DNA ploidy level as prognostic factor in low stage carcinoma of the uterine cervix

Tetraploidy and chromosomal instability are early events during cervical carcinogenesis

Chromosomal instability as manifested by increases in aneuploidy and structural chromosome aberrations is believed to play a critical role in the intermediate to late stages in the development of cervical malignancies. The current study was designed to determine the role of tetraploidy in the formation of aneuploidy and ascertain the occurrence of these alterations during the earlier stages of cervical carcinogenesis. Cervical cell samples, with diagnoses ranging from Normal to high-grade lesions, (HSIL) were obtained from 143 women and were evaluated for chromosomal alterations using dual-probe fluorescence in situ hybridization. Cervical cells from a subset of the group were also evaluated for chromosomal instability in the form of micronuclei. The frequencies of cells exhibiting either tetrasomy or aneusomy for Chromosomes 3 and 17 increased significantly with disease progression and displayed distinctive patterns where aneusomy was rarely present in the absence of tetrasomy. The frequencies of micronuclei that formed through either chromosomal loss or breakage increased significantly in both the low-grade and high-grade diagnostic categories and were highly correlated with both the number of tetrasomic and aneusomic cervical cells. In addition, a unique chromosomal alteration involving a significant non-random loss of Chromosome 17 specific to near-tetraploid aneusomic cells (trisomy 17 and tetrasomy 3) was observed. We conclude that tetraploidy and chromosomal instability are related events occurring during the early stages of cervical carcinogenesis that predispose cervical cells to the formation of aneuploidy frequently involving the loss of Chromosome 17.

Elevated levels of tetraploid cervical cells in human papillomavirus-positive Papanicolaou smears diagnosed as atypical squamous cells of undetermined significance

BACKGROUND

Recommendations for the proper treatment of women diagnosed with an equivocal atypical squamous cells of undetermined significance (ASCUS) Papanicolaou (Pap) smear are controversial. To the authors' knowledge, there currently are no methods available that can identify accurately ASCUS/human papillomavirus (HPV)-positive women who have an increased risk of developing progressive cervical lesions without the use of invasive procedures. An additional diagnostic tool is needed to triage women properly who are diagnosed with ASCUS. Numerical chromosomal abnormalities, such as tetraploidy and aneuploidy, frequently accompany cervical carcinoma development and are believed to represent early and important genetic alterations during cervical carcinogenesis. The identification of elevated levels of numerical chromosomal aberrations in women diagnosed with ASCUS Pap smears, therefore, may be of prognostic value.

METHODS

Multiple-probe fluorescence in situ hybridization was used to analyze 1000 cervical epithelial cells from each of 257 women for the presence of numerical chromosomal aberrations.

RESULTS

A statistically significant proportion of women diagnosed with HPV-positive ASCUS had elevated levels of tetraploid cervical cells (5 of 69 women) compared with normal/HPV-negative women (0 of 75 women) (P = 0.02).

CONCLUSIONS

The frequency of numerical chromosomal aberrations in cervical cells obtained from the majority of women diagnosed with an ASCUS Pap smear did not differ significantly from the frequency in women with smears that were diagnosed as normal. However, a modest but statistically significant proportion of women diagnosed as HPV-positive ASCUS did have elevated levels of tetraploid cervical cells, a genetic abnormality often associated with cervical carcinogenesis, suggesting that these women may be at an increased risk of developing more advanced cervical lesions. Given these results, the authors recommend performing additional studies with histologic follow-up.

Human papillomavirus biology and cervical neoplasia: implications for diagnostic criteria and testing

Human papillomaviruses are necessary for the development of cervical neoplasia. Progress in our understanding of the epithelial biology of this common pathogen has greatly influenced current concepts of cervical carcinogenesis. This understanding has provided a framework for understanding the biologic basis of many diagnostic criteria. Furthermore, classification schemes, diagnostic testing, and clinical management have been modified and clarified in light of this knowledge.

