The disease incidence increases over the age of 60 and due to the shifting demographics, the number of total cases is expected to increase over the next two decades.  As therapy continues to improve, the median survival for both low-grade and aggressive non-Hodgkin lymphoma continues to improve.

CLASSIFICATION OF LYMPHOMAS

In 2001, immunophenotype and genetic findings were incorporated into a new World Health Organization (WHO) classification intended to replace prior classification systems. In 2008 the WHO criteria were further refined to expand on the use of molecular markers. Previous classification systems can be translated into the present system but limited immunophenotypic and molecular analysis from older cases may preclude accurate classification under current criteria.

SANTA BARBARA COTTAGE HOSPITAL DATA

The data for SBCH were compiled and reviewed from 1998 to 2008. Survival data were compiled and reviewed from cases diagnosed from 1998 to 2001.

The incidence of NHL has remained relatively stable during this time period with no clear trend of increase or decrease in number of cases diagnosed per year. (Figure 1)

The incidence of diagnosis of NHL by age (pediatric through the tenth decade of life) at SBCH was compared with National Cancer Database (NCDB) statistics from 2000 to 2006. (Figure 2)

The distribution by age group was consistent with national hospital statistics. In the SBCH population there was a slightly higher proportion of diagnoses in men compared with the national hospital average - 61.2 percent versus 53.4 percent of cases. (Figure 3)  A formal statistical comparison to determine significance was not performed. The SBCH sample size is of course small compared to the cumulative national hospital cases.

Stage at the time of diagnosis at SBCH was also measured against national statistics from 2000 to 2006, and was grossly consistent with national averages with regard to breakdown by stage. At SBCH there were fewer cases of stage indeterminate disease 13.7 percent versus 20.6 percent, perhaps reflective of more thorough staging efforts made within our community. (Figure 4)

By histology the cases at SBCH with the most notable difference were in the percent of large cell lymphoma-51.7 percent versus 36.2 percent. There were fewer cases in the SBCH data set with an indeterminate (not otherwise specified) histopathology. (Figure 5)

As described, the classification system for lymphoma has changed during this time period which can cause variability in subclassification of the lymphomas over time, and geographic inconsistencies, depending on timeliness of incorporation of new classification schema at different hospitals.

Treatment modality for cases of Non-Hodgkin Lymphoma diagnosed at SBCH from 2000 to 2006 was compared with other hospitals. (Figure 6) The percent of cases treated with surgery alone was similar between the groups.

As surgery is not considered a definitive therapeutic approach to Non-Hodgkin Lymphoma, it can be assumed that these are cases whereby surgery is used for diagnosis and patients are subsequently followed with expectant observation or in the case of very advanced disease palliative therapy alone.

During this time period there have been significant advances in the quality and number of therapies available to treat Non-Hodgkin Lymphoma. These specific choices of therapies as they apply to stage, histology, and year of treatment were not available and thus not evaluated.

SURVIVAL

Survival data by stage were compared from cases diagnosed from 1998 to 2001. There are some important caveats to interpreting this data.

While early-stage lymphomas tend to carry a more favorable prognosis compared with advanced-stage disease, histologic classification is a critical determinant in survival.

In addition there were multiple prognostic factors which had been proven to impact survival in both follicular and diffuse large B-cell lymphoma. Without balancing for the factors, a stage by stage analysis between the SBCH data set and national data set is limited.

The five-year survival from time of diagnosis for cases diagnosed from 1998 to 2001 was consistent with the national data, with the exception of Stage II disease which had a drop-off after three years and a lower overall survival compared with the national average.

The five-year survival from time of diagnosis for cases diagnosed from 1998 to 2001 was consistent with the national data, with the exception of Stage II disease which had a drop-off after three years and a lower overall survival compared with the national average.

From the 2000 to 2006 data set there was a relative overrepresentation of Stage II cases at SBCH - 19.0 percent versus 13.5 percent. The difference in survival may be reflective of more aggressive histologies in the SBCH Stage II group, or other prognostic factors such as age, when compared with the national data set. (Figures 7 & 8.)

DEVELOPMENTS IN THE FIELD

The greatest impact on the treatment of B cell lymphomas since the last Santa Barbara Cottage Hospital report was prepared in 1995, has been the incorporation of rituximab, a monoclonal anti-CD20 antibody into therapy of both low grade and aggressive B cell lymphomas.

Response rates, progression-free, and overall survival have improved when compared with chemotherapy treatment alone.

In addition to the use of rituximab, the staging and assessment of response to treatment and non-Hodgkin lymphoma has advanced with the incorporation of PET scanning. As ongoing investigation into the use of PET scanning grows, it is anticipated that PET imaging will play a greater role in tailoring therapy for non-Hodgkin lymphoma.

Another development in the field has been the experimental application of nucleic acid microarray technology to risk stratification of lymphoma subtypes previously grouped together by conventional means. There are ongoing clinical trials intended to better risk stratify, and intensify treatment for lymphoma subtypes, which may carry a more aggressive biologic natural history determined at the outset by their microarray profile.

Radioimmunotherapy which employs an ionizing radiation source linked to a monoclonal antibody so that it can be targeted to lymphomas is now approved for use in the treatment of non-Hodgkin lymphoma.

Widespread development of newer forms of monoclonal antibodies to CD20, other cell surface targets, immunomodulatory agents, vaccine therapies, targeted small molecule inhibitors, and novel chemotherapies are expected to improve the breadth and efficacy of available treatment options for non-Hodgkin lymphoma over the next several years.  In addition, less toxic forms of autologous and allogeneic stem cell transplant have offered a new avenue of therapy to a broader population of patients with non-Hodgkin Lymphoma, that cannot be controlled by conventional means.

Through the combined efforts of the pathology, imaging, radiation oncology, and medical oncology subspecialties, patients diagnosed and treated at Santa Barbara Cottage Hospital will continue to receive state of the art care with new diagnostic strategies and treatments incorporated into therapy as they become available.

Data from Santa Barbara Cottage Hospital from 1998-2008 were reviewed.