Pelvic Radiation and Normal Tissue Toxicity

Clinical and Genomic Characterization of Secondary Rectal Cancer After Radiotherapy for Prostate Cancer

Importance

Patients treated with radiotherapy (RT) for prostate cancer (PC) have increased risk of secondary rectal cancer (SRC) and more limited treatment options.

Objective

To assess the tumor molecular profile, clinical characteristics, and oncologic outcomes of SRC after PC and compare them with those of primary rectal cancer (PRC).

Design, Setting, and Participants

This case-control study included patients with SRC diagnosed 5 or more years after RT for PC and patients with PRC who were treated at Memorial Sloan Kettering Cancer Center in New York between February 1, 1994, and September 31, 2022.

Main Outcomes and Measures

Clinical information and DNA sequencing data were analyzed. Oncologic outcomes were compared between patients with SRC and clinically matched patients with PRC using log-rank tests and Cox proportional hazards regression models. Numerical and categorical variables were compared using the Wilcoxon rank sum test and Fisher exact test, respectively.

Results

The analysis included 604 male patients with PRC (71.6%; median age, 55 [IQR, 46-66] years) and 64 male patients with SRC (median age, 78 [IQR, 72-82] years). Patients with SRC had more distal rectum (37 of 63 [58.7%] vs 131 of 581 [22.5%]; P < .001) and anterior rectal wall (20 of 57 [35.1%] vs 67 of 496 [13.5%]; P < .001) tumors, were less likely to receive neoadjuvant treatment (33 of 64 [51.6%] vs 570 of 604 [94.4%]), and had shorter 5-year overall survival (45.7% vs 64.9%; P = .01) and disease-free survival (40.3% vs 71.2%; P = .006) compared with clinically matched patients with PRC. Targeted DNA sequencing data from 31 SRC tumors identified lower mutational burden (median, 4.4 [IQR, 3.2-6.7] per megabase [Mb] vs 5.8 [IQR, 4.4-7.0] per Mb; P = .047), lower frequency of APC alterations (15 [48.4%] vs 432 [79.9%]; P < .001), and higher rates of SMAD4 inactivation (8 [25.8%] vs 54 [10.0%]; P = .01) compared with 541 PRC tumors. Whole-exome sequencing data from 17 SRC tumors identified a higher rate of frameshift deletions compared with 28 PRC tumors (median, 5.0 [IQR, 4.0-9.0] vs 2.5 [IQR, 1.0-4.2] variants; P < .001).

Conclusions and Relevance

In this case-control study, patients with SRC after RT for PC had worse survival and different molecular profiles than patients with PRC. These findings may help improve the clinical management of SRC.

Long-Term Toxicities of Adolescent and Young Adults Who Underwent Radiation Therapy for Cervix Cancer: A Cross-Sectional Analysis

Purpose: Survivors of adolescent and young adult (AYA) cervical cancer who undergo radiation therapy are at risk of significant long-term health sequelae. We seek to evaluate long-term toxicities and their impacts on survivors. Methods: Patients treated for cervical cancer with radiation therapy between ages 18 and 39 in the years 2000-2010 in British Columbia were eligible. One hundred eligible patients were identified and mailed a package containing a questionnaire devised by a multidisciplinary team and validated patient-reported quality of life surveys for patients with cervical cancer, the European Organization for Research and Treatment of Cancer (EORTC) QLQ-30 and CX-24. Results: A total of 22 responses were received. The average time since treatment was 17.0 years (range 12-22). Fertility preservation prior to treatment was discussed with 41% of respondents and offered to 36%. A single respondent had a child after treatment through adoption. The mean EORTC Quality of Life score was rated as 63.9. Mean functional status scores include 84.4, 83.3, 67.1, 70.6, and 77 for physical, role, emotional, cognitive, and social functioning, respectively. Elevated symptom scores include sexual/vaginal functioning (53.5), sexual worry (55.6), diarrhea (38.1), body image concerns (41.7), peripheral neuropathy (39.7), and menopausal symptoms (38.1). Many patients (32%) indicated sexual and vaginal health symptoms impacting quality of life. Other common symptoms include permanent bowel changes (27%), bladder changes (27%), mood disorders (27%), and lymphedema (18%). Multiple respondents (18%) commented on regrets for not pursuing fertility preservation. Conclusions: Long-term survivors of AYA cervix cancer have significant concerns, mood disorders, premature menopausal symptoms, and fertility issues. Respondents indicated a desire for improved fertility counseling.

Predicting grade II-IV bone marrow suppression in patients with cervical cancer based on radiomics and dosiomics

Objective

The objective of this study is to develop a machine learning model integrating clinical characteristics with radiomics and dosiomics data, aiming to assess their predictive utility in anticipating grade 2 or higher BMS occurrences in cervical cancer patients undergoing radiotherapy.

Methods

A retrospective analysis was conducted on the clinical data, planning CT images, and radiotherapy planning documents of 106 cervical cancer patients who underwent radiotherapy at our hospital. The patients were randomly divided into training set and test set in an 8:2 ratio. The radiomic features and dosiomic features were extracted from the pelvic bone marrow (PBM) of planning CT images and radiotherapy planning documents, and the least absolute shrinkage and selection operator (LASSO) algorithm was employed to identify the best predictive characteristics. Subsequently, the dosiomic score (D-score) and the radiomic score (R-score) was calculated. Clinical predictors were identified through both univariate and multivariate logistic regression analysis. Predictive models were constructed by intergrating clinical predictors with DVH parameters, combining DVH parameters and R-score with clinical predictors, and amalgamating clinical predictors with both D-score and R-score. The predictive model's efficacy was assessed by plotting the receiver operating characteristic (ROC) curve and evaluating its performance through the area under the ROC curve (AUC), the calibration curve, and decision curve analysis (DCA).

Results

Seven radiomic features and eight dosiomic features exhibited a strong correlation with the occurrence of BMS. Through univariate and multivariate logistic regression analyses, age, planning target volume (PTV) size and chemotherapy were identified as clinical predictors. The AUC values for the training and test sets were 0.751 and 0.743, respectively, surpassing those of clinical DVH R-score model (AUC=0.707 and 0.679) and clinical DVH model (AUC=0.650 and 0.638). Furthermore, the analysis of both the calibration and the DCA suggested that the combined model provided superior calibration and demonstrated a higher net clinical benefit.

Conclusion

The combined model is of high diagnostic value in predicting the occurrence of BMS in patients with cervical cancer during radiotherapy.

Kidney transplantation after pelvic radiotherapy: Increased morbidity?

INTRODUCTION

The impact of pelvic irradiation on kidney transplant surgery is still unclear. The main objective of our study is to evaluate the feasibility and the safety of renal transplantation following pelvic radiotherapy.

METHODS

We collected characteristics and kidney transplant data from patients with a history of pelvic cancer treated with pelvic irradiation between 2005 and 2021. These data were collected via the prospective information system "Computerized Data Validated in Transplantation" (DIVAT) and medical records. We carried out a comparative study with a non-irradiated matched control group to compare the data of intraoperative surgeries, complications reported postoperatively as well as survival of the graft and the patient. Patients were matched on age, sex, side of graft implantation, and graft rank.

RESULTS

Twenty-four patients were collected with an average age of 65, 18 patients were treated for prostatic adenocarcinoma, 4 for gynecological cancer and 2 testicular cancers. Twenty-one patients were treated by radiotherapy, 3 by brachytherapy. Eight patients had a target dose on the iliac lymph nodes. The comparative study showed a significant difference in operative difficulty (n=15 versus n=1, P<0.01), operative duration (190min versus 149min, P=0.005), occurrence of lymphocele (P=0.041). Urinary anastomosis surgical techniques were different, 83.3% of control patients had an uretero-vesical anastomosis against 58.3% of patients with a history of irradiation (P=0.057) and about 29% of irradiated patients had an uretero-ureteral anastomosis. There was no other significant difference in per and postoperative criteria or survival.

DISCUSSION

A history of pelvic irradiation significantly increases the technical complexity of kidney transplantation without impacting safety and kidney graft survival. A history of pelvic irradiation should not be a contraindication to kidney transplant.

LEVEL OF EVIDENCE: 3

Prevention and management of radiotherapy-related toxicities in gynecological malignancies. Position paper on behalf of AIRO (Italian Association of Radiotherapy and Clinical Oncology)

Multi-modal therapies for gynecological cancers management may determine a wide range of side effects which depend on therapy-related factors and patient characteristics and comorbidities. Curative or adjuvant pelvic radiotherapy is linked with acute and late toxicity due to irradiation of organs at risk, as small and large bowel, rectum, bladder, pelvic bone, vagina and bone marrow. Successful toxicity management varies with its severity, Radiation Centre practice and experience and skills of radiation oncologists. This position paper was designed by the Italian Association of Radiation and Clinical Oncology Gynecology Study Group to provide radiation oncologists with evidence-based strategies to prevent and manage acute and late toxicities and follow-up recommendations for gynecological cancer patients submitted radiotherapy. Six workgroups of radiation oncologists with over 5 years of experience in gynecologic cancers were setup to investigate radiotherapy-related toxicities. For each topic, PubMed database was searched for relevant English language papers from January 2005 to December 2022. Titles and abstracts of results were checked to verify suitability for the document. Reference lists of selected studies and review papers were added if pertinent. Data on incidence, etiopathogenesis, prevention, treatment and follow-up of acute and late side effects for each organ at risk are presented and discussed.

