Standardised Ki-67 proliferation index assessment in early-stage laryngeal squamous cell carcinoma in relation to local control and survival after primary radiotherapy

The relation between hypoxia and proliferation biomarkers with radiosensitivity in locally advanced laryngeal cancer

PURPOSE

Treatment decision-making in advanced-stage laryngeal squamous cell carcinoma (LSCC) is difficult due to the high recurrence rates and the desire to preserve laryngeal functions. New predictive markers for radiosensitivity are needed to facilitate treatment choices. In early stage glottic LSCC treated with primary radiotherapy, expression of hypoxia (HIF-1α and CA-IX) and proliferation (Ki-67) tumour markers showed prognostic value for local control. The objective of this study is to examine the prognostic value of tumour markers for hypoxia and proliferation on locoregional recurrent disease and disease-specific mortality in a well-defined cohort of patients with locally advanced LSCC treated with primary, curatively intended radiotherapy.

METHODS

In pre-treatment biopsy tissues from a homogeneous cohort of 61 patients with advanced stage (T3-T4, M0) LSCC primarily treated with radiotherapy, expression of HIF-1α, CA-IX and Ki-67 was evaluated with immunohistochemistry. Demographic data (age and sex) and clinical data (T- and N-status) were retrospectively collected from the medical records. Cox regression analysis was performed to assess the relation between marker expression, demographic and clinical data, and locoregional recurrence and disease-specific mortality.

RESULTS

Patients with high expression of HIF-1α developed significantly more often a locoregional recurrence (39%) compared to patients with a low expression (21%) (p = 0.002). The expression of CA-IX and Ki-67 showed no association with locoregional recurrent disease. HIF-1α, CA-IX and Ki-67 were not significantly related to disease-specific mortality. Clinical N-status was an independent predictor of recurrent disease (p < 0.001) and disease-specific mortality (p = 0.003). Age, sex and T-status were not related to locoregional recurrent disease or disease-specific mortality.

CONCLUSION

HIF-1α overexpression and the presence of regional lymph node metastases at diagnosis were independent predictors of locoregional recurrent disease after primary treatment with curatively intended radiotherapy in patients with locally advanced LSCC.

Investigation of low and high dose rate X-ray effects on histopathological changes and prognostic importance of Ki-67 in laryngeal cancer radiotherapy

The aim of this study is to analyze the effect on histopathological changes and Ki-67 expression levels of Flattening Filter (FF) and Flattening Filter Free (FFF) beams to investigate the radiobiological mechanisms underlying laryngeal cancer (LCa) post-radiotherapy (RT) on mice models. Forty adult NOD SCID gamma (NSG) mice models were randomly divided into four groups; the sham, LCa, FF-RT and FFF-RT groups. The head and neck region of mice in FF-RT and FFF-RT groups (LCa plus RT groups) were irradiated with a single dose of 18 Gy at 400 MU/min and 1400 MU/min. The NSG mice received radiotherapy 30 days after tumor transplantation and sacrificed 2 days after radiotherapy for analysis of histopathology parameters and K-67 expression levels. Comparing the LCa, FF-RT and FFF-RT groups with the sham group, statistically significant differences were observed in histopathological parameters depending on tumor tissue and dose rate (p < 0.05). When the histopathological effects of FF-RT beam on LCa tissue were compared with FFF-RT beam, it was observed that statistically significant differences occurred (p < 0.05). Comparing the LCa group with the sham group, it was observed that the Ki-67 level affected significantly depending on the development of cancer (p < 0.01). It was concluded that FF and FFF beams caused significant changes in the histopathological parameters and Ki-67 expression levels. When the effects of FFF beam on Ki-67 levels, cell nucleus and cytoplasmic findings were compared with FF beam, significant radiobiological differences were observed.

