***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: Abstract Use of the low-energy helium-neon laser ( LEL ) appears to be a simple atraumatic technique for the prevention and treatment of mucositis of various origins . Preliminary findings , and significant results obtained for chemotherapy-induced mucositis in a previous phase III study , prompted a r and omized multicenter double-blind trial to evaluate LEL in the prevention of acute radiation-induced stomatitis . Irradiation by LEL corresponds to local application of a high-photon-density monochromatic light source . Activation of epithelial healing for LEL-treated surfaces , the most commonly recognized effect , has been confirmed by numerous in vitro studies . The mechanism of action at a molecular and enzymatic level is presently being studied . From September 1994 to March 1998 , 30 patients were r and omized . Technical specification : 60 mW ( 25 mW at Reims , 1 patient ) , He-Ne , wavelength 632.8 nm . The trial was open to patients with carcinoma of the oropharynx , hypopharynx and oral cavity , treated by radiotherapy alone ( 65 Gy at a rate of 2 Gy/fraction , 5 fractions per week ) without prior surgery or concomitant chemotherapy .  The malignant tumor had to be located outside the tested laser application areas ( 9 points ) : posterior third of the internal surfaces of the cheeks , soft palate and anterior tonsillar pillars . Patients were r and omized to LEL or placebo light treatment , starting on the first day of radiotherapy and before each session . The treatment time ( t ) for each application point was given by the equation : t (s)=energy (J/cm2) × surface (cm2)/Power ( W ) . Objective assessment of the degree of mucositis was recorded weekly by a physician blinded to the type of treatment , using the WHO scale for grading of mucositis and a segmented visual analogue scale for pain evaluation . Protocol feasibility and compliance were excellent . Grade 3 mucositis occured with a frequency of 35.2 % without LEL and of 7.6 % with LEL ( P<0.01 ) . The frequency of " severe pain " ( grade 3 ) was 23.8 % without LEL , falling to 1.9 % with LEL ( P<0.05 ) . Pain relief was significantly reduced throughout the treatment period ( weeks 2–7 ) . LEL therapy is capable of reducing the severity and duration of oral mucositis associated with radiation therapy . In addition , there is a tremendous potential for using LEL in combined treatment protocol s utilizing concomitant chemotherapy and radiotherapy Background Radiation therapy ( RT ) comprises a key component in the treatment of breast cancer . Radiation-induced skin toxicity is the major adverse event experienced by patients ; however , radiodermatitis ( RD ) prevention and management remains trivial . It is proven that photobiomodulation ( PBM ) therapy using light-emitting diode ( LED ) increases wound healing and depicts an anti-inflammatory effect . This single-institute study evaluates the beneficial role of PBM-LED in preventing/reducing RD during breast cancer RT . Patients and methods Of 70 consecutively treated patients , 25 patients were treated with PBM-LED twice a week prior to adjuvant 3D conformal RT after breast-conserving surgery .  RD was reported using Common Toxicity Criteria for Adverse Events Version 4.0 and pain intensity using a visual analog scale ( VAS ) . For comparison , a control group ( n = 45 ) received RT without PBM-LED . In addition , a “ matched ” group ( n = 25 ) was generated from the control group based on propensity for potentially confounding variables . Results In the PBM group , 22 patients ( 88 % ) presented grade 1 and 3 ( 12 % ) grade 2 RD . In the control group , 25 patients ( 55.6 % ) developed grade 1 reactions , 18 patients ( 40 % ) grade 2 , and 2 ( 4.4 % ) patients grade 3 RD . Concerning pain intensity , 15 patients ( 60 % ) of the PBM treatment arm reported no pain , 5 patients ( 20 % ) VAS 2 , and 5 ( 20 % ) VAS 3 . In the control group , 13 patients ( 28.9 % ) reported no pain , 2 ( 4.4 % ) VAS 1 , 7 ( 15.6 % ) VAS 2 , 9 