The role of radical surgery followed by adjuvant therapy for high-risk early-stage cervical carcinoma patients with pelvic lymph node metastasis

OBJECTIVES

To identify a subgroup of high-risk node-positive patients in early-stage cervical cancers and to determine the role of radical hysterectomy followed by adjuvant therapy to these patients.

STUDY DESIGN

We conducted a retrospective review of 482 surgically-treated patients of clinical stage Ib and IIa cervical carcinoma from July 1986 to December 1994 at Kaohsiung Chang Gung Memorial Hospital. Of these, 96 patients had pelvic lymph node metastases. Clinicopathological variables, including the level of pretreatment squamous cell carcinoma antigen (SCC-Ag), DNA flow cytometry analysis, and the use of different adjuvant therapies were studied.

RESULTS

Disease-free survival was significantly worse among patients with S-phase fraction greater than 20% and pretreatment SCC-Ag level above 5 ng/ml. Utilizing these significant variables, we identified two distinct risk groups. Those patients without any of the risk variables were categorized as the low-risk group. Those patients with either one or both risk variables were categorized as the high-risk group. Five-year disease-free survival rates were 74% in the low-risk group and 43% in the high-risk group, (P=0.034). Disease recurred in 30.2% of the low-risk patients and 45. 3% of the high-risk patients. No survival advantages were found by using different adjuvant therapies.

CONCLUSIONS

Radical hysterectomy should not be attempted if either the pretreatment SCC-Ag level is above 5 ng/ml or S-phase fraction of the tumor greater than 20% due to its limited value despite applying aggressive postoperative adjuvant therapy.

Clear cell adenosquamous carcinoma of the cervix. An aggressive tumor associated with human papillomavirus-18

BACKGROUND

It is well recognized that adenocarcinomas and adenosquamous carcinomas of the cervix are frequently associated with human papillomavirus (HPV)-16 or -18. However, few studies have investigated associations between histologic variants of these tumors and specific types of HPV.

METHODS

Eleven cases of cervical adenosquamous carcinoma with an unusual histologic appearance were characterized using histochemical and immunohistochemical stains. Sections were tested for the presence of HPV DNA using the polymerase chain reaction (PCR) and type specific primers for HPV-16 and -18. Clinical outcome was determined from a chart review.

RESULTS

All tumors were histologically characterized by the presence of sheets of cohesive cells with prominent cell borders and a vacuolated or clear cytoplasm containing large amounts of glycogen. All tumors had focal gland formation and stained positive with mucicarmine stain. Using PCR, HPV-18 DNA was identified in all cases. The youngest patient was 24 years old and the oldest 74 years (mean, 43 years). Eight (73%) of the 11 patients have developed recurrent disease with a mean follow-up until recurrence of 9.5 months (range, 3-22 months). Seven (64%) of the 11 patients have died of their cervical tumors. Of the five patients with Stage IB disease, three (60%) have died of their cervical tumors.

CONCLUSIONS

A subset of invasive cervical adenosquamous carcinoma associated with HPV-18 that has a distinctive histologic appearance and an aggressive clinical course is described. The term "clear cell adenosquamous carcinoma" is proposed for this unique variant of invasive cervical carcinoma.

Changes in S-phase fraction and micronucleus frequency as prognostic factors in radiotherapy of cervical carcinoma

Twenty-five patients with cervical carcinoma were treated with combined external beam and high dose rate afterloading radiotherapy. Biopsies obtained at different time points in the course of therapy were analysed with respect to cell proliferation and cytogenetic damage. The fraction of cells with an S-phase DNA-content as well as the frequency of micronuclei were determined. These two parameters were then related to treatment outcome, in particular patient survival. Neither S-phase fraction nor the micronucleus frequency before radiotherapy were predictive of treatment outcome in this small group of patients. However, when changes in response to therapy were considered, patients whose S-phase fraction decreased and patients whose micronucleus frequency increased tended to have a better prognosis. Although statistical significance was not achieved with either criterion alone, when applied together the combination predicted patient survival quite reliably; the 5-year survival rate of those patients who showed a decrease in S-phase fraction as well as an increase in micronucleus frequency was about 90% in contrast to less than 30% for the non-responders (p < 0.03).

