How Imaging Advances Are Defining the Future of Precision Radiation Therapy.

Radiation therapy is fundamental in the treatment of cancer. Imaging has always played a central role in radiation oncology. Integrating imaging technology into irradiation devices has increased the precision and accuracy of dose delivery and decreased the toxic effects of the treatment. Although CT has become the standard imaging modality in radiation therapy, the development of recently introduced next-generation imaging techniques has improved diagnostic and therapeutic decision making in radiation oncology. Functional and molecular imaging techniques, as well as other advanced imaging modalities such as SPECT, yield information about the anatomic and biologic characteristics of tumors for the radiation therapy workflow. In clinical practice, they can be useful for characterizing tumor phenotypes, delineating volumes, planning treatment, determining patients' prognoses, predicting toxic effects, assessing responses to therapy, and detecting tumor relapse. Next-generation imaging can enable personalization of radiation therapy based on a greater understanding of tumor biologic factors. It can be used to map tumor characteristics, such as metabolic pathways, vascularity, cellular proliferation, and hypoxia, that are known to define tumor phenotype. It can also be used to consider tumor heterogeneity by highlighting areas at risk for radiation resistance for focused biologic dose escalation, which can impact the radiation planning process and patient outcomes. The authors review the possible contributions of next-generation imaging to the treatment of patients undergoing radiation therapy. In addition, the possible roles of radio(geno)mics in radiation therapy, the limitations of these techniques, and hurdles in introducing them into clinical practice are discussed. ©RSNA, 2024 Test Your Knowledge questions for this article are available in the supplemental material.

Effect of LHRH analogs on lower urinary tract symptoms associated with advanced prostate cancer in real clinical practice: ANALUTS study.

AIMS: To estimate the prevalence of lower urinary tract symptoms (LUTS) in patients with prostate cancer scheduled to receive LHRH analogs, and to assess the effectiveness of LHRH analogs on LUTS in patients presenting moderate/severe symptoms. METHODS: Prospective, noninterventional, multicenter study conducted at 28 centers in Spain and Portugal. LUTS were evaluated using the International Prostate Symptom Score (IPSS) at baseline, 24 and 48 weeks after initiation of treatment. Subanalyses were performed according to age and concomitant treatment (radiotherapy, alpha-blockers, and antiandrogens). RESULTS: A total of 354 patients were treated with LHRH analogs for 48 weeks. The percentage of patients with moderate/severe LUTS (IPSS > 7) decreased from 60.2% (n = 213/354) at baseline to 52.8% (n = 187/354) at Week 48. Among patients with moderate/severe LUTS at baseline: 73.7% (n = 157/213) still had moderate/severe LUTS at Week 48; percentage reductions of patients with LUTS at Week 48 were statistically significant (p < 0.05) overall and by age or concomitant treatment, except for alpha-blockers (84.2% patients receiving them still had moderate/severe LUTS at Week 48). All IPSS items, including quality of life for urinary symptoms, improved throughout the study. The only predictor of response to treatment with LHRH analogs that improved IPSS by 3 points after 48 weeks was baseline testosterone levels. Lower baseline testosterone levels were associated with greater improvement in IPSS after treatment with LHRH analogs (odds ratio 0.998, 95% confidence interval 0.996-1.000, p = 0.0277). CONCLUSION: LHRH analogs have a positive effect in patients with locally advanced or metastatic prostate cancer presenting moderate/severe LUTS regardless of age or concomitant treatment received (radiotherapy, antiandrogens, or alpha-blockers).

Health-related quality of life in men with localized prostate cancer treated with radiotherapy: validation of an abbreviated version of the Expanded Prostate Cancer Index Composite for Clinical Practice in Spain.

