Biological responses to low-dose and high-dose radiations are markedly different; the former produce beneficial effects and the latter at acute doses cause detrimental health effects such as cancer induction. High-dose radiations (>2 Gy) of low linear energy transfer are widely used in the treatment of cancer, but limitations are imposed due to normal tissue adverse reactions. Low-dose radiations (LDRs), such as X-rays (a few mGy), have been widely used in diagnosis of many diseases without any known adverse health effects. LDR preexposures have been known to suppress cancer induction by acute doses of radiation. This article briefly reviews the possible applications of LDR in cancer therapy and delineates the underlying radiobiological mechanisms in suppressing high-dose-induced cancer. It is further argued to develop LDR technology in preventing and for palliative outcomes in fighting COVID-19 pandemic infection among the populations. Furthermore, it is suggested to examine the average number of people living in high background radiation areas for susceptibility to COVID-19 infection and compare with the average infection rate in the general public for gaining new knowledge on the response of LDR-exposed population.

Background: Neoadjuvant chemoradiotherapy (NACTRT) is an established standard of care for the management of locally advanced rectal cancer (LARC). A retrospective analysis was conducted to assess the results of treatment and predictors of overall survival (OS) for patients treated in a tertiary care hospital in India from 2013 to 2019. Materials and Methods: Biopsy-proven 79 patients of LARC were included in the analysis. Clinical and treatment parameters were assessed. Prognostic factors associated with OS and pathologic response were studied. Treatment toxicities and sphincter preservation rates were documented. Results: There were 55(69.6%) patients with Stage III rectal cancer. Majority of the patients, i.e., 74 (93.7%), received long-course radiation therapy by intensity-modulated radiation therapy–volumetric modulated arc therapy technique after computed tomography + magnetic resonance imaging fusion-based simulation. Pathological complete response (pCR) was achieved in 20 (25.3%) while 45 (57%) showed tumor downstaging post-NACTRT. Time interval (TI) to surgery of ≤8 weeks was significantly associated with higher pCR and tumor downstaging. Actuarial 5-year OS rate was 64.4% and local recurrence-free survival (LRFS) rate of 72.2%. Both OS and LRFS were significantly higher in patients who showed pCR and tumor downstaging. Long-term gastrointestinal and genitourinary toxicities were seen in 11 (15%) and 15 (21.5%) patients, respectively. Conclusions: This study reaffirms the efficacy of preoperative NACTRT as an upfront standard of care in LARC in the Indian population. TI to surgery to the tune of ≤8 weeks yielded optimal pCR and tumor downstaging which translated into significantly better survival.

Purpose: Mold brachytherapy is an age old treatment for superficial tumors. Vaginal mold brachytherapy for gynecological malignancies of vaginal vault and vagina is being practiced in different institutes across the globe. We are reporting the technical aspects of vaginal mold and optimal treatment to the patient. Materials and Methods: This is a case of Carcinoma Cervix International Federation of Gynaecology and Obstetrics st-III_A(lower one-third vaginal involvement) with residual disease in the anterior wall of lower^d one-third of vagina after the completion of external beam radiotherapy. The patient was reluctant for interstitial implant brachytherapy and hence was planned for vaginal mold brachytherapy with an aim to boost residual tumor. Five stainless steel Implant needles attached to the sorbo from 9'o clock to 3'o clock position with adequate spacing between the needles. Modeling wax, which is nearly tissue equivalent, was used for making mold. The material was molded into a cast cylindrically over the needles and sorbo homogeneously taking care that there were no air gaps. After taking aseptic precautions the cylindrical mold with needles and sorbo was inserted into the vaginal cavity and stabilized with a T-bandage. Computed tomography scan was performed and images were imported to treatment planning system. Clinical target volume was contoured along with organs at risk (bladder and rectum) and geometric optimization was done to obtain proper dwell times and positions where the D₉₀was kept at 100% of the prescribed dose. Conclusion: Vaginal mold brachytherapy may be used as an alternative technique to interstitial implant brachytherapy as a boost treatment in vaginal malignancies. Patient-specific mold brachytherapy technique can be used in the cases where the target volume is superficial and limited to vagina. It is a minimally invasive technique which mimics the dose distribution of interstitial brachytherapy.

Background: Hepatocellular carcinoma (HCC) is the most common primary tumor of the hepatobiliary system. The Cyberknife represents a new, frameless stereotactic radiosurgery system with image-guided radiation delivery using fiducials as markers to overcome the movement of intra-abdominal organs due to respiration. However fiducial placement and treatment have its issues such as migration and other complications. Objectives: We evaluated the accuracy and feasibility of fiducial placement under image guidance and complications during and after placement such as migration including pain score. Materials and methods: A prospective observational study was carried out on 36 subjects with clinically and radiologically diagnosed hepatocellular carcinoma receiving Cyberknife based stereotactic based radiotherapy (SBRT). Fiducial markers for SBRT were introduced under percutaneous Ultrasound (US) or CT guidance. After placement, fiducial migration rate, pain score, fiducial placement related complications were noted during and after therapy. IBM SPSS statistical software version 21 was used for statistical analysis. Results: 8.4% had gross fiducial displacement on the day of the procedure. 90.9% had minimal migration during treatment.There was no gross migration seen during treatment or post-treatment. Post fiducial placement, 2.8 % had a major complication in the form of liver decompensation resulting in death while minor complications were observed in 13.9%. The average pain score was minimal (0.86) post fiducial placement. There was no pain in any of the patients during or after the treatment. Conclusion: Image-guided implantation of fiducial markers in the liver for stereotactic body radiation therapy had a high technical success rate and is a safe procedure with rare complications.There is minimal fiducial migration seen during the treatment. But being a descriptive study with a small sample size limits the generalizability of our study findings..

