Molecular profiles as predictive marker for the effect of overall treatment time of radiotherapy in supraglottic larynx squamous cell carcinomas

Overview on Molecular Biomarkers for Laryngeal Cancer: Looking for New Answers to an Old Problem

Laryngeal squamous cell cancer (LSCC) accounts for almost 25-30% of all head and neck squamous cell cancers and is clustered according to the affected districts, as this determines distinct tendency to recur and metastasize. A major role for numerous genetic alterations in driving the onset and progression of this neoplasm is emerging. However, major efforts are still required for the identification of molecular markers useful for both early diagnosis and prognostic definition of LSCC that is still characterized by significant morbidity and mortality. Non-coding RNAs appear the most promising as they circulate in all the biological fluids allowing liquid biopsy determination, as well as due to their quick and characteristic modulation useful for non-invasive detection and monitoring of cancer. Other critical aspects are related to recent progress in circulating tumor cells and DNA detection, in metastatic status and chemo-refractoriness prediction, and in the functional interaction of LSCC with chronic inflammation and innate immunity. We review all these aspects taking into account the progress of the technologies in the field of next generation sequencing.

Plasma proteins as prognostic biomarkers in radiotherapy treated head and neck cancer patients

Background

Blood-based protein biomarkers can be a useful tool as pre-treatment prognostic markers, as they can reflect both variations in the tumor microenvironment and the host immune response. We investigated the influence of a panel of plasma proteins for the development of any failure defined as recurrent disease in the T-, N-, or M-site in HNSCC.

Methods

We used a multiplex bead-based approach to analyze 19 proteins in 86 HNSCC patients and 15 healthy controls. We evaluated the associations between the biomarkers, loco-regional failure, failure in the T-, N-, or M-site, overall survival (OS), p16 status, and hypoxia.

Results

In 41 p16 positive oropharynx cancer patients we identified a profile of biomarkers consisting of upregulation of IL-2, IL-4, IL-6, IL-8, eotaxin, GRO-a, and VEGF and downregulation of VEGFR-1 and VEGFR-2 with a significantly reduced risk of failure (p < 0.01). None of the individual proteins were associated with outcome.

Conclusion

The identified plasma profile potentially reflects an activated immune response in a subgroup of the p16 positive patients.

Genetic determinants in head and neck squamous cell carcinoma and their influence on global personalized medicine

While sequencing studies have provided an improved understanding of the genetic landscape of head and neck squamous cell carcinomas (HNSCC), there remains a significant lack of genetic data derived from non-Caucasian cohorts. Additionally, there is wide variation in HNSCC incidence and mortality worldwide both between and within various geographic regions. These epidemiologic differences are in part accounted for by varying exposure to environmental risk factors such as tobacco, alcohol, high risk human papilloma viruses and betel quid. However, inherent genetic factors may also play an important role in this variability. As limited sequencing data is available for many populations, the involvement of unique genetic factors in HNSCC pathogenesis from epidemiologically diverse groups is unknown. Here, we review current knowledge about the epidemiologic, environmental, and genetic variation in HNSCC cohorts globally and discuss future studies necessary to further our understanding of these differences. Long-term, a more complete understanding of the genetic drivers found in diverse HNSCC cohorts may help the development of personalized medicine protocols for patients with rare or complex genetic events.

Radiation oncology in the era of precision medicine

Technological advances and clinical research over the past few decades have given radiation oncologists the capability to personalize treatments for accurate delivery of radiation dose based on clinical parameters and anatomical information. Eradication of gross and microscopic tumours with preservation of health-related quality of life can be achieved in many patients. Two major strategies, acting synergistically, will enable further widening of the therapeutic window of radiation oncology in the era of precision medicine: technology-driven improvement of treatment conformity, including advanced image guidance and particle therapy, and novel biological concepts for personalized treatment, including biomarker-guided prescription, combined treatment modalities and adaptation of treatment during its course.

