Doses to carotid arteries after modern radiation therapy for Hodgkin lymphoma: is stroke still a late effect of treatment?

Role of Radiation Therapy in Mortality among Adolescents and Young Adults with Lymphoma: Differences According to Cause of Death

Simple Summary

Despite its efficacy, emerging concerns exist regarding radiation therapy (RT)-associated toxicity in adolescent and young adult (AYA) lymphoma patients. However, the most current research studying the association between RT and outcome is based only on groups of lymphoma patients and is not compared with the general population, which could more accurately reveal the impact of RT on outcomes. This population-based analysis showed that after adjusting for potential confounders, RT administration is associated with a low risk of cause-specific mortality, including death due to the original diagnosis, second malignant neoplasms (SMNs), and noncancer causes, among AYA patients with lymphoma. This analysis may play a guiding role in the design of future lymphoma studies and the formulation of healthcare policies regarding the widespread use of RT, especially for AYA survivors.

Abstract

Background: Despite its efficacy, emerging concerns exist regarding radiation therapy (RT)-associated toxicity in adolescent and young adult (AYA) lymphoma patients. Few long-term follow-up studies have examined the association between RT and outcomes. Methods: Lymphoma patients aged 15–39 years were identified in the Surveillance, Epidemiology and End Results (SEER) database from 1992 to 2016. Mortality was assessed by comparing those with and without RT using the Fine–Gray competing risk model. Standardized mortality ratios (SMRs) were used to assess the relative risk of death compared with the general U.S. population. Results: In total, 29,686 patients were included; 10,708 (36.07%) received RT. Cause-specific mortality was compared between patients with and without RT while considering other competing events, including death due to index cancer, second malignant neoplasms (SMNs), and noncancer causes. Patients with RT had a lower probability of death and crude 5-year cumulative incidence of death. Moreover, there were significantly lower SMRs in patients with RT than in patients without RT. Differences between the two groups were greatest for mortality due to hematological malignancies and infections. Additionally, in the RT cohort, the SMR for index-cancer-related death was highest in the first year after diagnosis and gradually decreased. Hematological malignancies and infections were the most common specific SMN and noncancer causes of death, respectively. Conclusions: RT did not increase mortality from index cancer, SMNs, or noncancer causes in AYA patients with lymphoid malignancies. The current analysis may serve as a reference for healthcare providers monitoring RT application for AYA lymphoid malignancy survivors.

Biological optimization for mediastinal lymphoma radiotherapy - a preliminary study

Purpose: In current radiotherapy (RT) planning and delivery, population-based dose-volume constraints are used to limit the risk of toxicity from incidental irradiation of organs at risks (OARs). However, weighing tradeoffs between target coverage and doses to OARs (or prioritizing different OARs) in a quantitative way for each patient is challenging. We introduce a novel RT planning approach for patients with mediastinal Hodgkin lymphoma (HL) that aims to maximize overall outcome for each patient by optimizing on tumor control and mortality from late effects simultaneously.Material and Methods: We retrospectively analyzed 34 HL patients treated with conformal RT (3DCRT). We used published data to model recurrence and radiation-induced mortality from coronary heart disease and secondary lung and breast cancers. Patient-specific doses to the heart, lung, breast, and target were incorporated in the models as well as age, sex, and cardiac risk factors (CRFs). A preliminary plan of candidate beams was created for each patient in a commercial treatment planning system. From these candidate beams, outcome-optimized (O-OPT) plans for each patient were created with an in-house optimization code that minimized the individual risk of recurrence and mortality from late effects. O-OPT plans were compared to VMAT plans and clinical 3DCRT plans.Results: O-OPT plans generally had the lowest risk, followed by the clinical 3DCRT plans, then the VMAT plans with the highest risk with median (maximum) total risk values of 4.9 (11.1), 5.1 (17.7), and 7.6 (20.3)%, respectively (no CRFs). Compared to clinical 3DCRT plans, O-OPT planning reduced the total risk by at least 1% for 9/34 cases assuming no CRFs and 11/34 cases assuming presence of CRFs.Conclusions: We developed an individualized, outcome-optimized planning technique for HL. Some of the resulting plans were substantially different from clinical plans. The results varied depending on how risk models were defined or prioritized.