Exogenous APN protects normal tissues from radiation-induced oxidative damage and fibrosis in mice and prostate cancer patients with higher levels of APN have less radiation-induced toxicities

Radiation causes damage to normal tissues that leads to increased oxidative stress, inflammation, and fibrosis, highlighting the need for the selective radioprotection of healthy tissues without hindering radiotherapy effectiveness in cancer. This study shows that adiponectin, an adipokine secreted by adipocytes, protects normal tissues from radiation damage invitro and invivo. Specifically, adiponectin (APN) reduces chronic oxidative stress and fibrosis in irradiated mice. Importantly, APN also conferred no protection from radiation to prostate cancer cells. Adipose tissue is the primary source of circulating endogenous adiponectin. However, this study shows that adipose tissue is sensitive to radiation exposure exhibiting morphological changes and persistent oxidative damage. In addition, radiation results in a significant and chronic reduction in blood APN levels from adipose tissue in mice and human prostate cancer patients exposed to pelvic irradiation. APN levels negatively correlated with bowel toxicity and overall toxicities associated with radiotherapy in prostate cancer patients. Thus, protecting, or modulating APN signaling may improve outcomes for prostate cancer patients undergoing radiotherapy.

Evolving Standards of Care in the Management of Localized Colorectal Cancer

The treatment of patients with localized rectal cancer is complex and requires input from a multidisciplinary team. Baseline local staging and mismatch repair protein testing are vital to develop individualized treatment plans. There are multiple options in terms of treatment modalities and sequencing, including transanal excision, short-course radiation, long-course chemoradiation, chemotherapy doublet or triplet, nonoperative management, and immune checkpoint blockade for patients with mismatch repair deficient tumors. While localized colon cancer is typically treated with surgical resection and consideration of adjuvant chemotherapy, emerging data suggest that neoadjuvant chemotherapy may be beneficial in patients with higher-risk disease. Quality-of-life considerations are imperative to prevent potential chronic effects on psychosocial health, neuropathy, fertility, and bowel, bladder, and sexual function. The omission of radiation or surgery can mitigate these toxicities without diminishing oncologic outcomes. The optimal treatment plan and sequence is not a one-size-fits-all approach but rather should be personalized to the patient's disease burden, tumor location, comorbidities, and preferences.

PTCOG Gastrointestinal Subcommittee Lower Gastrointestinal Tract Malignancies Consensus Statement

Purpose

Radiotherapy delivery in the definitive management of lower gastrointestinal (LGI) tract malignancies is associated with substantial risk of acute and late gastrointestinal (GI), genitourinary, dermatologic, and hematologic toxicities. Advanced radiation therapy techniques such as proton beam therapy (PBT) offer optimal dosimetric sparing of critical organs at risk, achieving a more favorable therapeutic ratio compared with photon therapy.

Materials and Methods

The international Particle Therapy Cooperative Group GI Subcommittee conducted a systematic literature review, from which consensus recommendations were developed on the application of PBT for LGI malignancies.

Results

Eleven recommendations on clinical indications for which PBT should be considered are presented with supporting literature, and each recommendation was assessed for level of evidence and strength of recommendation. Detailed technical guidelines pertaining to simulation, treatment planning and delivery, and image guidance are also provided.

Conclusion

PBT may be of significant value in select patients with LGI malignancies. Additional clinical data are needed to further elucidate the potential benefits of PBT for patients with anal cancer and rectal cancer.

Precision assessment of bowel motion quantification using 3D cine-MRI for radiotherapy

Objective. The bowel is an important organ at risk for toxicity during pelvic and abdominal radiotherapy. Identifying regions of high and low bowel motion with MRI during radiotherapy may help to understand the development of bowel toxicity, but the acquisition time of MRI is rather long. The aim of this study is to retrospectively evaluate the precision of bowel motion quantification and to estimate the minimum MRI acquisition time.Approach. We included 22 gynaecologic cancer patients receiving definitive radiotherapy with curative intent. The 10 min pre-treatment 3D cine-MRI scan consisted of 160 dynamics with an acquisition time of 3.7 s per volume. Deformable registration of consecutive images generated 159 deformation vector fields (DVFs). We defined two motion metrics, the 50th percentile vector lengths (VL50) of the complete set of DVFs was used to measure median bowel motion. The 95th percentile vector lengths (VL95) was used to quantify high motion of the bowel. The precision of these metrics was assessed by calculating their variation (interquartile range) in three different time frames, defined as subsets of 40, 80, and 120 consecutive images, corresponding to acquisition times of 2.5, 5.0, and 7.5 min, respectively.Main results. For the full 10 min scan, the minimum motion per frame of 50% of the bowel volume (M50%) ranged from 0.6-3.5 mm for the VL50 motion metric and 2.3-9.0 mm for the VL95 motion metric, across all patients. At 7.5 min scan time, the variation in M50% was less than 0.5 mm in 100% (VL50) and 95% (VL95) of the subsets. A scan time of 5.0 and 2.5 min achieved a variation within 0.5 mm in 95.2%/81% and 85.7%/57.1% of the subsets, respectively.Significance. Our 3D cine-MRI technique quantifies bowel loop motion with 95%-100% confidence with a precision of 0.5 mm variation or less, using a 7.5 min scan time.

Patient reported long-term side effects on bowel function and anal pain in anal cancer survivors - 3- and 6-year results from the Swedish national ANCA study

AIM

The primary therapeutic option for anal cancer treatment is chemoradiotherapy resulting in 80% survival. The aim of this study was to assess long-term bowel function impairment and anal pain at 3 and 6 years after anal cancer diagnosis, based on a hypothesis of an increase in impairment over time. A secondary aim was to investigate if chemoradiotherapy increased the risk for bowel impairment, compared to radiotherapy alone.

METHOD

The ANal CAncer study (ANCA) consists of a national Swedish cohort of patients diagnosed with anal cancer between 2011-2013. Patients within the study were invited to respond to a study-specific questionnaire at 3- and 6-years after diagnosis. Descriptive analyses for the primary endpoint and ordinal logistic regressions for secondary endpoint were performed.

RESULTS

A total of 388 patients (84%) were included in the study. At 3 years of follow-up, 264 patients were alive. A total of 195 of these patients (74%) answered a study specific questionnaire, and at 6 years 154 patients (67%). Fifty-seven percent experienced bowel urgency at both 3 and 6 years. There was an increased risk for repeated bowel movement within 1 h (OR 2.44 [95% CI: 1.08-5.61, p = 0.03]) at 3 years in patients who had been treated by chemoradiation compared to radiotherapy alone.

CONCLUSIONS

Impairment in bowel function and anal pain after anal cancer treatment should be expected and remains after 6 years. This suggests that long-term follow-up may be necessary in some form after customary follow-up. The addition of chemotherapy increases long-term side effects of bowel function.

Human Intestinal Organoids and Microphysiological Systems for Modeling Radiotoxicity and Assessing Radioprotective Agents

Radiotherapy is a commonly employed treatment for colorectal cancer, yet its radiotoxicity-related impact on healthy tissues raises significant health concerns. This highlights the need to use radioprotective agents to mitigate these side effects. This review presents the current landscape of human translational radiobiology, outlining the limitations of existing models and proposing engineering solutions. We delve into radiotherapy principles, encompassing mechanisms of radiation-induced cell death and its influence on normal and cancerous colorectal cells. Furthermore, we explore the engineering aspects of microphysiological systems to represent radiotherapy-induced gastrointestinal toxicity and how to include the gut microbiota to study its role in treatment failure and success. This review ultimately highlights the main challenges and future pathways in translational research for pelvic radiotherapy-induced toxicity. This is achieved by developing a humanized in vitro model that mimics radiotherapy treatment conditions. An in vitro model should provide in-depth analyses of host-gut microbiota interactions and a deeper understanding of the underlying biological mechanisms of radioprotective food supplements. Additionally, it would be of great value if these models could produce high-throughput data using patient-derived samples to address the lack of human representability to complete clinical trials and improve patients' quality of life.

