Excellent long-term pain response and local control following postoperative radiotherapy in patients with multiple myeloma.

PURPOSE: Multiple myeloma is associated with osteolytic bone lesions, often requiring surgery of the spine and postoperative radiotherapy (RT). Although common, data for clinical and informed decision-making are sparse. In this monocentric retrospective study, we aim to report the outcome of patients who underwent spinal surgery and postoperative RT due to multiple myeloma. METHODS: A total of 54 patients with multiple myeloma who underwent prior spinal surgery and postoperative RT at our institution between 2009 and 2020 were analyzed. Spinal instability neoplastic score (SINS) and Bilsky score, posttherapeutic adverse events, clinical data, and outcomes were collected and analyzed. The primary endpoint of this study was overall survival (OS), secondary endpoints were progression-free survival (PFS), pain response, local control, and skeletal-related events (SRE). RESULTS: The 3­ and 5­year overall survival (OS) was 74.9% (95% confidence interval [CI]: 63.5-88.4%) and 58% (95% CI: 44.5-75.6%), respectively. Median survival was not reached and 75% survival was 34.3 months (95% CI: 28.7-95.4 months). Median follow-up was 63 months (95% CI: 49-94 months). The number of patients with good to adequate performance status (Karnofsky performance score [KPS] ≥ 70) significantly increased after surgery (p < 0.01). We observed no grade 3/4 toxicity and only 13 (24%) grade 1/2 adverse events. Two patients (4%) experienced SRE. Overall, 92% of patients reported reduced pain after radiotherapy, with 66% reporting complete pain response. There was no difference in pain response between patients with different Bilsky scores. Bisphosphonate therapy and lower Bilsky score at the start of RT were associated with improved OS in univariate analysis (all p < 0.05). Multivariate Cox regression confirmed a Bilsky score of 2 or 3 as an independent negative prognostic factor (HR 3.89; 95 CI 1.4-10.7; p < 0.01). We observed no in-field recurrences. CONCLUSION: In this study, we were able to show that the current standard of RT after spinal surgery of osteolytic lesions is safe. In addition, we observed a very low rate of SRE (4%) and no in-field recurrences, demonstrating the local efficacy of RT in multiple myeloma patients. Higher Bilsky scores were associated with worse OS in multivariate analysis, but had no effect on pain response.

Adjuvant chemoradiotherapy in elderly patients with head and neck cancer: a monoinstitutional, two-to-one pair-matching analysis.

PURPOSE: About one fifth of patients with head and neck cancer are aged 70 years and older at the time of diagnosis. In these patients, risk factors (R1 status or extracapsular extension of lymph node metastases, ECE) often lead to a need for combined chemoradiotherapy (CRT) in the postoperative setting. However, there is considerable concern about the toxicity of such therapy in this age group. METHODS: Retrospective evaluation of the data of 53 patients ≥ 70 years of age who underwent surgery in our hospital between 1999 and 2015 for tumors of the oral cavity, the oropharynx, the hypopharynx, or the larynx, who subsequently received adjuvant radiation therapy. Two younger patients (< 70 years) were assigned to each of the elderly patients in a matching procedure based on anatomic sublocalization and tumor stage. The total cohort was comprised of 154 patients. RESULTS: Univariate analyses revealed a statistically significant influence of many factors on overall survival (OS) and progression-free survival (PFS), including Karnofsky performance score (KPS), alcohol consumption, smoking, R status, ECE, chemotherapy, and discontinuation of RT. Younger patients had better OS and PFS compared to the elderly (p = 0.013 and 0.012, respectively). In a multivariate Cox regression, no independent influence of age on OS and PFS was found. Survival was primarily dependent on the addition of chemotherapy to radiotherapy (RT), application of the full course of RT, continued alcohol abuse, KPS, and the presence of ECE. Toxicity analysis showed a higher incidence of chronic renal failure but, generally, side effects for elderly patients were not substantially greater. CONCLUSION: Performance status and behavioral risk factors but not chronological age are crucial for the prognosis of patients who require adjuvant chemoradiation.