BACKGROUND: Health-related quality of life (HRQoL) is greatly affected by prostate cancer (PCa) and associated treatments. This study aimed to measure the impact of radiotherapy on HRQoL and to further validate the Spanish version of the 16-item Expanded Prostate Cancer Index Composite (EPIC-16) in routine clinical practice. METHODS: An observational, non-interventional, multicenter study was conducted in Spain with localized PCa patients initiating treatment with external beam radiotherapy (EBRT) or brachytherapy (BQT). Changes from baseline in EPIC-16, University of California-Los Angeles Prostate Cancer Index (UCLA-PCI), and patient-perceived health status were longitudinally assessed at end of radiotherapy (V2) and 90 days thereafter (V3). Psychometric evaluations of the Spanish EPIC-16 were conducted. RESULTS: Of 516 patients enrolled, 495 were included in the analysis (EBRT, n = 361; BQT, n = 134). At baseline, mean (standard deviation [SD]) EPIC-16 global scores were 11.9 (7.5) and 10.3 (7.7) for EBRT and BQT patients, respectively; scores increased, i.e., HRQoL worsened, from baseline, by mean (SD) of 6.8 (7.6) at V2 and 2.4 (7.4) at V3 for EBRT and 4.2 (7.6) and 3.9 (8.2) for BQT patients. Changes in Spanish EPIC-16 domains correlated well with urinary, bowel, and sexual UCLA-PCI domains. EPIC-16 showed good internal consistency (Cronbach's alpha = .84), reliability, and construct validity. CONCLUSION: The Spanish EPIC-16 questionnaire demonstrated sensitivity, strong discriminative properties and reliability, and validity for use in clinical practice. EPIC-16 scores worsened after radiotherapy in different HRQoL domains; however, a strong tendency towards recovery was seen at the 3-month follow-up visit.

Quality of life in patients with breakthrough cancer pain in radiation oncology departments in Spain: the CAVIDIOR study.

Aim: The CAVIDIOR study evaluated quality of life (QoL) in patients with breakthrough cancer pain receiving palliative radiation therapy in radiation oncology departments (RODs) in Spain. Patients & methods: Prospective observational study at 11 Spanish RODs (July 2016-November 2017). QoL was assessed using Short Form Health Survey 12. Secondary end points were sleep quality, caregiver burden and patient/perception of improvement. Results: QoL improved according to the Short Form Health Survey 12 mental component. Sleep quality and caregivers' burden improved significantly. Conclusion: Breakthrough cancer pain is highly prevalent and can be substantially reduced with appropriate diagnosis and management in RODs. Along with the QoL questionnaire, sleep quality and caregiver burden provide a more comprehensive assessment of overall health status in patients receiving radiation therapy in RODs. Clinical trial registration: NCT02836379 (ClinicalTrials.gov).

Advanced Imaging Techniques in Evaluation of Colorectal Cancer.

Imaging techniques are clinical decision-making tools in the evaluation of patients with colorectal cancer (CRC). The aim of this article is to discuss the potential of recent advances in imaging for diagnosis, prognosis, therapy planning, and assessment of response to treatment of CRC. Recent developments and new clinical applications of conventional imaging techniques such as virtual colonoscopy, dual-energy spectral computed tomography, elastography, advanced computing techniques (including volumetric rendering techniques and machine learning), magnetic resonance (MR) imaging-based magnetization transfer, and new liver imaging techniques, which may offer additional clinical information in patients with CRC, are summarized. In addition, the clinical value of functional and molecular imaging techniques such as diffusion-weighted MR imaging, dynamic contrast material-enhanced imaging, blood oxygen level-dependent imaging, lymphography with contrast agents, positron emission tomography with different radiotracers, and MR spectroscopy is reviewed, and the advantages and disadvantages of these modalities are evaluated. Finally, the future role of imaging-based analysis of tumor heterogeneity and multiparametric imaging, the development of radiomics and radiogenomics, and future challenges for imaging of patients with CRC are discussed. Online supplemental material is available for this article. ©RSNA, 2018.

Common genetic variation associated with increased susceptibility to prostate cancer does not increase risk of radiotherapy toxicity.

