice First
Skin cancer usually starts with something you can see before anything you can feel. A new growth that looks like a mole, bump, or scab. A rough patch that wasn’t there before. A sore that refuses to heal, sometimes for weeks or months. Changes to an existing mole or freckle, particularly one that’s getting bigger or shifting color.
As the lesion grows, you may start to feel it. Itching around a skin growth is common, and some people develop pain at the site. Bleeding or crusting can happen when the surface breaks down. These sensations aren’t always present, though. Many skin cancers cause no pain at all in the early stages, which is part of why they get missed.
For melanoma specifically, dermatologists use the ABCDE system to spot trouble: Asymmetry (one half doesn’t match the other), irregular Borders (ragged or blurred edges), uneven Color (mixed shades of brown, black, tan, or patches of white, red, or blue), Diameter larger than about a quarter inch, and Evolving shape or appearance over weeks or months.
How Each Type Damages Your Body
The three main types of skin cancer behave very differently, and that determines what happens next.
Basal Cell Carcinoma
Basal cell carcinoma is the most common and the least likely to spread beyond the skin. It almost never travels to distant organs. But “low risk” doesn’t mean harmless. Left untreated, it can slowly destroy the tissue around it, eating into cartilage and even bone. One particularly aggressive subtype grows beneath the surface in ways that aren’t visible, extending well beyond what you see on the skin. These tumors build their own network of tiny blood vessels that fuels their local destruction. On the face, this can mean damage to the nose, ears, or the tissue around the eyes.
Squamous Cell Carcinoma
Squamous cell carcinoma carries a higher risk of spreading. One of the more concerning things it can do is grow along nerve pathways, a process called perineural invasion. This happens in roughly 14.5% of an aggressive subtype. When cancer tracks along a nerve, it can cause numbness, tingling, or pain that radiates outward from the original tumor. It also makes the cancer harder to remove completely and increases the chance of recurrence or spread to lymph nodes.
Melanoma
Melanoma is the most dangerous because of its ability to metastasize. When it starts to spread, it typically travels first to a nearby lymph node. You might notice a swollen, firm lump under the skin near the original site, often in the armpit, groin, or neck. From the lymph nodes, melanoma can reach almost any organ.
What Happens When Skin Cancer Spreads
Advanced melanoma can affect your body in ways that feel nothing like a skin problem. The liver is the organ it reaches most often, found in roughly 58 to 68% of cases that spread to the digestive system. The small bowel, colon, stomach, pancreas, and spleen are all potential targets. The brain is another common destination.
The symptoms at this stage mimic other serious illnesses. Abdominal pain, persistent fatigue, dizziness, loss of appetite, and unexplained weight loss. If the cancer reaches the digestive tract, it can cause bowel obstruction, internal bleeding, or jaundice. One case documented in medical literature involved melanoma spreading to the stomach and cerebellum simultaneously, causing both digestive and neurological symptoms. Another patient’s only initial complaints were dizziness, loss of appetite, and fatigue, symptoms most people would attribute to something far less serious.
In rare cases, advanced skin cancer triggers paraneoplastic syndromes. These are symptoms caused not by the tumor itself but by your immune system’s response to it. As your body produces antibodies to fight the cancer, those antibodies can also attack healthy tissue, leading to skin conditions, muscle inflammation, or blood vessel damage that seem unrelated to the original cancer.
What Treatment Does to Your Body
The physical impact of skin cancer isn’t limited to the disease itself. Treatment leaves its own mark.
For early-stage cancers, surgical removal is the standard approach. Mohs surgery, the most precise method, is done as an outpatient procedure under local anesthesia. Recovery typically involves rest and basic wound care, with temporary discomfort, redness, or mild bleeding. The larger concern for many people is cosmetic. Scars can take up to a year to fully heal, gradually flattening and fading over that time. Depending on the size and location of the tumor, you may need reconstruction ranging from simply letting the wound heal on its own to more involved surgical repair. Cancers on the face, ears, or nose often require the most reconstruction.
For advanced melanoma, immunotherapy has become a primary treatment. These drugs work by releasing the brakes on your immune system so it can attack cancer cells more aggressively. The tradeoff is that those supercharged immune cells sometimes attack healthy tissue too. Skin rashes and intense itching are among the most common side effects, and for some people, they’re severe enough to stop treatment. Inflammation can also hit other organs, particularly the colon, which causes more serious problems than the skin reactions.
The Gap Between Early and Late Detection
The single biggest factor in what skin cancer does to you is timing. Localized melanoma, caught before it moves beyond the original site, has a five-year survival rate of 100% according to National Cancer Institute data from 2016 to 2022. That’s as close to curable as cancer gets. Melanoma that has metastasized to distant organs drops to a 34% five-year survival rate.
That gap means the same disease can be either a minor surgical procedure with a scar that fades over months, or a systemic illness affecting your liver, brain, and gut that requires aggressive treatment with significant side effects. Basal cell and squamous cell carcinomas have even better overall survival when caught early, though they can still cause permanent tissue damage and disfigurement if ignored for too long. The physical reality of skin cancer is shaped less by the diagnosis itself and more by how much time it has had to work.