Engineered organoids for biomedical applications

As miniaturized and simplified stem cell-derived 3D organ-like structures, organoids are rapidly emerging as powerful tools for biomedical applications. With their potential for personalized therapeutic interventions and high-throughput drug screening, organoids have gained significant attention recently. In this review, we discuss the latest developments in engineering organoids and using materials engineering, biochemical modifications, and advanced manufacturing technologies to improve organoid culture and replicate vital anatomical structures and functions of human tissues. We then explore the diverse biomedical applications of organoids, including drug development and disease modeling, and highlight the tools and analytical techniques used to investigate organoids and their microenvironments. We also examine the latest clinical trials and patents related to organoids that show promise for future clinical translation. Finally, we discuss the challenges and future perspectives of using organoids to advance biomedical research and potentially transform personalized medicine.

Enabling ultra-high dose rate electron beams at a clinical linear accelerator for isocentric treatments

BACKGROUND AND PURPOSE

Radiotherapy delivery with ultra-high dose rates (UHDR) has consistently produced normal tissue sparing while maintaining efficacy for tumour control in preclinical studies, known as the FLASH effect. Modified clinical electron linacs have been used for pre-clinical studies at reduced source-surface distance (SSD) and novel intra-operative devices are becoming available. In this context, we modified a clinical linac to deliver 16 MeV UHDR electron beams with an isocentric setup.

MATERIALS AND METHODS

The first Varian TrueBeam (SN 1001) was clinically operative between 2009-2022, it was then decommissioned and converted into a research platform. The 18 MeV electron beam was converted into the experimental 16 MeV UHDR. Modifications were performed by Varian and included a software patch, thinner scattering foil and beam tuning. The dose rate, beam characteristics and reproducibility were measured with electron applicators at SSD = 100 cm.

RESULTS

The dose per pulse at isocenter was up to 1.28 Gy/pulse, corresponding to average and instantaneous dose rates up to 256 Gy/s and 3⋅105 Gy/s, respectively. Beam characteristics were equivalent between 16 MeV UHDR and conventional for field sizes up to 10x10cm2 and an overall beam reproducibility within ± 2.5% was measured.

CONCLUSIONS

We report on the first technical conversion of a Varian TrueBeam to produce 16 MeV UHDR electron beams. This research platform will allow isocenter experiments and deliveries with conventional setups up to field sizes of 10x10 cm2 within a hospital environment, reducing the gap between preclinical and clinical electron FLASH investigations.

Marasmius androsaceus mitigates depression-exacerbated intestinal radiation injuries through reprogramming hippocampal miRNA expression

INTRODUCTION

Cancer patients commonly experience high levels of psychological stress, which poses significant risks to their well-being. Radiotherapy is a primary treatment modality for cancer; however, it often leads to intestinal injuries in these patients. Nevertheless, the impact of mental stress on radiotherapy-intertwined complications remains unclear.

METHODS

To induce intestinal injury, we employed total abdominal irradiation in our experimental model. We conducted high-throughput sequencing to analyze the expression profile of miRNAs in the hippocampus.

RESULTS

We observed that mice with depression exhibited more severe intestinal injuries following total abdominal irradiation. Remarkably, oral administration of Marasmius androsaceus not only alleviated the depressive phenotype but also mitigated radiation-induced intestinal toxicity. Notably, this radioprotective effect was not observed in mice without depression. Depression disrupted the hippocampal miRNA expression profile in mice subjected to local irradiation of the abdomen, leading to the accumulation of miR-139-5p and miR-184-3p in the hippocampus, serum, and small intestine tissues. However, treatment with Marasmius androsaceus reprogrammed the miRNA expression signature in mice with depression. Furthermore, intravenous injection of antagomirs targeting miR-139-5p and miR-184-3p ameliorated depression, up-regulated Spn expression, reduced radiation enteritis, and improved the integrity of the small intestine in irradiated mice.

CONCLUSION

Our findings demonstrate the efficacy of Marasmius androsaceus, a small mushroom, in alleviating depression-aggravated intestinal toxicity following radiotherapy by reprogramming hippocampal miRNA expression.

Preoperative Radiotherapy Decision-Tree for Rectal Cancer Patients: A Real-World Analysis Based on the Swedish Colorectal Cancer Registry

BACKGROUND

There are 3 widely used preoperative radiotherapy (RT) procedures in rectal cancer treatment including long-course RT (LRT), short-course RT with delayed surgery (SRTW), and short-course RT with immediate surgery (SRT). However, further evidence is required to determine which treatment option results in more optimal patient survival.

METHODS

This Swedish Colorectal Cancer Registry-based retrospective study of real-world data included 7766 stage I-III rectal cancer patients, of which 2982, 1089, 763, and 2932 patients received no RT (NRT), LRT, SRTW, and SRT, respectively. The Kaplan-Meier survival curve and Cox proportional hazard multivariate model were used to identify potential risk factors and to examine the independent association of RT with patient survival after adjusting for baseline confounding factors.

RESULTS

RT effects on survival differed by age and clinical T stage (cT) subgroups. Subsequent survival analysis by age and cT subgroups confirmed that patients ≥70 years old with cT4 benefited from any RT (P < .001, NRT as reference) and equally from any RT (P > .05 pairwise between RTs). In contrast, for cT3 patients ≥70 years, SRT and LRT were associated with better survival than SRTW (P < .001). In patients <70 years, LRT and SRTW had superior survival benefits in cT4 patients but inferior to SRT (P < .001); SRT was the only effective treatment in the cT3N+ subgroup (P = .032); patients with cT3N0 and <70 years did not benefit from any RT.

CONCLUSION

This study suggests that preoperative RT strategies may have varying effects on the survival of rectal cancer patients, depending on their age and clinical stage.

Twenty Years of Advancements in a Radiotherapy Facility: Clinical Protocols, Technology, and Management

BACKGROUND

Hypo-fractionation can be an effective strategy to lower costs and save time, increasing patient access to advanced radiation therapy. To demonstrate this potential in practice within the context of temporal evolution, a twenty-year analysis of a representative radiation therapy facility from 2003 to 2022 was conducted. This analysis utilized comprehensive data to quantitatively evaluate the connections between advanced clinical protocols and technological improvements. The findings provide valuable insights to the management team, helping them ensure the delivery of high-quality treatments in a sustainable manner.

METHODS

Several parameters related to treatment technique, patient positioning, dose prescription, fractionation, equipment technology content, machine workload and throughput, therapy times and patients access counts were extracted from departmental database and analyzed on a yearly basis by means of linear regression.

RESULTS

Patients increased by 121 ± 6 new per year (NPY). Since 2010, the incidence of hypo-fractionation protocols grew thanks to increasing Linac technology. In seven years, both the average number of fractions and daily machine workload decreased by -0.84 ± 0.12 fractions/year and -1.61 ± 0.35 patients/year, respectively. The implementation of advanced dose delivery techniques, image guidance and high dose rate beams for high fraction doses, currently systematically used, has increased the complexity and reduced daily treatment throughput since 2010 from 40 to 32 patients per 8 h work shift (WS8). Thanks to hypo-fractionation, such an efficiency drop did not affect NPY, estimating 693 ± 28 NPY/WS8, regardless of the evaluation time. Each newly installed machine was shown to add 540 NPY, while absorbing 0.78 ± 0.04 WS8. The COVID-19 pandemic brought an overall reduction of 3.7% of patients and a reduction of 0.8 fractions/patient, to mitigate patient crowding in the department.

CONCLUSIONS

The evolution of therapy protocols towards hypo-fractionation was supported by the use of proper technology. The characteristics of this process were quantified considering time progression and organizational aspects. This strategy optimized resources while enabling broader access to advanced radiation therapy. To truly value the benefit of hypo-fractionation, a reimbursement policy should focus on the patient rather than individual treatment fractionation.

Comparison of Gonadal Toxicity of Single-Fraction Ultra-High Dose Rate and Conventional Radiation in Mice

Purpose

Increasing evidence suggests that ultra-high-dose-rate (UHDR) radiation could result in similar tumor control as conventional (CONV) radiation therapy (RT) while reducing toxicity to surrounding healthy tissues. Considering that radiation toxicity to gonadal tissues can cause hormone disturbances and infertility in young patients with cancer, the purpose of this study was to assess the possible role of UHDR-RT in reducing toxicity to healthy gonads in mice compared with CONV-RT.

Methods and Materials

Radiation was delivered to the abdomen or pelvis of female (8 or 16 Gy) and male (5 Gy) C57BL/6J mice, respectively, at conventional (∼0.4 Gy/s) or ultrahigh (>100 Gy/s) dose rates using an IntraOp Mobetron linear accelerator. Organ weights along with histopathology and immunostaining of irradiated gonads were used to compare toxicity between radiation modalities.

Results

CONV-RT and UHDR-RT induced a similar decrease in uterine weights at both studied doses (∼50% of controls), which indicated similarly reduced ovarian follicular activity. Histologically, ovaries of CONV- and UHDR-irradiated mice exhibited a comparable lack of follicles. Weights of CONV- and UHDR-irradiated testes were reduced to ∼30% of controls, and the percentage of degenerate seminiferous tubules was also similar between radiation modalities (∼80% above controls). Pairwise comparisons of all quantitative data indicated statistical significance between irradiated (CONV or UHDR) and control groups (from P ≤ .01 to P ≤ .0001) but not between radiation modalities.

