How Fast Do Squamous Cell Carcinomas Grow?

Squamous cell carcinomas (SCCs) vary enormously in how fast they grow, from barely noticeable expansion over many months to measurable weekly increases that can double a tumor’s volume in under two months. One study tracking scalp SCCs calculated tumor doubling times as short as about 7 days in aggressive cases and around 16 days in slower ones. That range makes the question harder to answer with a single number than most people expect, because the speed depends on where the cancer is, how well differentiated its cells are, and whether the patient’s immune system is compromised.

What the Clinical Measurements Actually Show

Researchers have tried to pin down SCC growth rates by measuring tumors at two points in time and calculating a “tumor diameter doubling time,” essentially how many days it takes for the tumor’s diameter to double assuming exponential growth. In two documented scalp SCCs, one grew from 27 mm to 53 mm in 84 days, giving a doubling time of about 7.3 days. A second grew from 20 mm to 28 mm over 133 days, yielding a doubling time of roughly 16 days.¹ Those numbers refer to diameter, not volume, so even the “slower” tumor was still expanding substantially in real tissue terms.

A separate study focused on surgical wait times found that moderately differentiated cutaneous SCCs grew by about 0.24 cm per month of delay, while poorly differentiated ones grew by roughly 0.28 cm per month.² That might not sound like much, but over a three- or six-month wait for surgery, the cumulative growth can push a tumor into a higher stage and require a more complex procedure. The same study found that well-differentiated SCCs and basal cell carcinomas did not show the same pattern, reinforcing that differentiation grade matters a great deal.

For oral SCC specifically, imaging-based tracking has produced similar findings. One study measuring tumor volume on serial scans found a median volume doubling time of about 7.9 weeks, with the tumors growing at roughly 7.3 percent per week. About 30 percent of patients experienced stage progression during the interval between scans, and nearly a quarter developed new lymph node involvement.³ Patients whose tumors doubled in volume within eight weeks or less had significantly worse survival, suggesting that rapid growth is itself a marker of biological aggressiveness.

The Surprising Finding in Community Patients

Against that backdrop, one large community-based study produced a result that seems to cut the other way. When researchers looked at the sizes of SCCs at the time patients first presented for care, they found no consistent evidence that SCC size increased with the amount of time since the patient first noticed the lesion. By contrast, basal cell carcinomas showed a clear upward trend: average size nearly doubled in patients who had noticed the spot for five to ten years compared to those who sought care within two months.⁴

This does not mean SCCs stop growing. The likely explanation is selection bias: SCCs that grow quickly tend to prompt an earlier visit to a doctor because the patient notices rapid change, while slower-growing ones get ignored longer. When you pool all the cases together, you end up with a mix where the fast growers are caught early and the slow growers are caught late, flattening out the average. The data still tell you something useful, though. They suggest that many community-level SCCs are not ballooning uncontrollably the way some clinical case reports might imply. Plenty of them grow at a pace that gives patients time to seek care, as long as they do not ignore the spot entirely.

From Precancerous Spot to Invasive Cancer

Before an SCC becomes an SCC, most cutaneous versions start as an actinic keratosis (AK), a rough, scaly patch caused by cumulative sun damage. Not every AK becomes cancerous, but research estimates that roughly 10 percent will eventually progress to invasive SCC. That progression takes an average of about two years.⁵ So even before the cancer itself is growing, there is a precancerous phase measured in months to years during which the abnormal cells are accumulating genetic damage.

An early and central event in that transition is mutation of the TP53 gene, which normally acts as a brake on cell division. When TP53 is inactivated, cells that would otherwise repair their DNA or die off are allowed to survive and pick up additional mutations. Those additional changes are what eventually push an actinic keratosis into invasive SCC.⁶ This multi-step process explains why the precancerous window is relatively long: one mutation alone is usually not enough to turn cells fully malignant, and the immune system can hold partially transformed cells in check for a time.

What Makes Some SCCs Grow Faster Than Others

If you ask a dermatologist which SCC they worry about most, the answer almost always involves the patient’s immune status or the tumor’s differentiation grade. Those two factors are the biggest determinants of pace.

