Proliferative capacity in head and neck cancer

Accelerated Hyperfractionated Radiotherapy versus Conventional Fractionation Radiotherapy for Head and Neck Cancer: A Meta-Analysis of Randomized Controlled Trials

Objective

The benefits of accelerated hyperfractionated radiotherapy (HART) and conventional fractionation radiotherapy (CFRT) in the treatment of head and neck cancer (HNC) remain controversial. In this study, we analyzed the therapeutic effects of these two treatment regimens to explore whether HART can improve the overall survival (OS) rate and locoregional control (LRC) rate in patients with HNC.

Methods

The PubMed, EMBASE, and Cochrane Central Register of Controlled Trials (CENTRAL) databases were searched for eligible studies. The OS rate and LRC rate were considered as the efficacy outcomes. I² was used to test the heterogeneity among studies with a cutoff value of 50%. Potential publication bias was assessed by funnel plots and Egger's test. We also performed a sensitivity analysis to assess the stability of the results. In this meta-analysis, all analyses were performed using R 3.5.3 software.

Results

Twelve qualified articles including a total of 2,935 patients were identified. HART had a significant beneficial effect on OS rate (HR = 0.80, 95% CI: 0.65–0.98). Compared with CFRT, HART demonstrated a significantly higher LRC rate (HR = 0.82, 95% CI: 0.71–0.96).

Conclusion

Our meta-analysis showed that HART can significantly improve OS and LRC compared with CFRT in patients with HNC.

Determinants and clinical implications of chromosomal instability in cancer

Aberrant chromosomal architecture, ranging from small insertions or deletions to large chromosomal alterations, is one of the most common characteristics of cancer genomes. Chromosomal instability (CIN) underpins much of the intratumoural heterogeneity observed in cancers and drives phenotypic adaptation during tumour evolution. Thus, an urgent need exists to increase our efforts to target CIN as if it were a molecular entity. Indeed, CIN accelerates the development of anticancer drug resistance, often leading to treatment failure and disease recurrence, which limit the effectiveness of most current therapies. Identifying novel strategies to modulate CIN and to exploit the fitness cost associated with aneuploidy in cancer is, therefore, of paramount importance for the successful treatment of cancer. Modern sequencing and analytical methods greatly facilitate the identification and cataloguing of somatic copy-number alterations and offer new possibilities to better exploit the dynamic process of CIN. In this Review, we describe the principles governing CIN propagation in cancer and how CIN might influence sensitivity to immune-checkpoint inhibition, and survey the vulnerabilities associated with CIN that offer potential therapeutic opportunities.

Accelerated or hyperfractionated radiotherapy for esophageal carcinoma: a meta-analysis of randomized controlled trials

Objective

The goal of this study was to evaluate the efficacy and safety of modified (accelerated and/or hyperfractionated) radiotherapy in the treatment of esophageal carcinoma, compared with conventional radiotherapy.

Methods

Studies published in the PubMed, Cochrane Library, EMBASE, CBM, VIP, CNKI and Wanfang databases in the most recent two decades were searched for use in this meta-analysis. Only randomized controlled trials were included. The heterogeneity analysis and calculation of the pooled odds ratio (OR) were performed using RevMan 5.3 software. The assessment of publication bias and sensitivity analyses was conducted using Stata 13.0 software.

Results

Twenty trials with a total of 1,742 Chinese patients who met the inclusion criteria were included. The pooled results showed that modified radiotherapy improved the response rate compared with conventional schedules (OR =3.90, 95% confidence interval [CI]: 2.47–6.16, P<0.001). Favorable results were observed for the 1-year (OR =2.58, 95% CI: 2.05–3.26, P<0.001), 3-year (OR =2.30, 95% CI: 1.83–2.89, P<0.001) and 5-year (OR =2.36, 95% CI: 1.74–3.21, P<0.001) overall survival and for the 1-year (OR =2.46, 95% CI: 1.72–3.51, P<0.001), 3-year (OR =2.08, 95% CI: 1.49–2.90, P<0.001) and 5-year (OR =2.15, 95% CI: 1.38–3.34, P<0.001) overall local control rate in the modified fractionation radiotherapy group. However, the altered radiotherapy increased the risk of acute radiation esophagitis (OR =1.70, 95% CI: 1.27–2.28, P<0.001) and acute radiation tracheitis (OR =1.47, 95% CI: 1.09–1.99, P=0.01). No significant differences in the risk of esophageal perforation (OR =1.30, 95% CI: 0.51–3.32, P=0.58) or esophagorrhagia (OR =0.88, 95% CI: 0.41–1.88, P=0.74) were found between the two groups.