Induction of dormancy in hypoxic human papillomavirus-positive cancer cells.

Oncogenic human papillomaviruses (HPVs) are closely linked to major human malignancies, including cervical and head and neck cancers. It is widely assumed that HPV-positive cancer cells are under selection pressure to continuously express the viral E6/E7 oncogenes, that their intracellular p53 levels are reconstituted on E6/E7 repression, and that E6/E7 inhibition phenotypically results in cellular senescence. Here we show that hypoxic conditions, as are often found in subregions of cervical and head and neck cancers, enable HPV-positive cancer cells to escape from these regulatory principles: E6/E7 is efficiently repressed, yet, p53 levels do not increase. Moreover, E6/E7 repression under hypoxia does not result in cellular senescence, owing to hypoxia-associated impaired mechanistic target of rapamycin (mTOR) signaling via the inhibitory REDD1/TSC2 axis. Instead, a reversible growth arrest is induced that can be overcome by reoxygenation. Impairment of mTOR signaling also interfered with the senescence response of hypoxic HPV-positive cancer cells toward prosenescent chemotherapy in vitro. Collectively, these findings indicate that hypoxic HPV-positive cancer cells can induce a reversible state of dormancy, with decreased viral antigen synthesis and increased therapeutic resistance, and may serve as reservoirs for tumor recurrence on reoxygenation.

Stability and survival analysis of elderly patients with osteolytic spinal bone metastases after palliative radiotherapy : Results from a large multicenter cohort.

PURPOSE: This retrospective study aimed to evaluate the stability and fracture rates of osteolytic spinal bone metastases (SBM) in elderly patients following palliative radiotherapy (RT) and to derive prognostic factors for stability and survival. METHODS: A total of 322 patients aged at least 70 years received palliative RT at two major German academic medical centers or at the German Cancer Research Center. Stability assessment was based on the validated Taneichi score prior to RT and at 3 and 6 months after RT. The survival time following RT was assessed, and prognostic factors for stability and survival were analyzed. RESULTS: Prior to RT, 183 patients (57%) exhibited unstable SBM and 68 patients (21%) pathological fractures. At 3 and 6 months after RT, significant recalcification and stabilization were evident in 19% (23/118) and 40% (31/78) of surviving patients, respectively. Only 17 patients (5%) experienced new pathological fractures following RT. Tumor histology was found to significantly influence stabilization rates with only breast cancer patients exhibiting increased stabilization compared to patients with other histologies. The median survival time and 6­month survival rates following RT were 5.4 months (95% confidence interval 4.4-7.2 months) and 48%, respectively. The patients' performance status was found to be the strongest predictor for survival after RT in this patient cohort; further factors demonstrating a significant association with survival were the application of systemic treatment, the number of SBM and the primary tumor histology. To analyze the influence of age on survival after RT, study patients were stratified into 3 age groups (i.e., 70-74 years, 75-79 years, and ≥80 years). The subgroup of patients aged at least 80 years showed a strong trend towards a worse survival time following RT compared to younger patients (i.e., 6­month survival rate 39% vs. 51%; p = 0.06, log-rank test). CONCLUSIONS: Prognostic factors influencing overall survival such as performance status and histology should guide the choice for palliative RT for SBM. Strongly hypofractionated RT regimes may be advisable for most elderly patients considering the overall poor prognosis in order to reduce hospitalization times.

Long-term survival of patients after ipilimumab and hypofractionated brain radiotherapy for brain metastases of malignant melanoma: sequence matters.

