Transformation in the use of radiation therapy of Hodgkin lymphoma: new concepts and indications lead to modern field design and are assisted by PET imaging and intensity modulated radiation therapy (IMRT)

Results of consolidative radiotherapy for relapsed diffuse B-cell lymphoma

Background

Recurrent diffuse large B-cell lymphoma (DLBCL) is a disease with high mortality. The standard of care involves autologous stem-cell transplantation (ASCT), which is not always feasible. We investigated the impact of radiotherapy as part of the salvage treatment for patients with relapsed disease.

Materials and methods

Retrospective study of patients with recurrent DLBCL after chemotherapy and consolidative radiotherapy at a single institution. All patients were included if radiation was part of the first treatment.

Results

Of 359 patients assessed between 2010 and 2017, 65 (18.1%) presented a recurrence, but only 62 received further treatment and were included in the study. Mean overall survival was 18.6 months since diagnosis and progression-free survival after first progression (PFS2) was 7.7 months. Patients were divided into two groups according to whether they did (24.8%) or did not (75.8%) receive radiation as part of their salvage treatment. Patients that did not receive R-CHOP (rituximab plus cyclophosphamide, doxorubicin hydrochloride, vincristine, and prednisone) in the first line were treated more with radiation in the second line (p = 0.02). Six patients with in-field relapse were re-irradiated. Only 4 patients received ASCT as part of their treatment for relapsed disease. There was no difference in outcomes.

Conclusion

There is a place for radiotherapy in the treatment of relapsed DLBCL, particularly when patients do not receive ASCT. Radiotherapy is well-tolerated. More trials to assess the role of radiotherapy for these patients are needed.

Metabolic Tumor Volume Metrics in Lymphoma

Although visual assessment using the Deauville criteria is strongly recommended by guidelines for treatment response monitoring in all FDG-avid lymphoma histologies, the high rate of false-positives and concerns about interobserver variability have motivated the development of quantitative tools to facilitate objective measurement of tumor response in both routine and clinical trial settings. Imaging studies using functional quantitative measures play a significant role in profiling oncologic processes. These quantitative metrics allow for objective end points in multicenter clinical trials. However, the standardization of imaging procedures including image acquisition parameters, reconstruction and analytic measures, and validation of these methods are essential to enable an individualized treatment approach. A robust quality control program associated with the inclusion of proper scanner calibration, cross-calibration with dose calibrators and across other scanners is required for accurate quantitative measurements. In this section, we will review the technical and methodological considerations related to PET-derived quantitative metrics and the relevant published data to emphasize the potential value of these metrics in the prediction of patient prognosis in lymphoma.

Transesophageal Echocardiography and Radiation-induced Damages

The long-term sequelae of mantle therapy include, especially lung and cardiac disease but also involve the vessels and the organs in the neck and thorax (such as thyroid, aorta, and esophagus). We presented the case of 66-year-old female admitted for congestive heart failure in radiation-induced heart disease. The patient had undergone to massive radiotherapy 42 years ago for Hodgkin's disease (type 1A). Transesophageal echocardiography was performed unsuccessfully with difficulty because of the rigidity and impedance of esophageal walls. Our case is an extraordinary report of radiotherapy's latency effect as a result of dramatic changes in the structure of mediastinum, in particular in the esophagus, causing unavailability of a transesophageal echocardiogram.

Radiotherapy of Hodgkin and Non-Hodgkin Lymphoma

Purpose:

To improve the contouring of clinical target volume for the radiotherapy of neck Hodgkin/non-Hodgkin lymphoma by localizing the prechemotherapy gross target volume onto the simulation computed tomography using [18F]-fluorodeoxyglucose positron emission tomography/computed tomography.

Material and Methods:

The gross target volume delineated on prechemotherapy [18F]-fluorodeoxyglucose positron emission tomography/computed tomography images was warped onto simulation computed tomography using deformable image registration. Fifteen patients with neck Hodgkin/non-Hodgkin lymphoma were analyzed. Quality of image registration was measured by computing the Dice similarity coefficient on warped organs at risk. Five radiation oncologists visually scored the localization of automatic gross target volume, ranking it from 1 (wrong) to 5 (excellent). Deformable registration was compared to rigid registration by computing the overlap index between the automatic gross target volume and the planned clinical target volume and quantifying the V95 coverage.

