Metastasis of cutaneous squamous cell carcinoma in organ transplant recipients and the immunocompetent population: is there a difference? a systematic review and meta‐analysis

Abstract

Background Organ transplant recipients (OTR) have a higher risk of developing cutaneous squamous cell carcinoma (cSCC) compared to the immunocompetent population. Immunosuppression is often stated as a risk factor for metastasis. However, evidence for this is scarce.Objectives To investigate the cSCC metastasis risk in OTR and the immunocompetent population by systematically reviewing the literature.Methods A systematic review of the literature was performed up to January 2018 using: Medline; Embase; Web of Science and ISI Science Citation Index. Studies assessing cSCC metastasis risk in ORT or immunocompetent cohorts were considered. A pooled risk estimate for metastasis was calculated for the immunocompetent population and OTR separately. ResultsThe pooled metastasis risk estimate for OTR was, respectively, 7.3% (95% CI 6.2-8.4) for cSCC on total body, and 11.0% (95% CI 7.7-14.8) for cSCC of the head neck area. For the immunocompetent population reported risk estimate analysis showed a pooled metastatic risk of 3.1% (95% CI 2.8-3.4) in total body cSCC and of 8.5% (95% CI 7.3-9.8) in cSCC of the head and neck area.Pooled risk estimate per single cSCC in OTR was 1.3% (95% CI 1.0-1.7) in total body cSCC and 4.0% (95% CI 2.7-5.5) in cSCC of the head and neck area. In the immunocompetent population, these pooled risk estimates were, respectively, 2.4% (95% CI 2.1-2.6) and 6.7% (95% CI 5.7-7.8).Conclusions Organ transplant recipients show a higher overall risk of cSCC metastasis compared to the immunocompetent population. Metastasis risks per single cSCC were substantially lower in both groups. However, due to heterogeneity and differences between studies, comparisons are difficult. Comprehensive follow-up studies with defined cohorts are necessary to adequately asses the risk for cSCC metastasis.

Validation of a 40-gene expression profile test to predict metastatic risk in localized high-risk cutaneous squamous cell carcinoma

“…2,[4][5][6][7][8][9][10][11] The rates of metastasis of tumors with high-risk features can surpass 20%. 3,10,[12][13][14][15][16][17][18][19] Once metastasis is detected, 5-year survival rates drop to 50% to 83% and to less than 40% for patients with regional and distant metastasis, respectively. 16,[20][21][22] Because early detection of metastasis is correlated with better outcomes, accurate identification of patients at high risk for metastasis is critical, potentially allowing for early adjuvant therapy, while also avoiding overtreatment of low-risk tumors.…”

Incomplete Excision of Cutaneous Squamous Cell Carcinoma; Systematic Review of the Literature

“…Only a few studies reported on immunosuppressed patients in their cohort. Patients on immunosuppression develop cSCC that tend to behave more aggressively, with a higher rate of both local recurrence and metastasis compared to immunocompetent patients (9,(33)(34)(35). Also, peripheral tumor borders can be difficult to properly define because of severe damage to the surrounding skin.…”

The Role of Circular RNAs in Keratinocyte Carcinomas

“…In contrast to BCC that rarely metastasize, cSCC may form metastases in up to 10% of cases [4]. Crossing of the basal layer is considered a key factor in invading the underlying dermis and dissemination of tumour cells.…”

“…However, cSCC are more aggressive than BCC. In up to 10% of patients, metastases may develop, with a high mortality rate [3][4][5].…”