Clinical dose-volume histogram analysis in predicting radiation pneumonitis in Hodgkin's lymphoma

Acute and Late Pulmonary Effects After Radiation Therapy in Childhood Cancer Survivors: A PENTEC Comprehensive Review

OBJECTIVES

The Pediatric Normal Tissue Effects in the Clinic (PENTEC) pulmonary task force reviewed dosimetric and clinical factors associated with radiation therapy (RT)-associated pulmonary toxicity in children.

METHODS

Comprehensive search of PubMed (1965-2020) was conducted to assess available evidence and predictive models of RT-induced lung injury in pediatric cancer patients (<21 years old). Lung dose for radiation pneumonitis (RP) was obtained from dose-volume histogram (DVH) data. RP grade was obtained from standard criteria. Clinical pulmonary outcomes were evaluated using pulmonary function tests (PFTs), clinical assessment, and questionnaires.

RESULTS

More than 2,400 abstracts were identified; 460 articles had detailed treatment and toxicity data; and 11 articles with both detailed DVH and toxicity data were formally reviewed. Pooled cohorts treated during 1999 to 2016 included 277 and 507 patients age 0.04 to 22.7 years who were evaluable for acute and late RP analysis, respectively. After partial lung RT, there were 0.4% acute and 2.8% late grade 2, 0.4% acute and 0.8% late grade 3, and no grade 4 to 5 RP. RP risk after partial thoracic RT with mean lung dose (MLD) <14 Gy and total lung V20Gy <30% is low. Clinical and self-reported pulmonary outcomes data included 8,628 patients treated during 1970 to 2013, age 0 to 21.9 years. At a median 2.9- to 21.9-year follow-up, patients were often asymptomatic; abnormal PFTs were common and severity correlated with lung dose. At ≥10-year follow-up, multi-institutional studies suggested associations between total or ipsilateral lung doses >10 Gy and pulmonary complications and deaths. After whole lung irradiation (WLI), pulmonary toxicity is higher; no dose response relationship was identified. Bleomycin and other chemotherapeutics at current dose regimens do not contribute substantially to adverse pulmonary outcomes after partial lung irradiation but increase risk with WLI.

CONCLUSIONS

After partial lung RT, acute pulmonary toxicity is uncommon; grade 2 to 3 RP incidences are <1%. Late toxicities, including subclinical/asymptomatic impaired pulmonary function, are more common (<4%). Incidence and severity appear to increase over time. Upon review of available literature, there appears to be low risk of pulmonary complications in children with MLD < 14 Gy and V20Gy <30% using standard fractionated RT to partial lung volumes. A lack of robust data limit guidance on lung dose/volume constraints, highlighting the need for additional work to define factors associated with RT-induced lung injury.

Gene Signatures for Latent Radiation-Induced Lung Injury Post X-ray Exposure in Mouse

Objective

To investigate the X-ray-specific sensitive genes and potential signaling pathways involved in the latent period of radiation-induced lung injury (RILI) in mouse models.

Method

Mice were randomized into groups for whole thoracic irradiation with a single fraction of 20 Gy X-ray or 12.5 Gy carbon heavy ion. Lungs were harvested 3 weeks after the irradiation, whole RNA was extracted and detected with the genome-wide transcriptional microarrays. Differentially expressed genes (DEGs) were calculated for each group and the X-ray-specific sensitive genes were determined, followed by the gene enrichment analysis of those DEGs exploring the potentially relevant signaling pathways and biological processes in latent RILI.

Results

Three weeks after irradiation, gene expression levels varied between groups. 76 up-regulated DEGs were determined with mice in the X-ray group and gene ontology enrichment analysis for biological process (GO-BP) obtained several processes which were associated with radiation reaction, mitotic, immune cell chemotaxis or metastasis, immune factors, p53 apoptosis, and tissue remodeling. KEGG signaling pathway enrichment analysis showed that those 76 up-regulated DEGs were enriched in p53, IL-17, FoXO, melanoma, and non-small-cell lung cancer signaling pathways. By comparing the DEGs in X-ray and heavy ion groups, X-ray-specific sensitive genes were determined, the top 10 genes were Adamts9, Aacs, Col6a2, Fdps, Mdk, Mcam, Stbd1, Lbh, Ak3, and Emid1. The expression level of the top 10 genes was found to be significantly higher in the X-ray group than in the control and heavy ion groups.

Conclusion

Our research determined the X-ray-specific sensitive gene set in mice lungs after exposure to radiation. The gene set could be used as a genetic marker to suggest the latency of RILI. The enrichment analysis results suggested that the relevant signaling pathways were potentially involved in the development of RILI. Further validation of those genes and signaling pathways is needed to confirm these findings.

Pulmonary Toxicity of Hodgkin Lymphoma Treatment: A Prospective Single-Center Study

BACKGROUND

Standard bleomycin-containing first-line therapy and/or irradiation may cause pulmonary toxicity in Hodgkin lymphoma (HL) patients. Our aim was to prospectively assess effects of chest irradiation, bleomycin administration, and other factors on lung function in the treatment of patients with HL.

METHODS

Pulmonary function of newly diagnosed HL patients was assessed via a St. George Respiratory Questionnaire, dynamic inhalation lung scintigraphy, spirometry, and an assessment of the diffusion capacity of the lung for carbon monoxide (DLCO) before, during, and after treatment.

RESULTS

This prospective study was conducted at the University of Debrecen. The study included 84 patients with classical HL. Most patients received standard doxorubicin, bleomycin, vinblastine, and dacarbazine chemotherapy. Both intramuscular and intravenous administrations of bleomycin were used. Brentuximab vedotin combination chemotherapy was administered to 12 patients. Mediastinal involved-field irradiation therapy (IFRT) was used to treat 16 patients. Lung scintigraphy revealed pulmonary toxicity more sensitively than DLCO. Intravenous bleomycin administration decreased diethylenetriamine pentaacetic acid clearance. Intramuscular bleomycin had the lowest level of pulmonary toxicity among considered treatments. Currently used, mediastinal IFRT had a lower level of pulmonary toxicity than bleomycin. The current prospective evaluation confirmed previous results that determined that cumulative bleomycin dose and administration are major risk factors for pulmonary toxicity, while the currently used treatment method, mediastinal irradiation, was determined to be relatively safe for treating for HL patients.

