COVID-19 pandemic prompts emergency radiation therapy guidelines for hematologic malignancies
An International Lymphoma Radiation Oncology Group task force has developed emergency recommendations for the management of radiation therapy for patients with hematologic malignancies during the COVID-19 pandemic.
The recommendations, published in Blood, outline alternative radiation therapy (RT) regimens to address potential space, equipment and staff limitations, as well as to reduce the number of patient visits needed for RT.
The group plans to evaluate outcomes of patients treated according to emergency guidelines after the pandemic is over, according to Joachim Yahalom, MD, radiation oncologist at Memorial Sloan Kettering Cancer Center and an author of the recommendations.
“Analysis of the data will enable us to gain further knowledge on the appropriate selection criteria for omitting, delaying or shortening RT in lymphomas,” he told Healio.
Yahalom spoke with Healio about the development of the guidelines and the scenarios in which they should be deployed.
Question: What situations might warrant omitting RT for patients with hematologic malignancies?
Answer: Omitting RT is considered when the risk for severe outcomes from COVID-19 infection outweighs the benefit of RT, such as when a patient is aged 60 years or older and/or in the presence of serious underlying health conditions. For example, in a palliative setting, it might be possible to omit RT when alternatives such as optimizing pain control can be offered. It also is reasonable to omit RT in localized, low-grade lymphomas if they have been completely excised. Examples of these include follicular lymphoma, marginal zone lymphoma and localized nodular lymphocyte predominant Hodgkin lymphoma. Another example is when RT was considered for diffuse large B-cell lymphoma/aggressive non-Hodgkin lymphoma, but the patient has completed a full chemotherapy course and achieved complete remission.
Q: How might physicians evaluate situations in which additional chemotherapy might be needed to omit RT?
A: In this situation, the patient most often will be better served by getting RT — hypofractionated if possible. This should be considered before going to more immunosuppressive chemotherapy. In most clinics this will be possible, even if capacity is strained. My concern is that immunosuppression, longer hospitalization or acute admissions are more likely with longer/more intensive chemotherapy than with added localized RT. This, of course, is assuming that disease control benefit is similar with shorter chemotherapy and RT, as was shown in several studies.
Q: When would it be appropriate to delay RT?
A: For localized, indolent lymphomas — which grow very slowly — a delay of some weeks or even a couple of months will not materially alter the patient’s prognosis. Delay may also be considered in disseminated indolent lymphomas, where palliative RT can be delayed if the lymphoma is in a stable phase not requiring immediate treatment.
Q: How would a patient who develops COVID-19 prior to RT be managed? Would it always be preferable to treat the COVID-19 first?
A: For patients who develop COVID-19 before starting planned RT, it is best to wait with any treatment until the infection is over to avoid immunosuppression. However, if the lymphoma is progressing, local RT may control the symptomatic disease and allow bridging to later definitive treatment. Systemic immunosuppressive therapy would seem a risky choice.
Q: When would shortening the course of RT through alternative hypofractionation schemes be warranted?
A: This should be considered in cases where the irradiated volume is relatively small and not located in or close to very critical structures, such as the heart, large volumes of lung or the central nervous system.
Q: What are some of the risks and benefits that need to be considered in these cases?
A: Risks include increased incidence of late effects in the irradiated normal tissues. An experienced radiation oncologist will know what and when to avoid. The relatively low radiation doses needed for lymphomas make hypofractionation safe in many cases but, if more than minimal volume of heart and lungs are included, standard 2 Gy fractionation often is advisable. Benefits are fewer treatments, sparing patient and staff unnecessary COVID-19 infection risk, and sparing the treatment facility some treatments in a situation with limited RT capacity.
Q: How should these patients be monitored for immune function or risk for COVID-19 while undergoing RT?
A: The patients should be asked about possible COVID-19 symptoms at each treatment visit and should be appropriately tested if symptoms appear. It may be advisable to follow the white blood cell count, particularly the lymphocyte count. When imaging includes the chest, staff should be especially alert to pulmonary changes, and the situation should be reviewed immediately if even minor infiltrates start to appear.
Q: How do the emergency guidelines address the risk for late effects of RT among these patients?
A: In general, larger fractions increase the effective dose for late effects. However, modern highly conformal RT techniques ensure only minimal volumes of normal tissues receive the full dose. This is true of the total RT dose, but it also is true of each fraction. Hence, most of the normal tissues getting any dose with modern RT will get a low fraction size within the standard 2 Gy range, thereby reducing the risk for late effects. The emergency guidelines stress that optimal conformal RT technique is even more important when using hypofractionation. The technology allows for accurate assessment in each case of how much of every organ gets a fraction size larger than 2 Gy, and the experienced radiation oncologist will be able to judge whether this is acceptable or not. If not, the treatment plan can easily be transformed to conventional fractionation.
Q. How will you study the impact of the emergency guidelines after the pandemic is over?
A: We will evaluate the lymphoma control, acute and late effects of the altered fractionation in different lymphomas. – By Jennifer Byrne
Yahalom J, et al. Blood. 2020;doi:10.1182/blood.2020006028.
For more information:
Joachim Yahalom, MD, can be reached at Memorial Sloan Kettering Cancer Center, 1275 York Ave., New York, NY 10065.
Disclosure: Yahalom reports no relevant financial disclosures.