Suppressor protein p53 and its occurrence in oral tumours

Outcomes of oral squamous cell carcinoma in Taiwan after surgical therapy: factors affecting survival

PURPOSE

The study goal was to determine which clinical features correlated with 5-year survival in patients surgically treated for oral squamous cell carcinoma (OSCC) in Taiwan.

PATIENTS AND METHODS

The records of 378 OSCC patients surgically treated with or without chemotherapy and radiotherapy were reviewed retrospectively. Their 5-year survival in relation to age, gender, tumor site, lymph node involvement, presence of distant metastasis, staging, differentiation, and risk factors, including betel quid (BQ) chewing, cigarette smoking, and alcohol consumption, was analyzed.

RESULTS

The majority of the patients were men (male-to-female ratio, 5.87:1) with the mean age of 57.1 +/-11.7 years. Tumors occurred mainly at the buccal mucosa (BM) (100 of 378, 26.5%), gingiva (105 of 378, 27.8%), and tongue (103 of 378, 27.2%). Neck nodal metastasis occurred frequently at the floor of the mouth (in >60% of cases), followed by the gingiva (45.7%), buccal mucosa (34%), and tongue (20.4%), whereas early distant metastasis was rare (5.3%). There were 104 (27.5%) stage 1, 96 (25.4%) stage 2, 98 (25.9%) stage 3, and 80 (21.2%) stage 4 patients. OSCC at the BM and gingiva was most (and at the tongue least) associated with risk factors of BQ use and smoking. The 5-year survival was 75%, 65.6%, 49%, and 30% for patients with stage I, II, III, and IV, respectively. The size, nodal involvement, distant metastasis, staging, differentiation, and BQ use significantly affected the survival (P <.05, Kaplan-Meier analysis). BQ use also correlated most significantly with the younger age of occurrence of OSCC patients.

CONCLUSIONS

Our data suggest that early treatment is the key to increasing the survival of OSCC patients. Periodic screening of high-risk populations for OSCC represents an urgent need in Taiwan.

P53 and Ki-67 as outcome predictors for advanced squamous cell cancers of the head and neck treated with chemoradiotherapy

HYPOTHESIS

P53 and Ki-67 status will predict response to treatment, organ preservation, and survival in patients with advanced squamous cell cancers of the head and neck treated with chemoradiotherapy (CRT).

STUDY DESIGN

Retrospective analysis of p53 and Ki-67 status from the CRT arm of a randomized, controlled trial (n = 50) and from patients receiving the same treatment but not enrolled in the trial (n = 55).

METHODS

P53 and Ki-67 status were established from archived tissue samples using immunohistochemical (IHC) staining. Tumors were positive for p53 (p53+) when more than 2% of cells stained for p53 and were positive for Ki-67 (Ki-67+) when any cell stained for Ki-67. End points were tumor response, tumor recurrence, survival status, and organ preservation at last follow-up, and time to events. Predictive models were calculated for each outcome.

RESULTS

Neither marker predicted tumor response to treatment. P53+ status was associated with tumor recurrence (P =.003) and locoregional recurrence (P =.003). Adjusting for time to event, p53+ status was significantly related to a lower recurrence-free survival (P =.004), lower disease-specific survival (P =.04), lower overall survival with primary site preservation (P =.03), and lower disease-specific survival with primary site preservation (P =.003). Multivariate analysis revealed that p53+ status was significantly related to a lower recurrence-free survival (P =.01, risk ratio [RR] = 3.65) and lower disease-specific survival with organ preservation (P =.02, RR = 3.41). Ki-67+ status was not related to any variables. However, multivariate analysis revealed that Ki-67+ was significantly related to a lower overall survival (P =.05, RR = 2.03). The combination of both markers negative (p53-/Ki-67-) was associated with a lower incidence of tumor recurrence (P =.02), lower locoregional recurrence (P =.01), and fewer second primary lesions (P =.04). Adjusting for time to event, p53-/Ki-67- status was significantly related to a higher recurrence-free survival (P =.02), higher disease-specific survival with primary site preservation (P =.02), and higher overall survival with primary site preservation (P =.02). Multivariate analysis revealed that p53-/Ki-67- status was significantly related to a higher overall survival with site preservation (P =.01, RR = 2.78).

CONCLUSIONS

P53 and Ki-67 status appear to be related to the various survival end points considered in this study. However, this relation does not seem to be sufficient to warrant treatment modifications. Closer follow-up may be justified in both p53+ and Ki67+ patients to detect recurrence or a second primary at an earlier stage, possibly improving survival.