CONCLUSION

We agree with decreasing bleomycin dosage and number of cycles administered and we do not recommend avoiding mediastinal IFRT, unless multiple pulmonary risk factors are present.

Treatment-related sequelae in Hodgkin's lymphoma after mediastinal irradiation

BACKGROUND

Many studies have investigated treatment-related sequelae in Hodgkin's lymphoma (HL) in high-prevalence areas, but very few have been conducted in low-prevalence areas, including Taiwan and Japan.

MATERIALS AND METHODS

We retrospectively reviewed 101 HL patients who had received mediastinal radiotherapy between January 1997 and April 2013.

RESULTS

Nine patients had cardiac events and nine patients developed second malignancies. Univariate analysis showed that bulkiness of disease was significantly associated with higher incidence of cardiac events (HR 7.70, 95% CI 1.60-38.00, p = 0.012). Disease stage and cumulative dose of radiotherapy were significantly correlated with incidence of radiation pneumonitis (HR 1.40, 95% CI 1.00-2.10, p = 0.043 and HR 1.10, 95% CI 1.00-1.20, p = 0.009, respectively). All cases of grade III-IV radiation pneumonitis happened in patients receiving a radiation dose higher than 35 Gy and developed within 4 months after radiotherapy.

CONCLUSIONS

Despite the similar incidence rates of treatment-related sequelae among HL survivors between areas with high and low prevalence of HL, cardiac events and second malignancies cannot be overlooked in HL survivors in low-prevalence areas.

Pulmonary dose tolerance in hemithorax radiotherapy for Ewing sarcoma of the chest wall: Are we overestimating the risk of radiation pneumonitis?

BACKGROUND

Children with chest wall Ewing sarcoma with malignant pulmonary effusion or pleural stranding require hemithorax radiation, often with plans that exceed lung constraints. We investigated disease control and pneumonitis in children requiring hemithorax radiation.

PROCEDURE

Eleven children (median age 13 years) received hemithorax radiotherapy. Symptomatic radiation pneumonitis was considered National Cancer Institute Common Terminology Criteria for Adverse Events (CTCAE) grade 1+ with respiratory symptoms. Mean lung dose (MLD), volume of lung exposed to a dose ≥5 Gy (V5), ≥20 Gy (V20), and ≥35 Gy (V35) were recorded. Adult and pediatric lung constraints were obtained from Quantitative Analysis of Normal Tissue Effects in the Clinic (QUANTEC) guidelines and Children's Oncology Group (COG) protocols, respectively.

RESULTS

Median hemithorax dose was 15 Gy (1.5 Gy/fraction). Median total dose was 51 Gy (1.8 Gy/fraction). Most plans delivered both protons and photons. The ipsilateral MLD, V5, and V20 were 27.2 Gy, 100%, and 48.3%; the bilateral MLD, V20, and V35 were 14.1 Gy, 22.8%, and 14.3%, respectively. One hundred percent, 36%, and 91% of treatments exceeded recommended adult ipsilateral lung constraints of V5 <65%, V20 <52%, and MLD of 22 Gy; 64%, 45%, and 82% exceeded COG bilateral lung constraints of V20 <20%, MLD <15 Gy, and MLD <12 Gy, respectively; 82% of treatments exceeded the COG ipsilateral lung constraint of V20 <30%. At a median 36 months (range 12-129), the symptomatic radiation pneumonitis incidence was 0%. Two patients progressed with nonpulmonary metastatic disease and died at a median 12 months following radiotherapy.

CONCLUSIONS

Existing guidelines may overestimate pneumonitis risk, even among young children receiving multiagent chemotherapy. For children with chest wall Ewing sarcoma and other thoracic malignancies, more data are needed to refine pediatric dose-effect models for pulmonary toxicity.

Application of Radiomics for the Prediction of Radiation-Induced Toxicity in the IMRT Era: Current State-of-the-Art

Normal tissue complication probability (NTCP) models that were formulated in the Quantitative Analyses of Normal Tissue Effects in the Clinic (QUANTEC) are one of the pillars in support of everyday’s clinical radiation oncology. Because of steady therapeutic refinements and the availability of cutting-edge technical solutions, the ceiling of organs-at-risk-sparing has been reached for photon-based intensity modulated radiotherapy (IMRT). The possibility to capture heterogeneity of patients and tissues in the prediction of toxicity is still an unmet need in modern radiation therapy. Potentially, a major step towards a wider therapeutic index could be obtained from refined assessment of radiation-induced morbidity at an individual level. The rising integration of quantitative imaging and machine learning applications into radiation oncology workflow offers an unprecedented opportunity to further explore the biologic interplay underlying the normal tissue response to radiation. Based on these premises, in this review we focused on the current-state-of-the-art on the use of radiomics for the prediction of toxicity in the field of head and neck, lung, breast and prostate radiotherapy.

Risk of Pneumonitis and Outcomes After Mediastinal Proton Therapy for Relapsed/Refractory Lymphoma: A PTCOG and PCG Collaboration

PURPOSE

Despite high response rates, there has been reluctance to use radiation therapy for patients with relapsed/refractory (r/r) Hodgkin (HL) or aggressive non-Hodgkin lymphoma (NHL) given concerns for subacute and late toxicities. Symptomatic pneumonitis, a subacute toxicity, has an incidence of 17% to 24% (≥grade 2) even with intensity modulated radiation therapy. Proton therapy (PT), which has no exit radiation dose, is associated with a lower dose to lung compared with other radiation techniques. As risk of radiation pneumonitis is associated with lung dose, we evaluated whether pneumonitis rates are lower with PT.

METHODS AND MATERIALS

Within an international, multi-institutional cohort, we retrospectively evaluated the incidence and grade of radiation pneumonitis (National Cancer Institute Common Terminology Criteria for Adverse Events v4) among patients with r/r HL or NHL treated with PT.