BACKGROUND: Numerous germline single-nucleotide polymorphisms increase susceptibility to prostate cancer, some lying near genes involved in cellular radiation response. This study investigated whether prostate cancer patients with a high genetic risk have increased toxicity following radiotherapy. METHODS: The study included 1560 prostate cancer patients from four radiotherapy cohorts: RAPPER (n=533), RADIOGEN (n=597), GenePARE (n=290) and CCI (n=150). Data from genome-wide association studies were imputed with the 1000 Genomes reference panel. Individuals were genetically similar with a European ancestry based on principal component analysis. Genetic risks were quantified using polygenic risk scores. Regression models tested associations between risk scores and 2-year toxicity (overall, urinary frequency, decreased stream, rectal bleeding). Results were combined across studies using standard inverse-variance fixed effects meta-analysis methods. RESULTS: A total of 75 variants were genotyped/imputed successfully. Neither non-weighted nor weighted polygenic risk scores were associated with late radiation toxicity in individual studies (P>0.11) or after meta-analysis (P>0.24). No individual variant was associated with 2-year toxicity. CONCLUSION: Patients with a high polygenic susceptibility for prostate cancer have no increased risk for developing late radiotherapy toxicity. These findings suggest that patients with a genetic predisposition for prostate cancer, inferred by common variants, can be safely treated using current standard radiotherapy regimens.

Corrigendum to "Uroncor consensus statement: Management of biochemical recurrence after radical radiotherapy for prostate cancer: From biochemical failure to castration resistance". [Rep. Pract. Oncol. Radiother. 20 (2015) 259-272].

[This corrects the article DOI: 10.1016/j.rpor.2015.04.003.].

The metabolic syndrome and its components in patients with prostate cancer on androgen deprivation therapy.

PURPOSE: Androgen deprivation therapy may promote the development of the metabolic syndrome in patients with prostate cancer. We assessed the prevalence of the full metabolic syndrome and its components during the first year of androgen deprivation therapy. MATERIALS AND METHODS: This observational, multicenter, prospective study included 539 patients with prostate cancer scheduled to receive 3-month depot luteinizing hormone-releasing hormone analogs for more than 12 months. Waist circumference, body mass index, lipid profile, blood pressure and fasting glucose were evaluated at baseline and after 6 and 12 months. The metabolic syndrome was assessed according to NCEP ATP III criteria (2001) and 4 other definitions (WHO 1998, AACE 2003, AHA/NHLBI 2005 and IDF 2005). RESULTS: At 6 and 12 months after the initiation of androgen deprivation therapy, significant increases were observed in waist circumference, body mass index, fasting glucose, triglycerides, total cholesterol, and high-density and low-density lipoprotein cholesterol. No significant changes in blood pressure 130/85 or greater were detected. A nonsignificant increase of 3.9% in the prevalence of the full metabolic syndrome (ATP III) was observed (22.9% at baseline vs 25.5% and 26.8% at 6 and 12 months, respectively). The prevalence of the metabolic syndrome at baseline varied according to the definition used, ranging from 9.4% (WHO) to 50% (IDF). At 12 months significant increases in prevalence were observed with the WHO (4.1%) and AHA/NHLBI (8.1%) definitions. CONCLUSIONS: Androgen deprivation therapy produces significant early effects on waist circumference, body mass index, fasting glucose, triglycerides and cholesterol. The prevalence of and increase in the metabolic syndrome depend on the defining criteria. Counseling patients on the prevention, early detection and treatment of specific metabolic alterations is recommended.

Three linked nomograms for predicting biochemical failure in prostate cancer treated with radiotherapy plus androgen deprivation therapy.

BACKGROUND: Nomograms were established to predict biochemical recurrence (BCR) after radiotherapy (RT) with a low weight of the characteristic variables of RT and androgen deprivation therapy (ADT). Our aim is to provide a new stratified tool for predicting BCR at 4 and 7 years in patients treated using RT with radical intent. MATERIALS AND METHODS: A retrospective, nonrandomized analysis was performed on 5044 prostate cancer (PCa) patients with median age 70 years, who received RT-with or without ADT-between November 1992 and May 2007. Median follow-up was 5.5 years. BCR was defined as a rise in serum prostate-specific antigen (PSA) of 2 ng/ml over the post-treatment PSA nadir. Univariate association between predictor variables and BCR was assessed by the log-rank test, and three linked nomograms were created for multivariate prognosis of BCR-free survival. Each nomogram corresponds to a category of the Gleason score-either 6,7, or 8-10-and all of them were created from a single proportional hazards regression model stratified also by months of ADT (0, 1-6, 7-12, 13-24, 25-36, 36-60). The performance of this model was analyzed by calibration, discrimination, and clinical utility. RESULTS: Initial PSA, clinical stage, and RT dose were significant variables (p < 0.01). The model showed a good calibration. The concordance probability was 0.779, improving those obtained with other nomograms (0.587, 0.571, 0.554) in the database. Survival curves showed best clinical utility in a comparison with National Comprehensive Cancer Network (NCCN) risk groups. CONCLUSION: For each Gleason score category, the nomogram provides information on the benefit of adding ADT to a specific RT dose.

