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"Lobo, Dilson"
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Pre-treatment blood parameters as an economical predictive marker for predicting treatment response in locally advanced cervical cancer version 2; peer review: 1 approved, 1 approved with reservations
2025
Background
Cervical cancer poses a significant public health challenge, particularly in low and middle-income countries. Despite advancements in treatment, the disease remains a leading cause of cancer-related deaths among women globally. Chemoradiation utilizing cisplatin has been the cornerstone therapy for locally advanced cervical cancer. Prognostic biomarkers, including hematological parameters, have emerged as valuable tools in guiding treatment decisions and predicting outcomes.
Methodology
Data from patients treated between January 2021 and June 2022 were analyzed. Demographic information, histopathology, pre-treatment blood parameters, treatment details, and response assessments were collected. The parameters assessed included hemoglobin levels, neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), prognostic nutritional index (PNI), and eosinophil albumin ratio (EAR). Receiver operating characteristic (ROC) curve analysis was conducted to determine optimal cut-off values for these biomarkers.
Results
Of the 140 patients included, the majority had squamous cell carcinoma (92%) and were at stage II or III. Complete response to treatment was observed in 86.4% of patients. Non-responders demonstrated significantly higher levels of hemoglobin, NLR, and EAR, along with lower PNI levels compared to responders. ROC analysis revealed cut-off values for hemoglobin (< 9.5), NLR (< 2.98), PLR (> 289.26), PNI (< 37.67), and EAR (< 49.63) associated with treatment response.
Conclusion
The study highlights the potential utility of pre-treatment blood parameters as predictive markers for treatment response in locally advanced cervical cancer. Lower hemoglobin, higher NLR, and EAR, along with reduced PNI, were associated with poorer treatment outcomes. Integration of these biomarkers into clinical practice could aid in treatment planning and improve patient outcomes. Further validation and prospective studies are warranted to establish the role of these biomarkers in guiding personalized treatment strategies for cervical cancer patients.
Journal Article
Terrestrial radiotherapy alters microhardness and surface micromorphology of dental restorative materials: an in vitro study
by
Lobo, Dilson
,
Shenoy, Ramya
,
MS, Athiyamaan
in
Aesthetics
,
bulk-fill composite
,
Cancer therapies
2025
Therapeutic radiotherapy, commonly used in the treatment of head and neck cancers, may alter the mechanical and surface properties of restorative dental materials. Understanding these changes is essential for ensuring the long-term success of restorations in oncology patients.
An
study was conducted on 90 disc-shaped specimens (
= 30 each) of three restorative materials: 3M™ Filtek™ Bulk Fill, Charisma Topaz One, and Cention N. Samples were subjected to two radiation protocols: (i) 70 Gy in 35 fractions (2 Gy/day), and (ii) 45 Gy in 5 fractions (9 Gy/day). Vickers microhardness testing and scanning electron microscopy (SEM) were performed 48 h post-irradiation.
Filtek™ Bulk Fill exhibited the highest pre-radiation hardness (83.1 ± 2.3 HV), followed by Charisma Topaz One (74.5 ± 2.8 HV) and Cention N (69.8 ± 2.1 HV). After exposure to 70 Gy, a statistically significant reduction in microhardness was observed across all materials (
< 0.05), with Bulk Fill remaining the least affected (74.3 ± 2.1 HV). SEM images confirmed surface degradation in all groups, with varying degrees of filler particle exposure.
Ionizing radiation alters both microhardness and surface morphology of restorative materials, with bulk-fill composites demonstrating greater resilience. These findings warrant further investigation
to understand long-term clinical implications.