RESULTS

A total of 85 patients with r/r lymphoma (66% HL, 34% NHL; 46% primary chemorefractory) received thoracic PT from 2009 to 2017 in the consolidation (45%) or salvage (54%) setting. Median dose was 36 Gy(RBE). Before PT, patients underwent a median of 1 salvage systemic therapy (range, 0-4); 40% received PT within 4 months of transplant. With a median follow-up of 26.3 months among living patients, 11 patients developed symptomatic (grade 2) pneumonitis (12.8%). No grade 3 or higher pneumonitis was observed. Dose to lung, including mean lung dose, lung V5, and V20, significantly predicted risk of symptomatic pneumonitis, but not receipt of brentuximab, history of bleomycin toxicity, sex, or peritransplant radiation.

CONCLUSIONS

PT for relapsed/refractory lymphoma was associated with favorable rates of pneumonitis compared with historical controls. We confirm that among patients treated with PT, pneumonitis risk is associated with mean lung and lung V20 dose. These findings highlight how advancements in radiation delivery may improve the therapeutic ratio for patients with relapsed/refractory lymphoma. PT may be considered as a treatment modality for patients with relapsed/refractory lymphoma in the consolidation or salvage setting.

Fondazione Italiana Linfomi (FIL) expert consensus on the use of intensity-modulated and image-guided radiotherapy for Hodgkin's lymphoma involving the mediastinum

Aim

Advances in therapy have resulted in improved cure rates and an increasing number of long-term Hodgkin's lymphoma (HL) survivors. However, radiotherapy (RT)-related late effects are still a significant issue, particularly for younger patients with mediastinal disease (secondary cancers, heart diseases). In many Centers, technological evolution has substantially changed RT planning and delivery. This consensus document aims to analyze the current knowledge of Intensity-Modulated Radiation Therapy (IMRT) and Image-Guided Radiation Therapy (IGRT) for mediastinal HL and formulate practical recommendations based on scientific evidence and expert opinions.

Methods

A dedicated working group was set up within the Fondazione Italiana Linfomi (FIL) Radiotherapy Committee in May 2018. After a first meeting, the group adopted a dedicated platform to share retrieved articles and other material. Two group coordinators redacted a first document draft, that was further discussed and finalized in two subsequent meetings. Topics of interest were: 1) Published data comparing 3D-conformal radiotherapy (3D-CRT) and IMRT 2) dose objectives for the organs at risk 3) IGRT protocols and motion management.

Results

Data review showed that IMRT might allow for an essential reduction in the high-dose regions for all different thoracic OAR. As very few studies included specific dose constraints for lungs and breasts, the low-dose component for these OAR resulted slightly higher with IMRT vs. 3D-CRT, depending on the technique used. We propose a set of dose objectives for the heart, breasts, lungs, and thyroid. The use of IGRT is advised for margin reduction without specific indications, such as the use of breath-holding techniques. An individual approach, including comparative planning and considering different risk factors for late morbidity, is recommended for each patient.

Conclusions

As HL therapy continues to evolve, with an emphasis on treatment reduction, radiation oncologists should use at best all the available tools to minimize the dose to organs at risk and optimize treatment plans. This document provides indications on the use of IMRT/IGRT based on expert consensus, providing a basis for clinical implementation and future development.

lncRNA TPTEP1 competitively sponges miR‑328‑5p to inhibit the proliferation of non‑small cell lung cancer cells

Accumulating evidence suggests that lncRNAs are involved in almost all normal physiological processes and that aberrant expression of lncRNAs may be involved in the development of diseases, including non‑small cell lung cancer (NSCLC). However, the roles of lncRNA‑TPTE pseudogene 1 (TPTEP1) in lung cancer and the underlying molecular mechanisms have remained elusive. In the present study, significant downregulation of TPTEP1 in tumors compared with normal tissues from patients with NSCLC was observed. Overexpression of TPTEP1 inhibited cell proliferation and induced apoptosis in NSCLC cells. A bioinformatics analysis based on miRDB predicted microRNA (miR)‑328‑5p as a potential binding miRNA for TPTEP1. Using a dual‑luciferase reporter assay and western blot analysis, it was further validated that TPTEP1 sponged miR‑328‑5p to upregulate Src kinase signaling inhibitor 1 (SRCIN1) in NSCLC cells. Through regulation of SRCIN1, TPTEP1 was indicated to inactivate the Src and STAT3 pathways in NSCLC cells. Notably, silencing of SRCIN1 reversed the TPTEP1 overexpression‑induced inhibition of cell proliferation and increase of the apoptotic rate in NSCLC cells. Pearson correlation analysis revealed a significant positive correlation between TPTEP1 and SRCIN1 mRNA levels in NSCLC tumors. The present results provided insight into the roles of TPTEP1 in NSCLC and the underlying mechanisms.

New Clinical Features and Dosimetric Predictor Identification for Symptomatic Radiation Pneumonitis after Tangential Irradiation in Breast Cancer Patients

Background: Tangential irradiation is the most popular postoperative radiotherapy technique for breast cancer. However, irradiation has been related to symptomatic radiation pneumonitis (SRP), which decreases the quality of life of patients. This study investigated the clinical features and dosimetric parameters related to SRP of the ipsilateral lung to identify risk factors for SRP in breast cancer patients after three-dimensional conformal radiation therapy (3D-CRT) with tangential fields. Material and Methods: A total of 515 breast cancer patients were evaluated and divided into two groups: the local-regional irradiation group (259 patients) and the simple local irradiation group (256 patients). Clinical symptoms were registered and patient data collected. The relationship between the incidence of SRP and dosimetric parameters for the ipsilateral lung was assessed within 6 months after 3D-CRT. Dosimetric parameters were compared using t tests. The dosimetric predictors for SRP were estimated using a logistic regression model and receiver operating characteristic curve analysis. Results: In total, 19 patients (3.7%) developed grade 2 SRP. In the local-regional irradiation group, the probability of SRP in the lung body was greater than that in the lung apex (3.9% vs. 1.5%). V20 and V30 were independent predictors for SRP in the local-regional irradiation group (odds ratio = 1.152 and 1.439, both p = 0.030), whereas only V20 was an independent predictor of SRP in the simple local irradiation group (odds ratio = 1.351, p = 0.001). With 39.8% as the optimal threshold for V20 and 25.7% for V30 for local-regional irradiation, SRP could be predicted with an accuracy of 80.3% and 79.9%, a sensitivity of 61.5% and 69.2%, and a specificity of 81.3% and 80.5%, respectively. With 20.2% as the optimal V20 threshold for simple local irradiation, SRP could be predicted with an accuracy of 88.7%, a sensitivity of 83.3% and a specificity of 89.6%. Conclusions: SRP has become a rare complication with mild symptoms and occurs mainly in the lung body. V20 and V30 may be useful dosimetric predictors to evaluate SRP risk of the ipsilateral lung in breast cancer.

