Predicted cardiac and second cancer risks for patients undergoing VMAT for mediastinal Hodgkin lymphoma

Background and purpose To predict treatment-related cardiovascular disease (CVD) and second cancer 30-yea. absolute mortality risks (AMR30) for patients with mediastinal Hodgkin lymphoma in a large multicentre radiation oncology network in Ireland. Material and methods This study includes consecutive patients treated for mediastinal lymphoma using chemotherapy and involved site radiotherapy (RT) 2016–2019. Radiation doses to heart, left ventricle, cardiac valves, lungs, oesophagus, carotid arteries and female breasts were calculated. Individual CVD and second cancer AMR30 were predicted using Irish background population rates and dose–response relationships. Results Forty-four patients with Hodgkin lymphoma were identified, 23 females, median age 28 years. Ninety-eight percent received anthracycline, 80% received 4–6 cycles ABVD. Volumetric modulated arc therapy (VMAT) ± deep inspiration breath hold (DIBH) was delivered, median total prescribed dose 30 Gy. Average mean heart dose 9.8 Gy (range 0.2–23.8 Gy). Excess treatment-related mean AMR30 from CVD was 2.18% (0.79, 0.90, 0.01, 0.13 and 0.35% for coronary disease, heart failure, valvular disease, stroke and other cardiac diseases), 1.07% due to chemotherapy and a further 1.11% from RT. Excess mean AMR30 for second cancers following RT were: lung cancer 2.20%, breast cancer in females 0.34%, and oesophageal cancer 0.28%. Conclusion For patients with mediastinal lymphoma excess mortality risks from CVD and second cancers remain clinically significant despite contemporary chemotherapy and photon-RT. Efforts to reduce the toxicity of combined modality treatment, for example, using DIBH, reduced margins and advanced RT, e.g. proton beam therapy, should be continued to further reduce potentially fatal treatment effects (AU)

Proton Beam Therapy for Early Breast Cancer: A Systematic Review and Meta-analysis of Clinical Outcomes.

PURPOSE: Adjuvant proton beam therapy (PBT) is increasingly available to patients with breast cancer. It achieves better planned dose distributions than standard photon radiation therapy and therefore may reduce the risks. However, clinical evidence is lacking. METHODS AND MATERIALS: A systematic review of clinical outcomes from studies of adjuvant PBT for early breast cancer published in 2000 to 2022 was undertaken. Early breast cancer was defined as when all detected invasive cancer cells are in the breast or nearby lymph nodes and can be removed surgically. Adverse outcomes were summarized quantitatively, and the prevalence of the most common ones were estimated using meta-analysis. RESULTS: Thirty-two studies (1452 patients) reported clinical outcomes after adjuvant PBT for early breast cancer. Median follow-up ranged from 2 to 59 months. There were no published randomized trials comparing PBT with photon radiation therapy. Scattering PBT was delivered in 7 studies (258 patients) starting 2003 to 2015 and scanning PBT in 22 studies (1041 patients) starting 2000 to 2019. Two studies (123 patients) starting 2011 used both PBT types. For 1 study (30 patients), PBT type was unspecified. Adverse events were less severe after scanning than after scattering PBT. They also varied by clinical target. For partial breast PBT, 498 adverse events were reported (8 studies, 358 patients). None were categorized as severe after scanning PBT. For whole breast or chest wall ± regional lymph nodes PBT, 1344 adverse events were reported (19 studies, 933 patients). After scanning PBT, 4% (44/1026) of events were severe. The most prevalent severe outcome after scanning PBT was dermatitis, which occurred in 5.7% (95% confidence interval, 4.2-7.6) of patients. Other severe adverse outcomes included infection, pain, and pneumonitis (each ≤1%). Of the 141 reconstruction events reported (13 studies, 459 patients), the most prevalent after scanning PBT was prosthetic implant removal (34/181, 19%). CONCLUSIONS: This is a quantitative summary of all published clinical outcomes after adjuvant PBT for early breast cancer. Ongoing randomized trials will provide information on its longer-term safety compared with standard photon radiation therapy.