Journal Article
Clinical and dosimetric correlation in terms of treatment response, bladder and rectal toxicities in cervical cancer patients treated with cobalt 60 high dose rate brachytherapy
by
Kilikunnel, Johan Sunny
,
Lobo, Dilson
,
MariappanSenthiappan, Athiyamaan
in
Adult
,
Aged
,
Antineoplastic Agents - adverse effects
2024
High dose rate (HDR) image-guided brachytherapy with Cobalt-60 isotope is a relatively recent approach. The aim of the study is to evaluate the clinical and dosimetric parameters in terms of tumour response, bladder, and rectal toxicity in patients undergoing Co-60 HDR brachytherapy.
All patients were initially treated with chemoradiation (CT-RT) at our center or other referral centers with external beam radiation therapy (EBRT) for a dose of 45 Gy-60 Gy at 1.8-2Gy/fraction (including nodal boost) with concomitant chemotherapy with either cisplatin or carboplatin. Patients were then scheduled for brachytherapy within 1 week after completion of CT-RT and are assessed by local examination. Depending on local examination parameters at the time of brachytherapy they were eligible either for intracavitary brachytherapy (ICBT) or interstitial brachytherapy (ISBT).
The complete response (CR) observed in stage I, II, III, IVA were 60%, 79.4%, 86% and 76.2% respectively. Complete response was seen in patients with mean EQD2 of 78.67 Gy
, 83.33 Gy
, 84.23 Gy
, 85.63 Gy
in stages I, II, III, IVA respectively. 79.2% of cisplatin-treated patients and 87.5% of carboplatin-treated patients had a complete response indicating that patients treated with either chemotherapy had similar response rates.
According to results obtained from the study we conclude by saying that higher rates of complete response to treatment in cervical cancer is seen in patients with shorter overall treatment time (OTT), shorter interval between end of definitive CT-RT and beginning of brachytherapy and squamous cell histology. The study also noted the trend of increasing mean EQD2 to tumor with increasing stage for achieving complete response. Higher acute bladder and rectal toxicity is seen in patients who received EQD2 of ¿70-90Gy
and ¿70Gy
respectively. The study findings suggest that the clinical outcomes and the toxicities are clinically comparable with other radioisotope based HDR brachytherapy treatment.
Journal Article
Longitudinal Assessment of Neurocognitive Outcomes and Correlation with Limbic System Radiation Doses in Patients Undergoing Radiotherapy for Central Nervous System Tumours: A preliminary report
by
Lobo, Dilson
,
Baruah, Prerana
,
Srinivas, Challapalli
in
Adult
,
Attention - radiation effects
,
Brain Neoplasms
2025
Background Radiation therapy (RT) for central nervous system (CNS) malignancies can result in neurocognitive decline, affecting quality of life. While hippocampal-sparing approaches are well documented, limited data exist on the impact of radiation dose to other cognitive structures. This prospective study evaluates domain-specific cognitive changes following RT and explores correlations with radiation dose to key brain regions. Methodology Twenty-five patients with primary CNS tumours undergoing focal radiotherapy, with or without concurrent chemotherapy, were enrolled. Neurocognitive function was assessed using the Addenbrooke’s Cognitive Examination III (ACE-III) tool, pre- and six months post-treatment. Radiation dose-volume histogram (DVH) data were analyzed for structures including the hippocampus, amygdala, cerebellum, and corpus callosum. Patients were stratified based on ACE-III score decline (≥3 points vs. <3 points), and dose-response correlations were examined. Results A statistically significant decline in mean ACE-III scores was observed post-treatment (pre: 89.48 ± 6.84 vs. post: 87.91 ± 6.29, p = 0.007). Attention, language, and fluency were the most affected domains. Patients with cognitive decline received higher radiation doses to all examined structures, with the corpus callosum showing the strongest association (mean dose in decline group: 35.91 Gy vs. 30.70 Gy; p = 0.440). However, no dose-response relationship reached statistical significance. Conclusion This study highlights early, domain-specific neurocognitive decline following focal RT for CNS tumours, with attention and language being most vulnerable. Corpus callosum dose emerged as a key correlate. These findings suggest the need to broaden neuroprotection strategies beyond the hippocampus and emphasize the value of incorporating routine neurocognitive assessment.