Results:

The Dice similarity coefficient was 0.80 ± 0.07 (median ± quartiles). The physicians’ survey had a median score equal to 4 (good). By comparing the rigid versus deformable registration, the overlap index increased from a factor of about 4 and the V95 (percentage of volume receiving the 95% of the prescribed dose) went from 0.84 ± 0.38 to 0.99 ± 0.10 (median ± quartiles).

Conclusion:

This study demonstrates the impact of using deformable registration between prechemotherapy [18F]-fluorodeoxyglucose positron emission tomography/computed tomography and simulation computed tomography, in order to automatically localize the gross target volume for radiotherapy treatment of patients with Hodgkin/non-Hodgkin lymphoma.

Tailored strategies for radiation therapy in classical Hodgkin's lymphoma

Radiotherapeutic advances have contributed to the evolution of Hodgkin's lymphoma (HL) treatment paradigms. A reduction in radiation therapy (RT) field size and dose has the potential to significantly impact the therapeutic ratio by diminishing late toxicities while maintaining curability. Substantial progress in risk stratification has contributed to the development of tailored RT strategies which address both field design as well as dose. Technologic improvements have also enhanced the ability to adapt the RT technique to the individual patient. The refinement of the RT approach and its incorporation into current combined modality strategies in adult classical HL is the subject of ongoing investigation and is critically reviewed.

[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.

Applications of new irradiation modalities in patients with lymphoma: Promises and uncertainties

New highly conformal irradiation modalities have emerged for treatment of Hodgkin lymphoma. Helical tomotherapy offers both intensity-modulated irradiation and accurate patient positioning and was shown to significantly decrease radiation doses to the critical organs. Here we review some of the most promising applications of helical tomotherapy in Hodgkin disease. By decreasing doses to the heart or the breast, helical tomotherapy might decrease the risk of long-term cardiac toxicity or secondary breast cancers, which are major concerns in patients receiving chest radiotherapy. Other strategies, such as debulking radiotherapy prior to stem cell transplantation or total lymphoid irradiation may be clinically relevant. However, helical tomotherapy may also increase the volume of tissues that receive lower doses, which has been implicated in the carcinogenesis process. Prospective assessments of these new irradiation modalities of helical tomotherapy are required to confirm the potential benefits of highly conformal therapies applied to hematological malignancies.

[Hodgkin's Lymphoma]

With approximately 1500 cases per year in France, Hodgkin's lymphoma (HL) represents only 10 to 15 % of new cases of lymphomas, and 0.5 to 1 % of new cases of cancers. The management of this lymphoproliferative disease has undergone profound conceptual changes over time, allowing at present to obtain a cure rate of 75 to 80 % of all confused stage, and up to 90 % in case of early stage HL. If initial treatment consisted in an exclusive extensive (total or sub-total lymphoid) irradiation whatever the stage may be, the place of radiotherapy in the management of HL has evolved over time but remains today one of the cornerstones of the treatment. It becomes integrated within the framework of combined modality therapies associating chemotherapy then irradiation for the early stage HL, and stays a therapeutic alternative in all situations (in advanced stage and\or recurrent disease) which raises the issue of increasing the locoregional tumor control. Despite the undeniable contribution of radiotherapy in controlling the disease, delayed side effects of treatments are not negligible. So the long-term monitoring of treated patients is essential, mainly because of an increased risk of morbi-mortality due to cardiovascular events and/or secondary cancers. It is important to remember that even today the "Involved Field" irradiation type remains the gold standard, even if we witness at present the emergence of new types of irradiation, which aim to reduce the amount of irradiated tissues to try to limit the risks of delayed radio-induced complications. The purpose of this article is to clarify the specific aspects (epidemiological, radio-anatomical and prognostic characteristics) of HL, as well as the practical modalities of the irradiation (illustrated by a clinical case record) when an indication of radiotherapy is placed for its treatment.

