Combinatorial approach of immuno-proton therapy in cancer: Rationale and potential impact

Cancer management is an expansive, growing, and evolving field. In the last decade or so, immunotherapy (IT) and particle beam therapy have made a tremendous impact in this domain. IT has already established itself as the fourth pillar of oncology. Recent emphasis has been centred around combination therapy, postulating additive or multiplicative effects of combining IT with one or more of the three conventional "pillars," that is, surgery, chemotherapy, and radiotherapy. Radio-IT is being increasingly explored and has shown promising outcomes in both preclinical and clinical settings. Particle beam therapy such as protons, when used as the radiotherapeutic modality in conjunction with IT, can potentially limit toxicities and improve this synergism further. Modern proton therapy has demonstrated a reduction in integral dose of radiation and radiation-induced lymphopenia in various sites. Protons, by virtue of their inherent clinically desirable physical and biological characteristics, namely, high linear energy transfer, relative biological effectiveness of range 1.1-1.6, and proven anti-metastatic and immunogenic potential in preclinical studies, might have a superior immunogenic profile than photons. Proton-IT combination is being studied currently by various groups in lung , head neck and brain tumors, and should be evaluated further in other subsites to replicate preclinical outcomes in a clinical setting. In this review, we summarize the currently available evidence for combinatorial approaches and feasibility of proton and IT combination, and thereafter highlight the emerging challenges for practical application of the same in clinics, while also proposing plausible solutions.

Translation and pilot validation of Hindi, Marathi, and Bangla translation of quality of life EORTC module (QLQ-SH-22) for assessing sexual health-related quality of life

AIM

To translate and validate the European Organization for Research and Treatment for Cancer (EORTC) module for assessing the sexual health-related quality of life in cancer patients (QLQ-SH22), in Hindi, Marathi, and Bangla languages for clinical use.

METHODS AND RESULTS

The EORTC QLQ-SH-22 was translated into Hindi, Marathi, and Bangla by adopting standard guidelines given by EORTC. Initially, the original questionnaire was forward translated by two separate translators, followed by the reconciliation of the forward translations by a third person. This was followed by two back translations of the reconciled version into English by two other translators. These back-translated questions were then compared with the original EORTC questions for accuracy, and once acceptable, a preliminary questionnaire was prepared in all three languages. These questionnaires were then pilot tested with 30 patients (10 for each language) diagnosed with any of the cancers in the pelvic region who are expected to be at risk of sexual quality of life due to tumor or treatment like pelvic radiotherapy. Participated patients had never seen or filled the questionnaire before, each patient was interviewed after filling the questionnaire for difficulty in answering, confusion, difficulty understanding, or if any of the questions were upsetting and if patients would have asked the question differently.

RESULTS

None of the patients reported any changes or suggestions for all the three translations. All the translated questionnaires were well understood by all the patients. Pilot testing reports were sent to EORTC. After reviewing the entire report of Hindi, Marathi, and Bangla translations, these questionnaires were approved by the EORTC translation unit. The questionnaires are reliable with Cronbach's α for Hindi, Marathi, and Bangla being 0.69, 0.66, and 0.86, respectively.

CONCLUSION

The final Hindi, Marathi, and Bangla translations of SH 22 have been approved by the EORTC and can be used to assess the sexual health of cancer patients in routine oncology practices and/or clinical studies.

Successful Implementation of Image-Guided Pencil-Beam Scanning Proton Therapy in Medulloblastomas

Medulloblastoma is the most common malignant brain tumour in children, while much rarer in adults. Although the prognosis and outcomes have greatly improved in the era of modern multidisciplinary management, long-term treatment-induced toxicities are common. Craniospinal irradiation followed by a boost to the primary and metastatic tumour sites forms the backbone of treatment. Proton therapy has been endorsed over conventional photon-based radiotherapy due to its superior dosimetric advantages and subsequently lower incidence and severity of toxicities. We report here our experience from South-East Asia's first proton therapy centre of treating 40 patients with medulloblastoma (38 children and adolescents, 2 adults) who received image-guided, intensity-modulated proton therapy with pencil-beam scanning between 2019 and 2023, with a focus on dosimetry, acute toxicities, and early survival outcomes. All patients could complete the planned course of proton therapy, with mostly mild acute toxicities that were manageable on an outpatient basis. Haematological toxicity was not dose-limiting and did not prolong the overall treatment time. Preliminary data on early outcomes including overall survival and disease-free survival are encouraging, although a longer follow-up and data on long-term toxicities are needed.