A study of the dosimetric characteristics between different fixed-field IMRT and VMAT in early-stage primary mediastinal B-cell lymphoma

This analysis was designed to compare dosimetric parameters among different fixed-field intensity-modulated radiation therapy (IMRT) solutions and volumetric-modulated arc therapy (VMAT) to identify which can achieve the lowest risk of organs at risk (OARs) and treatment delivery efficiently. A total of 16 patients (8 male and 8 female) with early-stage primary mediastinal large B-cell lymphoma (PMBCL) were enrolled with planned gross tumor volume (PGTV) 45 Gy and planning target volume (PTV) 40 Gy. Four different plans were generated: 5-, 7, 9-field IMRT, and VMAT. The dose distributions for PGTV and PTV OARs (lungs, left ventricle, heart, thyroid gland, and breasts) were compared. The monitor units (MUs) and treatment delivery time were also evaluated. Mean conformity index (CI) and homogeneity index (HI) for PGTV in 5F-, 7F-, 9F-IMRT, and VMAT were 1.01 and 1.10, 1.01 and 1.10, 1.01 and 1.10, and 1.01 and 1.11 (p = 0.963 and 0.843), whereas these 2 indices for PTV were 1.04 and 1.22, 1.03 and 1.19, 1.03 and 1.17, and 1.08 and 1.14 (p = 0.964 and 0.969), respectively. D_mean (Gy), V4 (%), D50 (Gy), and D80 (Gy) to the left and right breasts increased by 0.7 Gy and 0.1 Gy, 6.8% and 7.7%, 0.9 Gy and 1.7 Gy, and 1.0 Gy and 1.5 Gy in VMAT, respectively. The 9-beam IMRT plan had the highest MUs (25,762.4 MUs) and the longest treatment delivery time (10.7 minutes); whereas, the VMAT had the lowest MUs (13,345.0) and the shortest treatment delivery time (5.9 minutes). Seven- and 9-field IMRT and VMAT provide improved tumor coverage compared with 5F-IMRT, whereas VMAT shows higher treatment delivery efficiency than IMRT technique. Seven- and 9-field IMRT slightly reduce the low dose radiation exposure of breasts compared with VMAT technique. The 7- and 9-field IMRT and VMAT techniques both can be safely and efficiently delivered to patients with PMBCL.

Does Bleomycin Lung Toxicity Increase the Risk of Radiation Pneumonitis in Hodgkin Lymphoma?

PURPOSE

Bleomycin pulmonary toxicity (BPT) is a well-known complication of treatment in patients with Hodgkin lymphoma (HL). We undertook the present study to investigate the risk of radiation pneumonitis (RP) in the setting of BPT and to determine the need for delay or omission of radiation therapy (RT) in these patients.

METHODS AND MATERIALS

We identified 123 HL patients treated with ABVD (Adriamycin, bleomycin, vinblastine, dacarbazine) followed by RT to the chest from January 2009 to December 2014. The medical records were reviewed for clinical, pathologic, and treatment information and toxicities. Our primary outcome was RP of any grade. Univariate and multivariate analyses were used to assess the association of BPT, baseline patient characteristics, and treatment variables with the incidence of RP.

RESULTS

A total of 123 patients were included, of whom 99 (80%) received consolidation intensity modulated RT after ABVD treatment. We identified 31 patients (25.2%) with BPT after frontline ABVD. Seventeen patients (13.8%) developed RP a median of 8 weeks (range 1-39) after RT completion. BPT did not correlate with the risk of developing RP (P=.36). We evaluated the RP outcomes with respect to the bleomycin to RT interval (≤6 weeks vs >6 weeks), and we found that this interval did not predict for RP risk (P=.60). Dosimetric parameters such as the volume covered by 5 Gy and the mean lung dose were analyzed. A volume covered by 5 Gy of >55% and mean lung dose >13.5 Gy increased the risk of RP by 1.14-fold (P=.002) and 4.24-fold (P=.007), respectively.

CONCLUSIONS

The results of our study suggest that BPT does not increase the risk of developing RP. Furthermore, RT initiation does not need to be delayed after chemotherapy, except to allow for the completion of steroid therapy or clinical recovery from BPT.

Modeling the risk of radiation-induced lung fibrosis: Irradiated heart tissue is as important as irradiated lung

PURPOSE

We used normal tissue complication probability (NTCP) modeling to explore the impact of heart irradiation on radiation-induced lung fibrosis (RILF).

MATERIALS AND METHODS

We retrospectively reviewed for RILF 148 consecutive Hodgkin lymphoma (HL) patients treated with sequential chemo-radiotherapy (CHT-RT). Left, right, total lung and heart dose-volume and dose-mass parameters along with clinical, disease and treatment-related characteristics were analyzed. NTCP modeling by multivariate logistic regression analysis using bootstrapping was performed. Models were evaluated by Spearman Rs coefficient and ROC area.

RESULTS

At a median time of 13months, 18 out of 115 analyzable patients (15.6%) developed RILF after treatment. A three-variable predictive model resulted to be optimal for RILF. The two models most frequently selected by bootstrap included increasing age and mass of heart receiving >30Gy as common predictors, in combination with left lung V5 (Rs=0.35, AUC=0.78), or alternatively, the lungs near maximum dose D2% (Rs=0.38, AUC=0.80).

CONCLUSION

CHT-RT may cause lung injury in a small, but significant fraction of HL patients. Our results suggest that aging along with both heart and lung irradiation plays a fundamental role in the risk of developing RILF.