PURPOSE: Since the introduction of ipilimumab (IPI) for the treatment of patients with metastatic malignant melanoma, we have observed remarkable responses after hypofractionated whole brain irradiation (WBRT) or stereotactic radiotherapy (STX) for brain metastases of malignant melanoma. We sought to investigate the impact of the sequence of these treatment modalities. METHODS: We retrospectively evaluated the survival of melanoma patients with brain metastases who were treated with WBRT or STX and received IPI in close temporal relation between October 2010 and March 2015. Follow-up was obtained until November 2016. A total of 27 patients with advanced melanoma and brain metastases who were treated with WBRT before 2010, and who had not received IPI, served as historical controls. RESULTS: We identified a total of 41 patients of whom 15 were treated with STX, 7 with a combination of STX and WBRT and 19 with WBRT alone. All patients received at least 2 doses of IPI. The median time interval between radiotherapy and IPI was 2 months. Patients treated with IPI after radiotherapy had a censored median survival of 11 months, compared with 3 months for the patients who received IPI prior to radiotherapy. Patients who received IPI before radiotherapy showed a similar survival as historical controls, who had not received IPI. We observed long-term survivors after radiotherapy of brain metastases followed by IPI. CONCLUSIONS: These data suggest that the sequence of RT and immune checkpoint inhibition with IPI may be crucial for the success of combined modality treatment of melanoma brain metastases.

Patterns of failure of diffuse large B­cell lymphoma patients after involved-site radiotherapy.

PURPOSE: Radiotherapy (RT) in combination with chemoimmunotherapy is highly efficient in the treatment of diffuse large B­cell lymphoma (DLBCL). This retrospective analysis evaluated the efficacy of the treatment volume and the dose concept of involved-site RT (ISRT). PATIENTS AND METHODS: We identified 60 histologically confirmed stage I-IV DLBCL patients treated with multimodal cytotoxic chemoimmunotherapy and followed by consolidative ISRT from 2005-2015. Progression-free survival (PFS) and overall survival (OS) were estimated by Kaplan-Meier method. Univariate analyses were performed by log-rank test and Mann-Whitney U­test. RESULTS: After initial chemoimmunotherapy (mostly R­CHOP; rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisolone), 19 (36%) patients achieved complete response (CR), 34 (64%) partial response (PR) or less. Excluded were 7 (12%) patients with progressive disease after chemoimmunotherapy. All patients underwent ISRT with a dose of 40 Gy. After a median follow-up of 44 months, 79% of the patients remained disease free, while 21% presented with failure, progressive systemic disease, or death. All patients who achieved CR after chemoimmunotherapy remained in CR. Of the patients achieving PR after chemotherapy only 2 failed at the initial site within the ISRT volume. No marginal relapse was observed. Ann Arbor clinical stage I/II showed significantly improved PFS compared to stage III/IV (93% vs 65%; p ≤ 0.021). International Prognostic Index (IPI) score of 0 or 1 compared to 2-5 has been associated with significantly increased PFS (100% vs 70%; p ≤ 0.031). Postchemoimmunotherapy status of CR compared to PR was associated with significantly increased PFS (100% vs 68%; p ≤ 0.004) and OS (100% vs 82%; p ≤ 0.026). Only 3 of 53 patients developed grade II late side effects, whereas grade III or IV side effects have not been observed. CONCLUSION: These data suggest that a reduction of the RT treatment volume from involved-field (IF) to involved-site (IS) is sufficient because no marginal failures occurred. The concept of IS will likely reduce the risk for late sequelae of RT.

Inclusion of PET-CT into planning of primary or neoadjuvant chemoradiotherapy of esophageal cancer improves prognosis.

