Methodology and clinical applications of cellular DNA content parameters determined by flow cytometry in squamous cell cancers of the head and neck

Do the Conventional Clinicopathologic Parameters Predict for Response and Survival in Head and Neck Cancer Patients Undergoing Neoadjuvant Chemotherapy?

Aims and Background

Neoadjuvant chemotherapy for head and neck carcinoma is still an important treatment modality. The prognostic value of patient and tumor parameters has been extensively evaluated in several trials, yielding mixed results. We report the prognostic factors emerging from a group of patients undergoing neoadjuvant chemotherapy.

Patients and methods

From April 1986 to June 1992, 149 consecutive patients received cisplatin-5-fluorouracil-based neoadjuvant chemotherapy. After four courses of chemotherapy, patients underwent local-regional treatment with surgery, radiation or both. A variety of patient and tumor characteristics were evaluated as predictors for response to chemotherapy and survival.

Results

The complete response, partial response and no response rates to NAC were 52%, 33% and 15%, respectively. No parameters predicted response to chemotherapy. At a maximum follow-up of 87 months, overall survival was 39% and disease-free survival was 49%. Variables shown to be predictors of survival in univariate analyses were age, performance status, histology, site, T, N, stage, and response to chemotherapy. Using the Cox regression analysis, only complete response to induction chemotherapy ( P = 0.0006), performance status ( P = 0.03), stage ( P = 0.01), age ( P = 0.03) and primary tumor site ( P = 0.04) emerged as independent prognostic factors for survival.

Conclusions

Complete response to chemotherapy was confirmed as the strongest prognostic factor influencing survival. However, conventional clinicopathologic factors did not predict response, hence, potential prognostic biologic and molecular factors for response must be sought. At present, much effort must be made for the improvement of the complete response rate, which seems to be a requisite to prolong survival.

Complex karyotypes in flow cytometrically DNA-diploid squamous cell carcinomas of the head and neck

In squamous cell carcinoma of the head and neck (SCCHN), DNA ploidy as determined by flow cytometry (FCM) has been found to yield prognostic information but only for tumours at oral sites. Cytogenetic findings have indicated complex karyotype to be a correlate of poor clinical outcome. In the present study, 73 SCCHN were investigated with the two techniques. Aneuploid cell populations were identified in 49 (67%) cases by FCM but in only 21 (29%) cases by cytogenetic analysis. The chromosome index (CI), calculated as the mean chromosome number divided by 46, was compared with the respective DNA index (DI) obtained by FCM in 15 tumours, non-diploid according to both techniques, DI being systematically 12% higher than CI in this subgroup. Eight (33%) of the 24 tumours diploid according to FCM had complex karyotypes, three of the tumours being cytogenetically hypodiploid, three diploid and two non-diploid. The findings in the present study may partly explain the low prognostic value of ploidy status as assessed by FCM that has been observed in SCCHN. In addition, we conclude that FCM yields information of the genetic changes that is too unspecific, and that cytogenetic analysis shows a high rate of unsuccessful investigations, thus diminishing the value of the two methods as prognostic factors in SCCHN.

The clinical application of DNA content and kinetic parameters in the treatment of patients with squamous cell carcinomas of the head and neck

Patients with squamous cell cancers of the head and neck (SCCHN) vary tremendously in their natural history and treatment outcome even amongst subgroups where the clinical and morphological parameters are similar. The ability to pretherapeutically identify individual patients and patient subgroups that differ in these regards would greatly facilitate clinical and basic science cancer research in this tumor. DNA content parameters are simple and accurate intermediate markers of a tumor's biology and reflect the fundamental process associated with the development of malignancy, chromosomal aneuploidy. In patients with SCCHN, DNA content parameters have been shown to be highly predictive of the natural history of the tumor and treatment outcome. They are also useful as intermediate markers for the study of the underlying molecular-genetic properties and processes responsible for the biological differences seen in these cancers. DNA content parameters therefore serve as fundamental 'translational' bridges in clinical and laboratory research in patients with SCCHN.

Development and optimization of tissue preparative methodology for DNA content analysis of soft tissue neoplasms

Data regarding DNA content parameters in soft tissue sarcoma is limited. Development and optimization of tissue specific preparative techniques for DNA flow cytometry was undertaken prior to routine DNA content analysis of soft tissue neoplasms; 154 soft tissue tumors were studied. Dissociation dependent differences in cellular yields, viabilities, maintenance of DNA aneuploid populations, coefficients of variation, and DNA index supported the need for these developmental studies. Fifty-six of eighty-nine patients had DNA aneuploid soft tissue sarcomas. A relationship between DNA aneuploidy and grade was seen in this series with 38% with low grade, 59% with moderate grade, and 69% with high grade tumors demonstrating DNA aneuploid populations (P < 0.005). The mean S-phase fraction for DNA diploid and aneuploid sarcomas was 7.2% and 13.3%, respectively (P < 0.001). When classified by histologic grade of the primary tumor, a greater percentage of metastatic lesions were DNA aneuploid (4 of 7 grade 2 lesions, and 15 of 16 grade 3 lesions). Decreases in cellular yields and rate of DNA aneuploidy were observed in a subgroup of patients with localized high grade sarcoma treated preoperatively, as compared to patients treated with initial surgery. Prospective correlation of DNA content parameters to prognosis and response to cytotoxic therapy are now possible and are ongoing.