Effect of organ size and position on out-of-field dose distributions during radiation therapy

Mantle field irradiation has historically been the standard radiation treatment for Hodgkin lymphoma. It involves treating large regions of the chest and neck with high doses of radiation (up to 30 Gy). Previous epidemiological studies on the incidence of second malignancies following radiation therapy for Hodgkin lymphoma have revealed an increased incidence of second tumors in various organs, including lung, breast, thyroid and digestive tract. Multiple other studies, including the Surveillance, Epidemiology and End Results, indicated an increased incidence in digestive tract including stomach cancers following mantle field radiotherapy. Assessment of stomach dose is challenging because the stomach is outside the treatment field but very near the treatment border where there are steep dose gradients. In addition, the stomach can vary greatly in size and position. We sought to evaluate the dosimetric impact of the size and variable position of the stomach relative to the field border for a typical Hodgkin lymphoma mantle field irradiation. The mean stomach dose was measured using thermoluminescent dosimetry for nine variations in stomach size and position. The mean doses to the nine stomach variations ranged from 0.43 to 0.83 Gy when 30 Gy was delivered to the treatment isocenter. Statistical analyses indicated that there were no significant differences in the mean stomach dose when the stomach was symmetrically expanded up to 3 cm or shifted laterally (medial, anterior or posterior shifts) by up to 3 cm. There was, however, a significant (P > 0.01) difference in the mean dose when the stomach was shifted superiorly or inferiorly by ≥2.5 cm.

The use of FDG-PET to target tumors by radiotherapy

Fluorodeoxyglucose positron emission tomography (FDG-PET) plays an increasingly important role in radiotherapy, beyond staging and selection of patients. Especially for non-small cell lung cancer, FDG-PET has, in the majority of the patients, led to the safe decrease of radiotherapy volumes, enabling radiation dose escalation and, experimentally, redistribution of radiation doses within the tumor. In limited-disease small cell lung cancer, the role of FDG-PET is emerging. For primary brain tumors, PET based on amino acid tracers is currently the best choice, including high-grade glioma. This is especially true for low-grade gliomas, where most data are available for the use of (11)C-MET (methionine) in radiation treatment planning. For esophageal cancer, the main advantage of FDG-PET is the detection of otherwise unrecognized lymph node metastases. In Hodgkin's disease, FDG-PET is essential for involved-node irradiation and leads to decreased irradiation volumes while also decreasing geographic miss. FDG-PET's major role in the treatment of cervical cancer with radiation lies in the detection of para-aortic nodes that can be encompassed in radiation fields. Besides for staging purposes, FDG-PET is not recommended for routine radiotherapy delineation purposes. It should be emphasized that using PET is only safe when adhering to strictly standardized protocols.

High-dose chemo-radiotherapy for relapsed or refractory Hodgkin lymphoma and the significance of pre-transplant functional imaging

We previously reported that three risk factors (RF): initial remission duration <1 year, active B symptoms, and extranodal disease predict outcome in relapsed or refractory Hodgkin lymphoma (HL). Our goal was to improve event-free survival (EFS) for patients with multiple RF and to determine if response to salvage therapy impacted outcome. We conducted a phase II intent-to-treat study of tailored salvage treatment: patients with zero or one RF received standard-dose ifosfamide, carboplatin, and etoposide (ICE); patients with two RF received augmented ICE; patients with three RF received high-dose ICE with stem cell support. This was followed by evaluation with both computed tomography and functional imaging (FI); those with chemosensitive disease underwent high-dose chemoradiotherapy and autologous stem cell transplantation (ASCT). There was no treatment-related mortality. Compared to historical controls this therapy eliminated the difference in EFS between the three prognostic groups. Pre-ASCT FI predicted outcome; 4-year EFS rates was 33% vs. 77% for patients transplanted with positive versus negative FI respectively, P = 0.00004, hazard ratio 4.61. Risk-adapted augmentation of salvage treatment in patients with HL is feasible and improves EFS in poorer-risk patients. Our data suggest that normalisation of FI pre-ASCT predicts outcome, and should be the goal of salvage treatment.

PET imaging in lymphoma

PET has become a cornerstone procedure in modern lymphoma management. This paper reviews, from a clinical point of view, the evidence for using PET in the different subtypes of lymphoma and the different steps of their management. The reader is given an overview of the current PET-based interventional lymphoma trials and an insight into possible future developments in the field, including new PET tracers.