Emerging developments of chemoradiotherapy in stage III NSCLC

Over the past decade, concomitant chemotherapy and radiotherapy has become the established treatment for patients with stage III non-small-cell lung cancer (NSCLC). Unfortunately, many patients with NSCLC are too old or have multiple comorbidities to withstand such aggressive treatments. Attempts to improve outcomes have included studies of radiotherapy dose escalation and new chemotherapy combinations, as well as adding biological agents and cancer vaccines to existing regimens. Technical radiotherapy modifications, including intensity-modulated radiotherapy and particle beam therapy, have also been investigated. Given the number of potential advances to current models of treatment development, phase III trials of any single new treatment can take years to complete, which is inadequate. To advance research within shorter timescales to improve patient outcomes, we need methods of improving clinical trial accrual, which might require changes in models of research governance, cooperative group activity, trial design and patient consent.

Potential prognostic and therapeutic role for angiogenesis markers in laryngeal carcinoma

Angiogenesis is a hallmark of cancer, fundamental to its growth. The 'angiogenic switch' occurs when pro-angiogenic factors are not balanced by anti-angiogenic factors. A correlation between angiogenic properties and oncological prognosis (for laryngeal squamous cell carcinoma (LSCC) too) was first hypothesized in the 1990s. An exhaustive literature review was performed to investigate available data on angiogenesis markers and their biological role and therapeutic potential in LSCC. The prognostic significance of microvascular density in LSCC was investigated with endothelial targets, e.g. CD105, CD34, and CD31. Epidermal growth factor receptor (EGFR), vascular endothelial growth factor (VEGF), VEGF receptor 2, angiogenin, hypoxia-inducible factor 1, and other biological markers were also studied. Only anti-EGFR therapy has been approved by the USFood and Drug Administration (FDA) for head and neck carcinoma in recent years, while several agents interfering with VEGF and its receptors are being studied. Experimental findings indicate that anti-CD105 monoclonal antibodies efficiently inhibit tumor angiogenesis. There are two main ways to approach the vascular profile of solid malignancies: by inhibiting new vessel formation (anti-angiogenic therapy) or selectively damaging neoplastic vessels (vascular targeting therapy). In advanced LSCC, both these strategies seem promising and warrant further preclinical and clinical investigation.

Epigenetic dysregulation in laryngeal squamous cell carcinoma

Laryngeal carcinoma is a common head and neck cancer with poor prognosis. Patients with laryngeal carcinoma usually present late leading to the reduced treatment efficacy and high rate of recurrence. Despite the advance in the use of molecular markers for monitoring human cancers in the past decades, there are still no reliable markers for use to screen laryngeal carcinoma and follow the patients after treatment. Epigenetics emerged as an important field in understanding the biology of the human malignancies. Epigenetic alterations refer to the dysregulation of gene, which do not involve the alterations of the DNA sequence. Major epigenetic changes including methylation imbalance, histone modification, and small RNA dysregulation could play a role in the development of human malignancies. Global epigenetic change is now regarded as a molecular signature of cancer. The characteristics and behavior of a cancer could be predicted based on the specific epigenetic pattern. We here provide a review on the understanding of epigenetic dysregulation in laryngeal carcinoma. Further knowledge on the initiation and progression of laryngeal carcinoma at epigenetic level could promote the translation of the knowledge to clinical use.

Biochemical markers predicting response to radiation- and radiochemo-therapy in cancer patients

In last years there is increasing interest in radiogenomics and the characterization of DNA array molecular profiles that can predict tumor and no tumor tissues radioresponse. Ongoing studies carried out worldwide in the banking of tumor and no tumor samples give evidence that perspective markers for response prediction in individual patient to intended radiation therapy can be some apoptotic indexes, spectrum a number of specific proteins, and DNA-based microarray molecular profiling analysis as well determination of single nucleotide polymorphisms in genome of the patients. So far there are only a few robust reports of molecular markers predicting tumor and no tumor tissues response to radiation. The results of new studies, which in future should be validated in larger definitive trials, are likely to see in nearest years. It is needed to determine technologies of methods and to define more precisely areas of its applications.

Gefitinib plus cisplatin and radiotherapy in previously untreated head and neck squamous cell carcinoma: a phase II, randomized, double-blind, placebo-controlled study

BACKGROUND AND PURPOSE

To assess the efficacy and safety of gefitinib given concomitantly and/or as maintenance therapy to standard cisplatin/radiotherapy for previously untreated, unresected, stage III/IV non-metastatic SCCHN.