Conclusions

The data presented here suggest that the short-term effects of UHDR-RT on the mouse gonads are comparable to those of CONV-RT.

Pulsed-beam transmission electron microscopy and radiation damage

We review the use of pulsed electron-beams in transmission electron microscopes (TEMs) for the purpose of mitigating specimen damage. We begin by placing the importance of TEMs with respect to materials characterization into proper context, and we provide a brief overview of established methods for reducing or eliminating the deleterious effects of beam-induced damage. We then introduce the concept of pulsed-beam TEM, and we briefly describe the basic methods and instrument configurations used to create so-called temporally structured electron beams. Following a brief overview of the use of high-dose-rate pulsed-electron beams in cancer radiation therapy, we review historical speculations and more recent compelling but mostly anecdotal findings of a pulsed-beam TEM damage effect. This is followed by an in-depth technical review of recent works seeking to establish cause-and-effect relationships, to conclusively uncover the presence of an effect, and to explore the practicality of the approach. These studies, in particular, provide the most compelling evidence to date that using a pulsed electron beam in the TEM is indeed a viable way to mitigate damage. Throughout, we point out current gaps in understanding, and we conclude with a brief perspective of current needs and future directions.

Dosimetric and feasibility evaluation of a CBCT-based daily adaptive radiotherapy protocol for locally advanced cervical cancer

PURPOSE

Evaluate a cone-beam computed tomography (CBCT)-based daily adaptive platform in cervical cancer for multiple endpoints: (1) physics contouring accuracy of daily CTVs, (2) CTV coverage with adapted plans and reduced PTV margins versus non-adapted plans with standard-of-care (SOC) margins, (3) dosimetric improvements to CTV and organs-at-risk (OARs), and (4) on-couch time.

METHODS AND MATERIALS

Using a Varian Ethos™ emulator and KV-CBCT scans, we simulated the doses 15 retrospective cervical cancer patients would have received with/without online adaptation for five fractions. We compared contours and doses from SOC plans (5-15 mm CTV-to-PTV margins) to adapted plans (3 mm margins). Auto-segmented CTVs and OARs were reviewed and edited by trained physicists. Physics-edited targets were evaluated by an oncologist. Time spent reviewing and editing auto-segmented structures was recorded. Metrics from the CTV (D99%), bowel (V45Gy, V40Gy), bladder (D50%), and rectum (D50%) were compared.

RESULTS

The physician approved the physics-edited CTVs for 55/75 fractions; 16/75 required reductions, and 4/75 required CTV expansions. CTVs were encapsulated by unadapted, SOC PTVs for 56/75 (72%) fractions-representative of current clinical practice. CTVs were completely covered by adapted 3 mm PTVs for 71/75 (94.6%) fractions. CTV D99% values for adapted plans were comparable to non-adapted SOC plans (average difference of -0.9%), while all OAR metrics improved with adaptation. Specifically, bowel V45Gy and V40Gy decreased on average by 87.6 and 109.4 cc, while bladder and rectum D50% decreased by 37.7% and 35.8%, respectively. The time required for contouring and calculating an adaptive plan for 65/75 fractions was less than 20 min (range: 1-29 min).

CONCLUSIONS

Improved dose metrics with daily adaption could translate to reduced toxicity while maintaining tumor control. Training physicists to perform contouring edits could minimize the time physicians are required at adaptive sessions improving clinical efficiency. All emulated adaptive sessions were completed within 30 min however extra time will be required for patient setup, image acquisition, and treatment delivery.

Effect of skeletal muscle loss during neoadjuvant imatinib therapy on clinical outcomes in patients with locally advanced GIST

BACKGROUND

Currently, the effect of skeletal muscle loss during neoadjuvant imatinib therapy on clinical outcomes in patients with locally advanced gastrointestinal stromal tumors (LA-GIST) remains unclear. This study aims to investigate the relationship between changes in skeletal muscle and postoperative complications, survival and tumor response in patients with LA-GIST during neoadjuvant therapy with imatinib.

METHODS

We retrospectively analyzed pre- and post-treatment computed tomography images of 57 GIST patients who underwent radical surgery after neoadjuvant therapy with imatinib from January 2013 to March 2019. Skeletal muscle index (SMI) was measured at the L3 vertebral level in all patients. A cut-off value (SMI < 52.3 cm²/m² and < 38.6 cm²/m² for men and women, respectively) published in a previous study was used to define sarcopenia. Based on gender, we defined ΔSMI (%)/250 days above 9.69% for men and ΔSMI (%)/250 days above 7.63% for women as significant muscle loss (SML). Factors associated with postoperative complications and tumor response were analyzed using logistic regression, and predictors affecting patient prognosis were analyzed using Cox regression.

RESULTS

Of the 57 patients, sarcopenia was present before and after neoadjuvant therapy in 20 (35.09%) and 28 (49.12%) patients, respectively. It was not associated with immediate or long-term clinical outcomes. However, patients with SML during neoadjuvant therapy had a higher incidence of postoperative complications (60.00% vs. 25.00%, p = 0.008), worse pathological regression (44.00% vs. 75.00%, p = 0.017) and worse 3-year survival (Male, 68.75% vs. 95.45%, p = 0.027; Female, 66.67% vs. 100.00%, p = 0.046) than patients without SML.

CONCLUSION

The development of SML during neoadjuvant therapy in LA-GIST patients, rather than pre- and post-treatment sarcopenia, is a major prognostic factor for the long-term prognosis and is also associated with recent postoperative complication rates and pathological regression.

Hypoxic Cell-Derived Extracellular Vesicles Aggravate Rectal Injury Following Radiotherapy via MiR-122-5p

Radiation-induced rectal injury is a common side effect of radiotherapy. Hypoxia often occurs after radiotherapy. This study aimed to explore the bystander effect of hypoxia on radiation-induced rectal injury. In vivo, apoptosis increased nearby the highly hypoxic area in the rectal tissues in the mouse models of radiation-induced rectal injury, indicating the potential involvement of hypoxia. In vitro, flow cytometry and Western blotting showed that both hypoxia and hypoxic human intestinal epithelial crypt (HIEC) cell supernatant promoted apoptosis in normoxic HIEC cells. The pro-apoptotic effect of extracellular vesicles (EVs) derived from hypoxic HIEC cell to normoxic HIEC cells was then determined. MiR-122-5p was chosen for further studies through a microRNA (miRNA) microarray assay and apoptosis was alleviated in cells receiving miR-122-5p inhibiting hypoxic EVs. Together, our study demonstrated that the miR-122-5p containing-EVs derived from hypoxic HIEC cells promoted apoptosis in normoxic HIEC cells. Hypoxic EV-derived miR-122-5p plays a critical pathologic role in radiation-induced rectal injury and may be a potential therapeutic target.

Concurrent Chemoradiotherapy With Nedaplatin Versus Cisplatin in Patients With Stage IIB-IVA Cervical Cancer: A Randomized Phase III Trial

Background

In this trial, we aimed to assess the efficacy and safety of radiotherapy with nedaplatin or cisplatin in patients with locally advanced cervical cancer.

Methods

We conducted an open-label, non-inferiority, phase III, randomized, controlled trial. Eligible patients with stage IIB-IVA cervical carcinoma were randomly assigned to receive either nedaplatin or cisplatin for two cycles concurrently with radiotherapy. We reported the therapy-associated harms and survival. The study was registered with chictr.org.cn, number ChiCTR1800020527.

Results

We randomly assigned 68 patients to nedaplatin-based or cisplatin-based concurrent chemoradiotherapy. Study treatment was stopped early after a data analysis found a higher number of patients suffered severe hematologic harms in the nedaplatin group than in the cisplatin group. Patients in the nedaplatin group had a significantly higher frequency of grade 3-4 neutropenia (19·4% vs. 13%; P < 0·001), severe thrombocytopenia (16·1% vs. 4·3%), and grade 1-2 anemia (51·6% vs. 43·5%) than patients in the cisplatin group. The 1-year PFS and OS in the nedaplatin and cisplatin groups were similar.

Conclusion

Our findings showed that nedaplatin-based concurrent chemoradiotherapy expressed remarkably higher severe hematologic harms which were mortal. Though the results were negative, the experiences and lessons we learned from it were important.

Online adaptive radiotherapy potentially reduces toxicity for high-risk prostate cancer treatment

BACKGROUND AND PURPOSE

With daily, MR-guided online adapted radiotherapy (MRgART) it may be possible to reduce the PTV in pelvic RT. This study investigated the potential reduction in normal tissue complication probability (NTCP) of MRgART compared to standard radiotherapy for high-risk prostate cancer.

