Late Urinary Toxicity and QoL with Curative Radiotherapy for High-Risk Prostate Cancer: Dose-Effect Relations in the POP-RT Randomized Phase III Trial

PURPOSE/OBJECTIVE(S)

Whole pelvic radiotherapy (WPRT) showed better biochemical failure-free survival and metastasis-free survival than prostate-only radiotherapy (PORT) in the phase III randomized POP-RT trial for high and very high-risk prostate cancer, albeit with higher RTOG grade 2 late urinary toxicity. We report updated long term, symptom-wise comparison and dose-effect relations from this trial.

MATERIALS/METHODS

Late urinary toxicity, and cumulative severity of each symptom over the follow-up period was graded using CTCAE v5.0. Grade 2+ toxicities were compared between the trial arms by chi square test. Bladder dosimetry in 5-Gy increments (V5, V10, V15...V65 Gy, V68 Gy) from the trial database of approved radiotherapy plans, was compared for each urinary symptom and overall late gr2+ toxicity by student t-test. Observed differences in dosimetric parameters were tested using multivariable logistic regression analysis, including age at diagnosis, known diabetes, tumor stage, trial arm, and prior transurethral resection of prostate (TURP). Urinary QOL scores were compared between arms using generalised linear mixed model.

RESULTS

Combined late symptom-wise toxicity and dose-volume data were available for analysis for 193/224 patients. At a median follow-up of 75 months, cumulative CTCAE gr2+ late urinary toxicity remained higher with WPRT than PORT, though not statistically significant (36.5% vs 26.8%, p = 0.15). Grade 3 toxicity was low and similar in both arms. Symptom-wise cumulative rates showed no significant difference between arms (Table 1). Dosimetric comparison showed significantly higher bladder V5-V15 in patients with gr2+ toxicity over those with

CONCLUSION

Compared to prostate-only radiotherapy, whole pelvic radiotherapy resulted similar Grade 3 urinary toxicity of about 5% with about 10% higher cumulative grade 2+ urinary toxicity over long term follow up. This difference was not reflected in patient-reported QOL. WPRT particularly increased urgency and hematuria. Larger bladder volume being irradiated with 5Gy to 15Gy dose range could contribute to increase in urinary symptoms.

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Affiliation(s)

G Maheshwari Department of Radiation Oncology, Tata Memorial Centre, Homi Bhabha National Institute, Mumbai, India
P Maitre Department of Radiation Oncology, Tata Memorial Centre, Homi Bhabha National Institute, Mumbai, India
J Sarkar Department of Radiation Oncology, Tata Memorial Centre, Homi Bhabha National Institute, Mumbai, India
V Raveendran Department of Medical Physics, Tata Memorial Centre, Homi Bhabha National Institute, Mumbai, India
R Phurailatpam Department of Radiation Oncology, Tata Memorial Centre, Homi Bhabha National Institute, Mumbai, India
P Singh Department of Radiation Oncology, Tata Memorial Centre, Homi Bhabha National Institute, Mumbai, India
V Murthy Department of Radiation Oncology, Tata Memorial Centre, Homi Bhabha National Institute, Mumbai, India

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Dynamic Role of Oxygen in Wound Healing: A Microbial, Immunological, and Biochemical Perspective

A wound is a temporary break in the continuity of the protective skin barrier. Wound healing is central in maintaining the body's normal homeostatic mechanism, and open wounds raise the risk of microbial infection and amputation. A successful wound healing event is achieved through a series of evolutionarily conserved biochemical pathways orchestrated by various cytokines, growth factors, and immune cells. Chronic wounds are generally oxygen-deficient, and wound hypoxia impairs the wound healing process. Therefore, the use of external oxygen may improve wound health by reducing wound hypoxia, promoting tissue regeneration and granulation tissue formation, reducing anaerobic bacteria colonization, and promoting the growth of beneficial aerobic bacteria. Relevant data were searched and gathered from scientific databases, including PubMed, ScienceDirect, and Google Scholar using relevant keywords, such as "Chronic Wounds", "Topical Oxygen Therapy", "Inflammatory Markers/ Lactate/ Matrix Metalloproteinase", "Collagen", and "Wound Healing". Relevant articles were shortlisted and used in the present study. Chronic wounds show higher expression of pro-inflammatory mediators, such as C-reactive protein, and higher levels of tissue-degrading matrix metalloproteinases. In addition, chronic wounds are generally oxygen-deficient, and wound hypoxia is directly associated with wound deterioration. Several microbial, immunological, and biochemical markers show a direct association with the oxygen availability in the wound. Therefore, a detailed understanding of these microbial, immunological, and biochemical markers will certainly help clinicians understand the interplay between various factors and topical oxygen therapy and may improve patient outcomes.