Proton Therapy For Lymphomas: Current State Of The Art

The combination of brief chemo-radiotherapy provides high cure rates and represents the first line of treatment for many lymphoma patients. As a result, a high proportion of long-term survivors may experience treatment-related toxic events many years later. Excess and unintended radiation dose to organs at risk (particularly heart, lungs and breasts) may translate in an increased risk of cardiovascular events and second cancers after a few decades. Minimizing dose to organs at risk is thus pivotal to restrain the risk of long-term complications. Proton therapy, with its peculiar physic properties, may help to better spare organs at risk and consequently to reduce toxicities especially in patients receiving mediastinal radiotherapy. Herein, we review the physical basis of proton therapy and the rationale for its implementation in lymphoma patients, with a detailed description of the clinical data. We also discuss the potential disadvantages and uncertainties of protons that may limit their application and critically review the dosimetric studies comparing the risk of late complications between proton and photon radiotherapy.

Cancer and Cerebrovascular Disease

PURPOSE OF REVIEW

To review the latest information about the interactions between cancer and cerebrovascular disease.

RECENT FINDINGS

Additional data support the finding that both ischemic and hemorrhagic stroke are important complications of cancer or its treatment. Reperfusion therapy is being given successfully to patients with stroke complicating cancer. Hemorrhagic stroke may occur with metastatic disease to the brain, coagulopathies from cancer, in particular leukemia, or as complications of chemotherapy. Ischemic stroke also may be a complication of metastatic disease with local invasion of vessels, a pro-thrombotic disorder such as non-bacterial thrombotic endocarditis (NBTE) or disseminated intravascular coagulation (DIC), or secondary to chemotherapy. Stroke also is a potential consequence of radiation therapy to the head and neck. Venous sinus thrombosis may develop with hematologic malignancies or chemotherapy. Although many patients will have a history of cancer at the time of stroke, a cerebrovascular event may be the initial manifestation of a malignancy.

Association of lung and heart dose with survival in patients with non-small cell lung cancer underwent volumetric modulated arc therapy

Background

Controversial conclusions had been reported in studies trying to confirm the impact of heart dose on overall survival (OS) reported in RTOG 0167 for non-small cell lung cancer (NSCLC) patients who underwent radiotherapy (RT). The purpose of this study is to investigate the association of lung and heart dosimetric parameters with OS in NSCLC patients treated by volumetric modulated arc therapy (VMAT).

Methods

Inoperable NSCLC patients treated by VMAT from March 2012 to December 2015 were retrospectively reviewed. OS and progression-free survival (PFS) were estimated with the Kaplan–Meier method. Univariate and multivariate analyses were conducted with Cox proportional hazards model. Multivariate model building was conducted using stepwise regression for variables with p-value smaller than 0.2 in the univariate analysis.

Results

There were 130 NSCLC patients enrolled in this study with a median age of 63 years (range from 34 to 82 y). The median prescription dose for these patients was 56 Gy (range 40–70 Gy) with a mean heart and lung dose of 14.8±8.5 Gy and 13.6±4.4 Gy, respectively. The rates of patients with above grade III radiation pneumonitis (RP) and fibrosis were 8.5% and 8.5%, respectively. The 2-year PFS and OS of these patients were 15.2% and 39.8%, with a median PFS and OS of 7.2 and 18.8 months, respectively. RP was correlated with OS (p=0.048) and lung V20 was associated with PFS (p=0.04) according to the univariate analysis. Multivariate analysis demonstrated that RP (HR 1.39, 95%CI 1.010–1.909, p=0.043) and heart V15 (HR 1.02, 95%CI 1.006–1.025 p=0.002) were progression factors of OS, and no factor was associated with PFS.

Conclusions

RP and heart V15 were associated with OS for patients with stage III NSCLC who underwent VMAT. Heart and lung dosimetric parameters were highly correlated with each other, sparing of heart and lung should be considered equally during the treatment planning.

Proton therapy for adults with mediastinal lymphomas: the International Lymphoma Radiation Oncology Group guidelines

Among adult lymphoma survivors, radiation treatment techniques that increase the excess radiation dose to organs at risk (OARs) put patients at risk for increased side effects, especially late toxicities. Minimizing radiation to OARs in adults patients with Hodgkin and non-Hodgkin lymphomas involving the mediastinum is the deciding factor for the choice of treatment modality. Proton therapy may help to reduce the radiation dose to the OARs and reduce toxicities, especially the risks for cardiac morbidity and second cancers. Because proton therapy may have some disadvantages, identifying the patients and the circumstances that may benefit the most from proton therapy is important. We present modern guidelines to identify adult lymphoma patients who may derive the greatest benefit from proton therapy, along with an analysis of the advantages and disadvantages of proton treatment.