Conclusion

Chinese patients with squamous cell esophagus carcinomas gained a significant benefit in terms of the response rate, survival and local control rates from the modified fractionation radiotherapy, but also had an increased risk of acute radiation reactions. Otherwise, there was no observed statistically significant difference in terms of early adverse reactions.

Long-term outcomes of late course accelerated hyper-fractionated radiotherapy for localized esophageal carcinoma in Mainland China: a meta-analysis

Published data on the long-term survival results of patients with localized esophageal carcinoma receiving late course accelerated hyper-fractionated radiotherapy (LCAF RT) versus conventional fractionated radiotherapy (CF RT) are inconclusive. In order to derive a more precise estimation of the both treatment-regimes, a meta-analysis based on systematic review of published articles was performed. A meta-analysis was performed using trials identified through Pubmed and Chinese national knowledge infrastructure. Results in 5-year survival and 5-year local control were collected from randomized trials comparing LCAF RT with CF RT. Review Manager (The Cochrane Collaboration, Oxford, England) and Stata software (Stata Corporation, College Station, TX, USA) were used for data management. A total of 11 trials were involved in this analysis with 572 cases and 567 controls. Our results showed that LCAF RT, compared with CF RT, significantly improved the 5-year survival (odds ratio [OR]= 2.93, 95% confidence interval [CI]: 2.15-4.00, P < 0.00001) and 5-year local control (OR = 3.96, 95% CI: 2.91-5.38, P < 0.00001). LCAF RT was more therapeutically beneficial than CF RT in the localized esophageal carcinoma.

The role of PET imaging in overcoming radiobiological challenges in the treatment of advanced head and neck cancer

PURPOSE

Despite the large variety of treatment methods available for the management of advanced head and neck carcinomas, these tumours remain highly challenging due to their aggressiveness and complex anatomical location. Among the treatment challenges associated with head and neck cancers, hypoxia and tumour repopulation during treatment are, most likely, the main reason for locoregional treatment failure. Whilst the number of techniques and predictive assays designed to assess the oxygenation status or the proliferative ability of tumours is rather large, they all come with drawbacks which limit their implementation as routine clinical procedures. Latest developments in the field of nuclear medicine have opened the road to new possibilities in functional imaging, thus overcoming some of the confines imposed by the more conventional techniques.

MATERIALS AND METHODS

The current paper presents the role of PET imaging as a quantitative evaluation tool for hypoxia status and proliferative ability of advanced head and neck tumours. Traditional as well as novel radioisotopes with high affinity towards hypoxia and proliferative tumour activity are presented and their pre-clinical/clinical results analysed.

RESULTS

While the number of clinical studies which aimed to validate novel radiotracers for head and neck cancer is limited, a number of results show promising correlation between uptake/marker activity and treatment outcome.

CONCLUSION

There is need for further studies and well designed clinical trials to obtain more conclusive results.

DNA ploidy, proliferative capacity and intratumoral heterogeneity in primary and recurrent head and neck squamous cell carcinomas (HNSCC) – Potential implications for clinical management and treatment decisions

Despite new diagnostic and therapeutic strategies (combined radiochemotherapy, EGFR antibody Cetuximab), the prognosis of head and neck squamous cell carcinoma (HNSCC) is still poor and more information regarding prognosis is essential to establish earlier and better treatment options. To elucidate the role of DNA ploidy and cellular proliferation, resected tumors of 48 patients with primary or recurrent HNSCC were analyzed by flow cytometry and in vitro-5-bromodeoxyuridine incorporation (BrdU). The results were compared with histopathological findings such as tumor size, lymph node involvement and tumor differentiation. To assess the influence of intratumoral heterogeneity of these biological parameters, multiple biopsies (>3) were analyzed by flow cytometry and BrdU-incorporation in 12 larger (>4 cm diameter) tumors. BrdU-labeling index (LI%) was significantly higher in aneuploid HNSCC and correlated significantly with poor histologic differentiation of the analyzed tumor tissues (P<0.001). Furthermore, a trend for higher LI% in nodal positive tumors was observed. Aneuploid HNSCC showed significantly more often tissue dedifferentiation (P=0.049) and in most cases an advanced tumor stage, especially in tumors with biclonal cell lines. Lymph node involvement was also seen more often in aneuploid and undifferentiated tumors. As in aneuploid tumors recurrent HNSCC showed in most cases a higher LI% and poor tissue differentiation, but as a result of the small collection of samples there was no correlation between aneuploidy and tumor recurrence. To proof the robustness of the acquired data and to estimate the influence of intratumoral heterogeneity to ploidy and LI% multiple biopsies were analyzed in larger tumors. Using a specific statistical algorithm a secure estimation of ploidy and LI% was possible by a single biopsy in these tumors. These findings indicate aneuploidy and proliferative activity as important findings for malignant progression in HNSCC. An estimation of these biological parameters may be useful for identification of patients with high risk for lymph node involvement or tumor recurrence and pre-treatment can be performed by a single biopsy. As a conclusion, these patients may benefit from more aggressive treatment.