Unusual Presentations of Acute Lymphoblastic Leukemia in Children: A Study of 9 Patients

Background: Acute lymphoblastic leukemia is the most common malignancy in children below 15 years of age. Bone marrow, CNS and the gonads are the three major sites of failure or relapse in acute lymphoblastic leukemia. Occasionally, leukemic cells can infiltrate the unusual sites and present with some unusual manifestations either at initial (diagnosis) presentation or during the course of disease. This study presents 9 such rare cases of unusual manifestations of acute lymphoblastic leukemia. Aim: To report the unusual presentation and management of acute lymphatic leukemia in children either at initial diagnosis or during the course of disease. Methods: Between 2000-2012, 1800 patients with acute lymphoblastic leukemia were treated at the Gujarat Cancer & Research Institute, Ahmedabad, a tertiary cancer care center and one of the largest regional cancer center of India. Among these patients a total of 317 cases were found to develop relapse at bone marrow, CNS, testicles etc. Out of these patients, a total of 9 patients were detected to have very unusual manifestations of the disease, either at initial presentation or during the course of their disease. These patients had parotid salivary gland involvement (1), maxillary sinus (2), bilateral blindness due to retinal detachment (1), bilateral facial nerve palsies (1), multiple symmetrical involvement of bones of both upper and lower extremities (1), small bone of the hand (4th metacarpal bone) (1), massive splenomegaly (1) and torsion of the testicle (1). The manifestations of such unusual clinical presentations, their evaluation, management and ultimate outcome is being presented in this presentation along with review of the literature. Results: Acute lymphoblastic leukemia can present with very unusual manifestation during initial diagnosis or later. Conclusion: ALL may occasionally present in some unusual way. Such uncommon presentation can create a diagnostic dilemma as well as difficulty in management. All such presentations require special attention from the treating consultant and team for the better outcome. We strongly recommend that all such rare presentations must be reported to enhance the understanding of the disease and enhance the literature.

Autocrine epidermal growth factor signaling stimulates directionally persistent mammary epithelial cell migration

Cell responses to soluble regulatory factors may be strongly influenced by the mode of presentation of the factor, as in matrix-bound versus diffusible modes. The possibly diverse effect of presenting a growth factor in autocrine as opposed to exogenous (or paracrine) mode is an especially important issue in cell biology. We demonstrate here that migration behavior of human mammary epithelial cells in response to stimulation by epidermal growth factor (EGF) is qualitatively different for EGF presented in exogenous (paracrine), autocrine, and intracrine modes. When EGF is added as an exogenous factor to the medium of cells that express EGF receptor (EGFR) but not EGF, cell migration speed increases while directional persistence decreases. When these EGFR-expressing cells are made to also express via retroviral transfection EGF in protease-cleaveable transmembrane form on the plasma membrane, migration speed similarly increases, but directional persistence increases as well. Addition of exogenous EGF to these cells abrogates their enhanced directional persistence, reducing their directionality to a level similar to wild-type cells. If the EGFR-expressing cells are instead transduced with a gene encoding EGF in a soluble form, migration speed and directional persistence were unaffected. Thus, autocrine presentation of EGF at the plasma membrane in a protease-cleavable form provides these cells with an enhanced ability to migrate persistently in a given direction, consistent with their increased capability for organizing into gland-like structures. In contrast, an exogenous/paracrine mode of EGF presentation generates a "scattering" response by the cells. These findings emphasize the functional importance of spatial restriction of EGFR signaling, and suggest critical implications for growth factor-based therapeutic treatments.

