a history of stable cll/sll or who present for the first time with cll/sll have: 1) rapidly worsening symptoms and/or signs, particularly enlarging lymph nodes or lesions in non-lymph node tissues (see presentation section); 2) fdg-pet-ct scans that may show involved tissues have high levels of fdg uptake; 3) excisional biopsy (surgical removal of an involved tissue such as a lymph node) or core biopsy (surgical removal of a portion of an involved tissue) which shows the histopathology of dlbcl-rt or hl-rt (fine-needle aspiration biopsies of involved tissues have not been clinically useful, accurate, or valuable in diagnosing cll/sll-rt.); and 4) gene and/or protein expression analyses that can differentiate pure dlblc-rt from de novo dlbcl-rt (see dlbcl-rt gene abnormalities section). a subgroup of cll/sll (∼23% of all cases) develop "accelerated" cll, i.e. malignant b lymphocytes that are proliferating rapidity. individuals with accelerated ccl/sll show worsening symptoms and signs as well as a microscopic histopathology of their involved tissues that can be difficult to distinguish from rts. fdg-pet-ct scans may help distinguish rt from accelerated cll/sll if they show that the involved tissue in rt take-up very high levels of fdg. nonetheless, the diagnosis of these rts can be difficult to distinguish form each other as well as from accelerated cll: the final diagnosis of rts should be made by a hematopathologist familiar with this area. treatment and prognosis dlbcl-rt treatment and prognosis as of 2021, there were no published randomized controlled trials that defined the optimal treatment for rt. dlbcl-rt cases have been treated with chemotherapy (therapy targeting the cancer cells) combined with immunotherapy (therapy targeting the immune system). the modified chop chemoimmunotherapy regimen termed -choep, which consists of rituximab (an immunotherapy antibody preparation that binds to cd20 cell surface protein), cyclophosphamide, doxorubicin, vincristine, and prednisone, has given overall response rates of 50–60% with median overall survival times of 15–21 months. other chemoimmunotherapy regimens have been used to treat dlbcl-rt. the r-epoch regimen of rituximab, etoposide, prednisone, vincristine, cyclophosphamide, and doxorubicin gave an overall response rate of 39% and a median overall survival rate of 5.9 months in a retrospective cohort study. r-dhap (rituximab, dexamethasone, cytarabine, and cisplatin), r-eshap (rituximab, etoposide, methylprednisolone, cytarabine, and cisplatin), and dose-intensified regimens such as r-hyper-cvad (rituximab with hyper-fractionated cyclophosphamide, vincristine, doxorubicin, and dexamethasone alternating with high-dose methotrexate and cytarabine as described elsewhere) have given higher complete response rates but also higher adverse events, higher treatment-related mortality, and shorter overall survival times compared to -choep. consequently, these other regimens are not commonly used to treat dlbcl-rt. recently, small molecule anti-cancer drugs (e.g. venetoclax, atezolizumab, duvelisib, ublituximab, zanubrutinib, obinutuzumab, olatuzumab, and blinatumomab) which are used to treat cll/sll and/or dlbcl-not rt have been added to chemotherapy and immunotherapy regimens to treat rt. while these studies are still in their early stages, i.e. stages i or ii, some have produced encouraging results. further studies of these small molecule drugs as well as studies using car-t technology to treat dlbcl-rt are underway. chemotherapy combined with immunotherapy is and will remain the gold standard for treating dlbcl-rt until future studies report on more effective regimens. patients with dlbcl-rt have been treated with autologous or allogenic hematopoietic stem cell transplantation. in these procedures, hematopoietic stem cells are isolated from the patient for an autologous or from a donor for allogenic transplant. the patients are then treated with an "ablation therapy regimen", i.e. high-dose chemotherapy with or without immunotherapy and radiotherapy to eradicate or at least stop or reduce further growth of his or her malignant b lymphocytes. after this therapy, patients are infused with their own or the donor's hematopoietic stem cells. one study reported a 3-year survival rate of 36% and another reported a median progression-free survival time (i.e. time disease does not worsen) of 11.2 months with a median overall survival time that was not reached after 54 months of follow-up. a meta-analysis of 4 previous studies reported that 72 individuals receiving allogenic hematopoietic stem cell transplant (ahsct) for rt (almost all cases were dlbcl-rt) achieved an overall response rate (percentage of patients showing a decrease in their disease) of 79%, complete response rate (percentage of patients showing an apparent disappearance of disease) of 33%, and 2-year and 5-year survival rates of 46 and 35%, respectively. since the overall mean survival time in many studies had been less than 10 months for individuals not treated with ahsct, the study concluded that ahsct is a reasonable treatment option for fit individuals whose disease responded to ablation therapy. however, these studies, as well as other studies on homologous and/or autologous transplantation for dlbcl-rt, selected individuals for transplantation based on their partial or complete responses to ablation therapy and often choose only patients who were physically and otherwise best fit to receive the transplant: in one study, only 20 of 148 individuals with dlbcl-rt were deemed eligible for transplantation. further studies, preferably randomized controlled trials, are needed to determine if this treatment regimen improves the outcome of such highly selected dlbcl-rt patients. hl-rt treatment and prognosis historically, hl-rt cases were typically treated with regimens directed against cll/sll or other malignancies but not those used to treat hodgkin's lymphomas not due to rt, i.e. hl-not rt. median overall survival times in individual treated with these regimens varied between 0.8–3.9 years. currently, hl-rt is treated with chemotherapy regimens such as abvd (i.e. adriamycin, bleomycin, vinblastine, and dacarbazine) which are used to treat hl-not rt. in a multicenter study, 62 individuals with hl-rt were treated with abvd or an avd-based regimen. these individuals had a median overall survival of 13.2 years, a time similar to that seen in most subtypes of hl-not rt when matched for patient age at the time of treatment. hematopoietic stem cell transplantation in 7 of these individuals did not improve their median overall survival times. based on this result, one study concluded that stem cell transplantation given as consolidation therapy (i.e. therapy given to improve the gains from the preceding therapy) is not recommended to treat hl-rt. in a study of 8 individuals with hl-rt treated with beacopp (2 cases), abvd (1 case), or other regimens (5 cases) directed against hl-not rt, the median overall survival time was 7 years. a retrospective review study of type 1 hl-rt cases (which have a poorer prognoses than type 2 hl-rt) found that individuals who received therapy regimens directed against hl-not rt had a median overall survival time of 57 months, significantly higher than those treated with regimens used to treat cll/css (medium overall survival time of 8.4 months). currently, regimens, particularly abvd, used to treat hl-not rt are the standard of care for treating hl-rt.