Times Not to Forget Radiotherapy When Treating Patients With Lymphoma

Charles A. Enke, MD

Disclosures

J Oncol Pract. 2019;15(4):167-172. 

In This Article

Abstract and Introduction

Abstract

Radiation therapy remains an important component of lymphoma treatment. It has evolved with improvements in technology and a better understanding of how to successfully integrate it into lymphoma treatment. There are specific clinical presentations where omission of radiation therapy could adversely affect patient outcome and should not be overlooked. Radiation therapy may serve an important role as primary treatment, as a component of combined modality therapy, as adjuvant therapy to maximize local control, and as an important component of salvage therapy for relapsed or primary refractory lymphoma and in the successful palliation of lymphoma. This review identifies those clinical presentations where the use of radiation therapy should not be overlooked or should at least be considered.

Introduction

Radiation therapy has been an integral component of lymphoma treatment for decades. It has been described as the most effective single agent in the treatment of lymphoma.[1] With numerous new systemic therapies available for treatment of lymphoma and the recognition of historical serious late adverse effects of radiation therapy, there is a risk of oncologists failing to recognize the clinical scenarios where radiation therapy still plays an important role in the treatment of lymphoma. To dismiss the use of radiation therapy over concern of potential late adverse effects (that occurred during an era when the radiation therapy treatment volumes were large and the radiation doses used were significantly increased) is no more appropriate than to broadly dismiss the use of alkylating agents with systemic therapy because of a recognized increased risk of secondary leukemia in patients treated for Hodgkin lymphoma.[2–4] Just as systemic therapy has evolved to maximize effectiveness while attempting to minimize the risk of adverse effects, the same can be said for the contemporary use of radiation therapy in the management of lymphoma.

Radiation therapy has evolved from a technological standpoint as well as how it is integrated with systemic therapy in the management of lymphoma. The use of sequential chemotherapy followed by radiotherapy results in a much smaller radiation treatment volume. Combined modality therapy approaches have also resulted in a significant decrease in the required radiation dose without any decrease in efficacy.

Image guidance technologies aid in the identification of individual lymphoma targets as opposed to the much larger treatment fields used previously. Involved site radiation therapy (ISRT) is the new standard. Functional imaging with positron emission tomography (PET)/computed tomography (CT)/magnetic resonance imaging results in more accurate target identification. The introduction of intensity-modulated radiation therapy (IMRT) has allowed the delivery of much more conformal radiation therapy, minimizing the risk of collateral damage to adjacent normal tissue. The use of advanced IMRT technologies, such as volumetric modulated arc therapy, allows the rapid delivery of IMRT treatment. Technology such as optical surface monitoring coupled with volumetric modulated arc therapy allows the introduction of treatment techniques such as gated deep inspiration breath hold, where patients receiving mediastinal irradiation receive treatment while being treated with a significantly inflated lung volume. This results in displacement of a significant amount of uninvolved normal lung away from the intended mediastinal target volume, reducing the radiation dose to normal lung tissue and decreasing the risk of interstitial pneumonitis.

Given the number of new systemic therapies for lymphoma that have been introduced, there is the risk of failing to recognize the clinical scenarios where radiation therapy still plays an important—or even vital—role in the treatment of lymphoma. Radiation therapy may be used as the primary definitive treatment of localized stage I or contiguous stage II indolent lymphoma. It may be integrated with systemic therapy as a critical component of treatment of primary testicular lymphoma and natural killer (NK)/T-cell lymphoma, nasal type. It may be integrated with systemic therapy for treatment of lymphoma presenting with bulky disease. It may be an important component of treatment of primary refractory or relapsed lymphoma where high-dose therapy followed by autologous transplantation is being considered. It may also be important for the subgroup of these patients who do not respond to salvage systemic therapy before consideration of high-dose therapy and autologous transplantation. Radiation therapy serves as an effective, well-tolerated form of palliation for symptomatic lymphoma presentations associated with local mass effect. This includes indolent lymphomas such as follicular grades 1 and 2, marginal zone B-cell lymphoma, and even mantle cell lymphoma. The International Lymphoma Radiation Oncology Group has published several guideline papers to assist in the optimal use of radiation therapy in the management of lymphoma.[5–7]

The following sections represent one radiation oncologist's opinion of clinical scenarios where it is still important to recognize the role of radiation therapy in the management of lymphoma.

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