Association of Radiation and Procarbazine Dose With Risk of Colorectal Cancer Among Survivors of Hodgkin Lymphoma.

Importance: Hodgkin lymphoma (HL) survivors have higher rates of colorectal cancer, which may be associated with subdiaphragmatic radiation therapy and/or alkylating chemotherapy. Although radiation dose-response associations with breast, lung, stomach, pancreatic, and esophageal cancer after HL have been demonstrated, the association of radiation therapy with colorectal cancer remains unclear. Objective: To quantify the rate of colorectal cancer according to radiation dose to the large bowel and procarbazine dose among HL survivors. Design, Setting, and Participants: A nested case-control study examined 5-year HL survivors at 5 hospital centers in the Netherlands. Participants had been diagnosed with HL in 1964 to 2000, when they were 15 to 50 years of age, and were followed for a median of approximately 26 years. Survivors of HL who developed colorectal cancer and survivors who were selected as controls were individually matched on sex, age at HL diagnosis, and date of HL diagnosis. Data were analyzed from July 2021 to October 2022. Exposures: Mean radiation doses to the large bowel were estimated by reconstructing individual radiation therapy treatments on representative computed tomography data sets. Main Outcomes and Measures: Excess rate ratios (ERRs) were modeled to evaluate the excess risk associated with each 1-gray increase in radiation dose, and potential effect modification by procarbazine was explored. Results: The study population included 316 participants (mean [SD] age at HL diagnosis, 33.0 [9.8] years; 221 [69.9%] men), 78 of whom were HL survivors who developed colorectal cancer (cases) and 238 who did not (controls). The median (IQR) interval between HL and colorectal cancer was 25.7 (18.2-31.6) years. Increased colorectal cancer rates were seen for patients who received subdiaphragmatic radiation therapy (rate ratio [RR], 2.4; 95% CI, 1.4-4.1) and those who received more than 8.4 g/m2 procarbazine (RR, 2.5; 95% CI, 1.3-5.0). Overall, colorectal cancer rate increased linearly with mean radiation dose to the whole large bowel and dose to the affected bowel segment. The association between radiation dose and colorectal cancer rate became stronger with increasing procarbazine dose: the ERR per gray to the whole bowel was 3.5% (95% CI, 0.4%-12.6%) for patients who did not receive procarbazine, and increased 1.2-fold (95% CI, 1.1-1.3) for each 1-g/m2 increase in procarbazine dose. Conclusions and Relevance: This nested case-control study of 5-year HL survivors found a dose-response association between radiation therapy and colorectal cancer risk, and modification of this association by procarbazine. These findings may enable individualized colorectal cancer risk estimations, identification of high-risk survivors for subsequent screening, and optimization of treatment strategies.

Predicted cardiac and second cancer risks for patients undergoing VMAT for mediastinal Hodgkin lymphoma.

BACKGROUND AND PURPOSE: To predict treatment-related cardiovascular disease (CVD) and second cancer 30-year absolute mortality risks (AMR30) for patients with mediastinal Hodgkin lymphoma in a large multicentre radiation oncology network in Ireland. MATERIAL AND METHODS: This study includes consecutive patients treated for mediastinal lymphoma using chemotherapy and involved site radiotherapy (RT) 2016-2019. Radiation doses to heart, left ventricle, cardiac valves, lungs, oesophagus, carotid arteries and female breasts were calculated. Individual CVD and second cancer AMR30 were predicted using Irish background population rates and dose-response relationships. RESULTS: Forty-four patients with Hodgkin lymphoma were identified, 23 females, median age 28 years. Ninety-eight percent received anthracycline, 80% received 4-6 cycles ABVD. Volumetric modulated arc therapy (VMAT) ± deep inspiration breath hold (DIBH) was delivered, median total prescribed dose 30 Gy. Average mean heart dose 9.8 Gy (range 0.2-23.8 Gy). Excess treatment-related mean AMR30 from CVD was 2.18% (0.79, 0.90, 0.01, 0.13 and 0.35% for coronary disease, heart failure, valvular disease, stroke and other cardiac diseases), 1.07% due to chemotherapy and a further 1.11% from RT. Excess mean AMR30 for second cancers following RT were: lung cancer 2.20%, breast cancer in females 0.34%, and oesophageal cancer 0.28%. CONCLUSION: For patients with mediastinal lymphoma excess mortality risks from CVD and second cancers remain clinically significant despite contemporary chemotherapy and photon-RT. Efforts to reduce the toxicity of combined modality treatment, for example, using DIBH, reduced margins and advanced RT, e.g. proton beam therapy, should be continued to further reduce potentially fatal treatment effects.