Distinct Biomarker Profiles and Clinical Characteristics in T1-T2 Glottic and Supraglottic Carcinomas

Background

In early stage laryngeal squamous cell carcinoma (LSCC) radiotherapy with curative intent is a major treatment modality. TNM classification is used to define patients eligible for radiotherapy. Studies in early stage glottic LSCC identified several predictive biomarkers associated with local control. However, we recently reported that this predictive value could not be confirmed in supraglottic LSCC.

Objective

To examine whether clinical behavior and protein expression patterns of these biomarkers differ between glottic and supraglottic LSCC.

Study Design

Retrospective cohort study.

Methods

Tumor tissue sections of 196 glottic and 80 supraglottic T1‐T2 LSCC treated primarily with RT were assessed immunohistochemically for expression of pAKT, Ki‐67 and β‐Catenin. Expression data of HIF‐1α, CA‐IX, OPN, FADD, pFADD, Cyclin D1, Cortactin and EGFR in the same cohort of glottic and supraglottic LSCC, were retrieved from previously reported data. The relationship between glottic and supraglottic sublocalization and clinicopathological, follow‐up, and immunohistochemical staining characteristics were evaluated using logistic regression and Cox regression analyses.

Results

Glottic LSCC were correlated with male gender (P = .001), hoarseness as a primary symptom (P < .001), T1 tumor stage (P < .001), negative lymph node status (P < .001), and an older age at presentation (P = .004). Supraglottic LSCC patients developed more post‐treatment distant metastasis when adjusted for gender, age, and T‐status. While supraglottic LSCC was associated with higher expression of HIF‐1α (P = .001), Cortactin (P < .001), EGFR (P < .001), and Ki‐67 (P = .027), glottic LSCC demonstrated higher expression of CA‐IX (P = .005) and Cyclin D1 (P = .001).

Conclusion

Differences in clinicopathological and immunohistochemical staining characteristics suggest that T1‐T2 glottic and supraglottic LSCC should be considered as different entities.

Level of Evidence

N/A. Laryngoscope, 2020

Standardised Ki-67 proliferation index assessment in early-stage laryngeal squamous cell carcinoma in relation to local control and survival after primary radiotherapy

Objectives

Ambiguous results have been reported on the predictive value of the Ki‐67 proliferation index (Ki‐67 PI) regarding local control (LC) and survival after primary radiotherapy (RT) in early‐stage laryngeal squamous cell cancer (LSCC). Small study size, heterogenic inclusion, variations in immunostaining and cut‐off values are attributing factors. Our aim was to elucidate the predictive value of the Ki‐67 PI for LC and disease‐specific survival (DSS) using a well‐defined series of T1‐T2 LSCC, standardised automatic immunostaining and digital image analysis (DIA).

Methods

A consecutive and well‐defined cohort of 208 patients with T1‐T2 LSCC treated with primary RT was selected. The Ki‐67 PI was determined using DIA. Mann‐Whitney U‐tests, logistic and Cox regression analyses were performed to assess associations between Ki‐67 PI, clinicopathological variables, LC and DSS.

Results

In multivariate Cox regression analysis, poor tumour differentiation (HR 2.20; 95% CI 1.06‐4.59, P = .04) and alcohol use (HR 2.84, 95% CI 1.20‐6.71; P = .02) were independent predictors for LC. Lymph node positivity was an independent predictor for DSS (HR 3.16, 95% CI 1.16‐8.64; P = .03). Ki‐67 PI was not associated with LC (HR 1.59; 95% CI 0.89‐2.81; P = .11) or DSS (HR 0.98; 95% CI 0.57‐1.66; P = .97). In addition, continuous Ki‐67 PI was not associated with LC (HR 2.03; 95% CI 0.37‐11.14, P = .42) or DSS (HR 0.62; 95% CI 0.05‐8.28; P = .72).

Conclusion

The Ki‐67 PI was not found to be a predictor for LC or DSS and therefore should not be incorporated in treatment‐related decision‐making for LSCC.