Clinical staging systems for cutaneous squamous cell carcinoma (cSCC) may need to be updated to include satellitosis or in-transit metastasis (S-ITM) given its increased risk for recurrence and poorer survival. These findings were published in a paper in JAMA Dermatology.

Patient records from the Cleveland Clinic and Brigham and Women’s Hospital collected from 2010 to 2020 were retrospectively queried for this study. Patients (n=72) who had node-negative cSCC with S-ITM were compared with cohorts of patients with tumor stage III (T3N0; n=341), tumor stage IV (T4N0; n=36), node-positive (N1 to 3; n=70), or metastasis stage I (M1; n=19) disease and assessed for cSCC recurrence and disease-specific survival (DSS). S-ITM was defined as the presence of dermal lesions between the first-echelon lymphatic nodal basins and primary tumor.

The S-ITM cohort was comprised 82% men, aged median 73.9 (range, 31.6-95.8) years at diagnosis, 96% were White, and 35% were immunosuppressed.


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At a median follow-up of 35.9 (range, 0.1-196.0) months, the 2-year cumulative cSCC recurrence rate was 30.1% and 5-year probability of DSS was 64.0% among all patients.

Stratified by disease, the 2-year cSCC recurrence incidence rate was highest in the S-ITM group (56.6%) followed by the N1 to 3 (53.2%), T4N0 (28.6%), and T3N0 (18.8%) cohorts. For 5-year DSS, survival was lowest for the N1 to 3 cohort (39.0%) followed by the S-ITM (41.0%), T4N0 (64.0%), and T3N0 (76.0%) groups.

Compared with S-ITM, patients with T3N0 (hazard ratio [HR], 0.21; 95% CI, 0.14-0.30; P <.001) and T4N0 (HR, 0.36; 95% CI, 0.19-0.68; P =.001) were at decreased risk for cSCC recurrence. Similarly, T3N0 (HR, 0.23; 95% CI, 0.15-0.35; P <.001) and T4N0 (HR, 0.37; 95% CI, 0.19-0.79; P =.006) were associated with decreased risk for disease-specific death.

N1 to 3 was associated with similar risk for cSCC recurrence (HR, 0.74; 95% CI, 0.48-1.14; P =.16) and DSS (HR, 0.77; 95% CI, 0.48-1.26; P =.30) as patients with S-ITM. Patients with M1 had similar DSS as patients with S-ITM (HR, 1.81; 95% CI, 0.84-3.93; P =.13).

This study may have been limited by not controlling for variation in treatment, it was noted.

The study authors concluded, “This multi-institutional cohort study suggests that S-ITM represents an aggressive risk factor for disease recurrence and skin cancer-related death associated with cSCC. While patients with this risk factor can be cured, the high recurrence risk and disease-related mortality should compel future cancer staging systems to formally incorporate S-ITM and should provide guidance to clinicians regarding intensified adjuvant and/or neoadjuvant therapy.”

Disclosure: Several authors declared affiliations with industry. Please refer to the original article for a full list of disclosures.

Reference

Smile TD, Ruiz ES, Kus KJB, et al. Implications of satellitosis or in-transit metastasis in cutaneous squamous cell carcinoma: a prognostic omission in cancer staging systems. JAMA Dermatol. 2022;e220001. doi:10.1001/jamadermatol.2022.0001