patients ( 20 % ) reported VAS 3 , 12 ( 26.7 % ) patients VAS 4 , and 2 ( 4.4 % ) patients VAS 5 . Conclusion PBM-LED therapy applied prior to RT might be effective in decreasing the incidence and sequelae of radiation-induced skin toxicity in breast cancer patients treated with breast-conserving surgery . ZusammenfassungHintergrundRadiotherapie ( RT ) ist integrativer Best and teil der multimodalen Therapie beim Mammakarzinom . Strahlentherapieinduzierte Hauttoxizität ist dabei das häufigste unerwünschte Ereignis ; dennoch sind Prävention und Management der Radiodermatitis ( RD ) weiterhin trivial . Klinische Studien ergaben , dass die Photobiomodulation ( PBM ) mit Leuchtdioden ( LED ) die Wundheilung fördern und entzündungshemmend wirken kann . Diese Single-Institut-Studie untersucht die Wertigkeit der PBM-LED zur Prävention und Linderung der RD während der adjuvanten Brustkrebs-RT.Patienten und Method enVon insgesamt 70 konsekutiv beh and elten Patienten wurden 25 Patienten nach brusterhaltender Operation 2‑mal wöchentlich mit PBM-LED vor adjuvanter 3D-RT beh and elt  . RD wurde nach den Common Toxicity Criteria Version 4.0 dokumentiert und RD-assoziierte Schmerzen mit der visuellen Analogskala ( VAS ) erfasst . Die Kontrollgruppe ( n = 45 ) erhielt keine PBM-LED vor RT . Zusätzlich wurde eine „ gematchte “ Gruppe ( n = 25 ) aus der Kontrollgruppe basierend auf der Neigung für potenzielle Störvariablen gebildet . ErgebnisseIn der PBM-Gruppe präsentierten 22 Patienten ( 88 % ) eine Grad-1-RD und 3 ( 12 % ) eine Grad-2-RD . In der Kontrollgruppe zeigten 25 Patienten ( 55,6 % ) eine Hauttoxizität vom Grad 1 , 18 ( 40 % ) vom Grad 2 und 2 ( 4,4 % ) eine Grad-3-RD . Hinsichtlich der Schmerzintensität hatten 15 Patienten ( 60 % ) der PBM-Gruppe keine Schmerzen , 5 ( 20 % ) VAS 2 und 5 ( 20 % ) VAS 3 . In der Kontrollgruppe hatten 13 Patienten ( 28,9 % ) keine Schmerzen , 2 ( 4,4 % ) VAS 1 , 7 ( 15,6 % ) VAS 2 , 9 ( 20 % ) VAS 3 , 12 ( 26,7 % ) VAS 4 und 2 ( 4,4 % ) Patienten VAS 5.SchlussfolgerungPBM-LED-Therapie vor adjuvanter RT könnte die Inzidenz und Ausprägung von RD bei Brustkrebspatientinnen nach brusterhaltender Operation verringern OBJECTIVES Radiotherapy ( RT ) is treatment of choice for Elderly Head and Neck Cancer ( HNC ) patients .  Oral mucositis ( OM ) during RT affects patient 's routine oral activities and overall health . Low Level Laser Therapy ( LLLT ) provided some promising results against cancer therapy induced OM in children and adults . No study specifically evaluated effects of LLLT against RT induced OM in elderly HNC patients until date , hence we did this study . MATERIAL AND METHODS This double blinded study r and omized 46 elderly HNC patients scheduled for RT [ Dosage=66 Gray ( 2 Gy/fraction ) , 5 fractions/week , total 33 fractions for 6.5 weeks ] , into laser ( 22 ) and placebo ( 24 ) groups . Laser group patients received LLLT [ Helium-Neon , λ=632.8 nm , power density=0.024 W/cm(2 ) , dosage=3.0 J/point at six anatomical sites bilaterally i.e. 12 locations , total dose/session=36 J , beam aperture diameter=0.6 mm , beam spot size=1 cm(2 ) , irradiated area diameter=1 cm(2 ) , irradiation time/point=125 s , 5 sessions/week , non-contact method -distance between probe and irradiated tissues < 1 cm , whereas placebo group did not receive laser . OM grade s ( RTOG/EORTC Scale ) , oral pain , weight loss , need for morphine analgesics and tube feeding , and RT break were recorded by a blinded assessor . Descriptive statistics and repeated measures ANOVA were used for analysis keeping p<0.05 . RESULTS Significant reduction in the incidence and duration of severe OM ( p=0.016 ) and severe pain ( p=0.023 ) and weight loss ( p=0.004 ) was observed in laser than placebo group . No difference was found for enteral feeding use ( p=0.667 ) between two groups . CONCLUSIONS LLLT decreased the severity of OM and oral pain in elderly HNC patients . Also , lesser weight loss , morphine analgesic use and radiation break happened in laser group Oral mucositis ( OM ) is an adverse