Effect of accurate heart delineation on cardiac dose during the CONVERT trial

OBJECTIVE

This study investigated the effect of deviation from protocol in heart delineation for the Concurrent Once-daily Versus twice-daily Radiotherapy (CONVERT) Trial ( ClinicalTrials.gov Identifier NCT00433563) quality assurance (QA) programme and the effect of that on mean cardiac dose and percentage of heart volume receiving ≥5 Gy (V5%) and percentage of heart volume receiving ≥30 Gy (V30%).

METHODS

Patients with limited-stage small-cell lung cancer in the CONVERT trial were randomized to receive 45 Gy in 30# twice daily or 66 Gy in 33# once daily radiotherapy, with concurrent chemotherapy in both arms. Of the 100 trial patient cases reviewed by the QA team [for patient selection, disease/organs at risk (OARs) outlining and treatment planning], 50 patient cases were selected, and the heart was reoutlined according to the "gold standard" trial protocol. Dose-volume histogram (DVH) data were extracted. The impact of change in heart volume on cardiac DVH is presented.

RESULTS

For gold standard cardiac outlines, an increase in V5% and V30% was seen in 77.3% and 81.8% of cases, respectively, in the control arm (45 Gy) and in 78.6% and 82.1% of cases, respectively, in the experimental arm (66 Gy). The median increase in V5% was 1.4% and in V30%, it was 3.4%. The average of the mean cardiac dose for the control arm increased by 2.1 Gy (from 15.2 Gy for the centres outline to 17.3 Gy for the gold standard outline) and for the experimental arm by 2.4 Gy (from 16.2 to 18.6 Gy).

CONCLUSION

This study demonstrates the importance of having a robust QA programme in place to ensure accuracy of cardiac delineation to facilitate future studies investigating the impact of cardiac dose on toxicity. Advances in knowledge: This study highlights the importance of ensuring accurate delineation of OARs in clinical trials, where conclusions about normal tissue toxicity are to be drawn.

Proton Therapy for Pediatric Hodgkin Lymphoma

BACKGROUND

Compared to X-ray radiation therapy, proton therapy (PT) reduces the radiation dose to organs at risk, which is expected to translate into fewer second cancers and less cardiac morbidity decades after treatment. The Children's Oncology Group high-risk pediatric Hodgkin lymphoma (PHL) protocol, AHOD1331, allows the use of PT, yet limited data exist on the use of PT in PHL.

PROCEDURE

Between 2010 and 2014, 22 pediatric patients were treated with PT for PHL at our institution: 7 intermediate-risk patients, 11 high-risk patients, and 4 relapsed patients. The patients' age ranged from 6 to 18 years old. Median follow-up was 36 months. All patients received chemotherapy before PT.

RESULTS

The 2-year and 3-year overall survival rates were both 94%, and the progression-free survival rate was 86%. Recurrences occurred in three high-risk patients: one isolated in-field cervical lymph node and two in-field and out-of-field. All recurrences occurred within 5 months of completing PT. No PT-related grade 3 or higher acute or late complications were observed.

CONCLUSION

PT for PHL showed no short-term severe toxicity and yields similar short-term control to recently published large multi-institutional clinical trials.

Late radiation toxicity in Hodgkin lymphoma patients: proton therapy's potential

In 2010, all young patients treated for intrathoracic Hodgkin lymphoma (HL) at one of 10 radiotherapy centers in the province of Quebec received 3D conformal photon therapy. These patients may now be at risk for late effects of their treatment, notably secondary malignancies and cardiac toxicity. We hypothesized that more complex radiotherapy, including intensity‐modulated proton therapy (IMPT) and possibly IMRT (in the form of helical tomotherapy (HT)), could benefit these patients. With institutional review board approval at 10 institutions, all treatment plans for patients under the age of 30 treated for HL during a six‐month consecutive period of 2010 were retrieved. Twenty‐six patients were identified, and after excluding patients with extrathoracic radiation or treatment of recurrence, 20 patients were replanned for HT and IMPT. Neutron dose for IMPT plans was estimated from published measurements. The relative seriality model was used to predict excess risk of cardiac mortality. A modified linear quadratic model was used to predict the excess absolute risk for induction of lung cancer and, in female patients, breast cancer. Model parameters were derived from published data. Predicted risk for cardiac mortality was similar among the three treatment techniques (absolute excess risk of cardiac mortality was not reduced for HT or IMPT (p>0.05,p>0.05) as compared to 3D CRT). Predicted risks were increased for HT and reduced for IMPT for secondary lung cancer (p<0.001,p<0.001) and breast cancers (p<0.001,p<0.001) as compared to 3D CRT.

PACS numbers: 87.55.dh, 87.55.dk