MATERIALS AND METHODS

Twenty patients treated with 78 Gy to the prostate and 56 Gy to elective pelvic lymph nodes were included. VMAT plans were generated with standard clinical PTV margins. Additionally to the planning MR, patients had three MRI scans during treatment to simulate an MRgART. A reference plan with PTV margins determined for MRgART was created per patient and adapted to each of the following MRs. Adapted plans were warped to the planning MR for dose accumulation. The standard plan was rigidly registered to each adaptation MR before it was warped to the planning MR for dose accumulation. Dosimetric impact was compared by DVH analysis and potential clinical effects were assessed by NTCP modeling.

RESULTS

MRgART yielded statistically significant lower doses for the bladder wall, rectum and peritoneal cavity, compared to the standard RT, which translated into reduced median risks of urine incontinence (ΔNTCP 2.8%), urine voiding pain (ΔNTCP 2.8%) and acute gastrointestinal toxicity (ΔNTCP 17.4%). Mean population accumulated doses were as good or better for all investigated OAR when planned for MRgART as standard RT.

CONCLUSION

Online adapted radiotherapy may reduce the dose to organs at risk in high-risk prostate cancer patients, due to reduced PTV margins. This potentially translates to significant reductions in the risks of acute and late adverse effects.

Effects of Sargassum virgatum extracts on the testicular measurements, genomic DNA and antioxidant enzymes in irradiated rats

BACKGROUND

Oxidative stress and reactive oxygen species (ROS) are primarily responsible for the development of male infertility after exposure to γ-irradiation. The present work aimed to assess the ameliorative and therapeutic roles of the aqueous and ethanolic extracts of the edible seaweed Sargassum virgatum (S. virgatum) on spermatogenesis and infertility in γ-irradiated Wistar rats.

MATERIALS AND METHODS

Induction of infertility was performed by exposing the rats to 137Cs-gamma rays, using a single dose of 3.5 Gy. γ-irradiated rats were given the S. virgatum ethanolic (S. virgatum-EtOH) and aqueous extracts intraperitoneally on a daily base for two consecutive weeks at doses of 100 and 400 mg/kg body weight (b.wt.) for each seaweed extract. Morphometric data of the testes, semen quality indices, antioxidant enzymes superoxide dismutase (SOD), catalase (CAT), glutathione (GSH), and glutathione peroxidase (GPx), and deoxyribonucleic acid (DNA) fragmentation were assessed. The results obtained were taken during two-time intervals of 15 and 60 days from the commencement of the algal treatments. In vitro antioxidant assays and polyphenolic compounds of S. virgatum were characterized.

RESULTS

Significant negative changes in the semen quality and morphometric data of the testes, as well as remarkable DNA fragmentation, were detected in the irradiated rats compared to the control. The levels of the endogenous antioxidant enzymes (SOD, CAT, GSH, and GPx) were also significantly diminished. Nonetheless, treatments of γ-irradiated rats with the S. virgatum-EtOH and aqueous extracts significantly improved the above-mentioned enzymes, in addition to noteworthy amendments in the dimensions of the testes, the semen quality, as well as the DNA structure.

CONCLUSIONS

The ameliorative potency of S. virgatum to cure γ-irradiation-induced male infertility, particularly 400 mg/kg ethanolic extract for 60 days, is the result of the consistent therapeutic interventions of its potent antioxidant and anti-apoptotic polyphenols, particularly protocatechuic, p-hydroxybenzoic, rosmarinic, chlorogenic, cinnamic and gentisic acids, as well as the flavonoids catechin, hesperidin, rutin and quercetin. Besides its high-value nutraceutical importance, S. virgatum could be a natural candidate for developing well-accepted radioprotectant products capable of treating γ-irradiation-induced male infertility.

Development of patient-reported outcomes item set to evaluate acute treatment toxicity to pelvic online magnetic resonance-guided radiotherapy

BACKGROUND

A new technology in cancer treatment, the MR-linac, provides online magnetic resonance-guided radiotherapy (MRgRT) that combines real-time visualization of the tumor and surrounding tissue with radiation therapy to deliver treatment more accurately. Online MRgRT makes it possible to minimize treatment volume, potentially reducing acute treatment toxicity. Patient-reported outcomes (PRO) add the patient perspective to evaluating treatment toxicity related to new technology. The objective of this mixed-methods study was to develop and explore the content validity of a set of PRO items to evaluate acute pelvic toxicity to radiotherapy including online MRgRT.

METHODS

A literature review and chart audit were conducted to identify symptomatic adverse events (AEs) to be selected from the Patient-Reported Outcomes Version of the Common Terminology Criteria for Adverse Events (PRO-CTCAE) library and European Organisation for Research and Treatment of Cancer (EORTC) item library. To validate the content, the item set was applied in a prospective pilot cohort of patients referred for primary pelvic RT with curative intent. Patients reported symptoms weekly during RT (4-8 weeks) and the subsequent 4 weeks. Follow-up reports were collected at 8, 12, and 24 weeks after RT. To ensure symptom coverage clinician-reported toxicity and individual patient interviews were conducted. The symptomatic AEs were included in the final item set if ≥20% of patients reported them.

RESULTS

Eighteen acute symptomatic AEs were selected for the initial item set. Forty patients (32 prostate cancer, 8 cervical cancer) were included in the pilot study. Patients with prostate cancer and those with cervical cancer both reported all 18 acute AEs. However, vomiting was not reported by > 20% of patients thus excluded from the item set. Adding a few diagnosis-specific AEs to the final item set was required for both prostate and cervical cancer patients.

CONCLUSIONS

A PRO item set for patients with pelvic cancer treated with radiotherapy with a curative intent was developed and content validity explored. In the pilot study, the item set captured the most common acute symptomatic AEs for patients with prostate and cervical cancer related to pelvic RT including online MRgRT. Further validation of the content in broader disease sites would be needed in future studies.

Neoadjuvant radiation above NCCN guidelines for rectal cancer is associated with age under 50 and early clinical stage

INTRODUCTION

Recent data suggest patients with early-onset rectal cancer (EORC) receive neoadjuvant radiation above recommended doses without oncologic benefit. The use of excessive radiation may lead to worse outcomes and patient harm. We sought to evaluate predictors of aggressive neoadjuvant radiation (A-XRT) use in EORC patients and compare this to late-onset rectal cancer (LORC) patients.

METHODS

The National Cancer Database from 2004 to 2014 was queried for rectal adenocarcinoma patients undergoing surgical resection. Patients with stage 0 or IV disease, positive margins, and incomplete data were excluded. Standard neoadjuvant radiation (S-XRT) was based upon NCCN guidelines: 25-50.4 Gray for stage II/III patients and none for stage I. Excess radiation was considered A-XRT. Patients diagnosed at age < 50 years were labeled EORC; those ≥ 50 years were LORC. Categorical data were analyzed with chi-square test. Logistic regression was used to analyze clinicodemographic associations with A-XRT.

RESULTS

45,403 patients were included: 7999 (17.6%) EORC and 37,404 (82.4%) LORC. Multivariable logistic regression demonstrated that A-XRT use among stage I patient was associated with male gender, age under 50, urban location, mucinous histology, and poor tumor differentiation. Among stage II and III patients, A-XRT use was associated with male gender, age under 50, higher education and income, and urban location. Cox hazards did not demonstrate a significant association of A-XRT use with survival.

CONCLUSION

Our data reaffirm that EORC patients more frequently receive A-XRT and that use is based on demographic features independent of tumor characteristics. Reasons for A-XRT, particularly in EORC patients, should be clarified to promote adherence to guidelines and minimize patient harm.

Functional recovery by colon organoid transplantation in a mouse model of radiation proctitis

Radiation proctitis is the collateral damage that occurs to healthy cells during radiation treatment of pelvic malignancies. Conservative treatment of radiation proctitis can mitigate inflammatory symptoms, but, to date, no therapeutic options are available for direct recovery of the damaged colonic epithelium. The present study assessed the ability of colon organoid-based regeneration to treat radiation proctitis. Radiation proctitis was induced in mice by irradiating their recta, followed by enema-based transplantation of mouse colon organoids. The transplanted colon organoids were found to successfully engraft onto the damaged rectal mucosa of the irradiated mice, reconstituting epithelial structure and integrity. Lgr5⁺ stem cells were shown to be pivotal to colon organoid mediated regeneration. Endoscopic examination showed the efficacy of localized transplantation of colon organoids with fibrin glue to irradiated sites. These findings provide useful insights into the use of colon organoid-based regenerative therapy for the treatment of radiation proctitis.

Management of Lower Urinary Tract Symptoms after Prostate Radiation

PURPOSE OF REVIEW

To present urologists with guidance on how to approach and manage lower urinary tract symptoms (LUTS) in patients who have undergone radiation therapy (RT) for prostate cancer.

