Study design: A matched-pair study on the relationship between proliferation associated markers Ki-67, PCNA, and p53 and treatment failure in carcinomas of the oropharynx and oral cavity.
Material and method: Fifty-six T1-T3 carcinomas of the oropharynx or oral cavity, treated uniformly with primary surgery and postoperative irradiation, were investigated. Twenty-eight patients had recurrent disease and were matched with 28 patients with nonrecurrent disease regarding stage and location of tumor as well as age and therapy. MIB1 staining was used to determine the Ki-67 labeling index. Immunohistochemical studies determined the p53 status and PCNA labeling index.
Results: Where treatment failed, the Ki-67 labeling index was significantly (p = 0.032) higher (mean = 59.1%) than in patients without recurrence (mean = 50.5%). Mean time to relapse was 45 months (n = 25) for carcinomas with a Ki-67 (MIB1) labeling index above the median (53.7%) of the general study population, compared to 61.7 months for those cases (n = 31) below this median (p = 0.029). The PCNA labeling index did not correlate significantly with tumor recurrence, nor with time to relapse. In 46% of all tumors, p53 overexpression was present. No significant correlation could be found between p53 overexpression and tumor recurrence or time to relapse.
Conclusion: Examination of Ki-67 is thought to provide useful prognostic information concerning squamous cell carcinomas of the oropharynx and oral cavity. Overexpression of p53 or PCNA status is not of prognostic value, which is consistent with earlier results. We conclude that the detection of Ki-67 is an unfavorable prognostic factor for squamous cell carcinoma of the oropharynx and oral cavity, at least if treated with a combination of surgery and postoperative irradiation.