Predictors of radiation pneumonitis in patients receiving intensity modulated radiation therapy for Hodgkin and non-Hodgkin lymphoma

PURPOSE

Few studies to date have evaluated factors associated with the development of radiation pneumonitis (RP) in patients with Hodgkin lymphoma (HL) and non-Hodgkin lymphoma (NHL), especially in patients treated with contemporary radiation techniques. These patients represent a unique group owing to the often large radiation target volumes within the mediastinum and to the potential to receive several lines of chemotherapy that add to pulmonary toxicity for relapsed or refractory disease. Our objective was to determine the incidence and clinical and dosimetric risk factors associated with RP in lymphoma patients treated with intensity modulated radiation therapy (IMRT) at a single institution.

METHODS AND MATERIALS

We retrospectively reviewed clinical charts and radiation records of 150 consecutive patients who received mediastinal IMRT for HL and NHL from 2009 through 2013. Clinical and dosimetric predictors associated with RP according to Radiation Therapy Oncology Group (RTOG) acute toxicity criteria were identified in univariate analysis using the Pearson χ(2) test and logistic multivariate regression.

RESULTS

Mediastinal radiation was administered as consolidation therapy in 110 patients with newly diagnosed HL or NHL and in 40 patients with relapsed or refractory disease. The overall incidence of RP (RTOG grades 1-3) was 14% in the entire cohort. Risk of RP was increased for patients who received radiation for relapsed or refractory disease (25%) versus those who received consolidation therapy (10%, P=.019). Several dosimetric parameters predicted RP, including mean lung dose of >13.5 Gy, V20 of >30%, V15 of >35%, V10 of >40%, and V5 of >55%. The likelihood ratio χ(2) value was highest for V5 >55% (χ(2) = 19.37).

CONCLUSIONS

In using IMRT to treat mediastinal lymphoma, all dosimetric parameters predicted RP, although small doses to large volumes of lung had the greatest influence. Patients with relapsed or refractory lymphoma who received salvage chemotherapy and hematopoietic stem cell transplantation were at higher risk for symptomatic RP.

Late morbidity and mortality in patients with Hodgkin's lymphoma treated during adulthood

BACKGROUND

Survivors of Hodgkin's lymphoma (HL) treated as adults are at risk for late effects of therapy. However, the burden of late morbidity and mortality among adults treated for HL remains incompletely characterized.

METHODS

Vital status and, for deceased, cause of death were determined for 746 adults treated on a first-line trial at a single center from 1975 to 2000. Survivors completed a detailed survey describing their physical and mental health. A severity score (grades 1-4, ranging from mild to life-threatening or disabling) was assigned to self-reported conditions.

RESULTS

At a median follow-up of 22 years, 227 of patients (30.4%) had died, 107 (47.1%) from HL, 120 (52.9%) from other causes, including second primary malignancies (SPMs) (n = 52) and cardiovascular disease (n = 27). Across the duration of follow-up, all-cause and SPM-specific risk of death remained higher than predicted by normative data. Among survivors, late morbidity survey data are available for 238 patients (45.9%). Ninety-four-point-one percent of respondents reported at least one morbidity, and 47.5% reported at least one grade 3 or 4 morbidity; 20.2% reported two or more grade 3 morbidities. Commonly reported morbidities included cardiovascular (54.6%), endocrine (68.5%), pulmonary disease (21.4%), and nonfatal second malignancy (23.1%). Anxiety, depression, and fear of recurrence were frequently reported.

CONCLUSIONS

Among a large cohort of patients treated for HL with extensive follow-up, risk of late mortality from causes other than HL and prevalence of late medical morbidity are high. Guidelines for prevention, screening, and management of late effects in adult survivors of HL are needed.

ACR appropriateness criteria follow-up of Hodgkin lymphoma

The main objectives of follow-up studies after completion of treatment for Hodgkin lymphoma are detection of recurrence for salvage therapy and monitoring for sequelae of treatment. The focus of the follow-up shifts, with time after treatment, from detection of recurrence to long-term sequelae. A majority of recurrence is detected by history and physical examination. The yield for routine imaging studies and blood tests is low. Although routine surveillance CT scan can detect recurrence not detected by history and physical examination, its benefit in ultimate survival and cost-effectiveness is not well defined. Although PET scan is a useful tool in assessing response to treatment, its routine use for follow-up is not recommended. Long-term sequelae of treatment include secondary malignancy, cardiovascular disease, pneumonitis, reproductive dysfunction, and hypothyroidism. Follow-up strategies for these sequelae need to be individualized, as their risks in general depend on the dose and volume of radiation to these organs, chemotherapy, age at treatment, and predisposing factors for each sequela. The ACR Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed every 3 years by a multidisciplinary expert panel. The guideline development and review include an extensive analysis of current medical literature from peer-reviewed journals and the application of a well-established consensus methodology (modified Delphi) to rate the appropriateness of imaging and treatment procedures by the panel. In those instances in which evidence is either lacking or not definitive, expert opinion may be used to recommend imaging or treatment.

ACR Appropriateness Criteria Pediatric Hodgkin Lymphoma

Pediatric Hodgkin lymphoma is a highly curable malignancy and potential long-term effects of therapy need to be considered in optimizing clinical care. An expert panel was convened to reach consensus on the most appropriate approach to evaluation and treatment of pediatric Hodgkin lymphoma. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed every 2 years by a multidisciplinary expert panel. The guideline development and review include an extensive analysis of current medical literature from peer reviewed journals and the application of a well-established consensus methodology (modified Delphi) to rate the appropriateness of imaging and treatment procedures by the panel. In those instances where evidence is lacking or not definitive, expert opinion may be used to recommend imaging or treatment. Four clinical variants were developed to assess common clinical scenarios and render recommendations for evaluation and treatment approaches to pediatric Hodgkin lymphoma. We provide a summary of the literature as well as numerical ratings with commentary. By combining available data in published literature and expert medical opinion, we present a consensus to the approach for management of pediatric Hodgkin lymphoma.

Pulmonary damage in Hodgkin's lymphoma patients treated with sequential chemo-radiotherapy: Predictors of radiation-induced lung injury

BACKGROUND

Our aim was to define predictors of late radiation-induced lung injury (RILI) in Hodgkin's lymphoma (HL) survivors treated with bleomycin-containing chemotherapy and radiotherapy.