Systematic review for deep inspiration breath hold in proton therapy for mediastinal lymphoma: A PTCOG Lymphoma Subcommittee report and recommendations.

PURPOSE: To systematically review all dosimetric studies investigating the impact of deep inspiration breath hold (DIBH) compared with free breathing (FB) in mediastinal lymphoma patients treated with proton therapy as compared to IMRT (intensity-modulated radiation therapy)-DIBH. MATERIALS AND METHODS: We conducted a systematic review in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guideline using the PubMed database to identify studies of mediastinal lymphoma patients with dosimetric comparisons of proton-FB and/or proton-DIBH with IMRT-DIBH. Parameters included mean heart (MHD), lung (MLD), and breast (MBD) doses, among other parameters. Case reports were excluded. Absolute differences in mean doses > 1 Gy between comparators were considered to be clinically meaningful. RESULTS: As of April 2021, eight studies fit these criteria (n = 8), with the following comparisons: proton-FB vs IMRT-DIBH (n = 5), proton-DIBH vs proton-FB (n = 5), and proton-DIBH vs IMRT-DIBH (n = 8). When comparing proton-FB with IMRT-DIBH in 5 studies, MHD was reduced with proton-FB in 2 studies, was similar (<1 Gy difference) in 2 studies, and increased in 1 study. On the other hand, MLD and MBD were reduced with proton-FB in 3 and 4 studies, respectively. When comparing proton-DIBH with proton-FB, MHD and MLD were reduced with proton DIBH in 4 and 3 studies, respectively, while MBD remained similar. Compared with IMRT-DIBH in 8 studies, proton-DIBH reduced the MHD in 7 studies and was similar in 1 study. Furthermore, MLD and MBD were reduced with proton-DIBH in 8 and 6 studies respectively. Integral dose was similar between proton-FB and proton-DIBH, and both were substantially lower than IMRT-DIBH. CONCLUSION: Accounting for heart, lung, breast, and integral dose, proton therapy (FB or DIBH) was superior to IMRT-DIBH. Proton-DIBH can lower dose to the lungs and heart even further compared with proton-FB, depending on disease location in the mediastinum, and organ-sparing and target coverage priorities.

Implementation of a comprehensive set of optimised CBCT protocols and validation through imaging quality and dose audit.

OBJECTIVES: Cone-beam computed tomography (CBCT) for radiotherapy treatment verification has increased in frequency; therefore, it is crucial to optimise image quality and radiation dose to patients. The aim of this study was to implement optimised CBCT protocols for the Varian TrueBeams for most tumour sites in adult patients. METHODS: A combination of patient size-specific CBCT protocols from the literature and developed in-house was used. Scans taken before and after optimisation were compared by senior radiographers and physicists to evaluate how changes affected image quality and clinical usability for online image registration. The change in dose for each new CBCT protocol was compared to the Varian default. A clinical audit was performed following implementation to evaluate the changes in imaging dose for all patients receiving a CBCT during that period. RESULTS: Ten CBCT protocols were introduced including head and neck and patient-size-specific thorax and pelvis/abdomen protocols. Scans from 102 patients with images before and after optimisation were assessed, none of the scans showed image quality changes compromising clinical usability and for some image quality was improved. Between November 2020 and June 2021, 1185 patients had CBCTs using the new protocols. The imaging dose was reduced for 52% of patients, remained the same for 37% and increased for 12%. CONCLUSIONS: This study showed that substantial dose reductions and image quality improvements can be achieved with simple changes in the default settings of the Varian TrueBeam CBCT without affecting the radiographers' confidence in online image registration. ADVANCES IN KNOWLEDGE: This study represents a comprehensive assessment and optimisation of CBCT protocols for most sites, validated on a large cohort of patients.

