Late Effects of Cytotoxic Agents on the Normal Tissue of Mice1

Author(s):  
Leslie E. Botnick ◽  
Eileen C. Hannon ◽  
Samuel Hellman
2013 ◽  
Vol 31 (15_suppl) ◽  
pp. 11116-11116
Author(s):  
Melvin Chua ◽  
Navita Somaiah ◽  
Sue Davies ◽  
Lone Gothard ◽  
Kai Rothkamm ◽  
...  

11116 Background: Critical opinions for the lack of success of DNA double-strand break (DSB) repair as a predictive marker of normal tissue radiosensitivity include the argument that in vitro cellular responses correlate poorly with in vivo responses due to the modifying influence of tissue environment. In this study, we test the hypothesis that a DNA damage assay based on in vivo irradiated skin tissues better predicts clinical responses in human skin, as opposed to the same assay performed in ex vivo irradiated lymphocytes. Methods: DSB levels (24 h post-4 Gy) were quantified using γH2AX/53BP1 immunostaining in irradiated skin tissues and G0 lymphocytes of 35 breast RT patients. Patients were selected on the basis of late RT effects in their breast and individuals with marked or minimal effects were classified as cases and controls, respectively. Risk factors of late effects established from multivariate analyses of outcomes of two breast RT trials were also considered in patient selection. They were 1) total RT dose, 2) RT dosimetry, 3) tumour bed boost, 4) breast size, 5) surgical cavity, and 6) axillary treatment. Results: Clinical parameters were balanced in both patient groups. Residual foci levels in skin epidermis and dermis were comparable between cases (n = 20) and controls (n = 15). Mean foci per cell were 3.29 in cases, 2.80 in controls for dermal fibroblasts (p = 0.07); 3.28 in cases, 2.60 in controls for endothelial cells (p = 0.08); 2.87 in cases, 2.41 in controls for superficial keratinocytes (p = 0.45); 2.32 in cases, 2.35 in controls for basal keratinocytes (p = 0.27). Residual foci levels in lymphocytes were however significantly higher among cases (foci per cell = 12.1) compared to controls (foci per cell = 10.3, p = 0.01). Of the different cell types, only residual foci levels of dermal fibroblasts and lymphocytes correlated with clinical severity (R = 0.722, p < 0.001; 0.593, p = 0.01, respectively). Interestingly, foci levels were not correlated between skin cells and lymphocytes of the same patients. Conclusions: DSB repair of ex vivo irradiated lymphocytes appears to be a better predictive marker of late effects to breast RT than DSB repair of in vivo irradiated skin.


2014 ◽  
Vol 32 (26) ◽  
pp. 2871-2878 ◽  
Author(s):  
Amato J. Giaccia

Traditional cytotoxic agents used in cancer therapy were initially discovered based on their ability to kill rapidly dividing cells. The targets of these early-generation agents were typically one or more aspects of DNA synthesis or mitosis. Thus, dose-limiting toxicities commonly associated with these agents include GI dysfunction, immunosuppression, and other consequences of injury to normal tissues in which cells are replicating under normal physiologic conditions. Although many of these agents still play an important role in cancer therapy when given concurrently with radiation therapy, the major thrust of radiobiology research in the last two decades has focused on discovering tumor-specific traits that might be exploited for more selective targeting that would enhance the efficacy of radiotherapy with less normal tissue toxicity. These newer generation molecular targeted therapies interfere with the growth of tumor cells by inhibiting genes and their protein products that are needed specifically by the tumor for survival and expansion. These agents can be complementary to radiotherapy, a spatially targeted agent. Although there have been extraordinary technical advances in radiotherapy in recent years, we are reaching the limits of improvements that radiotherapy delivery technology can bring and need different approaches. This review will highlight promising new tumor biology–based targets and other novel strategies to reduce normal tissue injury, increase tumor control, and expand the use of radiotherapy to treat widespread metastatic disease.


2013 ◽  
Vol 127 (3) ◽  
pp. 285-294 ◽  
Author(s):  
L A Joseph ◽  
J A Routledge ◽  
M P Burns ◽  
R Swindell ◽  
A J Sykes ◽  
...  