MATERIAL AND METHODS

Eighty consecutive patients treated with chemotherapy and subsequent supradiaphragmatic radiation therapy for HL were retrospectively reviewed for symptoms and/or radiological signs of RILI. Median patient age was 26 years (range 14-55). Left, right, and total lung dosimetric parameters along with clinical, disease, and treatment-related characteristics were analyzed. Multivariate logistic regression analyses were performed. A receiver operator characteristic (ROC) curve analysis was performed to find possible cutoff values dividing patients into high- and low-risk groups.

RESULTS

Seven of 80 (9%) patients had lung disease at baseline. Four of 80 (5%) had toxicity after chemotherapy and before the beginning of radiotherapy. These patients were excluded from further evaluation. At a median time of 10 months (range 9-18), 9/69 patients (13%) developed lung radiological changes on computed tomography (CT) after treatment. Four of nine patients were diagnosed RTOG grade ≥ 2. On multivariate analyses, left-lung V30 (p = 0.004, OR = 1.108 95% CI 1.033-1.189) and total-lung V30 (p = 0.009, OR = 1.146 95% CI 1.035-1.270) resulted to be predictors of lung CT changes with a cutoff value of 16% and 15%, respectively. When only symptomatic RILI was considered a left-lung V30 cutoff value of 32% was estimated.

CONCLUSION

Bleomycin and RT may cause lung injury in a small, but significant fraction of HL patients. Left-lung V30 predicts the risk of developing asymptomatic or symptomatic RILI after sequential chemo-radiotherapy.

Complications of thoracic radiotherapy

The issue of toxicity is a primary concern for chest irradiation, because it is a dose-limiting toxicity and because in some circumstances it can alleviate the survival benefit of radiation therapy. Potential acute and delayed side effects can compromise the patients' prognosis and generate significant morbidity. Here we review on chest complications of radiation therapy, with focus on cardiac and pulmonary radio-induced side effects. Most radiographic changes associated with thoracic irradiation are asymptomatic. However, chest irradiation generated by treatment of breast cancer, bronchopulmonary malignancies, or mediastinal lymphoma has been associated with a risk of acute radiation pneumonitis and late lung fibrosis. An increasing number of clinical studies suggest that some dosimetric factors (e.g. V20, V30, mean lung dose) should be considered for limiting the risk of lung toxicity. Improvements in radiation techniques as well as changes in indications, volumes and prescribed doses of radiation therapy should help to better spare lungs from irradiation and thus decreasing the risk of subsequent toxicity. Numerous other contributing factors should also be considered, such as chemotherapeutic agents, smoking, tumor topography, or intrinsic sensitivity. Cardiac toxicity is another clinically relevant issue in patients receiving radiation therapy for breast cancer or for lymphoma. This life threatening toxicity should be analyzed in the light of dosimetric factors (including low doses) but also associated systemic agents which almost carry a potential for additive toxicity toward myocardium or coronaries. A long-term follow-up of patients as well as an increasing knowledge of the underlying biological pathways involved in cardiac toxicity should help designing effective preventing strategies.

The use and QA of biologically related models for treatment planning: short report of the TG-166 of the therapy physics committee of the AAPM

Treatment planning tools that use biologically related models for plan optimization and/or evaluation are being introduced for clinical use. A variety of dose-response models and quantities along with a series of organ-specific model parameters are included in these tools. However, due to various limitations, such as the limitations of models and available model parameters, the incomplete understanding of dose responses, and the inadequate clinical data, the use of biologically based treatment planning system (BBTPS) represents a paradigm shift and can be potentially dangerous. There will be a steep learning curve for most planners. The purpose of this task group is to address some of these relevant issues before the use of BBTPS becomes widely spread. In this report, the authors (1) discuss strategies, limitations, conditions, and cautions for using biologically based models and parameters in clinical treatment planning; (2) demonstrate the practical use of the three most commonly used commercially available BBTPS and potential dosimetric differences between biologically model based and dose-volume based treatment plan optimization and evaluation; (3) identify the desirable features and future directions in developing BBTPS; and (4) provide general guidelines and methodology for the acceptance testing, commissioning, and routine quality assurance (QA) of BBTPS.

Dosimetric and clinical outcomes of involved-field intensity-modulated radiotherapy after chemotherapy for early-stage Hodgkin's lymphoma with mediastinal involvement

PURPOSE

To evaluate the dosimetric and clinical outcomes of involved-field intensity-modulated radiotherapy (IF-IMRT) for patients with early-stage Hodgkin's lymphoma (HL) with mediastinal involvement.

METHODS AND MATERIALS

Fifty-two patients with early-stage HL that involved the mediastinum were reviewed. Eight patients had Stage I disease, and 44 patients had Stage II disease. Twenty-three patients (44%) presented with a bulky mediastinum, whereas 42 patients (81%) had involvement of both the mediastinum and either cervical or axillary nodes. All patients received combination chemotherapy followed by IF-IMRT. The prescribed radiation dose was 30-40 Gy. The dose-volume histograms of the target volume and critical normal structures were evaluated.

RESULTS

The median mean dose to the primary involved regions (planning target volume, PTV1) and boost area (PTV2) was 37.5 Gy and 42.1 Gy, respectively. Only 0.4% and 1.3% of the PTV1 and 0.1% and 0.5% of the PTV2 received less than 90% and 95% of the prescribed dose, indicating excellent PTV coverage. The median mean lung dose and V20 to the lungs were 13.8 Gy and 25.9%, respectively. The 3-year overall survival, local control, and progression-free survival rates were 100%, 97.9%, and 96%, respectively. No Grade 4 or 5 acute or late toxicities were reported.

CONCLUSIONS

Despite the large target volume, IF-IMRT gave excellent dose coverage and a favorable prognosis, with mild toxicity in patients with early-stage mediastinal HL.

[Intensity-modulated radiotherapy and involved-node concept in patients with Hodgkin lymphoma: experience of the Gustave-Roussy Institute]

PURPOSE

To assess the clinical outcome of the involved-node radiotherapy concept with the use of intensity modulated radiotherapy (IMRT) in patients with localized supradiaphragmatic Hodgkin lymphoma.

