Bromodeoxyuridine labeling index in glioblastoma multiforme: relation to radiation response, age, and survival

Monocentric evaluation of Ki-67 labeling index in combination with a modified RPA score as a prognostic factor for survival in IDH-wildtype glioblastoma patients treated with radiochemotherapy

Purpose

The prognosis for glioblastoma patients remains dismal despite intensive research on better treatment options. Molecular and immunohistochemical markers are increasingly being investigated as understanding of their role in disease progression grows. O(6)-methylguanine-DNA methyltransferase (MGMT) promoter methylation has been shown to have prognostic and therapeutic relevance for glioblastoma patients. Other markers implicated in tumor formation and/or malignancy are p53, Alpha thalassemia/mental retardation syndrome X-linked (ATRX), Epidermal Growth Factor Receptor splice variant III (EGFRvIII), and Ki-67, with loss of nuclear ATRX expression and lower Ki-67 index being associated with prolonged survival. For p53 and EGFRvIII the data are contradictory. Our aim was to investigate the markers mentioned above regarding progression-free (PFS) and overall survival (OS) to evaluate their viability as independent prognostic markers for our patient collective.

Methods

In this retrospective study, we collected data on patients undergoing radiotherapy due to isocitrate dehydrogenase (IDH) wildtype glioblastoma at a single university hospital between 2014 and 2020.

Results

Our findings confirm Ki-67 labeling index ≤ 20% as an independent prognostic factor for prolonged PFS as well as MGMT promoter methylation for both prolonged PFS and OS, in consideration of age and Eastern Cooperative Oncology Group (ECOG) status, chemotherapy treatment, and total radiation dose for PFS as well as additionally sex, resection status, and receipt of treatment for progression or recurrence for OS. Additionally, Ki-67 labeling index ≤ 20% showed a significant correlation with prolonged OS in univariate analysis. Modification of the recursive partitioning analysis (RPA) score to include Ki-67 labeling index resulted in a classification with the possible ability to distinguish long-term-survivors from patients with unfavorable prognosis.

Conclusion

MGMT promoter methylation and Ki-67 labeling index were independent predictors of survival in our collective. We see further studies pooling patient collectives to reach larger patient numbers concerning Ki-67 labeling index as being warranted.

Supplementary Information

The online version of this article (10.1007/s00066-022-01959-6) contains supplementary material, which is available to authorized users.

Treatment of Glioblastoma Multiforme in Elderly Patients. Clinico-therapeutic Remarks in 22 Patients Older than 80 Years

We report our remarks on 22 patients, 80 years of age and older, who were treated for glioblastoma multiforme. The 16 patients who underwent a multimodality treatment (surgery + radiotherapy + chemotherapy) had an average survival of 16.7 months versus the 5.8 months of the 8 patients treated with biopsy followed by radiotherapy and/or chemotherapy (log-rank test, P <0.001). Moreover, we point out the importance of MGMT hypermethylation as a significant prognostic factor: the 9 patients with nonmethylated MGMT had a mean survival of 7.7 months vs 17.9 months of the 13 patients with the MGMT promoter methylated (log-rank test, P = 0.0006). Several studies have pointed out age as an important negative factor for the outcome of elderly patients affected by glioblastoma multiforme. Elderly patients with a diagnosis of glioblastoma multiforme are thus generally excluded from clinical trials of treatment for the neoplasm, because it is a common opinion that the prognosis for such patients is particularly poor. On the contrary, according to our clinical and surgical experience, we firmly believe that patients older than 80 years with a histologically proven diagnosis of glioblastoma multiforme and in good health conditions (Karnofsky performance status >60) should be treated in the same way as younger patients.

Clinicopathological analysis of HOXD4 expression in diffuse gliomas and its correlation with IDH mutations and 1p/19q co-deletion

Backgrounds

HOX (homologous box) is known as the dominant gene of vertebrate growth and cell differentiation. Abnormal expression of HOX gene in various tumors has attracted the attention of scholars. As a component of HOX clusters, HOXD4 plays a controversial role in the tumorigenesis of central nervous system.

Results

The data demonstrated that and the results demonstrated that HOXD4 was overexpressed in glioma tissues compared to that of normal brain tissues. patients with high HOXD4 expression had a significant shorter survival than those with low HOXD4 expression in total glioma cohort (p<0.001), WHO Grade II cohort (p=0.003) and Grade III cohort (p<0.001), but not in Grade IV cohort when OS (overall survival) was analyzed (p=0.216). The findings were confirmed by the large-scale omics data analysis including lower-grade glioma (LGG) and glioblastoma multiforme (GBM) in TCGA (the cancer genome atlas) and CGGA (Chinese glioma genome atlas). Moreover, it was revealed that the expression of HOXD4 have a significant impact on the OS of Grade IV glioma with IDH wild-type and 1p/19q intact according to TCGA data.

