Dysphagia Associated Organ Sparing Radiotherapy:Defining the Limits of Tolerance for Late Toxicity

Background:Dysphagia after radiotherapy in head and neck malignancies can severely impact a patient’s physical,social and psychological quality of life.Aspiration remains the major cause of non-disease related mortality in treated patients.The purpose of this study was to analyze the dosimetric correlates in a selective Asian subset of patients who are most eligible for Dysphagia aspiration related structure(DARS)sparing.Materials and Methods:Thirty patients with Oral or Oropharyngeal malignancies treated from March 2014 to September 2017 were analyzed for dosimetric parameters to DARS.A dosimetric and volumetric evaluation of dose parameters to the dysphagia and Aspiration associated normal structures were analyzed.The National cancer institute Common toxicity criteria for adverse events Version-3 was used to grade late dysphagia.Subjective evaluation of dysphagia was done with University of Washington Head and Neck related quality of life Questionnaire.Dosimetric comparison between IMRT and 3DCRT technique was done and correlated to toxicity.Results:Greater than Grade 2 dysphagia was observed in 10 patients(33%).In the 3DCRT cohort Grade 3&4 toxicity was higher,50%vs.25%.A threshold Mean dose of 63 Gy was identified as a significant parameter above which observed Gr 3/4 toxicity was 33%(P value=0.028).The maximum dose to the base of tongue(BOT)and Superior constrictor(SC)were dosimetric parameters which achieved significance(P value=0.013&0.005).There was no difference in the dose delivered to DARS between 3DCRT and IMRT.However,the patient reported Dysphagia scores were higher for pain(P=0.0014)in the 3DCRT cohort and can be attributed to a higher percentage of patients exceeding Parotid tolerance(70%vs.40%).The impact of Gr 3/4 toxicity on all aspects of quality of life parameters were significantly impaired with maximum compromise on late chewing,swallowing and general perception of well-being(P value=0.001).Conclusion:This suggests that a threshold mean dose(MD)of 63 Gy to the constrictors is statistically correlated to significant Gr 3/4 late toxicity.The high doses to the BOT and SC independently contribute to late toxicity.IMRT is more efficient in reducing severe late toxicity with a better patient reported quality of life parameters and should be the preferred treatment of choice.

Target Delineation in High-grade Glioma Do CTV Margins Make a Difference? ESTRO ACROP versus RTOG Guidelines a Comparative Dosimetric Study

Background and purpose:There exist two major consensus guidelines for target delineation in glioblastoma(GBM).Namely the established radiation therapy oncology group(RTOG)and the recently redefined European society for radiation oncology(EORTC)-advisory committee on radiation oncology practice(ACROP),clinical studies evaluating the pattern of recurrence with relation to the CTV margins have as of date not evidenced statistically significant difference in relation to the two guidelines.However,considering the standardization of concurrent chemo-radiation with Temozolomide nearly 20%off patients can be expected to survive 2years or beyond.Quality of life issues will play a higher role in defining the better protocol.In the current study,we have dosimetrically compared these guidelines in both perspectives.Material and methods:Thirty patients of GBM who had been planned for conformal radiotherapy during Jan 2017 to Feb 2019 were considered.Each patient dataset contoured with ESTRO-ACROP guidelines to create PLAN A and RTOG guidelines to create PLAN B.Both plans were compared to evaluate the volumetric difference in terms of PTV and the relative proximity to critical normal structures.Results:The median volume of brain irradiated to high doses(60Gy)was significantly greater in PLAN B,566cc vs 398 cc(P<0.0002).The organs at risk were better spared with PLAN A in terms of encroachment of high dose PTV volume.This achieved significance for Brainstem(P<0.01),Chiasma(P<0.04)and hippocampus(P<0.016).We were able to identify patients with PTV volume>400cc and with tumor in Parietal or Temporal regions wouldn’t benefit from PLAN A.Conclusion:The use of target delineation based on a single step plan,excluding expanded edema(ESTRO-ACROP)could potentially reduce high dose target volumes and significantly spare brainstem,optic-chiasma,and hippocampus.Patients with tumor volume<400 cc and frontal lesions are most likely to benefit.

Cervical Cancer in the COVID-19 Era – the Potential Role of Adapting Newer Treatment Protocols

Background:The COVID-19 pandemic has resulted in unprecedented problems in both cancer management and providing a safe organised workflow for oncological health care systems to operate.The treatment of advanced cervical cancer stage IIB-IVA has received higher priority in most international guidelines for risk adaptation in relation to COVID-19 situation.There is an urgent need to revise the established standard treatment protocol of concurrent chemo-irradiation followed by brachytherapy,usually delivered over 6-7 weeks,which is associated with technical difficulties and would pose risks to both the patient and treating health care personnel.Aims&Objectives:To propose alternative treatment protocols that are supported by scientific data and may be better suited to meet the needs of the unique situation.Methods:A systematic literature search was performed using PubMed and other search engines.The studies evaluated were those published from 1990 to April 2020.The focus was on scientific rationale and non-inferiority with standards of care.Conclusions:The authors propose Simultaneous Integrated Boost for treatment of large volume disease and Stereotactic Body Radiotherapy boost for smaller tumour volumes,where facilities are available.3DCRT with an integrated or sequential IMRT boost can be considered in institutes with technical limitations.

Editor’s Note

Dear readers,We are happy to bring to you this special issue,the focus of which is the impact of Covid-19 pandemic in the management of cancer patients who naturally form a high risk cohort because of their immune compromised status.There are considerable problems of managing an organized safe workflow for health care systems in delivering treatment without compromising survival.One probable solution would involve adapting cancer protocols supported by scientific data that can provide shorter treatment times/easier or faster treatment delivery.Exploring this landscape,we have in this edition a review article on adapting newer treatment protocols for managing cervical cancers,one of the top female malignancies worldwide.In addition to the theme this issue contains the regular article focusing on modern cancer research.Triple Negative Breast Cancer form a very unfavorable cohort with an aggressive behavior and a relatively poor response to current treatments especially when presenting in the metastatic setup.The newer insights on molecular subtypes and mutations within TNBC has allowed for the evolution of promising new treatment options including targeted therapies,immune check point inhibitors and antibody drug conjugates.We have a systemic review covering the promising new options and the probable scientific rationale and evidence currently supporting them.