MATERIALS AND METHODS

In this phase II, double-blind, study, 226 patients were randomized to gefitinib 250mg/day, 500mg/day or placebo in two phases: a concomitant phase (gefitinib or placebo with chemoradiotherapy), followed by a maintenance phase (gefitinib or placebo alone). Primary endpoint was local disease control rate (LDCR) at 2years; secondary endpoints were LDCR at 1year, objective response rate, progression-free survival, overall survival, and safety and tolerability.

RESULTS

Gefitinib (250 and 500mg/day) did not improve 2-year LDCR compared with placebo either when given concomitantly with chemoradiotherapy (32.7% vs. 33.6%, respectively; OR 0.921, 95% CI 0.508, 1.670 [1-sided p=0.607]) or as maintenance therapy (28.8% vs. 37.4%, respectively; OR 0.684, 95% CI 0.377, 1.241 [1-sided p=0.894]). Secondary efficacy outcomes were broadly consistent with the 2-year LDCR results. In both doses, gefitinib was well-tolerated and did not adversely affect the safety and tolerability of concomitant chemoradiotherapy.

CONCLUSION

Gefitinib was well-tolerated, but did not improve efficacy compared with placebo when given concomitantly with chemoradiotherapy, or as maintenance therapy alone.

Use of multiple biological markers in radiotherapy-treated head and neck cancer

OBJECTIVE

Management of patients with head and neck squamous cell carcinoma is often based on clinical parameters, with little appreciation of the underlying tumour biology. Single biological marker studies fail to acknowledge the complexity of these tumours. Our aim was to define a profile of biological markers associated with outcome.

DESIGN

This retrospective study involved consecutive patients with oropharyngeal squamous cell carcinoma treated with primary radiotherapy between 1996 and 2001. Pre-treatment biopsies were used to study the immunohistochemical expression of nine biological markers. Markers were chosen to reflect biologically relevant pathways.

RESULTS

Following analysis of nine markers, a profile of two markers was derived (carbonic anhydrase 9 and major vault protein), the co-expression of which conferred a significantly poor probability of locoregional control. The prognostic effect of these biomarkers in combination was greater than their effect individually.

CONCLUSION

Biomarker profiles can be established which highlight large differences in locoregional control. Identifying tumours that express both carbonic anhydrase 9 and major vault protein may facilitate patient selection for more aggressive treatment.

[Relation between epidermal growth factor receptor (EGFR) and p53 expression and radiocurability of laryngeal squamous cell cancer]

Radiotherapy and surgery are the most important treatment modalities for the majority of laryngeal cancers. Because of high efficacy and better organ preservation radiotherapy is generally preferred for early and intermediate stage of the disease. Some of patients with more locally advanced cancers can still be cured by means of radiotherapy, but we have not got reliable prognostics factors for predicting radiocurability. THE AIM OF MY STUDY: was to investigate the value of p53 and EGFR expression for predicting clinical outcomes of laryngeal cancer patients treated with radiotherapy.

METHODS AND MATERIALS

The study included 50 patients with laryngeal cancer treated in Department of Radiotherapy of Silesian Oncology Center between the years 1998 and 2003. Paraffin sections from archival material were studied immunohistochemically for detection p53 and EGFR and correlated with clinical parameters and local tumor control and patient survival.

RESULTS

Accumulation of p53 and EGFR were detected in 65% and 50% of tumor respectively. No relationship was observed between immunostaining for investigated proteins and clinicopathologic factors. The TNM tumor stage was the most significant prognostic factor for local control and overall survival. p53 was favorable prognostic factor with 5-years disease free survival rate 82% for patients p53-positive and 75% for p53-negative patients (p = 0.04).

CONCLUSION

The TNM tumor stage is the most important prognostic factor for laryngeal cancer. Tumors accumulating p53 have better prognosis what indicates possibly role for p53 immunohistochemical analysis for predicting outcomes of radiotherapy in patients with laryngeal cancer.