Deep inspiration breath-hold for mediastinal lymphoma patients: Evaluation of a 5-year service.

Deep inspiration breath-hold (DIBH) is an advanced radiotherapy technique that has been shown to have dosimetric benefits in the treatment of patients with mediastinal lymphoma. Whilst there is much published data on the use of DIBH in breast radiotherapy, reports on the use of the technique in mediastinal lymphoma patients remain limited. As the first NHS centre in the UK to implement DIBH in this pt group, we have evaluated our experience and success in using this technique over a 5 year period.

Introduction of deep inspirational breath-hold and Butterfly-VMAT techniques into clinical practice for the treatment of mediastinal lymphoma - Lessons learned from an experienced centre.

Deep inspiration breath-hold, butterfly volumetric modulated arc therapy and daily imaging techniques for mediastinal lymphoma patients have been introduced in a single department. Whilst introducing these techniques, there were many practical lessons to be learned across the patient pathway, from pre-treatment through to treatment delivery.Therapeutic radiographers were key members of the multi-disciplinary team implementing these techniques. This work reflects on the experience of introducing these advanced techniques for mediastinal lymphoma patients and the lessons learnt.

Informing radiotherapy decisions in stage I/IIa Hodgkin lymphoma: modeling life expectancy using radiation dosimetry.

In recent randomized trials, omitting consolidative radiotherapy (RT) in early-stage Hodgkin lymphoma (ESHL) increased relapses. However, decades of follow-up are required to observe whether lower initial disease control is compensated by reduced risk of late effects. Extrapolation beyond trial follow-up is therefore necessary to inform current treatment decisions. To this end, we developed a microsimulation model to estimate lifetime quality-adjusted life years (QALYs) after combined modality treatment (CMT) or chemotherapy-alone for stage I/IIa ESHL. For CMT, the model included risks of breast and lung cancer, coronary heart disease, and ischemic stroke. Comparative outcomes were assessed for a clinically relevant range of example patients differing by age, sex, smoking status, and representative organs at risk (OAR) radiation doses informed by the RAPID trial. Analysis was performed with and without a 3.5% discount rate on future health. Smoking status had a large effect on optimal treatment choice. CMT was superior for nearly all never smoker example patients regardless of age, sex, and OAR doses. At a maximum, CMT produced a 1.095 (95% CI: 1.054-1.137) gain in undiscounted QALYs for a 20-year-old male never smoker with unilateral neck disease. In contrast, current smokers could substantially gain from chemotherapy-alone treatment. Again at a maximum, a 20-year-old male current smoker with bilateral neck and whole mediastinum involvement gained 3.500 (95% CI: 3.400 to 3.600) undiscounted QALYs with chemotherapy-alone treatment. Overall, CMT was more favorable the younger the patient, when future health discounting was included, and in never smokers.

Proton Therapy in Supradiaphragmatic Lymphoma: Predicting Treatment-Related Mortality to Help Optimize Patient Selection.