Methods

Clinicopathological analysis of HOXD4 expression in 453 glioma patients was performed in the current study. Expression of HOXD4 was evaluated by qPCR and immunohistochemical (IHC) staining. Univariate and multivariate analysis were conducted to investigate the prognostic role of HOXD4 in glioma patients.

Conclusions

Expression of HOXD4 was closely related to the clinical outcomes of patients with gliomas, and HOXD4 may be a potential prognostic biomarker of gliomas.

Role of MIB1 in predicting survival in patients with glioblastomas

BACKGROUND

Histologic immunomarkers of cell cycle proteins have been utilized for prognosis in high-grade astrocytic tumors. One such marker, MIB1, an antibody immunoreactive throughout the cell cycle, is predictive of more aggressive disease and poorer prognosis in astrocytomas. An independent role of MIB1 analysis for survival prediction and clinical management within histologic grades has not been clearly proven.

METHODS

This study retrospectively evaluated MIB1 reactivity in tissue samples from 116 patients with glioblastomas on initial medical presentation. Clinical variables considered included gender, age, Karnofsky Performance Scores (KPS), extent of surgical resection, adjuvant radiation and survival.

RESULTS

Univariate and multivariate analyses were used to correlate these variables with MIB1 staining. MIB1 staining does not predict overall survival or response to adjuvant therapy as an independent risk factor.

CONCLUSION

MIB1 labeling does not predict patient survival as an independent variable and does not predict response to additional therapies. Patient survival with glioblastoma was predicted by KPS, age, extent of resection and use of adjuvant radiotherapy.

Techniques to assess the proliferative potential of brain tumors

Assessment of brain tumor proliferative potential provides important prognostic information that supplements standard histopathologic grading. Many laboratories rely on mitotic figures to quantify the proliferative potential of brain tumors, but this conventional cellular proliferative index is subject to inter-observer variability and not consistently predictive for low-and high-grade tumors. Recent advancements in technology have made it possible to use proliferative indices as a standard supplement in pathology laboratories. Non-invasive tumor tissue measurements of cell proliferation can be performed using- bromodeoxyuridine labeling index (BrdU LI), flow cytometry (FCM), MIB-1 antibody to the Ki-67 antigen (MIB-1), proliferating cell nuclear antigen (PCNA), and argyrophilic nucleolar organizing regions (AgNOR). Each of these assays has been described in the literature with respect to its ability to predict tumor grade or outcome. At the present time MIB-1 and AgNOR are the simplest and most reliable of these techniques. In addition, advances in our understanding of the genetic alterations associated with proliferation promise to provide more specific markers of proliferative potential. Beyond the pathology laboratory, radiographic studies such as positron emission tomography (PET), single photon emission computed tomography (SPECT), and most recently magnetic resonance spectroscopy (MRS) have been used as follow-up measures, assessing response to treatment and tumor recurrence, rather than as predictors of response to treatment. These radiographic tools, however, have the potential to provide an assessment of tumor proliferation without the need for invasive measures. In this article, we present a review of the current techniques utilized to understand the proliferative potential of brain tumors.

The treatment of elderly patients with high-grade gliomas

Elderly patients with cancer are frequently excluded from cancer therapy trials, treated suboptimally, or not treated at all because of the widely held belief that elderly patients do not tolerate chemotherapy and/or radiotherapy (RT) as well as younger patients. Excluding elderly patients from conventional treatment, chemotherapy in particular, is often based on ad hoc decisions rather than on sound scientific data. Malignant gliomas are the most common primary brain tumors in adults, and the age-adjusted incidence of high-grade gliomas has increased over recent years, especially in the elderly. However, few investigators focus on the treatment of high-grade gliomas in the elderly. Data from retrospective studies and meta-analyses suggest that elderly patients with high-grade gliomas have a poorer outcome than younger patients, possibly because of the presence of comorbidity, resistance to cancer therapy, genetic aberrations, different histology, neurodegeneration, or age discrimination. The optimal treatment of elderly patients with high-grade gliomas has not been determined. Surgical debulking and postoperative RT are associated with a significant increase in survival among elderly patients who are in good clinical condition. A recent report has shown that treatment with temozolomide (Temodar [US], Temodal [international]; Schering-Plough Corporation, Kenilworth, NJ) plus RT provides a significant survival benefit compared with RT alone and a significantly improved time to progression compared with RT plus standard chemotherapy (lomustine, procarbazine, and vincristine). Further, temozolomide was well tolerated in the elderly patient population and was less toxic than standard chemotherapy. Therefore, it could be recommended that a full course of RT be followed by adjuvant temozolomide in elderly patients with good prognostic factors. Further, temozolomide alone could be considered as a treatment option for elderly patients with glioblastoma with poorer performance status and for patients who cannot tolerate RT. Results from larger prospective trials will determine the optimal role of chemotherapy, particularly temozolomide, in elderly patients with malignant gliomas.