Cell adhesion and motility depend on nanoscale RGD clustering

Integrin adhesion receptors play a crucial role in regulating interactions between cells and extracellular matrix (ECM). Integrin activation initiates multiple intracellular signaling pathways and results in regulation of cell functions such as motility, proliferation and differentiation. Two key observations regarding the biophysical nature of integrin-mediated cell-matrix interactions motivated the present study: (1) cell motility can be regulated by modulating the magnitude of cell-substratum adhesion, by varying cell integrin expression level, integrin-ECM binding affinity or substratum ECM surface density; and (2) integrin clustering enables assembly of multiple cytoplasmic regulatory and structural proteins at sites of aggregated integrin cytoplasmic domains, activating certain intracellular signalling pathways. Here, using a minimal integrin adhesion ligand, YGRGD, we test the hypothesis that ligand clustering can affect cell migration in a manner related to its modulation of cell-substratum adhesion. We employ a synthetic polymer-linking method, which allows us to independently and systematically vary both the average surface density and the local (approx. 50 nm scale) spatial distribution of the YGRGD peptide, against a background otherwise inert with respect to cell adhesion. In this system, the ligand was presented in three alternative spatial distributions: singly, in clusters with an average of five ligands per cluster, or in clusters with an average of nine ligands per cluster; for each of these spatial distributions, a range of average ligand densities (1,000-200,000 ligands/micrometer(2)) were examined. Cluster spacing was adjusted in order to present equivalent average ligand densities independently of cluster size. The murine NR6 fibroblast cell line was used as a model because its migration behavior on ECM in the presence and absence of growth factors has been well-characterized and it expresses integrins known to interact with the YGRGD peptide. Using time-lapse videomicroscopy and analysis of individual cell movement paths, we find that NR6 cells can migrate on substrata where adhesion is mediated solely by the YGRGD peptide. As previously observed for migration of NR6 cells on fibronectin, migration speed on YGRGD is a function of the average surface ligand density. Strikingly, clustering of ligand significantly reduced the average ligand density required to support cell migration. In fact, non-clustered integrin ligands support cell attachment but neither full spreading nor haptokinetic or chemokinetic motility. In addition, by quantifying the strength of cell-substratum adhesion, we find that the variation of cell speed with spatial presentation of YGRGD is mediated via its effect on cell adhesion. These effects on motility and adhesion are also observed in the presence of epidermal growth factor (EGF), a known motility-regulating growth factor. Variation in YGRGD presentation also affects the organization of actin filaments within the cell, with a greater number of cells exhibiting stress fibers at higher cluster sizes of YGRGD. Our observations demonstrate that cell motility may be regulated by varying ligand spatial presentation at the nanoscale level, and suggest that integrin clustering is required to support cell locomotion.

Biophysical integration of effects of epidermal growth factor and fibronectin on fibroblast migration

Cell migration is regulated simultaneously by growth factors and extracellular matrix molecules. Although information is continually increasing regarding the relevant signaling pathways, there exists little understanding concerning how these pathways integrate to produce the biophysical processes that govern locomotion. Herein, we report the effects of epidermal growth factor (EGF) and fibronectin (Fn) on multiple facets of fibroblast motility: locomotion speed, membrane extension and retraction activity, and adhesion. A surprising finding is that EGF can either decrease or increase locomotion speed depending on the surface Fn concentration, despite EGF diminishing global cell adhesion at all Fn concentrations. At the same time, the effect of EGF on membrane activity varies from negative to positive to no-effect as Fn concentration and adhesion range from low to high. Taking these effects together, we find that EGF and Fn regulate fibroblast migration speed through integration of the processes of membrane extension, attachment, and detachment, with each of these processes being rate-limiting for locomotion in sequential regimes of increasing adhesivity. Thus, distinct biophysical processes are shown to integrate for overall cell migration responses to growth factor and extracellular matrix stimuli.

Deconstructing (and reconstructing) cell migration

An overriding objective in cell biology is to be able to relate properties of particular molecular components to cell behavioral functions and even physiology. In the "traditional" mode of molecular cell biology, this objective has been tackled on a molecule-by-molecule basis, and in the "future" mode sometimes termed "functional genomics," it might be attacked in a high-throughput, parallel manner. Regardless of the manner of approach, the relationship between molecular-level properties and cell-level function is exceedingly difficult to elucidate because of the large number of relevant components involved, their high degree of interconnectedness, and the inescapable fact that they operate as physico-chemical entities-according to the laws of kinetics and mechanics-in space and time within the cell. Cell migration is a prominent representative example of such a cell behavioral function that requires increased understanding for both scientific and technological advance. This article presents a framework, derived from an engineering perspective regarding complex systems, intended to aid in developing improved understanding of how properties of molecular components influence the function of cell migration. That is, cell population migration behavior can be deconstructed as follows: first in terms of a mathematical model comprising cell population parameters (random motility, chemotaxis/haptotaxis, and chemokinesis/haptokinesis coefficients), which in turn depend on characteristics of individual cell paths that can be analyzed in terms of a mathematical model comprising individual cell parameters (translocation speed, directional persistence time, chemotactic/haptotactic index), which in turn depend on cell-level physical processes underlying motility (membrane extension and retraction, cell/substratum adhesion, cell contractile force, front-vs.-rear asymmetry), which in turn depend on molecular-level properties of the plethora of components involved in governance and regulation of these processes. Hence, the influence of any molecular component on cell population migration can be understood by reconstructing these relationships from the molecular level to the physical process level to the individual cell path level to the cell population distribution level. This approach requires combining experimental, theoretical, and computational methodologies from molecular biology, biochemistry, biophysics, and bioengineering.