Exploring the role of cancer stem cells in radioresistance

Radiobiological research over the past decades has provided evidence that cancer stem cell content and the intrinsic radiosensitivity of cancer stem cells varies between tumours, thereby affecting their radiocurability. Translation of this knowledge into predictive tests for the clinic has so far been hampered by the lack of methods to discriminate between stem cells and non-stem cells. New technologies allow isolation of cells expressing specific surface markers that are differentially expressed in tumour cell subpopulations that are enriched for cancer stem cells. Combining these techniques with functional radiobiological assays holds the potential to elucidate the role of cancer stem cells in radioresistance in individual tumours, and to use this knowledge for the development of predictive markers for optimization of radiotherapy.

Clinical and biological factors affecting response to radiotherapy in patients with head and neck cancer: a review

OBJECTIVE

The main aim of this article was to review the clinical and biological factors that have been shown to influence the response of the head and neck squamous cell carcinoma (HNSCC) to primary radiotherapy and briefly discuss how some of these factors could be exploited to improve outcome.

DESIGN

Medline based search covering 1982-2006 to identify the HNSCC literature where the effect of clinical and biological factors on locoregional control and overall survival were investigated.

RESULTS

Clinical factors are routinely used in management decisions. Nevertheless, identically staged tumours receiving the same treatment may have different outcomes. Biological factors such as hypoxia, proliferation and radio-sensitivity play an important role in radiation response. However, these are not currently used in practise because tests that are clinically reliable and feasible are not available.

CONCLUSION

High-quality translational research will allow us to develop biological tests that can be used in routine clinical practise to tailor individual treatment, with the ability to improve patient outcome further by modifying the underlying tumour biology.

Rationale for adjuvant fatty acid therapy to prevent radiotherapy failure and tumor recurrence during early laryngeal squamous cell carcinoma

Information from a preceding lipid study contributed to the pathobiological assessment of laryngeal squamous cell carcinoma (LSCC). Lipid-driven signaling pathways are responsible for laryngeal carcinogenesis and immunodeficiency. The construction of fatty acid (FA) profiles for LSCC allowed the identification of FA role players. The integration of lipid and clinicomolecular information encountered in the literature, in turn, allowed the identification of biological prognostic markers to distinguish between early (less aggressive) and advanced (more aggressive) LSCCs. High arachidonic acid (AA) and cyclooxygenase (COX-2) activities are criteria for less aggressive growth, whilst low AA and COX-2 activities occur during more aggressive growth. Excessive tobacco use and environmental smoke or human papillomavirus (HPV) infection and alcohol abuse can, respectively, elicit cumulative oxidative stress and an oxidative burst or interfere with signaling pathways during essential fatty acid (EFA) metabolism, all factors and events which may cause LSCC. Research revealed that enhanced COX-2 activity and Bcl-2 expression prevent apoptosis and, hence, LSCCs become resistant to radiotherapy. It was also observed that recurrent laryngeal cancers become more aggressive after radiotherapy failure. It is predicted that manipulation of AA activity and consequently a cascade of downstream factors that include COX-2 and Bcl-2 expression responsible for LSCC may have therapeutic potential to improve radiotherapy outcome during early LSCC. Adjuvant FA therapy to improve early LSCC management by counteracting radiotherapy failure and unwanted complications for further management is proposed. FA therapeutic strategies before and during radiotherapeutic courses need to be evaluated.

Application of the Naïve Bayesian Classifier to optimize treatment decisions

BACKGROUND AND PURPOSE

To study the accuracy, specificity and sensitivity of the Naïve Bayesian Classifier (NBC) in the assessment of individual risk of cancer relapse or progression after radiotherapy (RT).

MATERIALS AND METHODS

Data of 142 brain tumour patients irradiated from 2000 to 2005 were analyzed. Ninety-six attributes related to disease, patient and treatment were chosen. Attributes in binary form consisted of the training set for NBC learning. NBC calculated an individual conditional probability of being assigned to: relapse or progression (1), or no relapse or progression (0) group. Accuracy, attribute selection and quality of classifier were determined by comparison with actual treatment results, leave-one-out and cross validation methods, respectively. Clinical setting test utilized data of 35 patients. Treatment results at classification were unknown and were compared with classification results after 3 months.

RESULTS

High classification accuracy (84%), specificity (0.87) and sensitivity (0.80) were achieved, both for classifier training and in progressive clinical evaluation.

CONCLUSIONS

NBC is a useful tool to support the assessment of individual risk of relapse or progression in patients diagnosed with brain tumour undergoing RT postoperatively.