PURPOSE: In some patients with Hodgkin lymphoma (HL), proton beam therapy (PBT) may reduce the risk of radiation-related cardiovascular disease (CVD) and second cancers (SC) compared with photon radiation therapy (RT). Our aim was to identify patients who benefit the most from PBT in terms of predicted 30-year absolute mortality risks (AMR30) from CVD and SC, taking into account individual background, chemotherapy, radiation, and smoking-related risks. METHODS AND MATERIALS: Eighty patients with supradiaphragmatic HL treated with PBT between 2015 and 2019 were replanned using optimal photon RT. To identify patients predicted to derive the greatest benefit from PBT compared with photon RT, doses and AMR30 from CVD and SC of the lung, breast, and esophagus were compared for all patients and across patient subgroups. RESULTS: For patients with mediastinal disease below the origin of the left main coronary artery (n = 66; 82%), PBT reduced the mean dose to the heart, left ventricle, and heart valves by 1.0, 2.7, and 3.6 Gy, respectively. Based on U.S. mortality rates, PBT reduced CVD AMR30 by 0.2%, from 5.9% to 5.7%. The benefit was larger if the mediastinal disease overlapped longitudinally with the heart by ≥40% (n = 23; 29%). PBT reduced the mean dose to the heart, left ventricle, and heart valves by 3.2, 5.6, and 5.1 Gy, respectively, and reduced CVD AMR30 by 0.8%, from 7.0% to 6.2%. For patients with axillary disease (n = 25; 31%), PBT reduced the mean lung dose by 2.8 Gy and lung cancer AMR30 by 0.6%, from 2.7% to 2.1%. Breast and esophageal doses were also lower with PBT, but the effects on AMR30 were negligible. The effect of smoking on CVD and lung cancer AMR30 was much larger than radiation and chemotherapy and the differences between radiation modalities. CONCLUSIONS: The predicted benefit of PBT is not universal and limited to certain categories of patients with lymphoma and lower mediastinal or axillary disease. Smoking cessation should be strongly encouraged in smokers who require thoracic RT.

Exposure of the oesophagus in breast cancer radiotherapy: A systematic review of oesophagus doses published 2010-2020.

BACKGROUND AND PURPOSE: Breast cancer radiotherapy can increase the risk of subsequent primary oesophageal cancer, with risk increasing according to oesophagus radiation dose. We describe oesophagus exposure from modern breast cancer regimens and discuss the risks of oesophageal cancer for women irradiated recently. MATERIALS AND METHODS: A systematic review was undertaken of oesophagus doses from breast cancer radiotherapy regimens published during 2010-2020. Mean and maximum oesophagus doses were described for different target regions irradiated and different radiotherapy techniques. RESULTS: In 112 published regimens from 18 countries, oesophagus doses varied with target region. For partial breast irradiation, average mean oesophagus dose was 0.2 Gy (range 0.1-0.4) in four regimens; maximum dose was not reported. For breast or chest wall radiotherapy, average oesophagus doses were mean 1.8 Gy (range 0.1-10.4) in 24 regimens and maximum 6.7 Gy (range 0.4-14.3) in seven regimens. For radiotherapy including a nodal region, average oesophagus doses were higher: mean 11.4 Gy (range <0.1-29.3) in 61 regimens and maximum 34.4 Gy (range 3.4-51.3) in 55 regimens. Average mean oesophagus doses were >10 Gy for intensity modulated nodal radiotherapy, but lower for other node techniques. CONCLUSIONS: Mean oesophagus doses from partial breast and breast/chest wall regimens were usually less than 2 Gy, hence radiation-risks will be very small. However, for radiotherapy including lymph nodes, average mean oesophagus dose of 11.4 Gy may nearly double oesophageal cancer risk. Consideration of oesophageal exposure during nodal radiotherapy planning may reduce the risks of radiation-related oesophageal cancer for women irradiated today.

The role of motion management and position verification in lymphoma radiotherapy.

In the last decades, the substantial technical progress in radiation oncology offered the opportunity for more accurate planning and delivery of treatment. At the same time, the evolution of systemic treatment and the advent of modern diagnostic tools allowed for more accurate staging and consequently a safe reduction of radiotherapy (RT) target volumes and RT doses in the treatment of lymphomas. As a result, incidental irradiation of organs at risk was reduced, with a consequent reduction of severe late toxicity in long-term lymphoma survivors. Nevertheless, these innovations warrant that professionals pay attention to concurrently ensure precise planning and dose delivery to the target volume and safe sparing of the organs at risk. In particular, target and organ motion should be carefully managed in order to prevent any compromise of treatment efficacy. Several aspects should be taken into account during the treatment pathway to minimise uncertainties and to apply a valuable motion management strategy, when needed. These include: reliable image registration between diagnostic and planning radiologic exams to facilitate the contouring process, image guidance to limit positioning uncertainties and to ensure the accuracy of dose delivery and management of lung motion through procedures of respiratory gating and breath control. In this review, we will cover the current clinical approaches to minimise these uncertainties in patients treated with modern RT techniques, with a particular focus on mediastinal lymphoma. In addition, since uncertainties have a different impact on the dose deposition of protons compared to conventional x-rays, the role of motion management and position verification in proton beam therapy (PBT) will be discussed in a separate section.