side effect among hematopoietic stem cell transplantation ( HSCT ) recipients . The objective of this retrospective study was to evaluate the preventive effect of photobiomodulation ( PBM ) applied three times per week versus seven times per week in patients undergoing HSCT . The risk factors related to the incidence and severity of OM were also assessed . This was a retrospective study that evaluated 99 HSCT recipients who received different PBM protocol s. Group I received three sessions per week , and group II received daily treatment . PBM was applied using a continuous-wave diode laser ( InGaAlP ; MM Optics , São Carlos , SP , Brazil ) at a wavelength of 660 nm ( visible-red ) and a total radiant energy of 0.24 J per point . The baseline disease , type of transplant , type of conditioning , prophylaxis against graft-versus-host disease , OM grade , absolute leukocyte and platelet counts , and levels of liver and renal function markers were collected from medical records . The patients ’ age ranged from 13 to 71 years ( mean/SD , 40.54 ± 16.45 ) . No significant difference was observed between groups I and II regarding sex , age , ethnic , diagnosis , donor type , and conditioning treatment . Both PBM protocol s were equally efficient in preventing OM ( p = 0.34 , ANOVA ) . Independent of the PBM protocol used , patients who received allogeneic transplant ( p < 0.01—Fischer ’s exact test ) , total body irradiation ( TBI-12Gy ) ( p = 0.01—chi-square test ) , busulfan + cyclophosphamide ( p < 0.01—chi-square test ) , or methotrexate-containing regimens ( p < 0.01—Fischer ’s exact test ) demonstrated higher OM incidence and severity . Myelosuppression ( p < 0.01—Mann-Whitney test ) and impaired renal function ( p = 0.02—Mann-Whitney test ) were also considered risk factors for OM . Based on this retrospective data , PBM was effective in preventing OM in patients undergoing HSCT even when it was applied three times a week . A prospect i ve study might be necessary to confirm these findings Low-level laser therapy (LLLT)/photobiomodulation ( PBM ) has been consistently shown in laboratory studies to have distinct biological effects , and has a dosedependent mechanism of action at the cellular level . Since the introduction of LLLT/PBM in 1967 , > 400 r and omized , double-blinded ( some placebo-controlled ) clinical trials have been published for multiple applications . Although the complex biological mechanisms underlying the therapeutic effects of LLLT/PBM have not been completely eluci date d , and may vary among different cell types and tissue states ( healthy versus stressed or hypoxic ) , laboratory and clinical studies suggest that LLLT/PBM significantly reduces inflammation and prevents fibrosis . Moreover , LLLT/PBM , when delivered appropriately , reduces pain and improves optimal function of the whole organism . In addition , in vivo studies show that LLLT/PBM is neuroprotective and may benefit neurodegenerative diseases and neurotrauma . Current data suggest that LLLT/PBM acts predominantly on cytochrome C oxidase ( CcO ) in the mitochondrial respiratory chain by facilitating electron transport , result ing in an increased transmembrane proton gradient that drives adenosine triphosphate ( ATP ) production . ATP is the universal energy source in living cells essential for all biologic reactions , and even a small increase in ATP levels can enhance bioavailability to power the functions of cellular metabolism . In addition , the absorption of red or near-infrared ( NIR ) light may cause a short , transient burst of reactive oxygen species ( ROS ) that is followed by an adaptive reduction in oxidative stress . A low concentration of R 
    Output:
    
The study that compared PBMT with other treatment modality showed better results in pain control with PBMT .
It appears that PBMT application frequency and potency impact on pain control .
The current evidence supports that PBMT is effective in pain control result ing from OM and radiodermatitis and may also reduce the need for analgesics .