Is EGFR a moving target during radiotherapy of carcinoma of the uterine cervix?

BACKGROUND

The epidermal growth factor receptor (EGFR) is frequently overexpressed in uterine cervix carcinoma. The role of the pre-treatment EGFR expression levels and the changes of expression induced by ionizing radiation (IR) have not been conclusively defined.

PATIENTS AND METHODS

The staining intensity (SI) and labeling index (LI) of EGFR were determined in 38 patients by immunohistochemistry (IHC). Biopsies were taken before after 1 week of RT. EGFR expression was correlated with cell cycle, apoptosis and angiogenesis.

RESULTS

Before RT, 87% and after 1 week of RT, 95% of samples were positive for EGFR (p=0.2). Two patterns were observed, either increasing or decreasing expression after initiating RT. An increase of the EGFR SI was seen in 63% of patients from a mean of 57 SI (SD+/-60) before RT to 142 SI (SD+/-80.8) (p=0.001) during RT. In 32% of cases, EGFR decreased from 165 SI before (SD+/-83.0) to 75 SI (SD+/-73.0) (p< or =0.001) during RT. Two of five (5%) patients negative for EGFR before RT remained negative. An increase of the RT-induced EGFR LI was associated with reduced microvessel density (MVD) (p=0.02). Changes of the EGFR LI did neither correlate with cell cycle arrest nor apoptosis.

CONCLUSIONS

EGFR expression changes unpredictably during RT. The implications of changing EGFR during RT remain to defined. Repeated biopsies and EGFR reassessment during RT may help to better define EGFR-targeted treatment.

The genomics revolution and radiotherapy

The expansion of our knowledge through the Human Genome Project has been accompanied by the development of new high-throughput techniques, which provide extensive capabilities for the analysis of a large number of genes or the whole genome. These assays can be carried out in various clinical samples at the DNA (genome), RNA (transcriptome) or protein (proteome) level. There is a belief that this genomic revolution, i.e. sequencing of the human genome and developments in high-throughput technology, heralds a future of personalised medicine. For clinical oncology, this progress should increase the possibility of predicting individual patient responses to radiotherapy. This review highlights some of the work involving sparsely ionising radiation and the new technologies.

Tumor microenvironment in head and neck squamous cell carcinomas: Predictive value and clinical relevance of hypoxic markers. A review

BACKGROUND

Hypoxia and tumor cell proliferation are important factors determining the treatment response of squamous cell carcinomas of the head and neck. Successful approaches have been developed to counteract these resistance mechanisms although usually at the cost of increased short- and long-term side effects. To provide the best attainable quality of life for individual patients and the head and neck cancer patient population as a whole, it is of increasing importance that tools be developed that allow a better selection of patients for these intensified treatments.

METHODS

A literature review was performed with special focus on the predictive value and clinical relevance of endogenous hypoxia-related markers.

RESULTS

New methods for qualitative and quantitative assessment of functional microenvironmental parameters such as hypoxia, proliferation, and vasculature have identified several candidate markers for future use in predictive assays. Hypoxia-related markers include hypoxia inducible factor (HIF)-1alpha, carbonic anhydrase IX, glucose transporters, erythropoietin receptor, osteopontin, and others. Although several of these markers and combinations of markers are associated with treatment outcome, their clinical value as predictive factors remains to be established.

CONCLUSIONS

A number of markers and marker profiles have emerged that may have potential as a predictive assay. Validation of these candidate assays requires testing in prospective trials comparing standard treatment against experimental treatments targeting the related microregional constituent.

Preclinical evaluation of molecular-targeted anticancer agents for radiotherapy

The combination of molecular-targeted agents with irradiation is a highly promising avenue for cancer research and patient care. Molecular-targeted agents are in themselves not curative in solid tumours, whereas radiotherapy is highly efficient in eradicating tumour stem cells. Recurrences after high-dose radiotherapy are caused by only one or few surviving tumour stem cells. Thus, even if a novel agent has the potential to kill only few tumour stem cells, or if it interferes in mechanisms of radioresistance of tumours, combination with radiotherapy may lead to an important improvement in local tumour control and survival. To evaluate the effects of novel agents combined with radiotherapy, it is therefore necessary to use experimental endpoints which reflect the killing of tumour stem cells, in particular tumour control assays. Such endpoints often do not correlate with volume-based parameters of tumour response such as tumour regression and growth delay. This calls for radiotherapy specific research strategies in the preclinical testing of novel anti-cancer drugs, which in many aspects are different from research approaches for medical oncology.

