A retrospective analysis of patients presenting with primary lymphoma of bone (PLB) was performed to determine clinical factors affecting prognosis in relation to histological subtype and treatment outcome. Data from 106 patients, presenting with a PLB between 1943 and 1996, were retrieved from the files of the Netherlands Committee on Bone Tumours and Leiden University Medical Centre. The lymphomas were reclassified according to the REAL and updated Kiel classification. The clinical presentation, survival and prognostic factors were investigated. Sixty patients had sufficient clinical information and adequate follow-up to be included in the study. All 33 PLB that could be immunophenotyped were of B cell origin. According to the REAL classification, most PLB were large (B) cell lymphomas (92%) and according to the Kiel classification 45% of the tumours were centroblastic multilobated. PLB presented most often in the long bones (48%), with Ann Arbor stage I (46%), II (16%), IV (16%) and unknown (20%). Stage IV disease was exclusively caused by the presence of multiple bone lesions. Notwithstanding the heterogeneous treatment, the 5-year overall survival was 61%; 46% of patients were progression free at 5 years. Patients at presentation older than 60 had a worse overall survival (76% vs 37%, P ‫؍‬ 0.0002) and a worse progression-free period (58% vs 28%, P ‫؍‬ 0.0073). Patients with the immunoblastic subtype had a worse survival than the centroblastic mono/polymorphic subtype or the centroblastic multilobated subtype (P ‫؍‬ 0.015). Primary lymphoma of bone represents an uncommon bone tumour with a relatively homogeneous morphology and clinical behaviour. Compared to other aggressive lymphomas, PLB have a favourable prognosis.

An International Prognostic Index (IPI) for patients with aggressive non-Hodgkin's lymphoma (NHL) has recently been published. The IPI is based on pretreatment clinical characteristics and developed on clinical trial patients, classified as intermediate grade according to the Working Formulation (WF). We applied this IPI in a population-based registry of NHL patients. This registry does not have the restrictions that usually hold for patients in clinical trials, eg, with respect to age and performance status. Moreover, it covers all the three WF classes (low, intermediate, and high). The IPI turned out to be of prognostic value for response rate and survival in our unselected cohort of 744 patients, as well. In each of the three WF classes separately, the four IPI classes showed going from low to high substantially decreasing response rates and survival percentages. For our cohort of WF intermediate grade patients 5-year survival levels were lower in all four IPI classes (59%, 34%, 14%, and 10%, respectively), probably reflecting the selection of clinical trial patients in the original study (73%, 51%, 43%, and 26%).

This study illustrates the homogeneity of PLB. The majority of cases are of the GC phenotype which has a favourable prognosis.

The prognostic significance of age was studied in 372 patients with diffuse large B-cell non-Hodgkin's lymphoma, in relation to the prognostic factors of overexpressed BCL2 and p53 oncoprotein. Overexpression of BCL2 and p53 oncoprotein was defined when more than 50% of the tumor cells showed positive staining. The data were analyzed with respect to the age groups < 65 and > or = 65 years of age. There was a trend for BCL2 overexpression to occur significantly more often among patients older than 65 years of age (P = 0.065). Patients with BCL2 overexpression showed significantly inferior disease free survival rate, but only for patients younger than 65 years (log-rank test P = 0.0002), and the overexpression showed also an independent prognostic significance (P < 0.001). With respect to overexpressed p53 a significant difference was reached for complete remission rate (P = 0.01) and 5-year survival rate (log-rank test P = 0.04), again only for the younger age group. When the analyses were repeated for the older patients who had been treated adequately, the same lack of significance was found, both for BCL2 and p53. This study demonstrates that the negative prognostic value of overexpressed BCL2 and p53 protein is not of concern for patients older than 65 years of age. Among elderly patients the International Prognostic Index score seems the predominant risk factor for inferior prognosis.

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