Are Current Staging Systems for Cutaneous Squamous Cell Carcinoma Satisfactory?
Posted: Wednesday, September 26, 2018
According to the results of a nested case-control study, “four current staging systems distinguished poorly to moderately between [cutaneous squamous cell carcinoma] patients who developed metastasis and those who did not.” The worst-performing system was that of American Joint Committee on Cancer (AJCC), 7th edition, in its “ability to cluster patients with similar outcomes within the same staging category,” wrote the researchers in JAMA Dermatology.
Ingrid Roscher, MD, of Oslo University Hospital, and colleagues also evaluated systems used by Breuninger et al and Boston’s Brigham and Women’s Hospital (Brigham), as well as the AJCC, 8th edition. They identified all patients in Norway diagnosed with primary invasive cutaneous squamous cell carcinoma between 2000 and 2004 (n = 6,721) and then the 112 patients diagnosed with metastasis within 5 years. These patients were randomly paired with 112 controls, matched for sex and age, whose cutaneous squamous cell carcinoma had not metastasized. Expert histologic reexamination of the biopsies yielded 103 patients with metastasis and 81 without.
Results indicated that in the systems used by Breuninger et al and Brigham, high-risk categories for diameter and tumor thickness (Breuninger) and the T2b category (Brigham) collected relatively homogeneous groups. And in both those systems, “risk of metastasis was significantly elevated with increasing stage or risk category.” External validation was performed by logistic regression, discrimination, and calibration statistics. The team found that all four staging systems were lacking in the ability to predict who would and who would not develop metastases.
“A staging system for [cutaneous squamous cell carcinoma] has to be suitable for use in everyday clinical practice,” revealed Dr. Roscher and colleagues. “Variables included in the four staging systems validated in this study may be difficult to assess accurately, which give them limited value for clinicians.”
