Incidence rates increase, time intervals decrease with every subsequent cSCC

Key takeaways:

• Incidence rates for second through sixth cSCCs increased (28% to 67%), while time intervals decreased (1.4 to 0.5 years).
• Solid organ transplant recipients and hematologic malignancy patients were most at risk.

Cutaneous squamous cell carcinoma risk rises with every subsequent occurrence while the time interval decreases, according to a large cohort study.

“With an annual incidence of 2.4 million cases, cutaneous squamous cell carcinoma (cSCC) is among the most common and still rising cancers worldwide,” Celeste Eggermont, MD, of the department of dermatology at Erasmus MC Cancer Institute at the University Medical Center in Rotterdam, the Netherlands, and colleagues wrote.

Using data from the Netherlands Cancer Registry on 12,345 patients diagnosed in 2007 or 2008 with a first, primary cSCC, Eggermont and colleagues investigated the cumulative incidence and timing of subsequent cSCCs, as well as the most at-risk populations.

Results showed that after their first cSCC, 4,325 (35%) patients had a second cSCC. Of these 2,010 had a third, 1,138 developed a fourth, 739 had a fifth and 501 had a sixth. The 5-year cumulative incidence rates for a subsequent cSCC increased from the second to sixth cSCC (28% to 67%; 95% CI, 27%-28% to 64%-71%, respectively).

Additionally, the median time interval for a patient to have a second through sixth cSCC decreased with each occurrence from 1.4 years (IQR [interquartile range] = 0.3-4.4) at second recurrence, to 1.2 years (IQR = 0.6-2.8) at third, 0.9 years (IQR = 0.3-2.1) at fourth, and 0.5 years (IQR = 0.2-1.5) at fifth, respectively.

Solid organ transplant recipients (SOTRs) were at the highest risk for subsequent cSCC with a 5-year cumulative incidence rate of 74% (95% CI, 68%-79%) for a second cSCC and 92% (95% CI, 86%-96%) for the sixth.

The next most at-risk patient group was those with a hematologic malignancy (HM). Their risk for experiencing a second cSCC was 41% (95% CI, 37%-45%) which increased to 64% (95% CI, 53%-73%) by the sixth cSCC.

“This nationwide cohort study provides valuable insights into the patterns and timing of subsequent cSCC development,” the authors said. “It highlights the progressive risk of subsequent cSCC, with even higher risks for SOTRs and HM patients, while the time interval between occurrences decreases for all patients.”