Uroncor consensus statement: Management of biochemical recurrence after radical radiotherapy for prostate cancer: From biochemical failure to castration resistance.

Management of patients who experience biochemical failure after radical radiotherapy with or without hormonal therapy is highly challenging. The clinician must not only choose the type of treatment, but also the timing and optimal sequence of treatment administration. When biochemical failure occurs, numerous treatment scenarios are possible, thus making it more difficult to select the optimal approach. Moreover, rapid and ongoing advances in treatment options require that physicians make decisions that could impact both survival and quality of life. The aim of the present consensus statement, developed by the Urological Tumour Working Group (URONCOR) of the Spanish Society of Radiation Oncology (SEOR), is to provide cancer specialists with the latest, evidence-based information needed to make the best decisions for the patient under all possible treatment scenarios. The structure of this consensus statement follows the typical development of disease progression after biochemical failure, with the most appropriate treatment recommendations given for each stage. The consensus statement is organized into three separate chapters, as follows: biochemical failure with or without local recurrence and/or metastasis; progression after salvage therapy; and treatment of castration-resistant patients.

No association between typical European mitochondrial variation and prostate cancer risk in a Spanish cohort.

Mitochondrial common variants (mtSNPs) and the haplogroups defined by them have been inconsistently correlated with increased prostate cancer risk. Here we aimed to investigate the influence of the mitochondrial genetic background on prostate cancer. A total of 15 single-nucleotide polymorphisms (SNPs) representing the common European branches of the mtDNA phylogeny were analyzed in a cohort of 620 Spanish prostate cancer patients and 616 matched population-based controls. Association tests were computed on mtSNPs and haplogroups. None of the evaluated mtSNPs or haplogroups were statistically associated with prostate cancer risk in our Spanish cohort. We show that previous association findings do not rest on solid grounds given that all of them (i) were based on underpowered studies, (ii) did not control for population stratification, (iii) lacked replication/confirmation cohorts, and (iv) and did not control for multiple test corrections. Taken together, a critical reassessment of the previous literature and the results obtained in the present study suggest that mtDNA common European variants are not correlated with increases in the risk for prostate cancer.

Evaluation of the criteria for renewal of LHRH agonists in patients with prostate cancer: results of the ANAREN Study.

Introduction: Injectable extended-release formulations of luteinizing hormone-releasing hormone agonists (LHRHa) have simplified the treatment of prostate cancer with a satisfactory level of androgen castration. This study aims to determine the percentage of patients whose initial LHRHa prescription was renewed during follow-up, how many changed formulation and how their quality of life evolved. Methods: This is an observational, prospective, multicentre study of men with prostate cancer who were to receive treatment with LHRHa (triptorelin every 3 or 6 months, leuprorelin every 3 or 6 months, or goserelin every 3 months) for 24 months. The treatment used was recorded and quality of life was assessed (QLQ-PR25 questionnaire) at four follow-up visits. Results: A total of 497 men (median age 75 years) were evaluated. The median exposure to LHRHa was 24 months. The initial prescription was renewed in 95.7% at follow-up 1 and 75% at follow-up 4. The main reason for changing from a 6-month to a 3-month formulation was a preference for sequential treatment (according to the investigator) and to see the physician more frequently (according to the patient). The main reason for switching from the 3-month to 6-month formulation was simplification of treatment (according to the investigator) and for convenience (according to the patient). Findings in the QLQ-PR25 questionnaire revealed no changes in urinary or bowel symptoms, though an improvement in sexual activity was reported. Practically all investigators and patients were satisfied/very satisfied with the treatment. Conclusion: Changes in formulation were scarce and generally justified by convenience factors or personal preferences. Patients maintained a good health status, with a high rate of retention of LHRHa treatment. Clinical Trial Registration: Study number: A-ES-52014-224.A plain language summary is provided as supplementary material (available at: https://www.drugsincontext.com/wp-content/uploads/2024/05/dic.2024-2-2-Suppl.pdf).