PATIENTS AND METHODS

Patients with early-stage supradiaphragmatic Hodgkin lymphoma were treated with chemotherapy prior to irradiation. Radiation treatments were delivered using the involved-node radiotherapy (INRT) concept according to the EORTC guidelines. Intensity modulated radiotherapy was performed free-breathing.

RESULTS

Forty-seven patients with Hodgkin lymphoma (44 patients with primary Hodgkin lymphoma and three patients with recurrent disease) entered the study from January 2003 to December 2010. The median age was 31 years (range 17 to 62). Thirty patients had stage I-IIA, 14 had stage I-IIB disease and three had relapse. Forty-two patients received three to six cycles of adriamycin, bleomycin, vinblastine and dacarbazine (ABVD). The median radiation dose to patients was 36 Gy (range: 20-40). Protection of various organs at risk was satisfactory. The median follow-up was 57.4 months (range: 5.4-94.3). For patients with primary Hodgkin lymphoma, the 5-year survival and 5-year progression-free survival rates were 96% (95% confidence interval: 80-99) and 92% (95% confidence interval: 78-97), respectively. None of the three patients with recurrent disease has relapsed. Recurrences occurred in three patients: one was in-field relapse and two were visceral recurrences. Grade 3 acute lung toxicity (transient pneumonitis) occurred in one case.

CONCLUSION

Our results suggest that patients with localized Hodgkin lymphoma can be safely and efficiently treated using the involved node irradiation concept and intensity modulated irradiation.

Long-Term Complications of Lymphoma and Its Treatment

As a result of therapeutic advances, there is a growing population of survivors of both Hodgkin's lymphoma (HL) and non-Hodgkin's lymphoma (NHL). A thorough understanding of the late effects of cancer and its treatment, including the risk of developing a second malignancy and non-neoplastic complications, most notably cardiac disease, is essential for the proper long-term follow-up care of these patients. For HL survivors cured in the past 5 decades, a large body of literature describes a range of long-term effects, many of which are related to extent of treatment. These studies form the basis for many of the follow-up recommendations developed for HL survivors. As HL therapy continues to evolve, however, with an emphasis toward treatment reduction, in particular for early-stage disease, it will be important to rigorously observe this new generation of patients long term to document and quantify late effects associated with modern treatments. Although data on late effects after NHL therapy have recently emerged, the formulation of structured follow-up plans for this heterogeneous group of survivors is challenging, given the highly variable natural history, treatments, and overall prognosis. However, the chemotherapy and radiation therapy approaches for some types of NHL are similar to that for HL; thus, some of the follow-up guidelines for patients with HL may also be transferrable to selected survivors of NHL. Additional work focused on treatment-related complications after NHL will facilitate the development of follow-up programs, as well as treatment refinements to minimize late effects in patients with various types of NHL.

ACR Appropriateness Criteria: follow-up of Hodgkin's lymphoma

In the follow-up of Hodgkin's lymphoma patients, the focus in the first 5 years is to detect recurrence, while after 5 years, the focus is on limiting and detecting late effects of treatment. In the first 5 years post-treatment, routine history and physical and computed tomography (CT) imaging (more frequent in the first 2 years) are generally appropriate. However, there are limited data to support the role of positron emission tomography scanning as routine follow-up. Beyond 5 years post-treatment, annual history and physical is appropriate, although there is no longer a role for routine imaging for recurrences. Women irradiated to the chest area at a young age (<35) would benefit from annual mammogram screening given the increased breast cancer risk. Magnetic resonance imaging can be considered, although there is a lack of data supporting its role in this population. Low-dose chest CT for lung cancer screening in patients with history of mediastinal irradiation and/or alkylating chemotherapy exposures and a smoking history can be considered, although data on its utility is lacking. Cardiac screening with echocardiogram and exercise tolerance tests in patients with history of mediastinal irradiation and/or adriamycin exposure may be appropriate, although the optimal screening interval would depend on mediastinal dose, adriamycin dose, presence of other cardiac risk factors and findings at the baseline screening. Patients at risk for cardiac disease due to treatment exposure would also benefit from lipid screening every 1-3 years.

Lung dose for minimally moving thoracic lesions treated with respiration gating

PURPOSE

To evaluate incidental doses to benign lung tissue for patients with minimally moving lung lesions treated with respiratory gating.

METHODS AND MATERIALS

Seventeen lung patient plans were studied retrospectively. Tumor motion was less than 5 mm in all cases. For each patient, mid-ventilation (MidVen) and mid-inhalation (MidInh) breathing phases were reconstructed. The MidInh phase was centered on the end-of-inhale (EOI) phase within a 30% gating window. Planning target volumes, heart, and spinal cord were delineated on the MidVen phase and transferred to the MidInh phase. Lungs were contoured separately on each phase. Intensity-modulated radiotherapy plans were generated on the MidVen phases. The plans were transferred to the MidInh phase, and doses were recomputed. The evaluation metric was based on dose indices, volume indices, generalized equivalent uniform doses, and mass indices for targets and critical structures. Statistical tests were used to establish the significance of the differences between the reference (MidVen) and compared (MidInh) dose distributions.

RESULTS

Statistical tests demonstrated that the indices evaluated for targets, cord, and heart differed by within 2.3%. The index differences in the lungs, however, are in excess of 6%, indicating the potentially achievable lung sparing and/or dose escalation.

CONCLUSIONS

Respiratory gating is a clinical option for patients with minimally moving lung lesions treated at EOI. Gating will be more beneficial for larger tumors, since dose escalation in those cases will result in a larger increase in the tumor control probability.

Radiation dose-volume effects in the lung

The three-dimensional dose, volume, and outcome data for lung are reviewed in detail. The rate of symptomatic pneumonitis is related to many dosimetric parameters, and there are no evident threshold "tolerance dose-volume" levels. There are strong volume and fractionation effects.

