Outcomes after radiotherapy for basaloid squamous cell carcinoma of the head and neck: a case-control study

Basaloid squamous cell carcinoma (BSCC) is an uncommon, high-grade variant of squamous cell carcinoma (SCC) of the head and neck. Its poorer prognosis compared with common SCC remains controversial. The authors investigated the outcomes of patients with BSCC who received radiotherapy and compared them with the outcomes of patients with SCC.

From 1994 to 2004, 1007 patients received radiotherapy for head and neck carcinoma with lymph node involvement. The histologic types consisted of 51 BSCC, 431 poorly differentiated SCC (PSCC), and 525 well or moderately differentiated SCC (WMSCC). A case-control analysis was performed with BSCC matched against both PSCC and WMSCC to compare disease-control and survival rates.

Patients with BSCC received treatment modalities similar to those received by patients with SCC: They received induction chemotherapy (12%) or concurrent chemotherapy (33%), and a median radiation dose of 70 Gray. Posttreatment viable tumor was present in 44%, 13%, and 28% of neck dissection specimens from patients with BSCC, PSCC, and WMSCC, respectively. The 5-year disease-free survival rates (63%, 77%, and 76%, respectively) and overall survival rates (85%, 70%, and 71%, respectively) demonstrated no statistically significant differences for BSCC, PSCC, or WMSCC, respectively.

In this study, a poorer prognosis could not be demonstrated for irradiated patients with BSCC compared with either PSCC or WMSCC. All patients in this study had positive lymph node status, and the majority of patients (84%) had oropharyngeal cancer. The BSCC cohort did have a relatively high rate of viable tumor in their posttreatment neck dissections, and they had a relatively high rate of distant disease. On the basis of the high rate of lung metastases and the possibility of efficient salvage, the authors recommend obtaining a chest computed tomography scan during initial staging and follow-up.