Journal Article
Clinical correlation of p16 expression with lymphatic invasion and epithelial-mesenchymal transition (EMT) in oropharyngeal carcinomas
by
Lobo, Dilson
,
Srinivas, Challapalli
,
Kini, Jyoti
in
Adult
,
Aged
,
Biomarkers, Tumor - metabolism
2025
Background/Aim To examine the clinical correlation of p16 expression with Epithelial–Mesenchymal Transition (EMT) markers and lymphatic invasion in OPSCC patients in terms of clinical status at presentation, subsequent progression, and survival. Methods Tissue blocks of biopsy-proven Oropharyngeal Squamous Cell Carcinoma were subjected to Immunohistochemistry (IHC) for evaluating the expression of p16, e-cadherin, vimentin and podoplanin. This expression pattern was correlated with the demographic details, treatment response and survival patterns. Results 60 patients were finally available for evaluation in this study. Prevalence of HPV infection in our study was found to be 11.7%. E-cadherin expression was found in all HPV-associated patients whereas vimentin was not expressed in any of these. 71.4% patients had low Podoplanin expression and 85.7% had low lymphatic vessel count. Among the HPV- associated patients, 85.8% had T3-T4 stage, 100% had N2-N3 disease and 95% had stage IV disease. It was also found that p16-positive patients had significantly higher 1-year Overall survival (OS) (80%, p=0.045), higher 1-year Progression-free survival (PFS) (60%) and higher 1-year Locoregional recurrence-free survival (LRRFS) (75%) when compared to p16-negative patients. Conclusion Prevalence of HPV infection was found to be similar to that of previous studies conducted in India. As previous literature suggests, the HPV-positive patients in our study presented with advanced nodal disease at presentation and thereby, an advanced overall stage. Further follow-up of these patients including their treatment details, determination of possible prognostic markers, and evaluation of their survival parameters can be done which can help in modifying the existing treatment modalities as HPV-associated OPSCC are known to have better prognosis according to literature.
Journal Article
Influence of air gap under bolus in the dosimetry of a clinical 6 MV photon beam
2020
Aim: In some situations of radiotherapy treatments requiring application of tissue-equivalent bolus material (e.g., gel bolus), due to material's rigid/semi-rigid nature, undesirable air gaps may occur beneath it because of irregularity of body surface. The purpose of this study was to evaluate the dosimetric parameters such as surface dose (Ds), depth of dose maximum (dmax), and depth dose along central axis derived from the percentage depth dose (PDD) curve of a 6 MV clinical photon beam in the presence of air gaps between the gel bolus and the treatment surface. Materials and Methods: A bolus holder was designed to hold the gel bolus sheet to create an air gap between the bolus and the radiation field analyzer's (RFA-300) water surface. PDD curves were taken for field sizes of 5 cm × 5 cm, 10 cm × 10 cm, 15 cm × 15 cm, 20 cm × 20 cm, and 25 cm × 25 cm, with different thicknesses of gel bolus (0.5, 1.0, and 1.5 cm) and air gap (from 0.0 to 3.0 cm), using a compact ionization chamber (CC13) with RFA-300 keeping 100 cm source-to-surface (water) distance. The dosimetric parameters, for example, \"Ds,\" \"dmax,\" and difference of PDD (maximum air gap vs. nil air gap), were analyzed from the obtained PDD curves. Results: Compared to ideal conditions of full contact of bolus with water surface, it has been found that there is a reduction in \"Ds\" ranging from 14.8% to 3.2%, 14.9% to 1.1%, and 12.6% to 0.7% with the increase of field size for 0.5, 1.0, and 1.5 cm thickness of gel boluses, respectively, for maximum air gap. The \"dmax\" shows a trend of moving away from the treatment surface, and the maximum shift was observed for smaller field size with thicker bolus and greater air gap. The effect of air gap on PDD is minimal (≤1%) beyond 0.4 cm depth for all bolus thicknesses and field sizes except for 5 cm × 5 cm with 1.5 cm bolus thickness. Conclusions: The measured data can be used to predict the probable effect on therapeutic outcome due to the presence of inevitable air gaps between the bolus and the treatment surface.
