An Evidence Review of the Long-Term Consequences Associated with Components of the CHOP Chemotherapy Regimen in Transplant Recipients

Introduction: Epstein-Barr virus-driven post-transplant lymphoproliferative disease (EBV ⁺ PTLD) can be an aggressive, often deadly disease without any approved treatments. Current available treatments for EBV ⁺ PTLD may include cyclophosphamide, doxorubicin, vincristine, and prednisone (CHOP). However, the long-term consequences of CHOP are poorly understood in immunocompromised transplant patients with cancer who may have different outcomes than immunocompetent cancer patients. This study reviewed and described the evidence for the long-term consequences associated with components of CHOP in transplant recipients.

Methods: Potential long-term consequences of the components of CHOP were identified from the Children's Oncology Group Long-Term Follow-Up (COG LTFU) Guidelines. Abstracts were screened and eligibility was based on reporting data for the identified COG LTFU long-term consequences along with pre-specified criteria (English, systematic review, randomized controlled trial n>100, observation study n>100, case series n>20). Relevant studies that met the criteria were extracted and synthesized; of these, studies were selected if they evaluated patients who received any type of transplantation as part of their primary cancer treatment.

Results: A total of 7 studies met the pre-specified selection criteria, all of which evaluated patients with hematopoietic stem cell transplantation (HCT) and none assessed solid organ transplant (SOT). None of the studies focused specifically on the CHOP regimen or EBV ⁺ PTLD. Long-term consequences of alkylating agents (eg, cyclophosphamide) and corticosteroids as primary treatment reported in these HCT studies included: hormone deficiencies and infertility (n=4 studies), osteonecrosis (n=2), and health status and quality of life (QoL; n=1).

Results from three studies suggested that cancer survivors who received alkylating agents experienced hormone deficiencies and those with a HCT had a high risk. One quantified this by showing that, compared with cancer survivors without a history of HCT (CS), cancer survivors with a history of HCT (CS-HCT) and a history of total body irradiation had significantly impaired follicle stimulating hormone (40.42 vs 9.39 mIU/ml, P<0.001), Estradiol (15.09 vs 25.13 pg/ml, P=0.04), Inhibin B (10.61 vs 32.92 pg/ml, P=0.003), anti-Müllerian hormone (0.01 vs 1.28 ng/ml, P<0.001), antral follicle count (0.71 vs 17.78, P<0.001) and ovarian volume (1.82 vs 8.21 ml, P<0.001). In one study on the risk of osteonecrosis, the CS-HCT group had a significantly increased risk of developing osteonecrosis compared to the CS group treated with chemotherapy (6.8% vs 1.4%, respectively); cumulative incidence of osteonecrosis was 3.8% in the CS group for a steroid dose >5,835 mg/m ² and 23.8% in the CS-HCT group for a post-transplant steroid dose >2,055 mg/m ²; and patients developed symptomatic osteonecrosis within a median of 2.4 years in the CS group with chemotherapy and 0.9 years after the first transplant in the CS-HCT group. A second study showed the rate ratio (RR) of osteonecrosis compared with a sibling comparison group was highest among the CS-HCT for acute lymphoblastic leukemia, acute myelogenous leukemia, and chronic myelogenous leukemia (RR = 26.9, 66.5, and 93.1, respectively; P<0.001 for all). One study reported that childhood acute leukemia survivors treated with HCT with preparative regimen with either busulfan-cyclophosphamide or total body irradiation/cyclophosphamide had a significantly lower QoL short-form (SF)-36 mental and physical composite scores in both treatment groups compared with norms.

Conclusions: Since only a small number of studies (7) of long-term consequences in transplant recipients were identified and none were seen in patients with EBV ⁺ PTLD or in SOT recipients, more research is needed to evaluate adverse consequences of CHOP or its components in EBV ⁺ PTLD, especially in SOT patients where no studies were found. Results from this review suggest that immunocompromised HCT recipients who were cancer survivors are significantly more impaired by long-term consequences (hormone deficiencies and infertility, osteonecrosis, and QoL) of alkylating agents (eg, cyclophosphamide) and corticosteroids as primary treatment compared with other cancer survivors without HCT.