PET-CT in radiation oncology: the impact on diagnosis, treatment planning, and assessment of treatment response

OBJECTIVE

To review the role of hybrid positron emission tomography (PET)-computed tomography (CT) systems in the design and management of cancer patients in the modern radiation oncology practice. PET is co-registered with CT and incorporated into a systematic approach to the staging, management, and assessment of response and surveillance of a variety of oncologic diagnoses.

METHODS

A review of the literature of functional imaging such as PET-CT in staging, treatment plan design, assessment of response and detection of recurrence for tumors involving the head and neck, lung, esophagus, rectum amongst others.

RESULTS

PET and PET-CT offer significant advantages which include more accurate staging which often results in management changes in roughly one-third of patients across a number of disease site. More accurate target definition may augment highly conformal radiation treatment plans using intensity-modulated radiation therapy and stereotactic radiosurgery and radiotherapy.

CONCLUSION

The emerging data appears to suggest the functional imaging may be a more useful tool to evaluate the therapeutic effect of treatment, detect early failures and prognosticate long-term outcome.

Involved-nodal radiation therapy as a component of combination therapy for limited-stage Hodgkin's lymphoma: a question of field size

PURPOSE

Combined-modality therapy is the standard of care for limited-stage Hodgkin's lymphoma (HL). Radiation therapy has evolved from extended-field radiation therapy (EFRT) to involved-field radiation therapy (IFRT), reducing toxicity while maintaining high cure rates. Recent publications recommend a further reduction to involved-nodal radiation therapy (INRT), however, this has not been clinically validated.

PATIENTS AND METHODS

We identified 325 patients with limited-stage HL, diagnosed between May 1, 1989 and April 1, 2005, and treated with chemotherapy and radiation therapy following era-specific guidelines: EFRT until 1996; IFRT from 1996 to 2001; INRT < or = 5 cm from 2001 to the present. INRT < or = 5 cm was defined as the prechemotherapy nodal volume with margins < or = 5 cm to account for physiological movement, set-up variation, and the limitations of conventional simulation and radiation therapy techniques. Exclusion criteria were age younger than 16, fluorine-18 fluorodeoxyglucose positron emission tomography, non-doxorubicin, bleomycin, vinblastine, and dacarbazine-like chemotherapy, and/or more than four chemotherapy cycles.

RESULTS

At diagnosis, median age was 35 years; 52% male; stage IA 29%; stage IIA 71%. Ninety-five percent of patients received two chemotherapy cycles. The three radiation therapy groups were: EFRT, 39%; IFRT, 30%; and INRT < or = 5 cm, 31%. Median follow-up of living patients was 80 months. Median time to relapse was 37 months. Twelve relapses occurred: four after EFRT (3%); five after IFRT (5%); and three after INRT < or = 5 cm (3%; P = .9). No marginal recurrences occurred after INRT < or = 5 cm. Locoregional relapse (LRR) occurred in five patients: three after EFRT; two with IFRT; and none with INRT < or = 5 cm. At 5 years, progression-free survival (PFS) was 97%, and overall survival (OS) was 95%. At 10 years, PFS and OS were 95% and 90%, respectively.

CONCLUSION

Reduction in field size appears to be safe, without an increased risk of LRR in patients receiving INRT < or = 5 cm.

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.

Chemotherapy plus involved-field radiation in early-stage Hodgkin's disease

BACKGROUND

Treatment of early-stage Hodgkin's disease is usually tailored in line with prognostic factors that allow for reductions in the amount of chemotherapy and extent of radiotherapy required for a possible cure.

METHODS

From 1993 to 1999, we identified 1538 patients (age, 15 to 70 years) who had untreated stage I or II supradiaphragmatic Hodgkin's disease with favorable prognostic features (the H8-F trial) or unfavorable features (the H8-U trial). In the H8-F trial, we compared three cycles of mechlorethamine, vincristine, procarbazine, and prednisone (MOPP) combined with doxorubicin, bleomycin, and vinblastine (ABV) plus involved-field radiotherapy with subtotal nodal radiotherapy alone (reference group). In the H8-U trial, we compared three regimens: six cycles of MOPP-ABV plus involved-field radiotherapy (reference group), four cycles of MOPP-ABV plus involved-field radiotherapy, and four cycles of MOPP-ABV plus subtotal nodal radiotherapy.

