Photo: St. Anna Children's Cancer Research Institute

eurekalert.org

Acute lymphoblastic leukemia (ALL) is the most common cancer in children, generally curable with contemporary chemotherapy. However, if the disease is classified as high-risk ALL and a stem cell transplantation becomes inevitable, total body irradiation is still the treatment of choice prior to transplantation. This was the conclusion drawn from the FORUM study, including 35 countries on five continents (Peters et al., Journal of Clinical Oncology 2020).

"As the largest study on this topic to date, we published the results in the top-ranked Journal of Clinical Oncology. Soon after that, Frontiers invited us – the international transplant consortium for ALL – to publish a collection of reviews and scientific reports on ALL in children," recalls Christina Peters, Affiliated Clinician at St. Anna Children's Cancer Research Institute (St. Anna CCRI) and Senior Physician at St. Anna Children's Hospital. The editorial board of this Research Topic is formed by Christina Peters together with Assoc.-Prof. Adriana Balduzzi, MD (University of Milano Bicocca, Italy) and Prof. Peter Bader, MD (Goethe University Frankfurt am Main, Germany).

Life at the Price of Long-Term Side Effects?

Although total body irradiation and hematopoietic stem cell transplantation (HSCT) from healthy donors can be life-saving, long-term side effects sometimes have a massive impact on the quality of life of children and young adults. These include organ damage, growth retardation, and the development of secondary cancers. Hence, there was a dire need to clearly outline recent and previously published data, as well as to discuss potential new approaches, as did the aforementioned reviews.

"One of the most burning questions for me is whether we still need stem cell transplantation in the era of modern immunotherapies," Christina Peters points out. In the future, CAR-T cell or antibody therapies directly targeting leukemia cells could replace HSCT, which is addressed by three of the reviews mentioned. Jochen Büchner, MD, PhD, and colleagues are discussing the question of whether and when CAR-T cell therapy could be considered to bridge the time until transplantation and under what conditions it could replace transplantation. Another review, authored by Assoc.-Prof. Tony H. Truong, MD, and colleagues, is dedicated to the question which children should receive a stem cell transplantation at all. Of course, transplantation should only be considered for those patients who would not have a realistic chance of survival with 'milder' therapies. But it is exactly these boundaries that are currently shifting.

More Than 59,000 Views of our Work

So far, the review of Bianca A. W. Hoeben, MD, PhD, and colleagues, which deals with new methods of total body irradiation, has had the most views in this online collection. "In total, we have more than 59,000 views of our Research Topic by now. Accordingly, it seems to be on many people's minds whether and how we can improve transplantation methods to reduce side effects," says Christina Peters. For example, different radiotherapy centers have developed new methods of total body irradiation to achieve a lower irradiation dose in certain organs. There are, however, limitations to shield organs at risk without compromising the anti-leukemic and immunosuppressive effects – the latter to preserve a rejection of the transplanted cells.

In addition to the aforementioned long-term effects of irradiation and transplantation, acute side effects of transplantation also play a major role. These include infections during the period in which the immune system reconstitutes (Olga Zajac-Spychala et al.), or complications arising from a donor cells’ attack against the patient's healthy tissue. The prevention and treatment of the so-called Graft-versus-Host Disease are addressed by six of the articles in this Research Topic (Steven J. Keogh et al., Anita Lawitschka et al., Jacob Rozmus et al., Agnieszka Sobkowiak-Sobierajska et al., Matthias Wölfl et al., Natalia Zubarovskaya et al.).

"The publication of this Research Topic is a huge success for St. Anna CCRI. Together with the valuable contributions of a number of clinicians of St. Anna Children's Hospital, we have published highly topical and clinically relevant manuscripts that are of utmost importance for the treatment of children with high-risk ALL," highlights Christina Peters.