Outcomes and patterns of use of Radium-223 in metastatic castration-resistant prostate cancer.

Introduction: Radium-223 dichloride (Ra-223) is recommended as a treatment option for metastatic castration-resistant prostate cancer (mCRPC) patients with symptomatic bone metastases and no visceral disease, after docetaxel failure, or in patients who are not candidates to receive it. In this study, we aimed to ambispectively analyze overall survival (OS) and prognostic features in mCRPC in patients receiving Ra-223 as per clinical routine practice and identify the most suitable treatment sequence. Patients and methods: This study is observational, multicentric, and ambispective. Eligibility criteria included mCRPC patients treated with Ra-223, with an Eastern Cooperative Oncology Group (ECOG) performance status of 0-2, without visceral metastases, and no more than three cm involved lymph nodes. Results: A total of 145 patients were included; the median age was 73.97 years, and a Gleason score of more than or equal to 7 in 61 (48%) patients; 73 (81%) had previously received docetaxel. The most important benefit was reached by those patients who received Ra-223 in the second-line setting, with a median OS of 17 months (95% CI, 12-21), and by patients who received six cycles of treatment, with a median OS of 19 months (95% CI, 14-21). An alkaline phosphatase (ALP) decrease was also identified as a prognosis marker. When performing the multivariate analysis, the time to develop castration-resistant disease longer than 24 months was the most important prognostic factor to predict the evolution of the patients receiving Ra-223. Ra-223 was well tolerated, with thrombocytopenia, anemia, and diarrhea being the main adverse events. Conclusion: There is a benefit for those patients who received Ra-223 in the second-line setting, regardless of prior use of docetaxel. In addition, a survival benefit for patients presenting with a decline in ALP was observed.

Certification system for multidisciplinary thoracic tumour boards.

In Spain, lung cancer (LC) is the fourth most common cancer. Managing LC involves different professionals, and cooperative and coordinated work is crucial. Therefore, important decisions are better made by Multidisciplinary Thoracic Tumour Boards (MTTBs). On the other hand, certification systems have proven to improve the structure of care, ultimately having a positive impact on patient survival. Herein, a multidisciplinary working group of 11 experts (a Radiologist, a Thoracic Surgeon, a Pulmonologist, a Radiotherapy Oncologist, four Medical Oncologists, a Hospital Managing Director, a Cytologist, and a Molecular Biologist specialist) proposed a standard to certify and evaluate MTTBs. The following components were suggested for the standard: minimum requirements for the MTTB, a mixed model developed in two stages (preparation and audit), a structure comprising three groups of indicators (Strategic and Management, Support, and Operational), three certification levels, and an audit process. In our opinion, certifying MTTBs is critical to improve the standard of care for LC patients.

CT perfusion in oncologic imaging: a useful tool?

OBJECTIVE: This article summarizes the current status of CT perfusion in oncologic imaging, including lesion characterization, staging, prediction of patient outcome or response to therapy, assessment of response to different therapies, and evaluation of tumor relapse. Technical limitations and drawbacks of CT perfusion are also discussed. CONCLUSION: Tumor angiogenesis is essential for cancer growth and provides an attractive target for oncologic therapies. CT perfusion is an emerging imaging tool that provides both qualitative and quantitative information regarding tumor angiogenesis.

Radiobiological Meta-Analysis of the Response of Prostate Cancer to Different Fractionations: Evaluation of the Linear-Quadratic Response at Large Doses and the Effect of Risk and ADT.

