It is Different the Survival of Primary Extranodal Non Hodgkin Lymphoma?.

There are few studies that evaluate the difference in incidence and survival of primary extranodal lymphomas (PEL) as compared to nodal lymphomas. In the Population Based Cancer Registry of Zaragoza (PCRZ) working since 1960, all incident cases of hematologic and non hematologic cancer are including. PCRZ is a data source for epidemiological studies.

1. Review and reclassify cases of NHL diagnosed during the period 1992-2004. 2. Define the incidence of PEL in PCRZ during this period. 3. Analyze the survival of the PEL and compare it with that of nodal NHL.

Based on the data PCRZ, we have reviewed and reclassified the patients with NHL according to REAL classification and the new WHO classification (2008), diagnosed during the period 1992-2004, to determine location and histology. The follow-up period of cases was completed by December 31, 2007 Data sources: medical records, histological reports and discharged hospital reports. Population at risk: 9,255,818 person-years. We have calculated crude incidence rates (IR) and standardized by age (SIR), using the European population as standard. For the calculation of survival and confidence intervals (95%) had used the Kaplan-Meier method and the log-rank test was used to compare survival curves.

During the period of study a total of 4,570 primary hematological disorders were included in the PCRZ; 1,987 (43.4%) were NHL (IR: 19×105 person-years), 331 (16.6%) of them were classified as PEL, which represented a 2.7 SIR x105 person-years (male: 183 cases (55.2%), mean age 59.2 years, SIR: 3.1 ×105 person-years and women 148 cases (44.7%), mean age 66.8 years, SIR: 2,4 ×105 person-years. Only 10% of cases will be reclassified related to histology or location. The most common site was gastrointestinal tract (50.4%), skin (19.8%), glands (10.0%), oral cavity and pharynx (7.9%), lung (2.9%), CNS (2.4%), orbit (2.1%) and other locations (4.5%). Histological types: MALT 60.2%, BDLCNHL: 18.3%, FNHL: 4.7%, MCNHL: 3.2%, MZNHL: 6.5%, T-NHL: 7.1%. Median survival for PEL was 6.61 years (95% CI: 3.7-9.5) and 5.01 years for nodal lymphomas (95% CI: 4.1-5.9). The survival at 5 years was 53.5% and 50% respectively. There were no statistically significant differences between PEL group and the nodal NHL, according to the location or by gender. The differences in survival were associated with histological subtype of lymphoma. These results were similar to those in the data EUROCARE.

No differences in incidence in PEL and nodal NHL were observed according to gender and age. There were no statistically significant differences between the survival of the PEL and nodal NHL, survival is more influenced by histology than by location.

This work partially funded by the project HAEMACARE

No relevant conflicts of interest to declare.