Predicted Risks of Cardiovascular Disease Following Chemotherapy and Radiotherapy in the UK NCRI RAPID Trial of Positron Emission Tomography-Directed Therapy for Early-Stage Hodgkin Lymphoma.

PURPOSE: The contemporary management of early-stage Hodgkin lymphoma (ES-HL) involves balancing the risk of late adverse effects of radiotherapy against the increased risk of relapse if radiotherapy is omitted. This study provides information on the risk of radiation-related cardiovascular disease to help personalize the delivery of radiotherapy in ES-HL. METHODS: We predicted 30-year absolute cardiovascular risk from chemotherapy and involved field radiotherapy in patients who were positron emission tomography (PET)-negative following three cycles of doxorubicin, bleomycin, vinblastine, and dacarbazine chemotherapy within a UK randomized trial of PET-directed therapy for ES-HL. Cardiac and carotid radiation doses and chemotherapy exposure were combined with established dose-response relationships and population-based mortality and incidence rates. RESULTS: Average mean heart dose was 4.0 Gy (range 0.1-24.0 Gy) and average bilateral common carotid artery dose was 21.5 Gy (range 0.6-38.1 Gy), based on individualized cardiovascular dosimetry for 144 PET-negative patients receiving involved field radiotherapy. The average predicted 30-year radiation-related absolute excess overall cardiovascular mortality was 0.56% (range 0.01%-6.79%; < 0.5% in 67% of patients and > 1% in 15%), whereas average predicted 30-year excess incidence was 6.24% (range 0.31%-31.09%; < 5% in 58% of patients and > 10% in 24%). For cardiac disease, the average predicted 30-year radiation-related absolute excess mortality was 0.42% (0.79% with mediastinal involvement and 0.05% without) and for stroke, it was 0.14%. CONCLUSION: Predicted excess cardiovascular risk is small for most patients, so radiotherapy may provide net benefit. However, for a minority of patients receiving high doses of radiation to cardiovascular structures, it may be preferable to consider advanced radiotherapy techniques to reduce doses or to omit radiotherapy and accept the increased relapse risk. Individual assessment of cardiovascular and other risks before treatment would allow personalized decision making about radiotherapy in ES-HL.

Dose-response relationships for radiation-related heart disease: Impact of uncertainties in cardiac dose reconstruction.

BACKGROUND AND PURPOSE: Radiation-related heart disease (RRHD) can occur many decades after thoracic radiotherapy for Hodgkin lymphoma (HL) or childhood cancer (CC). To quantify the likely risk of RRHD for patients treated today, dose-response relationships derived from patients treated in previous decades are used. Publications presenting these dose-response relationships usually include estimates of uncertainties in the risks but ignore the effect of uncertainties in the reconstructed cardiac doses. MATERIALS/METHODS: We assessed the systematic and random uncertainties in the reconstructed doses for published dose-response relationships for RRHD risk in survivors of HL or CC. Using the same reconstruction methods as were used in the original publications, we reconstructed mean heart doses and, wherever possible, mean left-ventricular doses for an independent case-series of test patients. These patients had known, CT-based, cardiac doses which were compared with the reconstructed doses to estimate the magnitude of the uncertainties and their effect on the dose-response relationships. RESULTS: For all five reconstruction methods the relationship between reconstructed and CT-based doses was linear. For all but the simplest reconstruction method, the dose uncertainties were moderate, the effect of the systematic uncertainty on the dose-response relationships was less than 10%, and the effects of random uncertainty were small except at the highest doses. CONCLUSIONS: These results increase confidence in the published dose-response relationships for the risk of RRHD in HL and CC survivors. This may encourage doctors to use these dose-response relationships when estimating individualised risks for patients-an important aspect of personalising radiotherapy treatments today.