BACKGROUND: PET-CT is widely used for both the staging and planning of primary or neoadjuvant chemoradiotherapy for esophageal cancer. Inclusion of PET-CT information into radiotherapy planning often leads to substantial modifications of the target volume. In the case of detection of distant metastases, it may also result in a switch to a palliative treatment approach. This spares patients from therapy-related toxicities that provide no clinical benefit. However, due to a lack of studies, it is currently unclear whether the advantages of PET-CT also translate into a measurable improvement in patient survival. PATIENTS AND METHODS: A retrospective analysis assessed the survival data of 145 patients with esophageal carcinoma stages I (eight patients; 5%), II (45; 31%), III (79; 55%), IV (8; 5%) and unknown (5; 4%). Patients were treated between 1999 and 2014 either with primary chemoradiation (n = 101) or neoadjuvant chemoradiation at the Department of Radiation Oncology, University Medical Center Mainz, followed by transabdominal or transthoracic tumor resection (n = 44). Of the 145 patients, 64 (44%) had undergone PET-CT. RESULTS: Univariate analysis showed the use of PET-CT to be associated with significantly longer local recurrence-free survival (p = 0.006) and tended to translate into a measurable improvement of overall survival (p = 0.071). Since more patients underwent surgery in the group planned using PET-CT (20% vs. 44%; p = 0.002), we carried out a multivariate Cox regression analysis to adjust for this possible confounding factor. Surgery (p = 0.042; HR 0.55; 95% confidence interval: 0.31-0.98) as well as the use of PET-CT (p = 0.048; HR 0.60; 95% confidence interval: 0.36-0.99) nearly halved the risk of local recurrence. It was only in the group of patients with PET-CT that a trend towards a shorter overall survival was evident in lymph node-positive patients (p = 0.16), whereas nodal stage did not impact on survival in patients staged without PET-CT (p = 0.97). CONCLUSION: To the best of our knowledge these data suggest for the first time that the use of PET-CT in the framework of staging and planning of primary or neoadjuvant chemoradiotherapy for esophageal cancer has a favorable impact on patient survival.

Multiparametric Analysis of the Tumor Microenvironment: Hypoxia Markers and Beyond.

We have established a novel in situ protein analysis pipeline, which is built upon highly sensitive, multichannel immunofluorescent staining of paraffin sections of human and xenografted tumor tissue. Specimens are digitized using slide scanners equipped with suitable light sources and fluorescence filter combinations. Resulting digital images are subsequently subjected to quantitative image analysis using a primarily object-based approach, which comprises segmentation of single cells or higher-order structures (e.g., blood vessels), cell shape approximation, measurement of signal intensities in individual fluorescent channels and correlation of these data with positional information for each object. Our approach could be particularly useful for the study of the hypoxic tumor microenvironment as it can be utilized to systematically explore the influence of spatial factors on cell phenotypes, e.g., the distance of a given cell type from the nearest blood vessel on the cellular expression of hypoxia-associated biomarkers and other proteins reflecting their specific state of activation or function. In this report, we outline the basic methodology and provide an outlook on possible use cases.

Tumor Oxygenation Status: Facts and Fallacies.

In this chapter we allude to a series of facts and fallacies often encountered in the description of tumor hypoxia, a relevant trait of the tumor microenvironment and a paramount driver of tumor aggressiveness and treatment resistance. The critical role of diffusion distances, terminological inconsistencies considering O2 partial pressures vs. O2 concentrations and with it the use of inept units, the impact of O2 depletion on proliferation and cell viability, the switch in the Warburg dogma , the distribution of hypoxic subvolumes within a tumor, the involvement of O2 diffusion shunts in the development of chronic hypoxia, and the role of endogenous biomarkers as surrogates for the assessment of hypoxia are discussed in more detail. Special emphasis is put on the clinical relevance of these misconceptions and misinterpretations and their impact on the assessment of hypoxia as well as hypoxia-targeted treatment planning.

Downregulation of EGFR in hypoxic, diffusion-limited areas of squamous cell carcinomas of the head and neck.

BACKGROUND: The receptor for the epidermal growth factor (EGFR) is widely considered to be one of the central drivers of oncogenesis in squamous cell carcinomas of the head and neck region (HNSCC). Inhibition of EGFR using monoclonal antibodies is established both in the curative and the palliative setting in this disease. HNSCCs are known to contain abundant hypoxic tissue areas and hypoxia has been shown to be involved in the (down)regulation of EGFR membrane expression. METHODS: A novel method for multiplex immunofluorescence and single-cell segmentation (via DAPI-stained nuclei) was established, to study the expression of EGFR, the endogenous hypoxia marker CA IX, and intratumoural diffusion distances from microvessels (using CD34 staining) in 58 human HNSCCs and 9 normal/cancer adjacent tissues. RESULTS: EGFR was found to be significantly downregulated with increasing distance from tumour microvessels, whereas the opposite was true for CA IX. Larger diffusion-limited areas were correlated with higher expression of CA IX. CONCLUSIONS: The hypoxic tumour microenvironment may have a major role in mediating resistance against anti-EGFR strategies by downregulating EGFR molecules on tumour cells.

