Optimization of treatment in DLBCL patients

Thesis event information

Date and time of the thesis defence

Place of the thesis defence

Auditorium 7 of Oulu University Hospital. Remote access: https://oulu.zoom.us/j/61113536698?pwd=QUtyQjZ2dWJFVFFvZTRjTENESk41QT09

Topic of the dissertation

Optimization of treatment in DLBCL patients

Doctoral candidate

M.D. Susanna Tokola

Faculty and unit

University of Oulu Graduate School, Faculty of Medicine, Cancer and Translational Medicine Research Unit

Subject of study

Oncology

Opponent

Docent Micaela Hernberg, Helsinki University Hospital

Custos

Professor Outi Kuittinen, Oulun University Hospital and University of Eastern Finland

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Radiotherapy to the bulky or residual tumor does not reduce the risk of relapse in a DLBCL patient - effect of RT and improvement of PET-CT accuracy by biopsy

According to a dissertation, radiotherapy to a residual tumor or a large tumor at the time of diagnosis did not affect the prognosis of a DLBCL patient. A large tumor significantly impaired the prognosis of patients with the limited stage disease, but radiotherapy could not improve it. PET-CT imaging provides additional information to evaluate treatment outcomes but is not reliable enough to make treatment decisions. According to the study, a tissue sample is needed before treatment can be intensified.

The dissertation evaluates factors affecting the prognosis of patients with diffuse large cell B-cell lymphoma (DLBCL). This study assesses the impact of the large baseline tumor (greater than 7.5 cm, bulky tumor) and the residual tumor after treatment on the prognosis of patients and the effect of radiotherapy on these factors. In addition, the study evaluates the reliability of PET-CT for assessing the treatment response and the results of BBBD treatment for brain lymphoma in Oulu.

DLBCL is one of the most aggressive lymphoid cancers and, in most cases, leads to death without treatment. The treatment is curative in 70% of patients. Nevertheless, the disease does not respond as expected to treatment or relapses soon after a complete response in some patients. The prognosis for these patients is poor. It is essential to recognize primary refractory diseases at the earliest possible stage to avoid ineffective treatments' adverse effects and allow intensification when needed.

Radiotherapy (RT) has long term adverse effects that can appear years or even decades after the treatment. Traditionally, bulky tumor at the time of diagnosis or residual tumor after the treatment has considered an indication for RT. This study demonstrates that bulky tumor significantly impacts the prognosis of patients with the limited-stage disease. However, RT to bulky sites was not able to improve the outcome. PET-negative bulky or residual tumor do not seem to affect the prognosis.

Hybrid positron emission tomography and -computed tomography (PET-CT) is a commonly used method for response evaluation in DLBCL and aims to identify patients with an insufficient response. However, PET-CT has a high rate of false positivity, resulting in the possibility of error. Treatment should be intensified in patients with active lymphoma tissue behind a positive PET finding, and it is crucial to identify patients with PET-positivity due to other reasons. For these patients, biopsy guided by PET-CT provides more accurate information.

Primary central nervous system lymphoma (PCNSL) is a rare disease. In nearly all registry-based studies, the PCNSL prognosis is dismal – with few, if any, long-term survivors. Follow-up results appear to be poor, especially in the setting of relapsed and refractory setting. The results of blood-brain barrier disruption treatment are promising, with tolerable adverse effects for patients with PCNSL
Last updated: 21.10.2021