Proton therapy and oral mucositis in oral & oropharyngeal cancers: outcomes, dosimetric and NTCP benefit

INTRODUCTION

Radiation-induced oral mucositis (RIOM), is a common, debilitating, acute side effect of radiotherapy for oral cavity (OC) and oropharyngeal (OPx) cancers; technical innovations for reducing it are seldom discussed. Intensity-modulated-proton-therapy (IMPT) has been reported extensively for treating OPx cancers, and less frequently for OC cancers. We aim to quantify the reduction in the likelihood of RIOM in treating these 2 subsites with IMPT compared to Helical Tomotherapy.

MATERIAL AND METHODS

We report acute toxicities and early outcomes of 22 consecutive patients with OC and OPx cancers treated with IMPT, and compare the dosimetry and normal tissue complication probability (NTCP) of ≥ grade 3 mucositis for IMPT and HT.

RESULTS

Twenty two patients, 77% males, 41% elderly and 73% OC subsite, were reviewed. With comparable target coverage, IMPT significantly reduced the mean dose and D32, D39, D45, and D50, for both the oral mucosa (OM) and spared oral mucosa (sOM). With IMPT, there was a 7% absolute and 16.5% relative reduction in NTCP for grade 3 mucositis for OM, compared to HT. IMPT further reduced NTCP for sOM, and the benefit was maintained in OC, OPx subsites and elderly subgroup. Acute toxicities, grade III dermatitis and mucositis, were noted in 50% and 45.5% patients, respectively, while 22.7% patients had grade 3 dysphagia. Compared with published data, the hospital admission rate, median weight loss, feeding tube insertion, unplanned treatment gaps were lower with IMPT. At a median follow-up of 15 months, 81.8% were alive; 72.7%, alive without disease and 9%, alive with disease.

CONCLUSION

The dosimetric benefit of IMPT translates into NTCP reduction for grade 3 mucositis compared to Helical Tomotherapy for OPx and OC cancers and encourages the use of IMPT in their management.

Critical Appraisal of Paediatric Embryonal Cancers Treated with Image-guided Intensity-modulated Proton Therapy

AIM

To carry out a comprehensive critical appraisal of image-guided intensity-modulated proton therapy practice for craniospinal irradiation (CSI).

MATERIALS AND METHODS

An image-guided intensity-modulated proton therapy database of 45 consecutive paediatric patients with central nervous system embryonal malignancies treated between January 2019 and April 2022 were critically appraised for demography, diagnosis, treatment planning strategy and treatment delivery accuracy.

RESULTS

Most patients (median age: 7.5 years; male:female ratio: 34:11) had medulloblastoma (56%), followed by recurrent ependymoma (19%), pinealoblastoma (5%), germ cell (5%) and others (15%). The dose to the planning target volume-craniospinal (PTV-CS; length 39.06-79.59 cm) varied from 21 to 35 GyRBE, whereas the combined median dose to craniospinal and boost was 54 GyRBE. In all patients, the 95% isodose line covered the cribriform plate completely and optic nerves mostly, with a median V95% of 100% and 82.96%, keeping Dmax to the lens <3.9 GyRBE. In skeletally immature patients (88.38%), the anterior vertebral body was completely covered in 18.18% and underdosed in 70.15% of the cases, resulting in a median Dmean of 10.11 GyRBE to the oesophagus. Lateral spine coverage was maintained on the edges of the vertebral body in 52.2%, whereas it extended beyond in 48.8%. The median V98% for clinical target volumes and V95% for PTVs of the brain, spine and craniospinal were >97%, with excellent conformity (0.89) and homogeneity (0.07) indices for PTV-CS. All neurological organs at risk received a median Dmax ranging from 36 to 44 GyRBE from the combined CSI and boost regimens. Analysis of patient-specific quality assurance results revealed that 545 (97.67%) planar dosage verification had gamma (3% at 3 mm) values >95%. The online patient set-up verification showed translational and rotational deviation within 2 mm and 0.5° in 88-94% and 97% of the cases. Systematic and random error were within 0.90 mm and 1.71 mm in translation and 0.1° and 0.2° in rotation.

CONCLUSION

A change in practice pattern was observed. The findings from our comprehensive critical appraisal add to the growing library of CSI practice and may serve as a reference for inter-institutional comparison.