Immunohistochemical markers for prognosis of cerebral glioblastomas

Glioblastoma is the commonest neuroectodermal tumor and the most malignant in the range of cerebral astrocytic gliomas. The prognostic utility of various biological markers for glioblastomas has been broadly tested but the results obtained are regarded as controversial. In the present study, 302 glioblastoma specimens were studied to evaluate a possible association between clinical outcome and expression of some immunohistochemical variables. Furthermore, tumors examined were subdivided on the three cytological subsets--small-cell (SGB), pleomorphic-cell (PGB) and gemistocytic (GGB). Immunohistochemical variables differed between various subsets: the number of p53-positive tumors was found to be prevailed among the PGB, whereas the number of tumors with EGFR and mdm2 positivity was significantly greater in SGB. GGB contained significantly lowest mean proliferating cell nuclear antigen (PCNA) labeling index (LI), greater number of p21ras positive cases, and higher mean apoptotic index (AI). Survival time in patients with SGB, EGFR and mdm2-positivity and PCNA LI >40% was found to be significantly shorter, whereas presence of p21ras and AI >0.5% were associated with prolonged survival. Multivariate analysis revealed that survival time is associated with SGB, EGFR-positivity, and AI (p = 0.0023, p = 0.0035 and p = 0.0029 respectively). We conclude that although some immunohistochemical variables were found to be significant for glioblastoma outcome, they appear to be closely related to biology of single cytological subsets. Furthermore, these variables exhibited no prognostic value when they were analyzed within each cytological subset separately. Therefore, the glioblastoma subdivision on three cytological subsets proposed by us is carrying some element of rationality but, undoubtedly, requires further prospective studies.

Ki-67 labeling is correlated with the time to recurrence in primary glioblastomas

The Ki-67 labeling index (LI) was shown in many cut-off studies to be significantly correlated to the postoperative survival probability in gliomas in univariate and multivariate analyses. However, a direct relationship of the Ki-67 LI and the growth fraction, respectively, to clinical growth parameters was not demonstrated in a single tumor type of this group until now. We compared the Ki-67 LI of 20 primary glioblastomas and their recurrent tumors with the time to reoperation for recurrence. Regression analyses showed (1) a high reproducibility of the LIs at the second versus the first operation corresponding to an inherent growth potential of a given individual tumor and (2) a strong inverse correlation of LI to time to recurrence (TR) (r = -0.92). Additionally to a lower LI (corresponding to a smaller growth fraction), a longer cycle time could be derived in slowly growing as compared to rapidly growing tumors. A direct relationship of the Ki-67 LI to a clinical time parameter (the TR) was obtained, and a predictive significance of individual LIs in glioblastomas could be defined.

Age and radiation response in glioblastoma multiforme

OBJECTIVE

Advanced age is a strong predictor of shorter survival in patients with glioblastoma multiforme (GM), especially for those who receive multimodality treatment. Radiographically assessed tumor response to external beam radiation therapy is an important prognostic factor in GM. We hypothesized that older GM patients might have more radioresistant tumors.

METHODS

We studied radiographically assessed response to external beam radiation treatment (five-level scale) in relation to age and other prognostic factors in a cohort of 301 GM patients treated on two prospective clinical protocols. A total of 223 patients (74%) were assessable for radiographically assessed radiation response. A proportional odds ordinal regression model was used for univariate and multivariate analysis.

RESULTS

Younger age (P = 0.006), higher Karnofsky Performance Scale score before radiotherapy (P = 0.027), and more extensive surgical resection (P = 0.028) predicted better radiation response in univariate analyses. Results were similar when clinical criteria were used to classify an additional 61 patients without radiographically assessed radiation response (stable versus progressive disease). In multivariate analyses, age and extent of resection were significant independent predictors of radiation response (P < 0.05); Karnofsky Performance Scale score was of borderline significance (P = 0.07).