Journal Article
Surface dose measurements in chest wall postmastectomy radiotherapy to achieve optimal dose delivery with 6 MV photon beam
2021
Aim: A tissue-equivalent bolus of sufficient thickness is used to overcome build up effect to the chest wall region of postmastectomy radiotherapy (PMRT) patients with tangential technique till Radiation Therapy Oncology Group (RTOG) Grade 2 (dry desquamation) skin reaction is observed. The aim of this study is to optimize surface dose delivered to chest wall in three-dimensional radiotherapy using EBT3 film. Materials and Methods: Measurements were conducted with calibrated EBT3 films with thorax phantom under \"open beam, Superflab gel (0.5 cm) and brass bolus conditions to check correlation against TPS planned doses. Eighty-two patients who received 50 Gy in 25# were randomly assigned to Group A (Superflab 0.5 cm gel bolus for first 15 fractions followed by no bolus in remaining 10 fractions), Group B or Group C (Superflab 0.5 cm gel or single layer brass bolus, respectively, till reaching RTOG Grade 2 skin toxicity). Results: Phantom measured and TPS calculated surface doses were within − 5.5%, 4.7%, and 8.6% under open beam, 0.5 cm gel, and single layer of brass bolus applications, respectively. The overall surface doses (OSD) were 80.1% ±2.9% (n = 28), 92.6% ±4.6% (n = 28), and 87.4% ±4.7% (n = 26) in Group A, B, and C, respectively. At the end of treatment, 7 out of 28; 13 out of 28; and 9 out of 26 patients developed Grade 2 skin toxicity having the OSD value of 83.0% ±1.6% (n = 7); 93.7% ±3.2% (n = 13); and 89.9% ±5.6% (n = 9) in Groups A, B, and C, respectively. At the 20th-23rd fraction, 2 out of 7; 6 out of 13; and 4 out of 9 patients in Groups A, B, and C developed a Grade 2 skin toxicity, while the remaining patients in each group developed at the end of treatment. Conclusions: Our objective to estimate the occurrence of optimal dose limit for bolus applications in PMRT could be achieved using clinical EBT3 film dosimetry. This study ensured correct dose to scar area to protect cosmetic effects. This may also serve as quality assurance on optimal dose delivery for expected local control in these patients.
Journal Article
Clinical implementation of brass mesh bolus for chest wall postmastectomy radiotherapy and film dosimetry for surface dose estimates
by
Lobo, Dilson
,
Srinivas, Challapalli
,
Banerjee, Sourjya
in
Breast cancer
,
Breast Neoplasms - radiotherapy
,
Breast Neoplasms - surgery
2019
Objective: This study presents the dosimetric data taken with radiochromic EBT3 film with brass mesh bolus using solid water and semi-breast phantoms, and its clinical implementation to analyze the surface dose estimates to the chest wall in postmastectomy radiotherapy (PMRT) patients.
Materials and Methods: Water-equivalent thickness of brass bolus was estimated with solid water phantom under 6 megavoltage photon beam. Following measurements with film were taken with no bolus, 1, 2, and 3 layers of brass bolus: (a) surface doses on solid water phantom with normal incidence and on curved surface of a locally fabricated cylindrical semi-breast phantom for tangential field irradiation, (b) depth doses (in solid phantom), and (c) surface dose measurements around the scar area in six patients undergoing PMRT with prescribed dose of 50 Gy in 25 fractions.