Radiotherapy with BRAF inhibitor therapy for melanoma: progress and possibilities.

The introduction of small molecule BRAF(V600) kinase inhibitors represents a milestone in the targeted therapy of patients with metastatic melanoma by a significant increase in therapeutic efficacy in terms of overall and progression-free survival compared with conventional chemotherapy. Beside BRAF(V600) inhibitor treatment, radiotherapy is a further mainstay for the therapy of metastatic melanoma and thus a concomitant or sequential application of BRAF(V600) inhibitors and radiotherapy is inevitable. Recent reports show a significant radiosensitization of the irradiated healthy tissue in patients with melanoma after the combination of radiotherapy and BRAF(V600) inhibitors, evoking concern in clinical practice. We review interactions of BRAF(V600) inhibitors and radiation with regard to antitumor effects and an increased radiotoxicity in the healthy tissue.

Hypoxia-Driven Adenosine Accumulation: A Crucial Microenvironmental Factor Promoting Tumor Progression.

Systematic studies on the oxygenation status of solid tumors have shown that the development of hypoxic/anoxic tissue subvolumes is a pathophysiological trait in a wide range of human malignancies. As a result of this characteristic property, adenosine (ADO) accumulation (range: 50-100 µM) occurs caused by intra- and extracellular generation of ADO. Extracellular nucleotide catabolism by hypoxia-/HIF-1α-sensitive, membrane-associated ecto-5'-nucleotidases most probably is the major source of ADO in the halo of cancer cells upon specific genetic alterations taking place during tumor growth. Extracellular ADO can act through autocrine and paracrine pathways following receptor-binding and involving different intracellular signalling cascades. Hypoxia-driven receptor activation can lead to a broad spectrum of strong immune-suppressive properties facilitating tumor escape from immune control (e.g., inhibition of CD4+, CD8+, NK and dendritic cells, stimulation of Treg cells). In addition, tumor growth and progression is promoted by ADO-driven direct stimulation of tumor cell proliferation, migration, invasion, metastatic dissemination, and an increase in the production of molecules stimulating tumor angiogenesis. Hypoxia- driven ADO accumulation in the tumor microenvironment thus plays a critical role in tumor growth and progression at multiple pathophysiological levels.

Tumor Hypoxia: Causative Mechanisms, Microregional Heterogeneities, and the Role of Tissue-Based Hypoxia Markers.

Tumor hypoxia is a hallmark of solid malignant tumor growth, profoundly influences malignant progression and contributes to the development of therapeutic resistance. Pathogenesis of tumor hypoxia is multifactorial, with contributions from both acute and chronic factors. Spatial distribution of hypoxia within tumors is markedly heterogeneous and often changes over time, e.g., during a course of radiotherapy. Substantial changes in the oxygenation status can occur within the distance of a few cell layers, explaining the inability of currently used molecular imaging techniques to adequately assess this crucial trait. Due to the possible importance of tumor hypoxia for clinical decision-making, there is a great demand for molecular tools which may provide the necessary resolution down to the single cell level. Exogenous and endogenous markers of tumor hypoxia have been investigated for this purpose. Their potential use may be greatly enhanced by multiparametric in situ methods in experimental and human tumor tissue.

Hypoxia-Associated Marker CA IX Does Not Predict the Response of Locally Advanced Rectal Cancers to Neoadjuvant Chemoradiotherapy.

