Outcome of patients with early-stage follicular lymphoma staged with 18F-Fluorodeoxyglucose (FDG) positron emission tomography (PET) and treated with radiotherapy alone
To evaluate the impact of positron emission tomography (PET) staging on overall survival (OS) and progression-free survival (PFS) in patients with early-stage (stages I and II) follicular lymphoma (ESFL) treated with radiation therapy alone.
Eighty-five patients with ESFL treated with curative-intent radiation therapy (RT) between December 2000 and May 2011 were identified. Of those, 13 who had no PET staging and 25 who received additional systemic therapy were excluded from the analysis. Thus, we analyzed 47 patients with PET-staged ESFL treated with definitive radiation therapy alone (dose > 23Gy). Tumour features, pre-treatment computed tomography (CT) and PET stage, dose fractionation, and radiation therapy field extent were recorded. The Kaplan–Meier method was used to estimate the OS and PFS. Patterns of failure were assessed as cumulative incidences assuming competing risks.
Median age was 57 years (range 24–83); 43% were females. Most were PET stage 1 (76.6%). Median maximum nodal diameter was 3 cm. Median pre-treatment lactate dehydrogenase (LDH) was 327.5 (range 123–607, upper normal limit = 220). Twenty-six patients (55.3%) had infra-diaphragmatic disease. All received 30–36Gy in 15–24 fractions, with 59.6% treated with involved-field radiation therapy (IFRT) techniques. There was no significant difference in PFS between CT stage I and stage II (HR 1.30 95% CI [0.25–6.72], p = 0.75) with a 5-year PFS of 77% and 78% respectively. However, stage I on PET staging had a significantly better PFS than stage II (HR 4.66 95% CI [1.15–18.8], p = 0.038), with 5-year PFS of 84% and 60% respectively. Ten patients had recurrent disease, with distant disease being the first site of failure in seven patients. Seven-year OS was 91% (95% CI 79–100) for the whole cohort.
FDG-PET should be considered an essential element in the evaluation of patients with ESFL being considered for RT.
Keywordslymphoma Positron emission tomography Prognosis Radiotherapy FDG
Compliance with ethical standards
Conflict of interest
Authors Sweet Ping Ng, Richard Khor, Mathias Bressel, Michael MacManus, John F Seymour, Rodney J. Hicks, and Andrew Wirth declare that they have no conflict of interest. Sweet Ping Ng is funded by the Australian Postgraduate Award, Radiological Society of North America (RSNA) Fellow Grant, and Royal Australian and New Zealand College of Radiologists (RANZCR) Research Grant. Professor Hicks is supported by an Australian National Health and Medical Research Council Practitioner Fellowship.
All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional research committee and with the 1964 Helsinki Declaration and its later amendments or comparable ethical standards.
This article does not contain any studies with human participants or animals performed by any of the authors.
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