Radiation-related treatment effects across the age spectrum: differences and similarities or what the old and young can learn from each other

Radiation related effects in children and adults limit the delivery of effective radiation doses and result in long-term morbidity affecting function and quality of life. Improvements in our understanding of the etiology and biology of these effects, including the influence of clinical variables, dosimetric factors, and the underlying biological processes have made treatment safer and more efficacious. However, the approach to studying and understanding these effects differs between children and adults. Using the pulmonary and skeletal organ systems as examples, comparisons are made across the age spectrum for radiation related effects, including pneumonitis, pulmonary fibrosis, osteonecrosis, and fracture. Methods for dosimetric analysis, incorporation of imaging and biology as well a length of follow-up are compared, contrasted, and discussed for both organ systems in children and adults. Better understanding of each age specific approach and how it differs may improve our ability to study late effects of radiation across the ages.

Helical tomotherapy in the radiotherapy treatment of Hodgkin's disease - a feasibility study

Radiation therapy for advanced Hodgkin's disease often requires large fields and may result in significant exposure of normal tissues to ionizing radiation. In long-term survivors, this may increase the risk for late toxicity including secondary malignancies. 3DCRT has been successfully used to treat this disease but treatment delivery is often complex requiring matching of photon with electron beams, utilization of field-in-field techniques and of partial transmission blocks. HT is an arc-rotational intensity modulated radiation therapy technique proven to achieve superior target dose conformality and sharp dose gradients around critical normal tissues. HT however, has also been associated with higher volumes of low dose regions in normal tissues and therefore, higher integral dose. The present study was undertaken to compare the dosimetry of 3DCRT to HT in a pediatric patient with advanced HD. Clinical target volume (CTV) included bilateral lower cervical and supraclavicular areas, mediastinum, bilateral hili, left axilla and bilateral diaphragmatic lymph nodes. The planning target volume (PTV) was derived by circumferentially expanding the CTV by 1 cm. Whole lung and heart irradiation was also planned due to bilateral pleural and pericardial effusions. The prescribed radiation dose was 21 Gy to the PTV and 10.5 Gy to the whole lung and heart. Target coverage was comparable for both plans. The minimum, maximum and mean PTV doses were 18.61 Gy, 22.45 Gy and 21.52 Gy with 3DCRT and 19.85 Gy, 22.36 Gy and 21.39 Gy with HT, respectively. HT decreased mean normal tissue dose by 21.6% and 20.07% for right and left breast, 20.40% for lung, 30.78% for heart and 22.74% for the thyroid gland. Integral dose also decreased with HT by 46.50%. HT results in significant dosimetric gain related to normal tissue sparing compared to 3DCRT. Further studies are warranted to evaluate clinical applications of HT in patients with HD.

Incidence and correlates of radiation pneumonitis in pediatric patients with partial lung irradiation

PURPOSE

To provide a radiation pneumonitis risk estimate and investigate the correlation of clinical and dosimetric factors in pediatric patients receiving chest irradiation.

METHODS AND MATERIALS

A total of 122 patients diagnosed with sarcoma or Hodgkin lymphoma who received radiotherapy to the chest were evaluated for symptomatic radiation pneumonitis (Common Toxicity Criteria Grade 1 with respiratory symptom or higher grade). Pneumonitis data were collected from either prospective toxicity screenings as part of a clinical trial or through chart review. Dosimetric parameters including V(10)-V(25), mean lung dose, binned lung dose, and tissue complication probability models were used, as well as clinical features to correlate with the development of pneumonitis.

RESULTS

The 1- and 2-year cumulative incidence of symptomatic radiation pneumonitis for all patients was 8.2% and 9.1%, respectively. Nine patients experienced symptomatic Grade 1 toxicity, and 2 experienced Grade 2. From univariate analysis, chemotherapy containing bleomycin (chi(2) test, p = 0.027) and V(24) (logistic regression, p = 0.019) were the clinical and dosimetric factors that resulted in statistically significant differences in the occurrence of pneumonitis. The probability of pneumonitis increased more dramatically with increasing V(24) in patients receiving bleomycin than in those who did not. Adult tissue complication models did not differentiate pediatric patients with radiation pneumonitis from those without.

CONCLUSIONS

The incidence of symptomatic radiation pneumonitis in pediatric patients is low and its severity mild. Parameters frequently used in adult radiation oncology provide some guidance as to risk, but pediatric patients warrant their own specific models for risk assessment, incorporating dosimetry and clinical factors.

Late effects of Hodgkin's disease and its treatment

Long-term survivors of Hodgkin's lymphoma are at increased risk for a number of late complications, including development of second malignancies and cardiovascular disease. Treatment-related factors and other modifying risk factors contributing to the risk of late effects have been identified. Survivors deemed at increased risk based on their treatment history and other exposures may benefit from early detection for late complications and risk reduction strategies. However, the optimal screening tests and prevention program, and their timing and frequency are not clear. It should be noted that treatment for Hodgkin's lymphoma has undergone considerable changes over the last several decades. Most of the current data on late effects after Hodgkin's lymphoma are based on patients treated with outdated chemotherapy and radiation therapy. As Hodgkin's lymphoma therapy evolve over time, continued documentation of late effects associated with newer treatment will be important for the follow-up of patients treated in the modern era.

The rationale and role of radiation therapy in the treatment of patients with diffuse large B-cell lymphoma in the Rituximab era

Developments in the evaluation and systemic management of diffuse large B-cell lymphoma (DLBCL) require ongoing assessment of the role of external beam radiotherapy in management. This review assesses data regarding the use of radiotherapy in the initial management of early stage and advanced DLBCL, and considers the implications of bulky and residual disease, and the contribution of PET scanning, to decisions regarding the use of radiotherapy after chemotherapy. Limited R-CHOP plus radiotherapy, or full dose R-CHOP alone, are both likely to cure approximately 90% of patients with low risk early stage disease. The choice of therapy will depend on considerations of acute and late toxicity of the two approaches, taking into account individual patient risk profiles and preferences. Unfavorable early-stage and advanced-stage disease require treatment with full dose R-CHOP. The presence of bulky disease predicts for a higher risk of relapse, which may be partly ameliorated by the addition of radiotherapy. The rapidity of response on PET scanning, the presence of a posttherapy residual mass, the potential toxicity of radiotherapy and the available salvage options all need to be considered on a patient by patient basis, when considering the use of radiotherapy for advanced disease.