Hypoxia-associated proteome changes have been shown to be associated with resistance to chemo- and radiotherapy. Our study evaluated the role of the hypoxia-inducible (HIF)-1 target gene carbonic anhydrase (CA) IX in the prediction of the response to neoadjuvant chemoradiotherapy in locally advanced rectal cancer (stages II and III). A total of 29 pretreatment biopsy specimens were stained for CA IX by immunohistochemistry, converted to digital images and evaluated in a quantitative fashion using image analysis software. Contrary to our expectations, a trend towards a correlation between better tumor regression (>50%) and higher expression of CA IX (p=0.056) was found. CA IX was also present more frequently in pathological tumor stage T1 (pT1) tumors (p=0.048). Conversely, no association with lymph node metastasis was identified. In conclusion, as a single marker, CA IX expression is not able to identify a hypoxia-related treatment resistant phenotype in rectal cancer.

Adjuvant temozolomide-based chemoradiotherapy versus radiotherapy alone in patients with WHO III astrocytoma: The Mainz experience.

BACKGROUND: It is currently unclear whether adjuvant therapy for WHO grade III anaplastic astrocytomas (AA) should be carried out as combined chemoradiotherapy with temozolomide (TMZ)--analogous to the approach for glioblastoma multiforme--or as radiotherapy (RT) alone. PATIENTS AND METHODS: A retrospective analysis of data from 90 patients with AA, who were treated between November 1997 and February 2014. Assessment of overall (OS) and progression-free survival (PFS) was performed according to treatment categories: (1) 50%, RT + TMZ according to protocol, (2) 11%, RT + TMZ with dose reduction, (3) 26%, RT alone, and (4) 13%, individualized, primarily palliative therapy. No dose reduction was necessary in the RT alone group. RESULTS: Median OS was 85, 69, and 43 months for treatment categories 1/2, 3, and 4, respectively. These differences were not statistically significant. PFS was 35, 29, 48, and 33 months for categories 1, 2, 3, and 4, respectively; again without significant differences between categories. In a subgroup of 39 patients with known IDH1 R132H status, the presence of this mutation correlated with significantly longer OS (p = 0.01) and PFS (p = 0.002). Complete or partial tumor resection and younger age also correlated with a significantly better prognosis, and this influence persisted in multivariate analysis. In the IDH1 R132H subgroup analysis, only this marker retained an independent prognostic value. DISCUSSION AND CONCLUSION: A general superiority of combined chemoradiotherapy compared to RT alone could not be demonstrated. Biomarkers for predicting the benefits of combination therapy using RT and TMZ are needed for patients with AA.

Strong adverse prognostic impact of hyperglycemic episodes during adjuvant chemoradiotherapy of glioblastoma multiforme.

BACKGROUND: In comparison to normal brain tissue, glioblastomas exhibit significantly increased glucose uptake. Brain edema is a common complication during adjuvant chemoradiotherapy, leading to a requirement for glucocorticoid treatment. Glucocorticoid treatment frequently causes considerable deregulation of blood glucose levels. Therefore, episodes of hyperglycemia may contribute to radio- and/or chemoresistance. PATIENTS AND METHODS: This study comprises a retrospective analysis of the influence of hyperglycemic episodes (HEs) during adjuvant therapy on the overall survival of 106 glioblastoma multiforme patients. RESULTS: The occurrence of one or more deregulated blood glucose value(s) > 10 mM is associated with a reduction in median overall survival from 16.7 to 8.8 months. A significantly poorer overall survival of patients with hyperglycemia could also be detected in subgroup analyses of patients with complete tumor resection and complete treatment according to the EORTC 22891/26891 trial protocol, as well as in a multivariate Cox proportional hazards analysis. A history of diabetes mellitus had no influence on prognosis. DISCUSSION: Our data suggest that the observed negative impact of elevated blood glucose levels on overall survival may not solely be explained by the patients' poorer general condition; the elevated blood glucose concentration itself may play a pathogenetic role. This could be due to increased activity of antioxidant systems, elevated expression of DNA damage response proteins and protection of hypoxic tumor cells against apoptosis combined with hypoxia-mediated radioresistance. CONCLUSION: A possible prognostic impact of elevated blood glucose levels during the period of adjuvant (chemo-) radiotherapy of glioblastoma should be evaluated in a prospective clinical trial.