RECENT FINDINGS

There are few studies that specifically examine treatment approaches for LUTS in patients who have undergone prostate cancer RT. LUTS after prostate RT are unique when compared to de novo LUTS. Understanding these distinctions is important for urologists' practice as well as patients' quality of life. Discussion of the risks and management of post-RT LUTS should be included in the shared decision-making process when counseling patients on various treatment options for prostate cancer. Further studies evaluating treatments for storage and voiding symptoms after RT are needed to help guide future care.

The Incorporation of Immunotherapy and Targeted Therapy Into Chemoradiation for Cervical Cancer: A Focused Review

In 2011 the Food and Drug Administration (FDA) approved anti-vascular endothelial growth factor (VEGF) therapy, bevacizumab, for intractable melanoma. Within the year, immunotherapy modulators inhibiting cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) and programmed cell death protein 1 (PD-1) were approved in addition to programmed death-ligand 1 (PD-L1) antibodies in 2012. Since then, research showing the effectiveness of targeted therapies in a wide range of solid tumors has prompted studies incorporating their inclusion as part of upfront management as well as refractory or relapsed disease. For treatment of cervical cancer, which arises from known virus-driven oncogenic pathways, the incorporation of targeted therapy is a particularly attractive prospect. The current standard of care for locally advanced cervical cancer includes concurrent platinum-based chemotherapy with radiation therapy (CRT) including external beam radiation therapy (EBRT) and brachytherapy. Building upon encouraging results from trials testing bevacizumab or immunotherapy in recurrent cervical cancer, these agents have begun to be incorporated into upfront CRT strategies for prospective study. This article will review background data establishing efficacy of angiogenesis inhibitors and immunotherapy in the treatment of cervical cancer as well as results of prospective studies combining targeted therapies with standard CRT with the aim of improving outcomes. In addition, the role of immunotherapy and radiation on the tumor microenvironment (TME) will be discussed.

The Effect of Prostate Cancer Radiotherapy on Testosterone Level: A Systematic Review and Meta-analysis

INTRODUCTION

In the current study, a systematic search and meta-analysis were performed to evaluate the effect of prostate cancer radiotherapy on testosterone levels of patients.

METHODS

To illuminate the effect of radiotherapy on the testosterone level of prostate cancer patients, a systematic search was conducted in accordance with the PRISMA guideline in electronic databases of Scopus, Embase, PubMed, Web of Science, and clinical trials up to December 2018 using relevant keywords. Based on a certain set of inclusion and exclusion criteria, 12 eligible studies that had data on the testosterone level following prostate cancer radiotherapy were included in the meta-analysis.

RESULTS

According to the various techniques of prostate cancer radiotherapy, the dose values scattered to the testicular tissues ranged from 0.31 to 10 Gy. Combining the findings from 12 studies, it was found that prostate cancer radiotherapy leads to a significant reduction in the testosterone level (Weighted Mean Difference [WMD]: -51.38 ng/dL, 95% CI: -75.86, -26.90, I2=0.0%, P<0.05). Furthermore, subgroup analysis by the patient number showed a significant reduction in the testosterone level at patient number < 50 (WMD: -80.32 ng/dL, 95% CI: -125.10, -35.55, I2= 0.0%) and 50 < patient number < 100 (WMD: -46.99 ng/dL, 95% CI: - 87.15, -6.82, I2= 0.0%). Subgroup analysis based on treatment technique type revealed a significant reduction in testosterone level after conventional radiotherapy (WMD: -56.67, 95% CI: -100.45,-12.88, I2= 34.3%) and IMRT/SBRT technique (WMD: -57.42, 95% CI: -99.39, -15.46, I2= 0.0%) in comparison with the proton therapy (WMD: 0.00, 95% CI: -80.24, 80.24).

CONCLUSION

The findings showed a significant decrease in the testosterone level of prostate cancer patients after radiotherapy compared with pre-treatment levels.

Association of bowel radiation dose-volume with skeletal muscle loss during pelvic intensity-modulated radiotherapy in cervical cancer

BACKGROUND

Radiation-induced bowel damage may compromise nutrient absorption and digestion and affect body composition during pelvic radiotherapy in patients with locally advanced cervical cancer (LACC). This study aimed to evaluate the relationship between bowel radiation dose-volume and body composition changes during pelvic radiotherapy.

METHODS

Data of 301 LACC patients treated with chemoradiotherapy were analyzed. Changes in skeletal muscle index (SMI) and density (SMD), and total adipose tissue index (TATI) were measured from computed tomography images at the L3 vertebral level. A reduction in SMI, SMD, or TATI of ≥10% was classified as "loss." Bowel V45 indicates the bowel volume (mL) receiving a radiation dose of ≥45 Gy. The relationship between body composition and bowel V45 was analyzed using logistic regression models.

RESULTS

After treatment, 61 (20.3%), 81 (26.9%), and 97 (32.2%) patients experienced SMI, SMD, and TATI loss, respectively. Increased bowel V45 was independently associated with increased odds of SMI loss (odds ratio [OR]: 1.012; 95% confidence interval [CI]: 1.007-1.018; p<0.001) and TATI loss (OR: 1.006; 95% CI: 1.001-1.010; p=0.01), but not with SMD loss (OR: 1.005; 95% CI: 1.000-1.009; p=0.054). The cut-off value with the highest accuracy for predicting SMI loss was V45 ≥222 mL; a higher rate of SMI loss was noted in 40.0% of patients with V45 ≥222 mL than in 13.7% of patients with V45 <222 mL (p<0.001).

CONCLUSIONS

Higher bowel dose-volume was significantly associated with muscle loss during pelvic radiotherapy. Bowel dose-volume consideration is required in individualized nutritional counseling and supportive care in clinical practice.

Strategies to Minimize Late Effects From Pelvic Radiotherapy

During the past 30 years, radiation treatment techniques have significantly improved, from conventional external-beam radiation therapy, to three-dimensional conformal radiation therapy, to current intensity-modulated radiation therapy, benefiting patients who undergo treatment of pelvic malignancies. Modern treatment options also include proton beam irradiation as well as low and high dose rate brachytherapy. Although the acute adverse effects of these modalities are well documented in clinical trials, less well known are the true incidence and optimal management of those late adverse effects that can occur months to years later. In a population of survivors of cancer that is steadily increasing, with many such patients receiving radiotherapy at some time during their disease course, these late effects can become a considerable management and quality-of-life issue. This review will examine the range of late toxicities that can occur from pelvic radiotherapy and explore strategies to prevent and mitigate them.

Radiotherapy-Specific Chronic Pain Syndromes in the Cancer Population: An Evidence-Based Narrative Review

While radiation therapy is increasingly utilized in the treatment paradigm of many solid cancers, the chronic effects of radiation therapies are poorly characterized. Notably, understanding radiation-specific chronic pain syndromes is paramount given that the diagnosis and management of these conditions can serve to prevent long-standing functional impairments, optimize quality of life, and even allow for continued radiotherapy candidacy. These radiation-specific chronic pain phenomena include dermatitis, mucositis, enteritis, connective tissue fibrosis, lymphedema, and neuropathic pain syndromes. It is necessary to maintain a low threshold of suspicion for appropriately diagnosing these conditions as there exists a variance in when these symptoms arise after radiation. However, we present key epidemiological data delineating vulnerable cancer populations for each pain syndrome along with the available evidence for the management for each specific condition.

Trends and outcome of neoadjuvant treatment for rectal cancer: A retrospective analysis and critical assessment of a 10-year prospective national registry on behalf of the Spanish Rectal Cancer Project

INTRODUCTION

Preoperative treatment and adequate surgery increase local control in rectal cancer. However, modalities and indications for neoadjuvant treatment may be controversial. Aim of this study was to assess the trends of preoperative treatment and outcomes in patients with rectal cancer included in the Rectal Cancer Registry of the Spanish Associations of Surgeons.

METHOD

This is a STROBE-compliant retrospective analysis of a prospective database. All patients operated on with curative intention included in the Rectal Cancer Registry were included. Analyses were performed to compare the use of neoadjuvant/adjuvant treatment in three timeframes: I)2006-2009; II)2010-2013; III)2014-2017. Survival analyses were run for 3-year survival in timeframes I-II.

RESULTS

Out of 14,391 patients,8871 (61.6%) received neoadjuvant treatment. Long-course chemo/radiotherapy was the most used approach (79.9%), followed by short-course radiotherapy ± chemotherapy (7.6%). The use of neoadjuvant treatment for cancer of the upper third (15-11 cm) increased over time (31.5%vs 34.5%vs 38.6%,p = 0.0018). The complete regression rate slightly increased over time (15.6% vs 16% vs 18.5%; p = 0.0093); the proportion of patients with involved circumferential resection margins (CRM) went down from 8.2% to 7.3%and 5.5% (p = 0.0004). Neoadjuvant treatment significantly decreased positive CRM in lower third tumors (OR 0.71, 0.59-0.87, Cochrane-Mantel-Haenszel P = 0.0008). Most ypN0 patients also received adjuvant therapy. In MR-defined stage III patients, preoperative treatment was associated with significantly longer local-recurrence-free survival (p < 0.0001), and cancer-specific survival (p < 0.0001). The survival benefit was smaller in upper third cancers.

