Late Effects and Long-Term Follow-Up

Allogeneic stem cell transplantation was successfully performed in 1968, and its use has grown significantly over the past five decades with the total number now exceeding 1.5 million patients (Niederwieser et al. Haematologica. 107:1045–1053, 2022). HSCT is a curative treatment for many haematological cancers and other disorders. Almost 40,000 HSCT procedures are performed Europe-wide per annum (Passweg et al. Bone Marrow Transplant. 51(6):786–92, 2016), and the number of transplant recipients achieving ‘long-term survival’ and with late effects directly related to their treatment (Majhail et al. Hematol Oncol Stem Cell Ther 5(1):1–30, 2012) is increasing (Penack et al. Blood Adv 4:6283–6290, 2020). This growth in survivors is the result of improvements in transplant knowledge and expertise, refinements to conditioning regimes, developments in supportive care and increased numbers of procedures due to broadening transplant indications.The most common cause of death after transplant is relapsed disease. Yet, even without disease relapse, long-term survival is complex for many as other causes of mortality such as graft versus host disease (GvHD), infection, second malignancy, respiratory disease and cardiovascular disease (CVD) (Savani et al. Blood. 117:3002–9, 2011) prove difficult to address.Recovery post-HSCT is challenging, lasting several months to years. These individuals are susceptible to the development of post-treatment physical and psychological sequelae years to decades after completion of treatment leading to a reduced life expectancy with greater morbidity when compared to an age-adjusted population (Socié et al. N Engl J Med 341:14–21, 1999). Survivors with late effects experience significantly poorer physical and mental health, report more unmet needs for care and have significantly greater use of health services compared with survivors without late effects (Treanor et al. Psychooncology 22(11):2428–2435, 2013).Furthermore, as the number of survivors continues to grow, their long-term health problems and subsequent needs demand increasing resource and attention from late effects services. These services must remain agile and responsive, develop capacity to provide continuing expertise and oversight and collaborate with the other specialist services for input when needed.The unpredictable, complex and multifactorial nature of these long-term and late effects in HSCT survivors means that patients require regular life-long assessment guided by rigorous protocols. However, it is important to remember that even using standardised protocols, these should be different for adults and children and the resulting care must be tailored to the needs of the individual. And finally, further consideration is needed for the growing number of young people and adult survivors in long-term follow-up who have been treated in childhood and transitioned into adult long-term follow-up care.