Multivariable modeling of radiotherapy outcomes, including dose–volume and clinical factors

PURPOSE

The probability of a specific radiotherapy outcome is typically a complex, unknown function of dosimetric and clinical factors. Current models are usually oversimplified. We describe alternative methods for building multivariable dose-response models.

METHODS

Representative data sets of esophagitis and xerostomia are used. We use a logistic regression framework to approximate the treatment-response function. Bootstrap replications are performed to explore variable selection stability. To guard against under/overfitting, we compare several analytical and data-driven methods for model-order estimation. Spearman's coefficient is used to evaluate performance robustness. Novel graphical displays of variable cross correlations and bootstrap selection are demonstrated.

RESULTS

Bootstrap variable selection techniques improve model building by reducing sample size effects and unveiling variable cross correlations. Inference by resampling and Bayesian approaches produced generally consistent guidance for model order estimation. The optimal esophagitis model consisted of 5 dosimetric/clinical variables. Although the xerostomia model could be improved by combining clinical and dose-volume factors, the improvement would be small.

CONCLUSIONS

Prediction of treatment response can be improved by mixing clinical and dose-volume factors. Graphical tools can mitigate the inherent complexity of multivariable modeling. Bootstrap-based variable selection analysis increases the reliability of reported models. Statistical inference methods combined with Spearman's coefficient provide an efficient approach to estimating optimal model order.

Radioresistance of K-Ras mutated human tumor cells is mediated through EGFR-dependent activation of PI3K-AKT pathway

BACKGROUND AND PURPOSE

In the context of EGFR-targeting strategies we investigated autocrine/paracrine factors leading to in vitro radioresistance of K-Ras mutated tumor cells through activation of EGFR mediated signal transduction.

PATIENTS AND METHODS

Ras mutated (Rasmt) and normal Ras (Raswt) presenting human tumor cell lines were used to analyze the potential of conditioned media (CM) of both cell types to mediate radioresistance and to activate EGFR-signaling cascades. Therefore, clonogenic assays as well as SDS-PAGE combined with immunoblotting was performed. Additionally, Ras-mutated cells were transfected with K-Ras-siRNA to investigate, how downregulation of mutated K-Ras affects secretion of EGFR-ligands, stimulation of EGFR-signaling and modulation of radiation response.

RESULTS

TGFalpha, Amphiregulin (ARG) and CM from Rasmt cells (Rasmt-CM) resulted in an increased clonogenic survival of irradiated Raswt cells. Both, EGFR ligands as well as Rasmt-CM led to a strong phosphorylation of EGFR and activation of downstream pathways, i.e. PI3K-AKT. However, neutralization of TGFalpha or ARG in Rasmt-CM led to a marked reduction of P-AKT. Furthermore, Rasmt-CM from K-Ras-siRNA transfected Rasmt-cells markedly inhibited phosphorylation of AKT in Raswt cells and enhanced radiation sensitivity of A549 cells transfected with the siRNA.

CONCLUSION

The data suggest that constitutively upregulated autocrine/paracrine secretion of EGF receptor ligands, especially ARG from K-Ras mutated cells, mediates radioresistance in Rasmt-cells through stimulation of EGFR-PI3K-AKT pathway.

Molecular markers predicting radiotherapy response: report and recommendations from an International Atomic Energy Agency technical meeting

PURPOSE

There is increasing interest in radiogenomics and the characterization of molecular profiles that predict normal tissue and tumor radioresponse. A meeting in Amsterdam was organized by the International Atomic Energy Agency to discuss this topic on an international basis.

METHODS AND MATERIALS

This report is not completely exhaustive, but highlights some of the ongoing studies and new initiatives being carried out worldwide in the banking of tumor and normal tissue samples underpinning the development of molecular marker profiles for predicting patient response to radiotherapy. It is generally considered that these profiles will more accurately define individual or group radiosensitivities compared with the nondefinitive findings from the previous era of cellular-based techniques. However, so far there are only a few robust reports of molecular markers predicting normal tissue or tumor response.