Development of a rat solid tumor model for continuous low-dose-rate irradiation studies using 125I and 103Pd sources

PURPOSE

To develop an experimental technique for studying the radiobiology of continuous low-dose-rate irradiation (CLDRI) using clinical brachytherapy sources emitting low energy photons for a rat solid tumor model.

METHODS AND MATERIALS

BA1112 tumors were grown between the ears of 14-week-old male WAG/Rij rats by interdermal inoculation. A radioactive source afterloading system, which consists of a lightweight helmet sutured to the rat and a nine-source polystyrene applicator, was fabricated for in vivo tumor irradiation by (125)I and (103)Pd brachytherapy sources. This system has a 12 x 12 mm opening in the center to accommodate the tumor and its growth during irradiation (the diameter of a typical BA1112 tumor was about 6 mm when radiation was applied). The spatial locations of the nine sources were optimized to produce an as uniform as possible three-dimensional dose distribution to the central portion of the applicator for both the (125)I and (103)Pd sources. Absolute dose delivered by the applicator was verified by point dose measurements using calibrated TLD in a polystyrene phantom that mimics the scattering environment of the tumor on the rat.

RESULTS

The feasibility of tumor cure experiments using the experimental technique presented in this work was demonstrated. The technique was used to study the influence of initial dose rate on the in vivo tumor cure probability of BA1112 tumors irradiated by (125)I and (103)Pd sources at dose rates varying from 8-20 cGy/h. The technique was also used for studying the in vitro tumor cell survival following in vivo CLDRI irradiation of the tumor.

CONCLUSION

An experimental technique using an in vivo tumor model has been developed for studying the radiobiological effects of continuous low-dose-rate irradiations using (125)I sources alone, (103)Pd sources alone, or a mixture of (125)I and (103)Pd sources.

Oral cytology assessment by flow cytometry of DNA adducts, aneuploidy, proliferation and apoptosis shows differences between smokers and non-smokers

Oral cytology and morphometric staining is used to identify malignant keratinocytes in oral premalignant or malignant lesions. To detect and to begin to assess changes in oral keratinocytes exposed to tobacco-derived carcinogens, which are at risk for malignant transformation, a novel method is required. The approach uses oral cytology harvested oral keratinocytes analyzed using flow cytometry (FC) for changes in DNA content, damage, cell cycle and apoptosis. Six smoker and six non-smoker oral keratinocytes were evaluated using flow cytometry in the form of laser scanning cytometry (LSC) and laser microdissection (LMD). Among smokers compared to non-smokers, the method detected and assessed DNA damage from tobacco smoke exposure quantifying an enhanced formation of DNA adducts, such as, 8-hydroxy-2'-deoxyguanine (8-OHdG) which creates oxidation lesions and benzo[a]pyrene(B[a]P), which produces a B[a]P)-N2-dG bulky adduct. Increased DNA content, aneuploidy, percentage of cells in synthesis (S) and G(2)+Mitosis (M), and apoptosis were recorded. Tissue and cell controls were used to verify these relationships. Data suggested healthy smokers were at increased risk for malignant transformation of oral keratinocytes because of the changes stated above. Using identical methods, keratinocytes exposed to the tobacco derived carcinogen, B[a]P parallel results obtained from smoke exposure indicating a direct link. Flow cytometric evaluation of oral cytology harvested keratinocytes can be used to measure exposure to tobacco carcinogens, and possibly establish a link to premalignant and malignant transformation before a lesion is noted.