IMPT of head and neck cancer: unsupervised machine learning treatment planning strategy for reducing radiation dermatitis

Radiation dermatitis is a major concern in intensity modulated proton therapy (IMPT) for head and neck cancer (HNC) despite its demonstrated superiority over contemporary photon radiotherapy. In this study, dose surface histogram data extracted from forty-four patients of HNC treated with IMPT was used to predict the normal tissue complication probability (NTCP) of skin. Grades of NTCP-skin were clustered using the K-means clustering unsupervised machine learning (ML) algorithm. A new skin-sparing IMPT (IMPT-SS) planning strategy was developed with three major changes and prospectively implemented in twenty HNC patients. Across skin surfaces exposed from 10 (S10) to 70 (S70) GyRBE, the skin's NTCP demonstrated the strongest associations with S50 and S40 GyRBE (0.95 and 0.94). The increase in the NTCP of skin per unit GyRBE is 0.568 for skin exposed to 50 GyRBE as compared to 0.418 for 40 GyRBE. Three distinct clusters were formed, with 41% of patients in G1, 32% in G2, and 27% in G3. The average (± SD) generalised equivalent uniform dose for G1, G2, and G3 clusters was 26.54 ± 6.75, 38.73 ± 1.80, and 45.67 ± 2.20 GyRBE. The corresponding NTCP (%) were 4.97 ± 5.12, 48.12 ± 12.72 and 87.28 ± 7.73 respectively. In comparison to IMPT, new IMPT-SS plans significantly (P < 0.01) reduced SX GyRBE, gEUD, and associated NTCP-skin while maintaining identical dose volume indices for target and other organs at risk. The mean NTCP-skin value for IMPT-SS was 34% lower than that of IMPT. The dose to skin in patients treated prospectively for HNC was reduced by including gEUD for an acceptable radiation dermatitis determined from the local patient population using an unsupervised MLA in the spot map optimization of a new IMPT planning technique. However, the clinical finding of acute skin toxicity must also be related to the observed reduction in skin dose.

NCOG-29. INFLUENCE OF RADIATION DOSES TO HIPPOCAMPAL SUBVOLUMES ON MEMORY OUTCOMES IN PITUITARY TUMORS: DOES THE ENTIRE HIPPOCAMPUS NEED TO BE SPARED?

INTRODUCTION

In patients treated with radiation (RT), doses to hippocampus influence neurocognitive outcomes. However, the role of hippocampal subvolumes in memory functioning has not been reported, which prompted the current study.

METHODS

Adults ( &gt; 18 years) with pituitary tumors treated with fractionated RT (45 Gy/ 25 fractions/ 5 weeks) were accrued in the prospective study. Hippocampus was delineated on T1-weighted 3D-FSPGR sequences with 1mm slice thickness. The head, body, and tail of hippocampus were drawn for the current study based on the consensus of two neuroradiologists. The anatomical landmarks were: head (basilar artery to interpeduncular cistern), body (interpeduncular cistern to superior colliculus), and tail (beyond superior colliculus). Memory assessment was done pre-RT and 18 months post-RT by dedicated neuropsychologist using Weschler Memory Scale. The dose-volume parameters (maximum, mean, D10-D100) were extracted from bilateral hippocampus and subvolumes individually, which were correlated with the memory outcomes. Binary endpoints of &gt; 5% drop of memory quotient (MQ) or not at 18 months were used for analysis using an independent t-test or Mann Whitney test as appropriate.

RESULTS

Of 25 patients included in the analysis, 11 had drop of MQ &gt; 5% at 18 months. The left and right hippocampus doses of D10, D20, and D30 were significantly higher in patients with higher memory decline. For the subvolumes, only dose to bilateral head had statistically significant impact on MQ. Mean doses for patients with &gt; 5% MQ drop for left and right heads were 26 Gy and 24 Gy compared to 21 Gy and 19 Gy, respectively, for the other group.

CONCLUSION

Doses to bilateral hippocampus were shown to impact short-term memory. Of the subvolumes, only head appeared significant in memory functioning from the current pilot study, opening a window for exploring stricter dose constraints towards hippocampal head for primary or metastatic brain tumors.

Standard Operating Procedure (SOP) for mould room practices and simulation of head neck cancer patients undergoing proton therapy

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Critical role of immobilization and simulation in head neck cancer patients undergoing radiation therapy.

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Special requirements of proton HN immobilization and simulation.

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Details of immobilization materials/equipment used for HN immobilization.

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Detailed steps of all mould room procedures for HN proton patients.

Head Neck cancer patients treated with modern proton therapy need special attention during mould room procedures. In addition to usual mould room practices, patients undergoing Intensity Modulated Proton Therapy (IMPT) require attention to the special characteristics of protons viz., sensitivity to beam path and its alteration, sharp dose fall off and end of range. In this article, we discuss the Standard Operating Procedure (SOP) for HNC immobilization and simulation for IMPT, developed and practiced at our centre. The SOP details each step during the immobilization and simulation process, with nuances specific to IMPT.

