Causes and Risk Factors
Most basal and squamous cell cancers are caused by cumulative ultraviolet (UV) damage from the sun or tanning beds. Risk is higher with:- Long-term sun exposure: Outdoor work, outdoor sports, and decades of Florida sunshine add up, even without memorable sunburns.
- Fair skin, light eyes, or light hair: Less natural pigment means less built-in UV protection.
- Older age and male sex: These cancers become much more common after age 50.
- A weakened immune system: Organ-transplant medicines and blood cancers such as chronic leukemia or lymphoma substantially raise risk.
- Previous sun damage or skin cancer: Actinic keratoses (rough, scaly precancerous spots) and any prior skin cancer increase the chance of another.
- Chronic wounds and prior radiation: Long-standing scars, non-healing ulcers, and previously irradiated skin are occasional sites for squamous cell cancers.
Symptoms
These cancers usually appear on sun-exposed skin — the face, ears, scalp, neck, arms, and hands. Basal cell cancers grow slowly and almost never spread internally, while squamous cell cancers can occasionally spread if neglected, which makes early recognition worthwhile. Warning signs include:- A pearly or waxy bump: Often with tiny visible blood vessels; typical of basal cell carcinoma.
- A sore that heals and reopens: Any spot that bleeds, crusts, or fails to heal within a month deserves evaluation.
- A firm, red nodule or a flat, scaly patch: Typical of squamous cell carcinoma, which can be tender or crusted.
- A persistent rough spot mistaken for a rash: Unlike dermatitis, a skin cancer does not come and go or respond to moisturizers.
Diagnosis
A clinician examines the spot and the rest of your skin, and a small biopsy taken under local anesthetic confirms the diagnosis and the cancer type. Because these cancers rarely spread internally, imaging is seldom needed for early lesions. The biopsy takes minutes in the office under local numbing, and results typically return within one to two weeks. If a squamous cell cancer looks aggressive, your clinician may also examine nearby lymph nodes.Treatment
Treatment depends on the size, depth, location, and type of the cancer:- Surgical removal: Simple excision cures most tumors; Mohs micrographic surgery spares healthy tissue for cancers on the face or other delicate areas.
- Destruction techniques: Freezing (cryotherapy) or scraping and cauterizing can treat certain small, superficial lesions.
- Topical and other options: Prescription creams, photodynamic therapy, or radiation may be used for selected superficial cancers or patients who cannot have surgery.
- Follow-up care: Having one skin cancer significantly raises the chance of developing another, so scheduled full-skin examinations become part of routine care afterward.
Prevention
Daily broad-spectrum sunscreen, sun-protective clothing and hats, avoiding midday sun, skipping tanning beds, and a yearly full-body skin examination catch problems while they are small and easily cured. Reapply sunscreen every two hours outdoors and after swimming, and remember that UV light passes through clouds and reflects off water and sand. If you have a spot that is new, growing, bleeding, or simply not healing, do not wait. Zimmer Medical Group's primary care team in St. Petersburg can evaluate suspicious lesions, perform or arrange biopsies, and coordinate dermatology care — schedule a skin evaluation today.After the Diagnosis: Treatment Choices and Follow-Up
A basal or squamous cell skin cancer is treated by removing it, and nearly everyone is cured. The decisions that matter are which method, how closely higher-risk squamous cancers are watched, and what prevents the next one.
Simple excision or Mohs surgery
Standard excision under local anesthetic suits most cancers on the trunk and limbs. Mohs surgery, in which tissue is examined layer by layer during the procedure, is reserved for the face, ears, nose, lips, and hands, for recurrent or large tumors, and for the aggressive growth patterns seen on biopsy, because it removes the least normal skin with the highest cure rate. Healing takes two to four weeks.
Which squamous cell cancers need more attention
A squamous cell carcinoma larger than two centimeters, one on the ear or lip, one that has grown deep or along a nerve, or any in a person on immune-suppressing medication or living with chronic leukemia or lymphoma carries a small but real chance of spreading to lymph nodes. Those are followed more closely, sometimes with radiation after surgery, and advanced disease that cannot be removed responds to immune checkpoint drugs such as pembrolizumab. Numbness near a scar, a lump in the neck or under the jaw, or a growth returning at the surgical site is reported promptly.
The follow-up schedule and the precancers
A full-skin examination every six to twelve months for the first several years, more often after a high-risk squamous cancer, finds new lesions while they are tiny. Many people develop a second skin cancer within a few years, so the schedule is kept even when the skin looks fine. Actinic keratoses are treated as they appear with freezing or a course of field-treatment cream, and every exam also screens for melanoma, which is rarer but far more serious. Our skin cancer screening in St. Petersburg article explains what an exam involves.
Sun protection that actually works here
Broad-spectrum SPF 30 or higher reapplied every two hours, clothing with a UPF rating, a wide-brimmed hat, and shade between ten and four. Boaters and anglers get reflected light from below the brim, and drivers get UVA through the side window. Oral nicotinamide, a form of vitamin B3, reduced new basal and squamous cancers in high-risk people in a clinical trial and is worth discussing. Long-term hydrochlorothiazide has been linked to a higher squamous cell risk; that is a conversation to have, not a reason to stop a blood pressure pill on your own. Our Florida sun safety guide and sun safety for eyes and skin article cover the details.
Transplant patients and other special situations
Anyone on long-term immune suppression after an organ transplant develops squamous cell cancers at many times the usual rate and is examined more often, sometimes every three months. Our dermatologic team performs biopsies and coordinates Mohs referral. The National Cancer Institute, the CDC, and MedlinePlus publish patient guidance on treatment and prevention.
If you have had a skin cancer and are not on a regular exam schedule, or have a spot that has changed, schedule a visit.