CONCLUSION

There was an increasing trend and a potential overuse of neoadjuvant treatment in cancer of the upper rectum. Most ypN0 patients received postoperative treatment. Involvement of CRM in lower third tumors was reduced after neoadjuvant treatment. Stage III and MRcN + benefited the most.

Effects of Environment and Lifestyle Factors on Anovulatory Disorder

Anovulatory disorder comprises around 30% of female infertility. The origin of ovulatory failure is rooted in pituitary FSH secretion. Any factor or process that disrupts the finely tuned interactions of hypothalamo-pituitary-ovarian axis can potentially lead to anovulation. The World Health Organization (WHO) has classified anovulatory disorders into three categories: hypothalamic-pituitary failure, hypothalamic-pituitary dysregulation, and ovarian failure. Due to industrial development, environmental pollution, and global warming, the human living environment has undergone tremendous changes. Industrial waste, noise, pesticides, fertilizers, and vehicular emission are visible pollutants responsible for environmental contamination and ill effects on health of all living systems. A considerable body of research suggests that chemical exposures in the environment or workplace may be associated with endocrine disruption of the synthesis, secretion, transport, binding, or elimination of natural hormones. For instance, some advanced biological mechanisms suggest that heavy metals may affect progesterone production, which possibly disturbs endocrine function in pregnant women. On the other hand, our lifestyle factors have also changed accordingly, which greatly influence overall health and well-being, including fertility. Many lifestyle factors such as nutrition, weight, exercise, and psychological stress can have substantial effects on female ovulation.

Ultra-High Dose Rate (FLASH) Radiotherapy: Silver Bullet or Fool's Gold?

Radiotherapy is a cornerstone of both curative and palliative cancer care. However, radiotherapy is severely limited by radiation-induced toxicities. If these toxicities could be reduced, a greater dose of radiation could be given therefore facilitating a better tumor response. Initial pre-clinical studies have shown that irradiation at dose rates far exceeding those currently used in clinical contexts reduce radiation-induced toxicities whilst maintaining an equivalent tumor response. This is known as the FLASH effect. To date, a single patient has been subjected to FLASH radiotherapy for the treatment of subcutaneous T-cell lymphoma resulting in complete response and minimal toxicities. The mechanism responsible for reduced tissue toxicity following FLASH radiotherapy is yet to be elucidated, but the most prominent hypothesis so far proposed is that acute oxygen depletion occurs within the irradiated tissue. This review examines the tissue response to FLASH radiotherapy, critically evaluates the evidence supporting hypotheses surrounding the biological basis of the FLASH effect, and considers the potential for FLASH radiotherapy to be translated into clinical contexts.

Prehabilitation for patient positioning: pelvic exercises assist in minimizing inter-fraction sacral slope variability during radiation therapy

Reproducible patient positioning is essential for precision in radiation therapy (RT) delivery. We tested the hypothesis that a structured daily pre-treatment stretching regimen is both feasible and effective for minimizing variability in positioning, as measured by sacral slope angles (SSA). Eight female subjects undergoing pelvic radiotherapy performed a structured daily hip exercise regimen (extension and external rotation) immediately prior to both simulation imaging and daily treatment, throughout their RT course. This exercising cohort was compared to a retrospective review of 20 subjects (17 women and 3 men) undergoing RT, who had usual care. SSA measurements from daily pre-treatment imaging were compared to SSA measurements from the simulation CT. The average variation in SSA among the intervention subjects was 0.91° (± 0.58°), with a range among subjects of 0.57°-1.27°. The average variation for the control subjects was 2.27° (± 1.43°), ranging 1.22°-5.09°. The difference between the two groups was statistically significant (p = 0.0001). There was a statistically significant SSA variation between groups at each week of treatment. There was no significant variation among the intervention subjects between week 1 and later weeks, whereas subjects in the control group demonstrated significant SSA variation between week 1 and later weeks. We demonstrated a significant decrease in the variability of SSA by implementing a simple pre-treatment exercise program, while control subjects exhibited increasing variation in SSA over the course of treatment. We conclude that there is a potential benefit of prehabilitation during pelvic RT; however, a larger randomized control trial is required to confirm the findings.Clinical Trial: This research project was approved by the University of Massachusetts Medical School IRB (IRB ID H00012353) on January 21, 2017. The study is listed on ClinicalTrials.gov, provided by the U.S. National Library of Medicine, found with identifier NCT03242538.

A multi-disciplinary model of survivorship care following definitive chemoradiation for anal cancer

Following definitive chemoradiation for anal squamous cell carcinoma (ASCC), patients face a variety of chronic issues including: bowel dysfunction, accelerated bone loss, sexual dysfunction, and psychosocial distress. The increasing incidence of this disease, high cure rates, and significant long-term sequelae warrant increased focus on optimal survivorship care following definitive chemoradiation. In order to establish our survivorship care model for ASCC patients, a multi-disciplinary team of experts performed a comprehensive literature review and summarized best practices for the multi-disciplinary management of this unique patient population. We reviewed principle domains of our survivorship approach: (1) management of chronic toxicities; (2) sexual health; (3) HIV management in affected patients; (4) psychosocial wellbeing; and (5) surveillance for disease recurrence and survivorship care delivery. We provide recommendations for the optimization of survivorship care for ASCC patients can through a multi-disciplinary approach that supports physical and psychological wellness.

A systematic review of radiation-induced testicular toxicities following radiotherapy for prostate cancer

BACKGROUND

Prostate cancer is the second most common malignancy in men in the world, and radiotherapy is used as a standard treatment modality for this cancer. Although this treatment modality effectively kills prostate cancerous cells, it unavoidably irradiates the organs/tissues that are away from the treatment site. In this regard, radiation-induced testicular toxicities following prostate radiotherapy can affect sexual function, reproduction, and quality of life in cancer survivors. This review summarizes the available data on testicular exposure to radiation during prostate radiotherapy and the consequences on testicular function.

METHODS

To illuminate the radiation-induced testicular toxicities following prostate radiotherapy, a systematic search was conducted based on the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guideline in PubMed, Web of Science, Scopus, Embase, and clinical trials electronic databases up to September 2018. According to a set of prespecified inclusion and exclusion criteria, 31 eligible articles providing data on testicular function following radiotherapy in patients with prostate cancer were included in the study.

RESULTS

According to the different radiotherapeutic techniques used for prostate cancer treatment, the total tumor dose and scattered testicular dose values were ranging from 36.25 to 78.00 Gy and 0.06 to 6.48 Gy, respectively. Luteinizing hormone and follicle-stimulating hormone levels after prostate radiotherapy were significantly higher in comparison with the pretreatment levels. Around 60% of the studies showed that testosterone levels after prostate radiotherapy were significantly lower than the pretreatment levels. Furthermore, erectile dysfunction (ED), as an adverse side effect resulting from prostate radiotherapy, was reported and this complication is significantly correlated with lower satisfaction with sexual life. Testicular atrophy following prostate radiotherapy has also been observed and its frequency in patients with prior prostate radiotherapy is 2.5 times more than that in the patients without prior radiotherapy.

CONCLUSION

The data revealed that the scattered dose to testicular tissues during prostate radiotherapy can lead to testicular atrophy, variation of the male sex hormones, and quality of sexual life.

Definitive hyperfractionated, accelerated proton reirradiation for patients with pelvic malignancies

Introduction

Pelvic reirradiation (re-RT) presents challenges due to concerns for late toxicity to tissues-at-risk including pelvic bone marrow (PBM). We routinely utilize a hyperfractionated, accelerated re-RT for recurrent rectal or anal cancer in the setting of prior radiation. We hypothesized that proton beam radiation (PBR) is uniquely suited to limit doses to pelvic non-target tissues better than photon-based approaches.

Materials and methods

All patients who received hyperfractionated, accelerated PBR re-RT to the pelvis from 2007 to 2017 were identified. Re-RT was delivered twice daily with a 6 h minimum interfraction interval at 1.5 Gray Relative Biological Effectiveness (Gy(RBE)) per fraction to a total dose of 39-45 Gy(RBE). Concurrent chemotherapy was given to all patients. Comparison photon plans were generated for dosimetric analysis. Dosimetric parameters compared using a matched-pair analysis and the Wilcoxon signed-rank test. Survival analysis was performed Kaplan Meier curves.

Results

Fifteen patients were identified, with a median prior pelvic RT dose of 50.4 Gy (range 25-80 Gy). Median time between the initial RT and PBRT re-RT was 4.7 years (range 1.0-36.1 years). In comparison to corresponding photon re-RT plans, PBR re-RT plans had lower mean PBM dose, and lower volume of PBM getting 5 Gy, 10 Gy, 20 Gy, and 30 Gy (p < 0.001, p < 0.001, p < 0.001, and p = 0.033, respectively).With median 13.9 months follow-up after PBR re-RT, five patients had developed local recurrences, and four patients had developed distant metastases. One-year overall survival following PBR re-RT was 67.5% and one-year progression free survival was 58.7%. No patients developed acute or late Grade 4 toxicity.