Clinical Intensity Modulated Proton Therapy for Hodgkin Lymphoma: Which Patients Benefit the Most?

PURPOSE: Radiation therapy (RT) improves control of Hodgkin lymphoma (HL), but patients who undergo RT are at risk for late effects, including cardiovascular disease and second cancers, because of radiation doses to organs at risk (OARs). Proton therapy (PT) can reduce OAR doses compared with conventional photon RT. However, access to PT is currently limited, so referrals must be appropriately selective. We aimed to identify subgroups of patients with HL who could benefit the most dosimetrically from RT with PT based on the prechemotherapy disease characteristics. METHODS AND MATERIALS: Normal tissue radiation doses were calculated for 21 patients with HL who were treated with deep-inspiration breath-hold pencil-beam scanning (PBS) PT and compared with doses from 3-dimensional conformal (3D-CRT) and partial arc volumetric modulated (PartArc) photon RT. Prechemotherapy disease characteristics associated with significant dosimetric benefits from PBS compared with photon RT were identified. RESULTS: Treatment with PBS was well tolerated and provided with good local control. PBS provided dosimetric advantages for patients whose clinical treatment volume extended below the seventh thoracic level and for female patients with axillary disease. In addition, an increasing dosimetric benefit for some OARs was observed for increasing target volume. PBS significantly reduced the mean dose to the heart, breast, lungs, spinal cord, and esophagus. Dose homogeneity and conformity within the target volume were also superior with PBS, but some high-dose measures and hot spots were increased with PBS compared with partial arc volumetric modulated photon RT. CONCLUSIONS: PBS gives good target coverage and local control while providing reductions in radiation dose to OARs for individuals who receive RT for HL compared with advanced photon RT. Our findings highlight groups of patients who would be expected to gain more dosimetric benefit from PBS. These findings facilitate the selection of patients who should be considered a priority for PT.

Risk of heart failure in survivors of Hodgkin lymphoma: effects of cardiac exposure to radiation and anthracyclines.

Hodgkin lymphoma (HL) survivors treated with radiotherapy and/or chemotherapy are known to have increased risks of heart failure (HF), but a radiation dose-response relationship has not previously been derived. A case-control study, nested in a cohort of 2617 five-year survivors of HL diagnosed before age 51 years during 1965 to 1995, was conducted. Cases (n = 91) had moderate or severe HF as their first cardiovascular diagnosis. Controls (n = 278) were matched to cases on age, sex, and HL diagnosis date. Treatment and follow-up information were abstracted from medical records. Mean heart doses and mean left ventricular doses (MLVD) were estimated by reconstruction of individual treatments on representative computed tomography datasets. Average MLVD was 16.7 Gy for cases and 13.8 Gy for controls (Pdifference = .003). HF rate increased with MLVD: relative to 0 Gy, HF rates following MVLD of 1-15, 16-20, 21-25, and ≥26 Gy were 1.27, 1.65, 3.84, and 4.39, respectively (Ptrend < .001). Anthracycline-containing chemotherapy increased HF rate by a factor of 2.83 (95% CI: 1.43-5.59), and there was no significant interaction with MLVD (Pinteraction = .09). Twenty-five-year cumulative risks of HF following MLVDs of 0-15 Gy, 16-20 Gy, and ≥21 Gy were 4.4%, 6.2%, and 13.3%, respectively, in patients treated without anthracycline-containing chemotherapy, and 11.2%, 15.9%, and 32.9%, respectively, in patients treated with anthracyclines. We have derived quantitative estimates of HF risk in patients treated for HL following radiotherapy with or without anthracycline-containing chemotherapy. Our results enable estimation of HF risk for patients before treatment, during radiotherapy planning, and during follow-up.