RESULTS

The median follow-up was 92 months. In the H8-F trial, the estimated 5-year event-free survival rate was significantly higher after three cycles of MOPP-ABV plus involved-field radiotherapy than after subtotal nodal radiotherapy alone (98% vs. 74%, P<0.001). The 10-year overall survival estimates were 97% and 92%, respectively (P=0.001). In the H8-U trial, the estimated 5-year event-free survival rates were similar in the three treatment groups: 84% after six cycles of MOPP-ABV plus involved-field radiotherapy, 88% after four cycles of MOPP-ABV plus involved-field radiotherapy, and 87% after four cycles of MOPP-ABV plus subtotal nodal radiotherapy. The 10-year overall survival estimates were 88%, 85%, and 84%, respectively.

CONCLUSIONS

Chemotherapy plus involved-field radiotherapy should be the standard treatment for Hodgkin's disease with favorable prognostic features. In patients with unfavorable features, four courses of chemotherapy plus involved-field radiotherapy should be the standard treatment. (ClinicalTrials.gov number, NCT00379041 [ClinicalTrials.gov].).

Radiotherapy of hodgkin lymphoma: indications, new fields, and techniques

In recent years, radiotherapy in patients with Hodgkin lymphoma has evolved considerably because of sophisticated imaging technologies and radiation delivery techniques. Even more recently, a new radiation field concept has emerged to ensure better normal tissue protection while preserving an excellent clinical outcome. The role of radiation therapy is also rapidly changing because the concept of a risk-adapted treatment strategy, in which combined-modality treatments were the order of the day, is now expanding into a concept of response-adapted treatments.

2-[18F]fluoro-2-deoxyglucose positron-emission tomography in staging, response evaluation, and treatment planning of lymphomas

2-[18F]fluoro-2-deoxyglucose positron-emission tomography (FDG-PET) is used increasingly in the clinical management of lymphomas. With regard to staging, FDG-PET is more sensitive and specific than conventional staging methods in FDG avid lymphomas (ie, Hodgkin lymphoma and most aggressive non-Hodgkin lymphomas). Despite methodological problems, in particular the lack of a valid reference test, FDG-PET is approved and generally used for this purpose. With regard to response evaluation, FDG-PET at the end of treatment seems to aid considerably in differentiating between residual masses with or without residual lymphoma. Hence, new revised response criteria have been proposed, incorporating the result of FDG-PET at the end of treatment. An early interim FDG-PET scan after 1 to 3 cycles of chemotherapy is a very strong predictor of outcome, and trials are now in progress testing treatment modifications on this basis. With regard to treatment planning, in the context of combined-modality therapy, radiotherapy for lymphomas is moving toward more conformal techniques reducing the irradiated volume to include only the macroscopic lymphoma. In this situation, accurate imaging is essential, and FDG-PET coregistered with the planning computed tomography (CT) scan is used increasingly. The availability of PET/CT scanners suited for virtual simulation has aided this process. However, clinical data evaluating this technique are at present sparse.

Overview of early response assessment in lymphoma with FDG-PET

Early assessment of response to chemotherapy with fluorine-18 fluorodeoxyglucose positron emission tomography (FDG-PET) is becoming a routine part of management in patients with Hodgkin lymphoma (HL) and histologically aggressive non-Hodgkin lymphoma (NHL). Changes in FDG uptake can occur soon after the initiation of therapy and they precede changes in tumour volume. Recent studies in uniform populations of aggressive lymphomas (predominantly diffuse large B cell lymphomas) and HL have clarified the value of early response assessment with PET. These trials show that PET imaging after 2-3 chemotherapy cycles is far superior to CT-based imaging in predicting progression-free survival and can be at least as reliable as definitive response assessment at the end of therapy. This information is of great potential value to patients, but oncologists should be cautious in the use of early PET response in determining choice of therapy until some critical questions are answered. These include: When is the best time to use PET for response assessment? What is the best methodology, visual or quantitative? (For HL at least, visual reading appears superior to an SUV-based assessment). Can early responders be cured with less intensive therapy? Will survival be better for patients treated more intensively because they have a poor interim metabolic response? In the future, early PET will be crucial in developing response-adapted therapy but without further carefully designed clinical trials, oncologists will remain uncertain how best to use this new information.