People on long-term immunosuppressive drugs, particularly organ transplant recipients, face not only a much higher risk of developing SCC but also a different kind of SCC when they do. In transplant recipients, squamous cell carcinomas tend to run a more aggressive course with a higher rate of metastasis and a tendency toward multifocal growth, meaning multiple tumors developing in different areas at the same time.⁷ A broader analysis of immunosuppressive medications reported to the FDA’s adverse events database confirmed a similar pattern: patients who develop SCC in the setting of immune-suppressing drugs tend to get more aggressive and rapidly progressing forms of the disease.⁸

Differentiation grade is the other key variable. “Well-differentiated” means the cancer cells still resemble normal squamous cells under a microscope; “poorly differentiated” means they look abnormal and disorganized. As the surgical delay study showed, well-differentiated SCCs may not grow detectably over months, while poorly differentiated tumors add millimeters per month.² High levels of the cell-division marker Ki67 within tumor tissue have also been linked to worse clinical staging, higher metastasis rates, and shorter survival in oral SCC, giving pathologists a tool for estimating a tumor’s biological aggressiveness beyond what physical measurements alone can show.⁹

The Keratoacanthoma Question

If you have ever seen a dome-shaped nodule appear on sun-exposed skin over just a few weeks, there is a decent chance it was a keratoacanthoma rather than a classic SCC. Keratoacanthomas are rapidly growing squamous tumors that can look alarming because of their speed, sometimes reaching a centimeter or more within a month. Historically, they have been classified as benign because many of them stop growing and eventually regress on their own. The problem is that keratoacanthomas can be very difficult to distinguish from true SCC under the microscope, and a subset of them may not regress at all.¹⁰

This overlap is relevant to the growth-speed question because many of the fastest-appearing skin “SCCs” patients report are actually keratoacanthomas, which grow by a different biological playbook. A nodule that appears seemingly overnight and doubles in weeks is more consistent with keratoacanthoma behavior than with typical invasive SCC. Most dermatologists treat keratoacanthomas as though they are SCC anyway, precisely because the distinction is unreliable. But if you are trying to understand the natural growth trajectory of conventional squamous cell carcinoma, it helps to know that the most dramatic examples of explosive speed may belong to a related but distinct entity.

How Blood Vessel Recruitment Fuels Growth

Once an SCC reaches a certain size, it needs its own blood supply to keep growing. Tumors accomplish this by sending out chemical signals that recruit new blood vessels from surrounding tissue, a process called angiogenesis. In oral SCC, researchers have shown that low-oxygen conditions within the tumor activate signaling proteins that cooperate to drive vessel formation, directly supporting tumor expansion.¹¹ In cutaneous SCC, a molecule called CXCL17 has been identified as a driver of angiogenesis. When researchers knocked out CXCL17 in an animal model, tumors showed significantly less blood vessel formation. Clinically, higher CXCL17 levels were associated with increased nerve invasion and more aggressive tumors overall.¹²

This matters practically because it explains a common clinical observation: small SCCs can sit relatively dormant for a while, but once they reach the point where new blood vessels are being actively recruited, growth can accelerate. A tumor that seemed stable at 8 mm might start expanding faster once it crosses into a phase of active vessel formation. It also opens a window for therapeutic intervention, since drugs that target blood vessel growth are already used in other cancers and are being studied in SCC.

When SCC Invades Nerves

One of the more worrying ways SCC can “grow” is not outward in diameter but inward along nerves. Perineural invasion means the cancer cells have entered the sheath surrounding a nerve and are spreading along it, sometimes far beyond the visible border of the tumor on the skin surface. This pattern is rare but carries a significantly worse prognosis. In one reported case, a forehead SCC was found on imaging to have invaded along the supratrochlear nerve, visible as nerve thickening on MRI.¹³

Perineural invasion can cause symptoms like tingling, numbness, or pain in the area around the tumor, and those symptoms sometimes precede any visible growth. A patient who has had an SCC removed and later develops facial numbness or tingling on the same side should seek evaluation promptly. The nerve-tracking pattern of spread also makes recurrence more likely after surgery, because tumor cells may extend along the nerve beyond the surgical margin without being visible to the surgeon.

