Epidemiological and clinical aspects of T-cell lymphoma

Sammanfattning: T-cell lymphoma (TCL) is a rare group of malignancies and one of the important aims in this thesis has been to broaden the general knowledge of TCL with descriptive patient data. Main focus has been to examine prognosticfactors for overall survival (OS) and progression-free survival (PFS), and to evaluate different treatment approaches and follow-up (FU) after treatment.The purpose of the first study was to analyse outcome and risk factors in newly diagnosed anaplastic lymphoma kinase positive (ALK+) anaplastic large cell lymphoma (ALCL) patients from Denmark and Sweden and to compare outcome after CHOP (cyclophosphamide, doxorubicin, vincristine, and prednisone) vs CHOEP (CHOP + etoposide) treatment. Male gender was associated with worse OS and all 10 patients with bone marrow involvement had a relapse, progression or died. CHOEP treatment was associated with better OS than standard treatment with CHOP in patients aged 41-65 years, and the addition of etoposide to CHOP could therefore be a reasonable choice in ALK+ ALCL patients < 65 years.In the second study, the outcome and FU of Swedish and Danish peripheral (P)TCL patients in first complete remission (CR) was investigated. FU guidelines in Sweden and Denmark were similar except that routine imaging was not recommended in Sweden. There was no significant difference in outcome between the countries, neither when analysing all patients, nor in subtype specific analyses. For patients without relapse 2 years after CR, the mortality was significantly higher than for a matched background population, possibly to some extent related to late relapses and poor response to salvage treatment.The third study aimed to describe clinical characteristics and outcomes of > 800 older (≥ 70 years) PTCL patients from Sweden and California. Comorbidity information was organized according to the Charlson Comorbidity Index (CCI). Increased CCI score was related to worse survival although prognosis for patients without comorbidity was poor as well, with a median OS of less than a year. Lymphoma was the most common cause of death regardless of CCI score. For Swedish patients responding to treatment, survival was over 3.5 years and no survival difference was seen between untreated patients and patients not receiving CR/CR unconfirmed (u) after chemotherapy.Some older PTCL patients benefit from multiagent chemotherapy, and it is important not to exclude the elderly from potentially curative treatment.In the fourth study (manuscript), outcome and prognostic factors in limited-stage nodal PTCL patients from Denmark and Sweden were analysed. Adult patients receiving CHOP(-like) treatment ± radiotherapy (RT) were included. Achieving CR/CRu compared to partial response (PR) was associated with significantly increased survival. Age ≥ 60 years and B-symptoms were the risk factors associated with worse prognosis. No significant differences in response rates or survival after treatment were seen between patients treated with 3-4 cycles of CHOP ± RT vs 6-8 cycles ± RT after adjusting for risk factors. For patients in continous CR/CRu, survival was normalized to a matched background population within 24 months from remission. To end FU at this timepointcould therefore be reasonable in limited-stage PTCL.In summary, survival and response to treatment in T-cell lymphoma is poor. In this thesis four comparatively large population-based studies with valuable data on prognostic factors, clinical characteristics, and treatment are presented. Information about the rarely studied subgroups of older and limited-stage patients is provided, and hopefully the knowledge of T-cell lymphoma is increased to some extent with this thesis.