Influence of different treatment techniques on radiation dose to the LAD coronary artery

Background

The purpose of this proof-of-principle study was to test the ability of an intensity-modulated radiotherapy (IMRT) technique to reduce the radiation dose to the heart plus the left ventricle and a coronary artery. Radiation-induced heart disease might be a serious complication in long-term cancer survivors.

Methods

Planning CT scans from 6 female patients were available. They were part of a previous study of mediastinal IMRT for target volumes used in lymphoma treatment that included 8 patients and represent all cases where the left anterior descending coronary artery (LAD) could be contoured. We compared 6 MV AP/PA opposed fields to a 3D conformal 4-field technique and an optimised 7-field step-and-shoot IMRT technique and evaluated DVH's for several structures. The planning system was BrainSCAN 5.21 (BrainLAB, Heimstetten, Germany).

Results

IMRT maintained target volume coverage but resulted in better dose reduction to the heart, left ventricle and LAD than the other techniques. Selective dose reduction could be accomplished, although not to the degree initially attempted. The median LAD dose was approximately 50% lower with IMRT. In 5 out of 6 patients, IMRT was the best technique with regard to heart sparing.

Conclusion

IMRT techniques are able to reduce the radiation dose to the heart. In addition to dose reduction to whole heart, individualised dose distributions can be created, which spare, e.g., one ventricle plus one of the coronary arteries. Certain patients with well-defined vessel pathology might profit from an approach of general heart sparing with further selective dose reduction, accounting for the individual aspects of pre-existing damage.

Stem cell transplantation in Hodgkin lymphoma

Hematopoietic stem cell transplantation is an effective treatment for patients with relapsed or refractory Hodgkin lymphoma. Treatment outcome is better among patients who demonstrate sensitivity to salvage chemotherapy. Approximately half of the patients undergoing autologous stem cell transplantation will be cured and sequential high-dose therapy has been proposed as a means of improving these results further. Lifelong medical surveillance is required following transplantation to monitor for late toxicity, including second malignancy. For young patients who relapse following transplantation, reduced-intensity allogeneic transplantation has shown encouraging response rates, while second autologous stem cell transplantation, radiotherapy and palliative single-agent chemotherapy are other options. For patients with multiple relapses and chemotherapy refractory disease, novel approaches are necessary.

Comparison of three different mediastinal radiotherapy techniques in female patients: Impact on heart sparing and dose to the breasts

BACKGROUND AND PURPOSE

To study different radiotherapy techniques for female patients with mediastinal target volumes. Especially in highly curable diseases such as lymphoma, long-term survivors might develop late cardiac damage and radiation-induced second cancer.

PATIENTS AND METHODS

Planning CT scans were obtained in eight cases. We contoured the clinical target volume (three different scenarios with or without lower mediastinum and hili) and organs at risk and compared standard 6MV ap-pa opposed fields to a 3D conformal 4-field technique and a 7-field step-and-shoot IMRT technique and evaluated DVHs for each structure. The planning system was BrainSCAN 5.21 (BrainLAB, Heimstetten, Germany).

RESULTS

Target volume coverage did not improve significantly with 4-field or IMRT techniques. However, IMRT resulted in better dose reduction to the heart than the other techniques. The median heart dose (intermediately sized target volume) was 98% (95-100) with ap-pa fields, 56% (52-79) with the 4-field technique, and 39% (36-65) with IMRT, for example (p<0.05). Better heart sparing was achieved at all dose levels down to the 15% isodose. The median maximum dose to the breasts was lowest with IMRT. The breast volume receiving low doses (15% or less), however, was highest with IMRT. There was also a disadvantage in mean lung dose.

CONCLUSIONS

IMRT might result in a reduced cardiac complication risk. In younger females, however, this advantage might be offset by the risk of breast cancer. The best technique for a given patient depends on age, comorbidity, and the individual risk estimates for breast cancer and cardiac morbidity, respectively.