CONCLUSION

Older GM patients are less likely to have good responses to postoperative external beam radiation therapy. Karnofsky Performance Scale score before radiation treatment and extent of surgical resection are additional predictors of radiographically assessed radiation response in GM.

EGFR overexpression and radiation response in glioblastoma multiforme

PURPOSE

Recent studies have suggested relative radioresistance in glioblastoma multiforme (GM) tumors in older patients, consistent with their shorter survival. Two common molecular genetic abnormalities in GM are age related: epidermal growth factor receptor (EGFR) overexpression in older patients and p53 mutations in younger patients. We tested whether these abnormalities correlated with clinical heterogeneity in GM response to radiation treatment.

METHODS AND MATERIALS

Radiographically assessed radiation response (5-level scale) was correlated with EGFR immunoreactivity, p53 immunoreactivity, and p53 exon 5-8 mutation status in 170 GM patients treated using 2 prospective clinical protocols. Spearman rank correlation and proportional-odds ordinal regression were used for univariate and multivariate analysis.

RESULTS

Positive EGFR immunoreactivity predicted poor radiographically assessed radiation response (p = 0.046). Thirty-three percent of tumors with no EGFR immunoreactivity had good radiation responses (>50% reduction in tumor size by CT or MRI), compared to 18% of tumors with intermediate EGFR staining and 9% of tumors with strong staining. There was no significant relationship between p53 immunoreactivity or mutation status and radiation response. Significant relationships were noted between EGFR score and older age and between p53 score or mutation status and younger age.

CONCLUSION

The observed relative radioresistance of some GMs is associated with overexpression of EGFR.

Results of a pilot study involving the use of an antisense oligodeoxynucleotide directed against the insulin-like growth factor type I receptor in malignant astrocytomas

PURPOSE

Preclinical animal experiments support the use of an antisense oligodeoxynucleotide directed against the insulin-like growth factor type I receptor (IGF-IR/AS ODN) as an effective potential antitumor agent. We performed a human pilot safety and feasibility study using an IGF-IR/AS ODN strategy in patients with malignant astrocytoma.

PATIENTS AND METHODS

Autologous glioma cells collected at surgery were treated ex vivo with an IGF-IR/AS ODN, encapsulated in diffusion chambers, reimplanted in the rectus sheath within 24 hours of craniotomy, and retrieved after a 24-hour in situ incubation. Serial posttreatment assessments included clinical examination, laboratory studies, and magnetic resonance imaging scans.

RESULTS

Other than deep venous thrombosis noted in some patients, no other treatment-related side effects were observed. IGF-IR/AS ODN-treated cells, when retrieved and assessed, were < or = 2% intact by trypan blue exclusion, and none of the intact cells were viable in culture thereafter. Parallel Western blots disclosed IGF-IR downregulation to < or = 10% after ex vivo antisense treatment. At follow-up, clinical and radiographic improvements were observed in eight of 12 patients, including three cases of distal recurrence with unexpected spontaneous or postsurgical regression at either the primary or the distant intracranial site.

CONCLUSION

Ex vivo IGF-IR/AS ODN treatment of autologous glioma cells induces apoptosis and a host response in vivo without unusual side effects. Subsequent transient and sustained radiographic and clinical improvements warrant further clinical investigations.

Prognostic significance of endothelial surface score and MIB-1 labeling index in glioblastoma

The aim of this study is to investigate the usefulness of a vascular endothelial surface score (VESS) and MIB-1 labeling index (MIB-1 LI), in a defined series of glioblastomas, as biological markers with prognostic significance of survival. Tumor tissue and survival were studied in a series of 38 patients with glioblastoma, previously treated by surgical resection and radiotherapy. For each tumor, immunohistochemical and morphometric studies were performed in order to study MIB-1 LI, and VESS, expressed as the CD-34 immunostained endothelial surface per 1000 tumor cells. The survival for the entire patient population of the series was 48.1+/-14.1 weeks, and the mean VESS for the tumors of the series ranged from 16.7 to 107 microm2 per 1000 tumor cells (mean: 38.7+/-18.2). Factors such as age or MIB-1 LI were not significatively associated with survival, but the median survival for the 18 patients with a VESS less than 35 was 50.7+/-3.7 weeks, versus 45.9+/-2.8 weeks for the 20 patients showing a VESS higher than 36 (p < 0.05). Our present results suggest that tumor VESS, expressed as the CD-34 immunostained endothelial surface per each 1000 tumor cells, may have usefulness, as angiogenic-related factor influencing survival, in patients with glioblastoma.