RESULTS

Many centers in different countries have initiated tissue and tumor banks to store samples from clinical trials for future molecular profiling analysis, to identify profiles that predict for radiotherapy response. The European Society for Therapeutic Radiology and Oncology GENEtic pathways for the Prediction of the effects of Irradiation (GENEPI) project, to store, document, and analyze sample characteristics vs. response, is the most comprehensive in this regard.

CONCLUSIONS

The next 5-10 years are likely to see the results of these and other correlative studies, and promising associations of profiles with response should be validated in larger definitive trials.

The possible role of TP53 mutation status in the treatment of squamous cell carcinomas of the head and neck (HNSCC) with radiotherapy with different overall treatment times

BACKGROUND AND PURPOSE

TP53-mutations have been shown to influence the radiosensitivity of HNSCC. Furthermore, HNSCC with mutated TP53, may have a higher proliferative potential caused by a lack of control in G1 checkpoint. Our aim of the study was to identify the role of TP53 mutations for the outcome of radiotherapy.

PATIENTS AND METHODS

DNA extracted from 180 paraffin-embedded formalin-fixed pretreatment biopsies of HNSCC was screened for mutations in exon 4C-10 by denaturing high-pressure liquid chromatography (DHPLC) followed by sequencing. Treatment was 66-68Gy, 2Gy/fx with overall treatment times of 6.5 and 5.5 weeks according to the DAHANCA-guidelines. Endpoints were local control at T-site, disease-specific and crude survival.

RESULTS

125 of 180 carcinomas (69%) carried in total 176 mutations. 72 carcinomas were WT (40%) and 108 carcinomas (60%) carried mutations giving dysfunctional p53. Overall, mutations in TP53 were not associated with the endpoints. However, when dichotomising according to TP53 status and evaluating the effect of the overall treatment time then tumours with mutant TP53 did benefit from 6 instead of 5fx/wk regarding local control, P=0.005; RR: 0.33 (C.I 95%:0.15-0.75) whereas WT-tumours did not (P=0.9). These observations were also reflected in the disease-specific and crude survival.

CONCLUSIONS

If all patients were considered regardless of treatment schedule, then TP53-mutations were not related to local control or survival. However, mutations in TP53 may be associated with HNSCC that benefit of a reduced overall treatment time of radiotherapy.

The influence of epidermal growth factor receptor and tumor differentiation on the response to accelerated radiotherapy of squamous cell carcinomas of the head and neck in the randomized DAHANCA 6 and 7 study

BACKGROUND AND PURPOSE

Reduction of the overall treatment time of radiotherapy has increased locoregional control and disease specific survival in squamous cell carcinomas of the head and neck (HNSCC), but the response is heterogeneous. EGFr is often overexpressed in HNSCC and has been related to the repopulation taking place during radiotherapy. The aim of the current study was to address the influence of EGFr and histopathological differentiation when the overall treatment time of radiotherapy was moderately reduced.

PATIENTS AND METHODS

Eight hundred and three patients with representative pretreatment tissue samples from the randomized DAHANCA 6 and 7 study of 5 vs. 6 fx/wk of radiotherapy. EGFr was visualized using immunohistochemistry and separated into high and low expression before correlation with clinical data.

RESULTS

Tumors with high EGFr (84%) responded better to moderately accelerated radiotherapy, than carcinomas with low EGFr, using locoregional control as endpoint and a similar pattern was seen, stratifying by well/moderate vs. poor tumor differentiation. Therefore, a combined parameter was constructed showing a more prominent separation of response: tumors with high EGFr and well/moderate differentiation did benefit from moderate acceleration of treatment regarding locoregional control, HR 0.54 (0.37-0.78), whereas such an effect was not seen in tumors with low EGFr and/or poor differentiation, HR 0.8 (0.51-1.25). These results reflected the disease specific survival as well and were confirmed in multivariable analyses.

CONCLUSIONS

Moderately accelerated fractionation is superior to conventional treatment in HNSCC but the response is heterogeneous and may be predicted by high expression of EGFr and well/moderate tumor differentiation.