Clinical impact of FDG-PET/CT in the planning of radiotherapy for early-stage Hodgkin lymphoma

BACKGROUND

Early-stage Hodgkin lymphoma (HL) has excellent survival rates but carries a high risk of late treatment-related adverse effects. Modern, individualised therapeutic strategies require an accurate determination of the extent of the disease. This study investigated the potential impact of 2-[18F]-fluoro-2-deoxy-d-glucose positron emission tomography/computerised tomogrpahy (FDG-PET/CT) in the planning of involved field radiotherapy (IFRT).

PATIENTS AND METHODS

Thirty patients received staging FDG-PET/CT before therapy, and IFRT after a short course of ABVD (adriamycin, bleomycin, vinblastine, dacarbazine) chemotherapy. IFRT planning was performed using only the CT data from the FDG-PET/CT scan. Later, the IFRT planning was performed anew using the FDG-PET/CT data as basis for contouring.

RESULTS

In 20 out of 30 patients, the radiotherapy (RT) course was unaffected by the addition of FDG-PET/CT. FDG-PET/CT would have increased the irradiated volume in seven patients where the volume receiving a minimum of 90% of the target dose was increased by 8-87%. FDG-PET/CT decreased the volume in two patients where the volume was reduced by 18% and 30%.

CONCLUSIONS

When used for RT planning, FDG-PET/CT results in larger IFRT treatment volumes. If FDG-PET/CT is introduced to RT planning, the method should be accompanied by a change in RT treatment strategy, aiming at more targeted therapy in order to best avoid radiation to normal tissues.

Chemotherapy and radiotherapy in Hodgkin's lymphoma: joining in or splitting up?

PURPOSE OF REVIEW

Radiotherapy is very effective in local control of Hodgkin's lymphoma. Unfortunately, long-term survivors exhibit an excess of life-threatening radiation-related late side effects. Consequently, there have been calls to cease the use of radiation in the primary treatment of Hodgkin's lymphoma, although there is also support for the judicious use of combined modality treatment.

RECENT FINDINGS

Most patients treated for Hodgkin's lymphoma are being cured with modern approaches. Recent publications confirm the superior efficacy of combined modality treatment over chemotherapy alone, but the initial gain in cure rate may be outweighed by late deaths due to various treatment-related diseases. Many patients may already be cured by chemotherapy alone. Classical risk factors can be used to distinguish favourable and unfavourable subgroups of patients with Hodgkin's lymphoma, but these risk factors cannot predict outcome in individual cases. A simple test to predict the likelihood of cure in individual patients would be of great benefit. Fluoro-deoxyglucose-PET scan investigation holds this promise.

SUMMARY

The present review deals with the role of radiation therapy in the treatment of Hodgkin's lymphoma.

Different histopathological subtypes of Hodgkin lymphoma show significantly different levels of FDG uptake

Positron emission tomography using 2-[18F]fluoro-2-deoxy-D-glucose (FDG-PET) enables quantitative analysis of metabolic activity. This study investigated standardized uptake value (SUV) levels in the different histopathological subtypes of Hodgkin lymphoma (HL). Sixty patients with newly diagnosed HL underwent staging FDG-PET/CT after lymph node biopsy. Maximum SUV in each patient (SUV(max/total)) and in each affected region or organ (SUV(max)) were recorded. Mean SUV(max/total) was 9.3 g/ml in seven nodular lymphocyte predominance (NLP) patients, 16.3 g/ml in 38 nodular sclerosis (NS) patients, 20.8 g/ml in 11 mixed cellularity (MC) patients, and 19.5 g/ml in four patients with unclassified classical HL (CHL-NOS), (ANOVA, p = 0.011). Out of 780 sites (600 lymph node regions plus 180 organs), 208 sites were found to be affected with HL. Mean SUV(max) was 8.3 g/ml in the 12 sites with NLP, 11.2 g/ml in the 147 sites affected with NS, 14.6 g/ml in the 36 sites with MC, and 13.1 g/ml in the 13 sites with CHL-NOS (ANOVA, p = 0.002). There is a significant difference in FDG/glucose uptake between the different histopathological subtypes of HL.