The purpose of this work was to investigate the response of prostate cancer to different radiotherapy schedules, including hypofractionation, to evaluate potential departures from the linear-quadratic (LQ) response, to obtain the best-fitting parameters for low-(LR), intermediate-(IR), and high-risk (HR) prostate cancer and to investigate the effect of ADT on the radiobiological response. We constructed a dataset of the dose-response containing 87 entries/16,536 patients (35/5181 LR, 32/8146 IR, 20/3209 HR), with doses per fraction ranging from 1.8 to 10 Gy. These data were fit to tumour control probability models based on the LQ model, linear-quadratic-linear (LQL) model, and a modification of the LQ (LQmod) model accounting for increasing radiosensitivity at large doses. Fits were performed with the maximum likelihood expectation methodology, and the Akaike information criterion (AIC) was used to compare the models. The AIC showed that the LQ model was superior to the LQL and LQmod models for all risks, except for IR, where the LQL model outperformed the other models. The analysis showed a low α/ß for all risks: 2.0 Gy for LR (95% confidence interval: 1.7-2.3), 3.4 Gy for IR (3.0-4.0), and 2.8 Gy for HR (1.4-4.2). The best fits did not show proliferation for LR and showed moderate proliferation for IR/HR. The addition of ADT was consistent with a suppression of proliferation. In conclusion, the LQ model described the response of prostate cancer better than the alternative models. Only for IR, the LQL model outperformed the LQ model, pointing out a possible saturation of radiation damage with increasing dose. This study confirmed a low α/ß for all risks.

Variation of the relative biological effectiveness with fractionation in proton therapy: Analysis of prostate cancer response.

BACKGROUND: In treatment planning for proton therapy a constant Relative Biological Effectiveness (RBE) of 1.1 is used, disregarding variations with linear energy transfer, clinical endpoint, or fractionation. PURPOSE: To present a methodology to analyze the variation of RBE with fractionation from clinical data of tumor control probability (TCP) and to apply it to study the response of prostate cancer to proton therapy. METHODS AND MATERIALS: We analyzed the dependence of the RBE on the dose per fraction by using the LQ model and the Poisson TCP formalism. Clinical tumor control probabilities for prostate cancer (low and intermediate risk) treated with photon and proton therapy for conventional fractionation (2 Gy(RBE)×37 fractions), moderate hypofractionation (3 Gy(RBE)×20 fractions) and hypofractionation (7.25 Gy(RBE)×5 fractions) were obtained from the literature and analyzed aiming at obtaining the RBE and its dependence on the dose per fraction. RESULTS: The theoretical analysis of the dependence of the RBE on the dose per fraction showed three distinct regions with RBE monotonically decreasing, increasing or staying constant with the dose per fraction, depending on the change of (α, ß) values between photon and proton irradiation (the equilibrium point being at (αp /ßp ) = (αX /ßX )(αX /αp )). An analysis of the clinical data showed RBE values that decline with increasing dose per fraction: for low risk RBE≈1.124, 1.119, and 1.102 for 1.82 Gy, 2.73 Gy and 6.59 Gy per fraction (physical proton doses), respectively; for intermediate risk RBE≈1.119 and 1.102 for 1.82 Gy and 6.59 Gy per fraction (physical proton doses), respectively. These values are nonetheless very close to the nominal 1.1 value. CONCLUSIONS: In this study, we have presented a methodology to analyze the RBE for different fractionations, and we used it to study clinical data for prostate cancer and evaluate the RBE versus dose per fraction. The analysis shows a monotonically decreasing RBE with increasing dose per fraction, which is expected from the LQ formalism and the changes in (α, ß) values between photon and proton irradiation. However, the calculations in this study have to be considered with care as they may be biased by limitations in the modeling assumptions and/or by the clinical data set used for the analysis.

A Biomathematical Model of Tumor Response to Radioimmunotherapy With αPDL1 and αCTLA4.