Proliferation measurements with flow cytometry Tpot in cancer of the uterine cervix: correlation between two laboratories and preliminary clinical results

PURPOSE

To assess the prognostic value of the pretreatment potential doubling time (Tpot) in carcinoma of the uterine cervix, relative to other established clinical factors.

METHODS AND MATERIALS

Fifty-two patients with cervical cancer were studied prospectively from March 1991 to October 1993. Pretreatment evaluation included examination under anesthesia and tumor biopsy 6 h following the intravenous administration of bromodeoxyuridine (200 mg). Tpot was determined by deriving the labeling index (LI) and S-phase synthesis time (Ts) using flow cytometry. Six patients were not evaluable and excluded. The remaining 46 patients (average age 55 years) were treated uniformly with radical radiation therapy. There were 39 squamous carcinomas and 7 adenocarcinomas. Fédération Internationale de Gynécologie et d'Obstétrique (FIGO) stages were: Ib and IIa, 12 patients; IIb, 18 patients; III and IV, 16 patients. The median external beam dose was 50 Gy (range, 45-52.8 Gy) delivered in 25 fractions. The median intracavitary dose was 40 Gy (range. 25.5-40 Gy) delivered with a single line source to a point 2 cm lateral of the midline, with a mean dose rate of 0.71 Gy/h. The median overall treatment time was 45 days (range, 34-73 days). As of July 31, 1994, 12 patients had died of disease, and the average follow-up for alive patients was 1.4 years (range, 0.5-3.3 years).

RESULTS

There were 27 tumors with diploid deoxyribonucleic acid (DNA) content and 19 tumors were aneuploid. The median and mean Tpot for the 46 patients were 5.5 and 6.6 days, respectively [range, 2.0-25.6 days; coefficient of variation (CV), 74%]. For 25 patients where Tpot measurements were performed at two separate laboratories, there was a fair correlation (r = 0.74), but systematic differences were detected suggesting that the lack of agreement was not simply due to intratumoral variation. To date, 30 patients remained disease free, while 8 patients had pelvic failure and 9 patients developed distant metastases as the first failure site (1 patient developed both at the same time). In univariate analysis, the only significant prognostic factor for disease-free survival was tumor size (p = 0.004). A short Tpot (or high LI) and long overall treatment time (OTT) were weakly associated with poorer disease-free survival, although not statistically significant (1/Tpot, p = 0.14; LI, p = 0.23; OTT, p = 0.04). Age, FIGO stage, hemoglobin level, S-phase fraction, DNA ploidy, and Ts were not associated with disease-free survival. Multiple regression analysis was not performed because of the relatively small number of patients and short follow-up.

CONCLUSIONS

Tpot values determined with current techniques by different laboratories cannot be used interchangeably for the purpose of therapy decisions. Vigorous quality assurance and standardization of the laboratory procedures and analysis methods are important to reduce interlaboratory variation. In this uniformly treated group of patients with cancer of the uterine cervix, traditional clinical prognostic factors remain the most important. Preliminary data suggest that the flow cytometry-determined Tpot and labeling index predict for disease-free survival, although a larger number of patients with longer follow-up is required to assess the true prognostic significance of these assays and to determine if their effect is independent of other clinical factors.

DNA cell-cycle analysis of cervical cancer by flow cytometry using simultaneous cytokeratin labelling for identification of tumour cells