GLUT-1 expression is largely unrelated to both hypoxia and the Warburg phenotype in squamous cell carcinomas of the vulva.

BACKGROUND: Strongly increased uptake of glucose is a hallmark of solid malignant tumors. This phenotype can be triggered by hypoxia-induced gene expression changes or can occur independently of hypoxia as a consequence of malignant transformation itself, and is often referred to as the Warburg effect. The glycolytic phenotype has been associated with malignant progression and resistance to radio- and chemotherapy. METHODS: We have chosen squamous cell carcinomas of the vulva (SCC-V) as a representative solid tumor entity to study the central players of this pathway, namely glucose transporter (GLUT)-1, carbonic anhydrase (CA) IX, hexokinase (HK)-2 and pyruvate kinase (PK)-M2, and have investigated their relationships to tumor microvessels (CD34, αSMA) and proliferation (Ki67). Expression of these proteins was analyzed in 38 SCC-Vs, 5 vulvar dysplasias and 10 non-neoplastic squamous epithelia of the vulva using multiparametric immunohistochemistry in registered serial sections (MIRSS). RESULTS: Expression of GLUT-1 in invasive carcinomas was predominantly located in the outer layers of the tumor cell aggregates close to the vascularized tumor stroma, and only to a lesser extent colocalized with CA IX, which was repeatedly found at larger diffusion distances away from microvessels. CA IX expression was lower in invasive carcinomas compared to dysplasias and non-neoplastic tissue and higher in recurrent vs. primary tumors. Ki67-positive proliferating cells were partially colocalized with GLUT-1. However, HK-2 and PK-2--proteins centrally involved in the Warburg phenotype--did not show such a correlation. CONCLUSIONS: Consistent with prior studies, the pattern of GLUT-1 clearly indicated that a large part of its expression is presumably unrelated to hypoxia. However, there was also no association with HK-2 and PK-M2, suggesting that the functional background of this expression is also independent of aerobic glycolysis. CA IX may be worth consideration as a marker of biological hypoxia, as should its pathophysiological consequences in SCC-V.

Hypoxia in tumors: pathogenesis-related classification, characterization of hypoxia subtypes, and associated biological and clinical implications.

Hypoxia is a hallmark of tumors leading to (mal-)adaptive processes, development of aggressive phenotypes and treatment resistance. Based on underlying mechanisms and their duration, two main types of hypoxia have been identified, coexisting with complex spatial and temporal heterogeneities. Chronic hypoxia is mainly caused by diffusion limitations due to enlarged diffusion distances and adverse diffusion geometries (e.g., concurrent vs. countercurrent microvessels, Krogh- vs. Hill-type diffusion geometry) and, to a lesser extent, by hypoxemia (e.g., in anemic patients, HbCO formation in heavy smokers), and a compromised perfusion or flow stop (e.g., due to disturbed Starling forces or intratumor solid stress). Acute hypoxia mainly results from transient disruptions in perfusion (e.g., vascular occlusion by cell aggregates), fluctuating red blood cell fluxes or short-term contractions of the interstitial matrix. In each of these hypoxia subtypes oxygen supply is critically reduced, but perfusion-dependent nutrient supply, waste removal, delivery of anticancer or diagnostic agents, and repair competence can be impaired or may not be affected. This detailed differentiation of tumor hypoxia may impact on our understanding of tumor biology and may aid in the development of novel treatment strategies, tumor detection by imaging and tumor targeting, and is thus of great clinical relevance.

Is bilateral radiotherapy necessary for patients with unilateral squamous cell carcinoma of unknown primary of the head and neck region?