Prognostic relevance of MIB-1 immunoreactivity, S-phase fraction, 5-bromo-2'-deoxyuridine labeling indices, and mitotic figures in gliomas

Prognostic relevance of cell proliferation markers was evaluated in 27 glioma patients. By 1) flow cytometry (FCM), i.e., S-phase fraction (SPF), and BrdUrd-labeling index (LIfcm); 2) immunohistochemistry (IHC), i.e., BrdUrd-labeling index (LIihc) and MIB-1 immunoreactivity (MIB-1 LIihc); and 3) histologic examination, i.e., the presence or absence of cells in mitoses, were assessed. A longer local progression free survival (LPFS) was significantly associated with low SPF, low LIfcm, and low MIB-1 LIihc. For LIihc, no significant association was found. LIfcm appeared to be a more promising prognosticator than MIB-1 LIihc. In comparison with this marker, the presence or absence of mitotic figures appeared to be an even stronger prognosticator. Prognostic significance of LIfcm appeared to be of importance in low-grade gliomas. The number of patients in our study is limited. Our findings were: 1) the presence or absence of cells in mitoses (M-phase activity) appeared to be of more prognostic significance than LIfcm (S-phase activity) and MIB-1 LIihc (non-G0-phase activity); 2) of the tested experimental cell proliferation markers, LIfcm appeared to be of more prognostic significance than MIB-1 LIihc, SPF, and LIihc; and 3) LIfcm is likely to be an important prognosticator in low-grade gliomas and is, therefore, not definitive and only of potential interest.

S-phase fraction, 5-bromo-2'-deoxy-uridine labelling index, duration of S-phase, potential doubling time, and DNA index in benign and malignant brain tumors

Seventy-one histologically malignant brain tumors, 52 histologically benign brain tumors, and 14 cerebral metastases were characterized according to DNA content and proliferative capacity. DNA ploidy, DNA index (DI), S-phase fraction (SPF), 5-bromo-2'-deoxy-uridine (BrdUrd) labelling index (LI), duration of S-phase (Ts), and potential doubling time (Tpot) were assessed by flow cytometry (FCM). In histologically benign tumors, a high percentage of DNA diploid tumors and a low proliferative capacity in DNA diploid tumors were found. Histologically malignant tumors and cerebral metastases were both found to be characterized by a low percentage of DNA diploid tumors and a high proliferative capacity in DNA diploid tumors. The proliferative capacity of DNA aneuploid benign tumors and that of DNA aneuploid malignant tumors, however, appeared not to differ significantly. The number of DNA aneuploid tumors was small. Duration of S-phase was short (range 3.9-4.7 hr) and appeared not to differ between the three groups. From this, the observed differences in Tpot values should be accredited mainly to differences in LI. High-grade as well as low-grade gliomas both appeared to be characterized by malignant (FCM) features, i.e., 1) a high percentage DNA aneuploidy, 2) a high mean DI (for DI > 1), and 3) a high proliferative capacity.

[Radiotherapy of glioblastoma]

Glioblastoma cells appear to be inherently radioresistant and to present a significant fraction of hypoxic cells. The most significant prognostic factors to compare results achieved in several series of patients are the age, performance status and quality of surgical resection. Several randomized trials have provided evidence supporting the efficacy of radiation therapy in the treatment of glioblastoma. Prescription of a 60-Gy dose delivered according to a conventional dose-fractionation scheme (single daily fractions of 1.7 to 2 Gy five times per week) in a target volume with a 2-3 cm margin of tissue surrounding the perimeter of the contrast enhancing lesion on computerized tomography and magnetic resonance imaging is derived from observations made in several retrospective and prospective studies. Evidence of improvement in survival was observed neither in patients receiving hyperfractioned and accelerated radiotherapy, nor in patients for whom radiation sensitizers such as nitroimidazole compounds or halogenated pyrimidine analogs were associated to radiation therapy. The addition of nitrosourea to radiotherapy increases the 2-year survival rate by about 10%. Combination of full-dose external beam radiotherapy and brachytherapy or radiosurgery boost in selected patients with glioblastoma leads to an increase in the median survival, while external beam radiation alone in patients with similar prognosis does not.