DNA ploidy and cell-cycle distribution were determined by flow cytometry in fresh tumour tissue of 53 cervical carcinomas. Epithelial cells were labelled by a fluorescein-isothiocyanate-conjugated cytokeratin antibody (CK6, CK18) to study the influence of contaminating stromal and inflammatory cells on results of cell-cycle analysis of tumour cells. Without identification of cytokeratin-positive cells 30/53 (57%) tumours were found to be DNA-aneuploid compared to 43/53 (81%) after gating for cytokeratin. Only 7 of 15 DNA-multiploid tumours could be detected without cytokeratin staining. In addition, cytokeratin-negative cells, which are found in all tumours, can be used as an internal standard for the calculation of ploidy and for quality control (coefficient of variation, linearity) of each individual sample. Cell-cycle analysis revealed significantly higher S-phase and G2M-phase fractions in cytokeratin-gated compared to ungated samples (13.1% versus 10.0% and 8.0% versus 5.4%; P < 0.001). This difference was more pronounced in DNA-diploid than DNA-aneuploid tumours. In conclusion, about 30% of DNA-aneuploid tumours could only be detected after cytokeratin labelling of epithelial cells. Owing to the identification of cytokeratin-positive cells the influence of non-tumoural cell elements on cell-cycle analysis was reduced markedly. Therefore, in cervical cancer, cytokeratin labelling can optimize both the determination of DNA ploidy and cell-cycle analysis.

The prognostic significance of hyperploid cells in squamous carcinoma of the uterine cervix treated with radiotherapy

Smears were obtained from patients undergoing radiotherapy for Stage I-IV squamous cell carcinoma of the cervix. The presence of cells with large or multiple nuclei in smears taken during or not more than 1 month following therapy was found to be associated with a significantly increased risk of early relapse.

Deoxyribonucleic acid ploidy and S-phase fraction are not significant prognostic factors for patients with cervical cancer

OBJECTIVE

Our purpose was to determine the usefulness of deoxyribonucleic acid ploidy and S-phase fraction as prognostic factors in patients with cervical cancer.

STUDY DESIGN

Paraffin-embedded tumor specimens were obtained from 123 patients with cervical cancer (mean age 51 years, range 21 to 87 years). The mean follow-up period was 6.4 years. Deoxyribonucleic acid ploidy and S-phase fraction were determined by flow cytometry.

RESULTS

A total of 119 patients were evaluable for deoxyribonucleic acid ploidy and 92 were evaluable for S-phase fraction. The overall rate of deoxyribonucleic acid aneuploidy was 60%, and the median S-phase fraction was 12.5%. Neither factor was significantly related to stage of disease. In univariate survival analyses patients with deoxyribonucleic acid aneuploid tumors had slightly better early survival than did patients with deoxyribonucleic acid diploid tumors (median survivals 2.7 and 1.4 years, respectively, p = 0.08 [Wilcoxon]), but the overall survival was not significantly different, p = 0.37 (log-rank). In multivariate analyses deoxyribonucleic acid ploidy was not a significant predictor of survival. S-phase fraction was not statistically significant in either analysis.

CONCLUSION

Deoxyribonucleic acid ploidy and S-phase fraction are not useful prognostic factors for patients with cervical cancer.

The uses and limitations of DNA flow cytometry in stage IB or II cervical carcinoma

BACKGROUND

The role of flow cytometry in predicting prognosis for cervical carcinoma remains unclear.

METHODS

Flow cytometric analysis was performed on tissues, fixed in formaldehyde solution and embedded in paraffin, from 411 patients with Stage IB or II cervical carcinoma who had been treated with radical abdominal hysterectomy and bilateral pelvic lymphadenectomy.

RESULTS

DNA aneuploid-multiploid tumors were found in 37.5%, tetraploid in 4.6%, and diploid-peridiploid in 57.9%. Five-year recurrence-free survival rates of the three groups were 74.3%, 77.8%, and 76.4%, respectively (P > 0.05). DNA aneuploidy and DNA index (DI) of greater than 1.3 were highly correlated to parametria extension. In univariate analysis, pelvic lymph node metastases, stage, parametrial extension, depth of cervical stromal invasion, tumor size, and DI (1.3, 1.4, 1.5 as breakpoint) were significant prognostic factors. DNA ploidy, S-phase fraction, and S-G2M fraction were not significant. In multivariate analysis, DI of greater than 1.3, pelvic node metastases, clinical Stage II, and depth of stromal invasion greater than two-thirds of full cervical thickness were independent and significant variables. The prognostic index (PI), defined by the model, was able to categorize the patients into three distinct risk groups. The 5-year recurrence free survival rates of the low-, intermediate-, and high-risk groups were 89.5%, 73.0%, and 58.9%, respectively (P < 0.0001).