Background and Purpose: Squamous cell carcinoma of unknown primary (SCC-CUP) of the head and neck region remains a clinical challenge, with uncertainty surrounding the necessity of contralateral irradiation of cervical lymphatic drainage in cases of unilateral involvement. Materials and Methods: A retrospective study was conducted at the Department of Radiation Oncology, University Medical Center Mainz, on a cohort of 50 patients with unilateral SCC-CUP of the head and neck region treated between 2005 and 2019. 30 patients received bilateral and 20 received unilateral cervical radiotherapy. The majority (n = 38, 76 %) were treated with modern IMRT/ VMAT (Intensity-modulated Radiation Therapy/ Volumetric Modulated Arc Therapy) techniques. Results: After a median follow-up of 64.5 months, locoregional recurrences occurred in 26 % of cases (n = 13/50), all of which were ipsilateral and predominantly within the volume of the previous irradiated CTV (clinical target volume) (85 %, n = 11/13). No patient treated unilaterally developed a contralateral recurrence in the neck. After 3 years, we observed 7 locoregional recurrences in the bilateral irradiated group (n = 7/30, 23 %), and 5 locoregional recurrences in the unilateral irradiated group (n = 5/20, 25 %). After 3 years, 12 patients had died in the bilateral irradiated group (n = 12/30, 40 %), and 7 in the unilateral irradiated group (n = 7/20, 35 %). 7 Patients showed distant metastases after 3 years in the bilateral irradiated group (n = 7/30, 23 %), and 2 in the unilateral irradiated group (n = 2/20, 10 %). Locoregional control (LRC) at 5 years was 66.2 % in the bilaterally irradiated group, and 70.0 % in the unilaterally irradiated group. Overall survival (OS) was 52.6 % (bilateral) and 64.0 % (unilateral). Distant metastasis-free survival (DMFS) was 74.7 % (bilateral) and 84.4 % (unilateral). No significant differences were observed in OS (p = 0.37), LRC (p = 0.91), and DMFS (p = 0.91) between the groups.Acute toxicity ≥ °2 accordingly CTCAE (Common Terminology Criteria of Adverse Events) was high with 97% while late toxicity ≥ °2 was moderate with 31%. There was no statistically significant difference between the group of unilateral and bilateral irradiated patients. Conclusion: These data suggest that contralateral cervical irradiation may be of limited benefit in patients with SCC-CUP, as recurrences occured ipsilaterally, and predominantly within the area of prior irradiation. Unilateral irradiation seems to be adequate for carefully selected patients.

Tumor-stroma contact ratio - a novel predictive factor for tumor response to chemoradiotherapy in locally advanced oropharyngeal cancer.

The growth pattern of oropharyngeal squamous cell carcinomas (OPSCC) varies from compact tumor cell aggregates to diffusely infiltrating tumor cell-clusters. The influence of the growth pattern on local tumor control and survival has been studied mainly for surgically treated oral cavity carcinomas on a visual basis. In this study, we used multiplex immunofluorescence staining (mIF) to examine the antigens pan-cytokeratin, p16INK4a, Ki67, CD271, PD-L1, and CD8 in pretherapeutic biopsies from 86 OPSCC. We introduce Tumor-stroma contact ratio (TSC), a novel parameter, to quantify the relationship between tumor cells in contact with the stromal surface and the total number of epithelial tumor cells. mIF tumor cores were analyzed at the single-cell level, and tumor-stromal contact area was quantified using the R package "Spatstat". TSC was correlated with the visually assessed invasion pattern by two independent investigators. Furthermore, TSC was analyzed in relation to clinical parameters and patient survival data to evaluate its potential prognostic significance. Higher TSC correlated with poor response to (chemo-)radiotherapy (r = 0.3, p < 0.01), and shorter overall (OS) and progression-free (PFS) survival (median OS: 13 vs 136 months, p < 0.0001; median PFS: 5 vs 85 months, p < 0.0001). Visual categorization of growth pattern according to established criteria of tumor aggressiveness showed interobserver variability increasing with more nuanced categories (2 categories: k = 0.7, 95 %-CI: 0.55 - 0.85; 4 categories k = 0.48, 95 %-CI: 0.35 - 0.61). In conclusion, TSC is an objective and reproducible computer-based parameter to quantify tumor-stroma contact area. We demonstrate its relevance for the response of oropharyngeal carcinomas to primary (chemo-)radiotherapy.