Aim: The aim of the study was to see the feasibility of hyperfractionated radiotherapy with concurrent chemotherapy in the treatment of locally advanced carcinoma cervix and to evaluate the result in terms of locoregional control, acute toxicities, weekly tumor regression rate, and radiation dose required for 50% and 80% reduction of previous tumor volume and to compare results with standard protocol in a retrospective manner. Materials and Methods: A pilot study of patients of carcinoma uterine cervix FIGO Stage IIB to IVA was undertaken. The study group consisted of 11 patients, treated by hyperfractionated schedule of 60 Gy/50 fractions/5 days/week over 5 weeks. Two fractions of 120 cGy per fraction per day were given at interval of 6 h. Injection cisplatin (50 mg/m²) I/V was administered on day 1, followed by injection 5-fluorouracil (750 mg/m²) I/V for 5 days, and the same regimen was repeated in the last week of external radiotherapy. After observing encouraging results, we compared our study with standard protocol in a retrospective manner which included 11 patients as a control group, who were treated by conventional fractionation of 50 Gy/25 fractions, 2 Gy/fraction/5 days/week for 5 weeks with injection cisplatin 50 mg I/V weekly. Results: The observed complete response was 72% and 81.8% in the control and study groups, respectively. Acute toxicities such as nausea, vomiting, and anemia were observed slightly higher in the study group, but all were well managed. The weekly tumor regression rate was much better in the study arm. Treatment-resistant depression (TRD) 50 and TRD₈₀were also in favor of the study arm. Conclusion: Hyperfractionated radiotherapy along with concurrent chemotherapy has produced a promising local control of locally advanced cervical cancer with an acceptable complication rate as compared to standard protocol.

Background: Rituximab is a chimeric monoclonal antibody, approved by the US Food and Drug Administration for the immunotherapy of non-Hodgkin's lymphoma (NHL).¹⁷⁷Lu-labeled rituximab has been identified as a potential agent for the radioimmunotherapy of NHL and is presently under clinical investigations. The objective of the present study is to estimate the magnitude of apoptotic cell death and cell-cycle phase arrest. Materials and Methods: Characterization of¹⁷⁷Lu-rituximab was performed by using instant thin-layer chromatography as well as by high-performance liquid chromatography. About 37 MBq (1 mCi) of¹⁷⁷Lu-rituximab was incubated with Raji cells up to 48 h at 37°C in a humidified atmosphere of 5% CO₂. Simultaneously, an equivalent amount of rituximab present in 37 MBq (1 mCi) of¹⁷⁷Lu-rituximab complex was used as a vehicle control. All cell samples (treated, vehicle control, and control cells) were harvested post 24 and 48 h of incubation to perform different assays such as lactate dehydrogenase, XTT, cell viability by flowcytometer, apoptosis, and cell cycle analysis. Results: The studies revealed that¹⁷⁷Lu-rituximab induced higher cell death and apoptosis compared to unlabeled rituximab. Similarly, an increase in cell population in G1-phase of cell cycle was observed, upon treatment of Raji cells with¹⁷⁷Lu-rituximab complex for 24 h, while an increase in G2/M phase population was observed at 48 h of incubation. Conclusions: The present studies demonstrate that¹⁷⁷Lu-rituximab is more effective in inducing apoptotic cell death and cell cycle-phase arrest compared to its unlabeled counterpart, indicating¹⁷⁷Lu-rituximab may have better potential in the therapy of B-cell lymphoma.

Ewing's sarcoma of the nasal cavity and paranasal sinuses (PNS) is extremely rare and a very few cases have been reported so far.Diagnosing Ewing's sarcoma requires the use of radiological studies, histopathological examination, immunohistochemistry(IHC), and cytogenetic studies.CD 99 or Mic 2 membranous expression on Immunohistochemistry and antibody against FLI 1 are the hallmark in the diagnosis of Ewing's sarcoma.Management of sinonasal Ewing's sarcoma includes surgery,chemotherapy and radiotherapy. Radiation treatment plays an important role in the treatment of Ewing's sarcoma as an adjuvant treatment. We are reporting a case of a 9 year old female child presented with complaints of epistaxis, nasal obstruction and swelling over right side of the face. Biopsy of the right sino nasal mass was done. Histopathologically the tumour composed of sheets of ovo-sphenoid cells.IHC showed positivity for Mic-2 and p53 protein.PET-CT scan showed an FDG avid uniformly enhancing soft tissue mass around 7.7x3.4x5.8 centimetres involving the nasopharynx, sphenoid bone,sphenoid sinus,ethmoid sinus, maxillary sinus,nasal cavity,infiltration through the optic canal into the right orbit with intracranial extension.Patient underwent Neo-adjuvant chemotherapy with Ewing's Family Tree EFT(Ewing's Family Tree)-2001 protocol and had complete response on assessment.We treated the patient with adjuvant radiation treatment to a dose of 52 Gy in 29 fractions (1.8 Gy/fraction) over 6 week to the pre-chemo tumour bed by VMAT technique..No major acute toxicities were noticed during the course of treatment. Patient needs to be assessed for local control and late toxicities. A multidisciplinary team approach involving oncosurgery, medical oncology and radiation oncology is very crucial in attaining better outcomes.Radiation as an adjuvant treatment helps us in achieving better local control and disease free survival.Radiation techniques like VMAT,IMRT can deliver treatment with homogenous dose distribution within target and sparing organs at risk.