For patients with head and neck cutaneous squamous cell carcinoma (HNCSCC), the Brigham and Women’s Hospital (BWH) tumor classification system is better at predicting metastases and death than the American Joint Committee on Cancer Staging Manual, 8th edition (AJCC 8), based on a study involving 459 patients.
Using the AJCC 8 system, twice as many tumors were considered to be in a high tumor class, compared with the BWH system, reported lead author Emily Stamell Ruiz, MD, of Brigham and Women’s Hospital in Boston, and her colleagues. Using the BWH system could minimize the number of patients undergoing intensive monitoring and possibly therapy without missing those at high risk for poor outcomes.
“Identification of … tumors with significant risk of recurrence, progression to unresectability, or death is challenging owing to lack of accurate [cutaneous squamous cell carcinoma] risk stratification,” the investigators wrote in JAMA Dermatology.
Although AJCC 7 offered a method of classifying such tumors, validation and refinement have been challenging because of a lack of relevant data in the Surveillance, Epidemiology, and End Results Program. A previous study showed that the BWH system outperformed AJCC 7; however, until now, no study has compared the BWH system with AJCC 8, which was released in January 2018 with updated HNCSCC classifications. The BWH has four possible classifications defined by number of high-risk factors and presence or absence of bone invasion: T1, T2a, T2b, and T3. In comparison, the AJCC 8 has five possible classifications defined by tumor size and level of invasion: T1, T2, T3, T4a, and T4b.
The present study involved 459 patients with 680 HNCSCCs. The patients were staged by both BWH and AJCC 8 systems, then compared for accuracy of predicting poor outcomes, including nodal metastases, local recurrence, disease specific death, and overall survival.
The analysis showed that the BWH system had a specificity of 93% for predicting metastases or death, compared with 85% for the AJCC 8 (P less than .001). Sensitivity was not statistically significant between the two groups; however, the BWH system had a better positive predictive value, at 30%, compared with 17% from the AJCC 8. Of note, the AJCC 8 system grouped almost one-quarter of patients (23%) into the T2 and T3 groups, which led to poorer risk prediction, according to the investigators. These patients had a 13% risk of nodal metastasis and an 8% risk of disease-specific death. In contrast, the BWH system confined most poor outcomes into the T2b and T3 groups, which included just 9% of patients, raising risk of disease-specific death to 17% and risk of nodal metastasis to 24%, the latter of which aligns with previously published data.
“One reason for the equivalent outcomes in AJCC 8 T2 and T3 is that poor differentiation is not a risk factor,” the investigators explained. “Approximately 50% of nodal metastasis and overall death in AJCC 8 T2 occurred in patients with poorly differentiated tumors, increasing the risk of poor outcomes in this group. The risk of poor outcomes was lower in AJCC 8 T3, compared with BWH T2b because AJCC 8 T3 tumors are only required to have one of four risk factors whereas two risk factors are required for BWH T2b tumor class.”
The investigators concluded by highlighting the real-world benefits of the BWH system. “Use of BWH tumor classification may minimize the number of patients recommended for radiologic evaluation, close surveillance, and possible adjuvant therapy while still identifying most patients at risk for recurrence, metastasis, and death.”
The investigators reported no conflicts of interest.
SOURCE: Ruiz ES et al. JAMA Dermatol. 2019 Apr 10. doi: 10.1001/jamadermatol.2019.0032.