Encouraging early outcomes with image guided pencil beam proton therapy for cranio-spinal irradiation: first report from India

Background

To report our experience with image guided pencil beam proton beam therapy (PBT) for craniospinal irradiation (CSI).

Materials and Methods

Between January 2019 and December 2021, we carried out a detailed audit of the first forty patients treated with PBT. We had recorded acute toxicities, reporting early outcomes and discuss limitations of current contouring guidelines during CSI PBT planning.

Results

Median age of the patient cohort was 8 years, and histologies include 20 medulloblastoma, 7 recurrent ependymoma, 3 pineoblastoma, 3 were germ cell tumors and remaining 7 constituted other diagnoses. Forty percent patients received concurrent chemotherapy. Median CSI dose was 23.4 Gy (Gray; range 21.6–35 Gy). Thirty-five patients (87.5%) completed their CSI without interruption, 5 required hospital admission. No patient had grade 2/ > weight loss during the treatment. Forty-five percent (18) developed grade 1 haematological toxicities and 20% (8) developed grade 2 or 3 toxicities; none had grade 4 toxicities. At median follow up of 12 months, 90% patients are alive of whom 88.9% are having local control. Special consideration with modification in standard contouring used at our institute helped in limiting acute toxicities in paediatric CSI patients.

Conclusion

Our preliminary experience with modern contemporary PBT using pencil beam technology and daily image guidance in a range of tumours suitable for CSI is encouraging. Patients tolerated the treatment well with acceptable acute toxicity and expected short-term survival outcome. In paediatric CSI patients, modification in standard contouring guidelines required to achieve better results with PBT.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13014-022-02085-4.

LINC-12. Encouraging early outcomes with image guided pencil beam proton therapy for cranio-spinal irradiation and unique considerations for paediatric population – First report from India

BACKGROUND: To report our experience with image guided pencil beam proton beam therapy (PBT) for craniospinal irradiation (CSI). MATERIALS AND METHODS: Between January 2019 to Dec 2021, we carried out a detailed audit of the first forty patients treated with PBT. All patients were carefully selected after approval from our institutional multidisciplinary tumour and proton board meetings. Median age of the patient cohort was 8 years, and histologies include 20 medulloblastoma, 7 recurrent ependymoma, 3 pineoblastoma, 3 were germ cell tumors and remaining 7 constituted other diagnoses. Forty percent patients received concurrent chemotherapy. We had recorded acute toxicities on a prospectively maintained database. We also report early outcomes in this cohort and discuss limitations of current contouring guidelines during CSI PBT planning. RESULTS: Median CSI dose was 23.4 GyE (Gray Equivalent; range 21.6 - 35). Thirty-five patients (87.5%) completed their CSI without interruption as an outpatient procedure. Five patients required hospital admission during treatment, while one developed grade 3 mucosal toxicity, requiring plan adaptation and treatment break. No patient had grade 2 or more weight loss during the treatment. Forty-five percent (18) developed grade 1 hematological toxicities and 20% (8) developed grade 2 or 3 toxicities; none had grade 4 toxicities. At median follow up of 12 months, 90 % patients are alive of whom 88.9 % are having local control. Special consideration with modification in standard contouring used at our institute helped in limiting acute toxicities in paediatric CSI patients. CONCLUSION: Our preliminary experience with modern contemporary PBT using pencil beam technology and daily image guidance in a range of tumours suitable for CSI is encouraging. Patients tolerated the treatment well with acceptable acute toxicity and expected short-term survival outcome. In paediatric CSI patients, modification in standard contouring guidelines required to achieve better results with PBT

Primary diffuse large B cell lymphoma of Uterine Cervix: Treatment outcomes of a rare entity with literature review

BACKGROUND

Primary lymphomas involving the female genital tract are rare, and those arising from cervix are extremely uncommon. They are often misdiagnosed because of their rarity.

METHODS AND CASES

The treatment and clinical outcomes of the four cases treated at our institution were compared with the previously published studies. Written informed consent was taken. We highlight four cases of primary diffuse large B-cell lymphoma of cervix treated at our institution with immunochemotherapy and radiotherapy. The mean age was 50 years (range, 39-62 years). Three patients had stage I disease while one had stage II disease. All the patients were in complete remission following treatment with immunochemotherapy and radiation therapy. The average disease free survival was 20 months (range, 8-43 months). None of the patients had any local or systemic relapse.

CONCLUSION

These cases highlight the physicians to be aware of this entity as their management, natural history and prognosis is completely different from squamous carcinomas of the cervix. Surgery should not be attempted in these patients. Immunochemotherapy and radiotherapy results in favorable clinical outcomes.