AbstractBackground:Few studies have prospectively investigated psychological morbidity in UK head and neck cancer patients. This study aimed to explore changes in psychological symptoms over time, and associations with patients' tumour and treatment characteristics, including toxicity.Methods:Two hundred and twenty patients were recruited to complete the Hospital Anxiety and Depression Scale and the Late Effects on Normal Tissue (Subjective, Objective, Management and Analytic) (‘LENT-SOMA’) questionnaires, both pre- and post-treatment.Results:Anxiety was highest pre-treatment (38 per cent) and depressive symptoms peaked at the end of treatment (44 per cent). Anxiety significantly decreased and depression significantly increased, comparing pre- versus post-treatment responses (p < 0.001). Hospital Anxiety and Depression Scale scores were significantly correlated with toxicity, age and chemotherapy (p < 0.01 for all).Conclusion:This is the first study to analyse the relationship between Hospital Anxiety and Depression Scale scores and toxicity scores in head and neck cancer patients. It lends support for the use of the Hospital Anxiety and Depression Scale and the Late Effects on Normal Tissue (Subjective, Objective, Management and Analytic) questionnaire in routine clinical practice; furthermore, continued surveillance is required at multiple measurement points.


Cancers ◽  
2019 ◽  
Vol 11 (10) ◽  
pp. 1578 ◽  
Author(s):  
Simone de Leve ◽  
Florian Wirsdörfer ◽  
Verena Jendrossek

Radiotherapy (RT) is a central component of standard treatment for many cancer patients. RT alone or in multimodal treatment strategies has a documented contribution to enhanced local control and overall survival of cancer patients, and cancer cure. Clinical RT aims at maximizing tumor control, while minimizing the risk for RT-induced adverse late effects. However, acute and late toxicities of IR in normal tissues are still important biological barriers to successful RT: While curative RT may not be tolerable, sub-optimal tolerable RT doses will lead to fatal outcomes by local recurrence or metastatic disease, even when accepting adverse normal tissue effects that decrease the quality of life of irradiated cancer patients. Technical improvements in treatment planning and the increasing use of particle therapy have allowed for a more accurate delivery of IR to the tumor volume and have thereby helped to improve the safety profile of RT for many solid tumors. With these technical and physical strategies reaching their natural limits, current research for improving the therapeutic gain of RT focuses on innovative biological concepts that either selectively limit the adverse effects of RT in normal tissues without protecting the tumor or specifically increase the radiosensitivity of the tumor tissue without enhancing the risk of normal tissue complications. The biology-based optimization of RT requires the identification of biological factors that are linked to differential radiosensitivity of normal or tumor tissues, and are amenable to therapeutic targeting. Extracellular adenosine is an endogenous mediator critical to the maintenance of homeostasis in various tissues. Adenosine is either released from stressed or injured cells or generated from extracellular adenine nucleotides by the concerted action of the ectoenzymes ectoapyrase (CD39) and 5′ ectonucleotidase (NT5E, CD73) that catabolize ATP to adenosine. Recent work revealed a role of the immunoregulatory CD73/adenosine system in radiation-induced fibrotic disease in normal tissues suggesting a potential use as novel therapeutic target for normal tissue protection. The present review summarizes relevant findings on the pathologic roles of CD73 and adenosine in radiation-induced fibrosis in different organs (lung, skin, gut, and kidney) that have been obtained in preclinical models and proposes a refined model of radiation-induced normal tissue toxicity including the disease-promoting effects of radiation-induced activation of CD73/adenosine signaling in the irradiated tissue environment. However, expression and activity of the CD73/adenosine system in the tumor environment has also been linked to increased tumor growth and tumor immune escape, at least in preclinical models. Therefore, we will discuss the use of pharmacologic inhibition of CD73/adenosine-signaling as a promising strategy for improving the therapeutic gain of RT by targeting both, malignant tumor growth and adverse late effects of RT with a focus on fibrotic disease. The consideration of the therapeutic window is particularly important in view of the increasing use of RT in combination with various molecularly targeted agents and immunotherapy to enhance the tumor radiation response, as such combinations may result in increased or novel toxicities, as well as the increasing number of cancer survivors.


1971 ◽  
Vol 7 (1) ◽  
pp. 33-39 ◽  
Author(s):  
F.Ch. Izsak ◽  
E. Eylan ◽  
A. Gazith ◽  
J. Shapiro ◽  
S. Naharin ◽  
...  

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