Conclusion

PBR re-RT affords improved sparing of PBM compared with photon-based re-RT. Clinically, PBR re-RT is well-tolerated. However, given modest control rates with definitive re-RT without subsequent surgical resection, a multidisciplinary approach should be favored in this setting when feasible.

Optimal dose limitation strategy for bone marrow sparing in intensity-modulated radiotherapy of cervical cancer

BACKGROUND

To quantify the dosimetric parameters of different bone marrow sparing strategies and to determine the optimal strategy for cervical cancer patients undergoing postoperative intensity-modulated radiotherapy (IMRT).

METHODS

Fifteen patients with cervical cancer were selected for analysis. The planning target volume (PTV) and the organs at risks (OAR) including small bowel, bladder, rectum, femoral heads, os coxae (OC), lumbosacral spine (LS) and bone marrow (BM) were contoured. For each patient, four IMRT plans with different strategies were generated, including one plan without BM as the dose-volume constraint, namely IMRT (N) plan, and three bone marrow sparing (BMS-IMRT) plans. The three BMS-IMRT plans used the BM, OC, OC and LS respectively, as the BM OAR, namely as IMRT (BM), IMRT (OC) and IMRT (OC + LS) plans. Dose volumes for the target and the OARs were compared using analysis of variance (ANOVA).

RESULTS

Compared with IMRT (N) plans, the dose to the small bowel, bladder, rectum and femoral heads showed no increase in the three BMS-IMRT plans. However, the irradiated dose to BM, OC and LS significantly decreased. In particular, the mean dose of BM, OC and LS decreased by about 5Gy (p < 0.05) in IMRT (BM) plans while the average volume receiving ≥20, ≥30, ≥40Gy decreased by 7.1-24.2%. The LS volume receiving 40Gy showed the highest decrease (about 31.2%, p < 0.05) in IMRT (OC + LS) plans. On the other hand, in comparison with IMRT (BM), IMRT (OC) reduced the dose volume of to the OC, but increased the dose to LS while IMRT (OC + LS) plans reduced both the OC and the LS volume at all dose levels. Specifically, the V20 of OC and LS in the IMRT (OC + LS) plan decreased by 11.5 and 11.2%, respectively.

CONCLUSION

By introducing the os coxae and lumbosacral spine as the dose-volume constraints, the IMRT plans exhibited the best sparing of the bone marrow without compromising the dose to surrounding normal structures. Therefore, we recommend adding the os coxae and lumbosacral spine as the BM OAR in such plans.

Role of adjuvant radiation or re-excision for early stage vulvar squamous cell carcinoma with positive or close surgical margins

OBJECTIVES

This study aims to evaluate whether re-excision or adjuvant radiation for stage I vulvar squamous cell carcinoma (SCC) with either a close or positive surgical margin improves recurrence-free survival.

METHODS

Patients with pathologically confirmed FIGO stage I vulvar SCC who underwent primary surgical management between January 1, 1995 and September 30, 2017 and had positive or close (<8 mm) surgical margins were included. Kaplan-Meier curves were generated and compared using the log-rank test.

RESULTS

Of 150 patients with stage I vulvar SCC, 47 (31.3%) had positive or close margins. Median follow-up time was 25 months (IQR 13-59 months). Twenty-one (44.6%) patients received additional treatment with re-excision (n = 17) or vulvar radiation (n = 4); 26 (55.3%) patients received no additional therapy. Patients with positive margins were more likely to receive additional therapy compared to patients with close margins (80% vs 35.1%, p = 0.03). The 2-year recurrence rates were similar between the no further therapy and the re-excision/vulvar radiation groups (11.5% vs 4.8%, p = 0.62). Local recurrence-free survival (RFS) and overall survival (OS) were similar between patients who received re-excision/vulvar radiation and patients who received no further therapy (p = 0.10 and p = 0.16, respectively). Subgroup analysis of the 37 patients with close margins demonstrated no difference in RFS or OS when patients received re-excision or adjuvant vulvar radiation compared to no additional therapy (p = 0.74 and p = 0.82, respectively).

CONCLUSIONS

In our study, any additional treatment following primary surgical resection did not improve RFS or OS in stage IA and IB vulvar SCC. Larger studies are warranted in order to definitively determine the role of re-excision and adjuvant radiation in early stage disease.

Safety of combining radiotherapy with immune-checkpoint inhibition

Immune-checkpoint inhibitors targeting cytotoxic T- lymphocyte antigen 4 (CTLA-4), programmed cell death protein 1 (PD-1), or programmed cell death 1 ligand 1 (PD-L1) have transformed the care of patients with a wide range of advanced-stage malignancies. More than half of these patients will also have an indication for treatment with radiotherapy. The effects of both radiotherapy and immune-checkpoint inhibition (ICI) involve a complex interplay with the innate and adaptive immune systems, and accumulating evidence suggests that, under certain circumstances, the effects of radiotherapy synergize with those of ICI to augment the antitumour responses typically observed with either modality alone and thus improve clinical outcomes. However, the mechanisms by which radiotherapy and immune-checkpoint inhibitors synergistically modulate the immune response might also affect both the type and severity of treatment-related toxicities. Moreover, in patients receiving immune-checkpoint inhibitors, the development of immune-related adverse events has been linked with superior treatment responses and patient survival durations, suggesting a relationship between the antitumour and adverse autoimmune effects of these agents. In this Review, we discuss the emerging data on toxicity profiles related to immune-checkpoint inhibitors and radiotherapy, both separately and in combination, their potential mechanisms, and the approaches to managing these toxicities.

MRI Radiomic Analysis of IMRT-Induced Bladder Wall Changes in Prostate Cancer Patients: A Relationship with Radiation Dose and Toxicity

BACKGROUND

The main purpose of this study was to assess the structural changes in the bladder wall of prostate cancer patients treated with intensity-modulated radiation therapy using magnetic resonance imaging texture features analysis and to correlate image texture changes with radiation dose and urinary toxicity.

METHODS

Ethical clearance was granted to enroll 33 patients into this study who were treated with intensity-modulated radiation therapy for prostate cancer. All patients underwent two magnetic resonance imagings before and after radiation therapy (RT). A total of 274 radiomic features were extracted from MR-T2W-weighted images. Wilcoxon singed rank-test was performed to assess significance of the change in mean radiomic features post-RT relative to pre-RT values. The relationship between radiation dose and feature changes was assessed and depicted. Cystitis was recorded as urinary toxicity. Area under receiver operating characteristic curve of a logistic regression-based classifier was used to find correlation between radiomic features with significant changes and radiation toxicity.

RESULTS

Thirty-three bladder walls were analyzed, with 11 patients developing grade ≥2 urinary toxicity. We showed that radiomic features may predict radiation toxicity and features including S5.0SumVarnc, S2.2SumVarnc, S1.0AngScMom, S0.4SumAverg, and S5. _5InvDfMom with area under receiver operating characteristic curve 0.75, 0.69, 0.65, 0.63, and 0.62 had highest correlation with toxicity, respectively. The results showed that most of the radiomic features were changed with radiation dose.

CONCLUSION

Feature changes have a good correlation with radiation dose and radiation-induced urinary toxicity. These radiomic features can be identified as being potentially important imaging biomarkers and also assessing mechanisms of radiation-induced bladder injuries.

Randomized, double-blind, placebo-controlled phase II trial of nanocurcumin in prostate cancer patients undergoing radiotherapy

Clinical potential of curcumin in radiotherapy (RT) setting is outstanding and of high interest. The main purpose of this randomized controlled trial (RCT) was to assess the beneficial role of nanocurcumin to prevent and/or mitigate radiation-induced proctitis in prostate cancer patients undergoing RT. In this parallel-group study, 64 eligible patients with prostate cancer were randomized to receive either oral nanocurcumin (120 mg/day) or placebo 3 days before and during the RT course. Acute toxicities including proctitis and cystitis were assessed weekly during the treatment and once thereafter using CTCAE v.4.03 grading criteria. Baseline-adjusted hematologic nadirs were also analyzed and compared between the two groups. The patients undergoing definitive RT were followed to evaluate the tumor response. Nanocurcumin was well tolerated. Radiation-induced proctitis was noted in 18/31 (58.1%) of the placebo-treated patients versus 15/33 (45.5%) of nanocurcumin-treated patients (p = 0.313). No significant difference was also found between the two groups with regard to radiation-induced cystitis, duration of radiation toxicities, hematologic nadirs, and tumor response. In conclusion, this RCT was underpowered to indicate the efficacy of nanocurcumin in this clinical setting but could provide a considerable new translational insight to bridge the gap between the laboratory and clinical practice.