CONCLUSIONS

The prognostic value of the DI as a single variable is promising and warrants additional investigation to establish its appropriate use.

Measurement of cell kinetics in cervical tumours using bromodeoxyuridine

The pre-treatment cell kinetics of 120 cervical tumours were assessed following the in vivo labelling with the thymidine analogue Bromodeoxyuridine (BrdUrd). In 89% both static and temporal kinetic parameters could be measured. Through the analysis of multiple biopsies from each tumour marked intra tumour heterogeneity was demonstrated. The median values for the most highly labelled sample analysed for each tumour were; S-phase duration (Ts) 12.1 h, BrdUrd labelling index (CLI) 9.5% and potential tumour doubling time 4.4 days. There was a significant elevation in CLI, but no difference in Ts, between tumour and non-neoplastic cervical tissue. There was a significant elevation in CLI, advanced stage and large size tumours. Although a significant elevation in CLI was found in aneuploid tumours this is likely to represent the systemic bias of the calculation methods, with no difference being seen between aneuploid and diploid tumours when BrdUrd labelling was measured with-out reference to the nuclei DNA content. The majority of these patients were treated with radiotherapy and cell kinetic data will be correlated with treatment response when adequate follow up has been achieved.

Human papillomavirus type 16 in tumor tissue of low-stage squamous carcinoma of the uterine cervix in relation to ploidy grade and prognosis

BACKGROUND

The relationship among the presence of human papillomavirus (HPV) in tumor cells, DNA ploidy, and the prognosis of squamous cell carcinoma of the uterine cervix was studied.

METHODS

HPV 16 was detected using the polymerase chain reaction on paraffin-embedded material from 69 patients with Stage IB and IIA carcinoma of the uterine cervix. The presence or absence of HPV was related to age, survival, and ploidy status as measured by DNA flow cytometry. All patients were treated by radical surgery.

RESULTS

Thirty-four patients had HPV 16, and 35 did not. The mean age of the patients differed statistically significantly between the HPV-positive group (51.1 years) and the HPV-negative group (45.1 years, P = 0.015). No difference was found in the mean DNA index (1.21 versus 1.22, P = 0.85) or 5-year survival rate (85% versus 86%, P = 0.87) between the two groups.

CONCLUSIONS

The high prevalence of HPV 16 in cervical cancer, which appeared to be correlated with age (in combination with its presence in diploid and aneuploid tumors), indicated the important role of HPV 16 in the evolution of cervical cancer. However, using stepwise Cox regression analysis, the presence of HPV 16 had no additional prognostic value over lymph node metastases findings.

Prognostic value of flow cytophotometric DNA content analysis in single treatment stage IB-IIA squamous cell carcinoma of the cervix

DNA content was measured flow cytometrically in archival tissue from 65 single-treatment stage IB and IIA squamous cell carcinomas of the cervix with at least 5 years of clinical follow-up. Thirty-five cases were treated exclusively by hysterectomy and thirty exclusively by radiation therapy. Tumors were categorized into four groups on the basis of DNA content and cell cycle distribution. DNA content was measured relative to the position of the first resolvable cell peak. G2/M and S-phase fractions were estimated as percentage of cells with DNA contents greater than or equal to relative position 1.70 and percentage of cells with relative positions between 1.20 and 1.70, respectively. The 40 tumors characterized as either aneuploid or nondemonstrably aneuploid with high S-phase fraction estimate had a 5-year recurrence rate significantly higher than that of the 25 tumors categorized as tetraploid or nondemonstrably aneuploid with low S-phase fraction estimate (52 and 4%, respectively; chi 2 = 15.8, P less than 0.001). Similar results were found when radiation and surgically treated tumors were considered independently (chi 2 = 7.95, P less than 0.005 and chi 2 = 5.7, P less than 0.025, respectively). These data suggest that an increased 5-year recurrence rate is associated with both abnormal DNA content and elevated S-phase fraction in stage IB-IIA squamous cell carcinoma of the cervix, and that this relationship is largely independent of treatment method.