There is evidence of synergy between radiotherapy and immunotherapy. Radiotherapy can increase liberation of tumor antigens, causing activation of antitumor T-cells. This effect can be boosted with immunotherapy. Radioimmunotherapy has potential to increase tumor control rates. Biomathematical models of response to radioimmunotherapy may help on understanding of the mechanisms affecting response, and assist clinicians on the design of optimal treatment strategies. In this work we present a biomathematical model of tumor response to radioimmunotherapy. The model uses the linear-quadratic response of tumor cells to radiation (or variation of it), and builds on previous developments to include the radiation-induced immune effect. We have focused this study on the combined effect of radiotherapy and αPDL1/ αCTLA4 therapies. The model can fit preclinical data of volume dynamics and control obtained with different dose fractionations and αPDL1/ αCTLA4. A biomathematical study of optimal combination strategies suggests that a good understanding of the involved biological delays, the biokinetics of the immunotherapy drug, and the interplay between them, may be of paramount importance to design optimal radioimmunotherapy schedules. Biomathematical models like the one we present can help to interpret experimental data on the synergy between radiotherapy and immunotherapy, and to assist in the design of more effective treatments.

Radiogenomics in lung cancer: Where are we?

Huge technological and biomedical advances have improved the survival and quality of life of lung cancer patients treated with radiotherapy. However, during treatment planning, a probability that the patient will experience adverse effects is assumed. Radiotoxicity is a complex entity that is largely dose-dependent but also has important intrinsic factors. One of the most studied is the genetic variants that may be associated with susceptibility to the development of adverse effects of radiotherapy. This review aims to present the current status of radiogenomics in lung cancer, integrating results obtained in association studies of SNPs (single nucleotide polymorphisms) related to radiotherapy toxicities. We conclude that despite numerous publications in this field, methodologies and endpoints vary greatly, making comparisons between studies difficult. Analyzing SNPs from the candidate gene approach, together with the study in cohorts limited by the sample size, has complicated the possibility of having validated results. All this delays the incorporation of genetic biomarkers in predictive models for clinical application. Thus, from all analysed SNPs, only 12 have great potential as esophagitis genetic risk factors and deserve further exploration. This review highlights the efforts that have been made to date in the radiogenomic study of radiotoxicity in lung cancer.

Large-scale meta-genome-wide association study reveals common genetic factors linked to radiation-induced acute toxicities across cancer types.

BACKGROUND: This study was designed to identify common genetic susceptibility and shared genetic variants associated with acute radiation-induced toxicity across 4 cancer types (prostate, head and neck, breast, and lung). METHODS: A genome-wide association study meta-analysis was performed using 19 cohorts totaling 12 042 patients. Acute standardized total average toxicity (STATacute) was modelled using a generalized linear regression model for additive effect of genetic variants, adjusted for demographic and clinical covariates (rSTATacute). Linkage disequilibrium score regression estimated shared single-nucleotide variation (SNV-formerly SNP)-based heritability of rSTATacute in all patients and for each cancer type. RESULTS: Shared SNV-based heritability of STATacute among all cancer types was estimated at 10% (SE = 0.02) and was higher for prostate (17%, SE = 0.07), head and neck (27%, SE = 0.09), and breast (16%, SE = 0.09) cancers. We identified 130 suggestive associated SNVs with rSTATacute (5.0 × 10‒8 < P < 1.0 × 10‒5) across 25 genomic regions. rs142667902 showed the strongest association (effect allele A; effect size ‒0.17; P = 1.7 × 10‒7), which is located near DPPA4, encoding a protein involved in pluripotency in stem cells, which are essential for repair of radiation-induced tissue injury. Gene-set enrichment analysis identified 'RNA splicing via endonucleolytic cleavage and ligation' (P = 5.1 × 10‒6, P = .079 corrected) as the top gene set associated with rSTATacute among all patients. In silico gene expression analysis showed that the genes associated with rSTATacute were statistically significantly up-regulated in skin (not sun exposed P = .004 corrected; sun exposed P = .026 corrected). CONCLUSIONS: There is shared SNV-based heritability for acute radiation-induced toxicity across and within individual cancer sites. Future meta-genome-wide association studies among large radiation therapy patient cohorts are worthwhile to identify the common causal variants for acute radiotoxicity across cancer types.