# Local recurrence and locoregional metastases as precursors of death by cutaneous squamous cell carcinoma

## TL;DR

This study explores how local recurrence and lymph node metastases in skin cancer can lead to patient death.

## Contribution

The study introduces a multistate model to estimate progression risks and their association with cSCC-specific death.

## Key findings

- Only 8.9% of patients experienced local recurrence or lymph node metastasis.
- LM is associated with a higher risk of death compared to LR.
- The median time from progression to death was 1.3 years.

## Abstract

In cutaneous squamous cell carcinoma (cSCC), there is a paucity of data regarding local recurrence (LR) and regional lymph node metastasis (LM) as precursors to tumor death.

We estimated parameters of a multistate model with a proportion of patients without risk of progression using maximum likelihood. For seven risk factors, the relative risks of progression to LR, LM, and LR&LM were compared with the relative risks of cSCC death among patients with progression.

Of the 1,400 patients, 124 (8.9%) were diagnosed with either LR (68), LM (42), or LR&LM (14). cSCC‐specific death occurred in 33 patients (2.4%), 10 by LR, 14 by LM, and 9 by LR&LM, among these 10 distant metastases. Conversely, 493 patients (35.2%) died from other causes. The risk of death from cSCC was 14.7% for LR, 33.3% for LM, and 64.3% for LR&LM. The median time to disease‐related death was 1.3 years.

The risk of progression is limited to approximately 25% of patients. LM has been found to be associated with a higher risk of disease‐specific death in comparison to LR. The median interval from progression to disease‐specific death was found to be 1.3 years.