Abstract
Induction chemotherapy is likely to be effective for biologically distinct subgroups of patients with cancer with biomarker detection. To investigate the prognostic and predictive values of cyclin D1 expression in patients with oral squamous cell carcinoma (OSCC) who were treated in a prospective, randomized, phase III trial evaluating standard treatment with surgery and postoperative radiotherapy preceded or not by induction docetaxel, cisplatin, and 5-fluorouracil (TPF), immunohistochemical staining for cyclin D1 was conducted in pretreatment biopsy specimens of 232 out of 256 clinical stage III/IVA OSCC patients randomized to the clinical trial. Cyclin D1 index was estimated as the proportion of tumor cells with cyclin D1 nuclear staining. A low cyclin D1 expression predicted significantly better overall survival (OS; P = 0.001), disease-free survival (P = 0.005), locoregional recurrence-free survival (P = 0.003), and distant metastasis-free survival (DMFS; P = 0.002) compared with high cyclin D1 expression. Cyclin D1 expression levels were not predictive of benefit from induction TPF in the population overall. However, patients with nodal stage cN2 whose tumors had high cyclin D1 expression treated with TPF had significantly greater OS (P = 0.025) and DMFS (P = 0.025) when compared with high cyclin D1 cN2 patients treated with surgery upfront. Patients with low cyclin D1 level or patients with cN0 or cN1 disease did not benefit from induction chemotherapy. This study indicates that cN2 OSCC patients with high cyclin D1 expression can benefit from the addition of TPF induction chemotherapy to standard treatment. Cyclin D1 expression could be used as a biomarker in further validation studies to select cN2 patients that could benefit from induction therapy.