1142P - Personalized decision making in cutaneous squamous cell carcinoma: Integrating a clinico-pathological model for absolute metastatic risk into the staging systems

Background

Cutaneous squamous cell carcinoma (cSCC) is the second most common skin cancer, causing a staggering death toll comparable to that of melanoma, despite its low propensity to metastasize (2-5%). However, until recently, cSCC has been perceived as a non-life-threatening tumor, and current clinical practices are suboptimal: clinical staging systems cannot consistently and reliably identify patients at high risk of metastasis, and they do not provide absolute metastatic risk. Therefore, decisions about follow-up schedules and treatment cannot be personalized.

Methods

We sought to improve the risk stratification as defined by the American Joint Committee on Cancer (AJCC) and the Brigham and Women's Hospital (BWH), by integrating a recently developed clinico-pathological (CP) model for metastatic risk in cSCC patients. We tried to identify patients at increased risk within the low-risk group (AJCC: T1-T2, BWH: T1-T2a) and in the high-risk group (AJCC: T3-T4, BWH: T2b-T3), We performed our analysis in a Dutch nested case-control cohort (n=390); binarized the 5-year metastatic risk into CP High-Risk and CP Low-Risk, by selecting thresholds based on likelihood ratios.

Results

In the low-risk group, the metastatic risk is 1.1% (AJCC) and 1.2% (BWH). Within this group CP High-Risk patients (AJCC: 2.6%, BWH=1.9%) have an increased risk (AJCC: 10.3%, BWH: 16.2%) and would be offered follow-up; but not the CP Low-Risk patients (AJCC: 97.4%, BWH=98.1%) with a decreased risk (AJCC: 0.9%, BWH: 0.98%). In the high-risk group, the metastatic risk is 5.7% (AJCC) and 12.8% (BWH). Within this group, CP High-Risk (AJCC:7.9 %, BWH=21.8%) have an increased risk (AJCC: 40.5%, BWH: 43.4%) and could be offered more intensive follow-up and treatment (e.g., adjuvant treatment).

Conclusions

Our data show that our risk model can enhance the AJCC and BWH staging systems, by refining the risk stratification in both the low-risk and high-risk groups. This has the potential to help clinicians, dermatologists, radiotherapists, and clinical oncologists make more personalized decisions about more intense follow-up schedules and treatment of their cSCC patients.

Clinical trial identification

Editorial acknowledgement

Legal entity responsible for the study

Erasmus MC.

Funding

This study is funded by a PPP Allowance made available by Health∼Holland, Top Sector Life Sciences & Health, to stimulate public-private partnerships. In this case a public-private partnership between Erasmus MC and SkylineDx BV.

Disclosure

M. Wakkee: Financial Interests, Institutional, Funding: Sanofi, Regeneron; Financial Interests, Personal, Speaker, Consultant, Advisor: Regeneron. L. Pozza, S. Alex: Financial Interests, Personal, Full or part-time Employment: SkylineDx BV. J. Dwarkasing: Financial Interests, Personal, Full or part-time Employment: SkylineDx BV; Financial Interests, Personal, Stocks/Shares: SkylineDx BV. D. Bellomo: Financial Interests, Personal, Full or part-time Employment: SkylineDx BV; Financial Interests, Personal, Stocks/Shares: SkylineDx. All other authors have declared no conflicts of interest.