Results: Water-equivalent thickness (per layer) of brass bolus 2.09 ± 0.13 mm was calculated. Surface dose measured by film under the bolus with solid water phantom increased from 25.2% ±0.9% without bolus to 62.5% ± 3.1%, 80.1% ± 1.5%, and 104.4% ± 1.7% with 1, 2, and 3 layers of bolus, respectively. Corresponding observations with semi-breast phantom were 32.6% ± 5.3% without bolus to 96.7% ± 9.1%, 107.3% ± 9.0%, and 110.2% ± 8.7%, respectively. A film measurement shows that the dose at depths of 3, 5, and 10 cm is nearly same with or without brass bolus and the percentage difference is <1.5% at these depths. Mean surface doses from 6 patients treated with brass bolus ranged from 79.5% to 84.9%. The bolus application was discontinued between 18th and 23rd fractions on the development of Grade 2 skin toxicity for different patients. The total skin dose to chest wall for a patient was 3699 cGy from overall treatment with and without bolus.
Conclusions: Brass mesh bolus does not significantly change dose at depths, and the surface dose is increased. This may be used as a substitute for tissue-equivalent bolus to improve surface conformity in PMRT.
Journal Article
Comparison of two high dose rate intracavitary brachytherapy regimens in treatment of cervical cancer: a preliminary report
2023
Background
To assess and compare the local control and toxicities between HDR Intracavitary Brachytherapy with 7.5 Gy and 9 Gy per fraction after EBRT in treatment of carcinoma cervix.
Methodology
A total of 180 patients were randomly assigned to 2 arms. Arm A received HDR intracavitary brachytherapy with a dose of 7.5 Gy per fraction, 1 fraction per week for 3 fractions and Arm B received 9 Gy per fraction, 1 fraction per week for 2 fractions. Patients were evaluated on follow up for assessment of local control and toxicities.
Results
The median follow up was 12 months (6–18 months). In arm A 89% of the patient had complete response and 11% had recurrence or metastasis. In arm B 93% of the patient had complete response and 7% had recurrence or metastasis. Grade 2/3 diarrhoea was seen in 4.4% of patients in Arm A and in 7.7% in Arm B. Grade 2/3 proctitis was seen in 3.3% of patients in 7.5 Gy arm and in 6.6% in 9 Gy arm. One patient in each arm had grade 1 haematuria. The overall duration of treatment was significant lower in Arm B compared to Arm A (59 days vs 68 days, p = 0.01).
Conclusion
The result of this clinical study shows that Intracavitary brachytherapy with a dose of 9 Gy per fraction is non inferior to other schedules in term of local control and does not result in increased toxicity.
Journal Article
Fabrication and development of a thorax phantom to evaluate 3D CRT treatment planning techniques for post-mastectomy chest wall radiotherapy
2021
The aim of this study was to design and fabricate a thorax phantom to quantify the radiation doses to the region of the chest wall (with 3 ionization chambers), the organ at risk (OAR) (lung), and the surface using radiochromic films (EBT3) for three different 3D CRT treatment planning techniques. Anthropomorphic phantoms are one of the best tools for verifying the quality of the radiotherapy treatment plans generated by treatment planning systems since they can provide equivalent human tissue densities. Thirty acrylic plates were cut into ellipses 21 cm in height and 31 cm in width, and slots were created to insert lung equivalent cork material and bone equivalent Teflon material. Three treatment planning techniques were designed: (A) tangential pair beams, (B) tangential pair beams with wedges and (C) tangential beams followed by an anterior oblique beam. The percentage difference between the measured point doses and the calculated doses (measured with three CC13 ionization chambers) ranged from − 3.2 to 1.6%, with a mean deviation of − 1.04 ± 1.3%. The measured mean percentage doses on the target surface with EBT3 film were 90.3% and 95.1% of the prescribed dose with 5-mm and 10-mm boluses, respectively. Finally, the average absolute dose difference between the measured and calculated surface doses was within 10 cGy in all three planning techniques. The developed thorax phantom is suitable for point dose measurements using ionization chambers and for surface dose measurements using EBT3 Gafchromic films in post-mastectomy chest wall radiotherapy.
Journal Article