SCC in Younger Adults

SCC is overwhelmingly a disease of older adults with decades of accumulated sun or carcinogen exposure. When it does appear in adolescents or young adults, it behaves differently enough to warrant separate attention. A study comparing oral SCC in younger patients (generally under 40) with older ones found that tumors in the younger group were far more often located on the tongue and more frequently showed a superficial spreading growth pattern. These tumors also showed higher rates of certain aggressive markers, including abnormal p53 patterns and high tumor budding, where small clusters of cancer cells break off from the tumor front.¹⁴

A superficial spreading pattern means the tumor extends laterally across a wider area rather than growing deep into tissue early on. That can make a young person’s SCC look deceptively flat and mild on the surface while it is covering significant territory. Because oral SCC in young people is uncommon, it is also more likely to be misdiagnosed initially as a canker sore or an infection, delaying biopsy. The combination of unusual growth pattern and diagnostic delay can lead to a larger tumor at the time treatment finally begins.

Practical Timelines for Patients

Pulling the clinical data together, a rough timeline emerges for typical cutaneous SCC. The precancerous actinic keratosis phase can last around two years on average before becoming invasive.⁵ Once a tumor is established, a well-differentiated SCC may grow slowly enough that waiting a few months for surgery does not measurably change its size. A moderately or poorly differentiated SCC, on the other hand, may grow roughly a quarter of a centimeter per month, meaning a three-month wait could add close to a centimeter of tissue that needs to be removed.² For oral SCC, where volume doubling can happen in about eight weeks, even moderate treatment delays can lead to stage progression in a meaningful fraction of patients.³

For immunosuppressed patients the calculus shifts further. Their SCCs tend to grow faster, recur more readily, and metastasize at higher rates, which means the safe window for waiting is shorter.⁷ Dermatologists generally recommend that transplant recipients and others on chronic immune suppression undergo skin checks more frequently and have suspicious lesions biopsied promptly rather than adopting a wait-and-watch approach.

None of this means every SCC is an emergency. The majority of cutaneous SCCs caught at a small size and treated surgically are cured. But the evidence consistently shows that the window between “easy to treat” and “complicated to treat” is narrower for SCC than for its more common cousin, basal cell carcinoma. A spot that is growing, crusting, or failing to heal deserves a biopsy sooner rather than later, because the speed of the cancer you happen to have is something you can only learn after the fact.

1
Actas Dermo-Sifiliográficas. Tumor Doubling Time in Skin Cancer: Can It Be Estimated and Is It Useful?
2
PubMed. Surgical delays of less than 1 year in Mohs surgery associated with tumor growth in moderately- and poorly-differentiated squamous cell carcinomas but not lower-grade squamous cell carcinomas or basal cell carcinomas
3
PubMed. Tumour growth kinetics and stage progression during treatment delay in oral squamous cell carcinoma
4
Journal of the American Academy of Dermatology. Basal cell carcinoma and squamous cell carcinoma growth rates and determinants of size in community patients
5
PubMed. The kinetics of skin cancer: progression of actinic keratosis to squamous cell carcinoma
6
PubMed Central. The Role of p53 in Progression of Cutaneous Squamous Cell Carcinoma
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PubMed Central. Squamous cell carcinomas in organ transplant recipients
8
PubMed Central. A retrospective analysis of drugs associated with the development of cutaneous squamous cell carcinoma reported by patients on the FDA’s adverse events reporting system
9
PubMed Central. Ki67 Labelling Index predicts clinical outcome and survival in oral squamous cell carcinoma
10
PubMed Central. Keratoacanthoma versus Squamous-Cell Carcinoma: Histopathological Features and Molecular Markers
11
PubMed Central. The hypoxia-inducible factor-responsive proteins semaphorin 4D and vascular endothelial growth factor promote tumor growth and angiogenesis in oral squamous cell carcinoma
12
Cancer Research. Abstract 4796: CXCL17 Drives angiogenesis to promote progression in cutaneous squamous cell carcinoma
13
PubMed Central. Squamous Cell Carcinoma with Clinical Perineural Invasion: Challenges and Review in Single Case Study
14
PubMed Central. Early-Stage Oral Squamous Cell Carcinoma in Adolescents and Young Adults Compared with Older Patients Exhibits Distinct Clinicopathological Features