Abstracts: ISEE 21st Annual Conference, Dublin, Ireland, August 25–29, 2009: Symposium Abstracts: Symposia Presentations
Background and Objective:
Associations between serum levels of organochlorines and risk of NHL have been examined in both population-based case-control and prospective cohort studies. The former have generally evaluated cases phlebotomized before treatment, to avoid potential treatment bias. Our previous report of 42 cases with low-grade follicular NHL treated with cyclophosphamide, doxorubicin, etoposide, and prednisone showed a significant decline in organochlorine serum levels following chemotherapy. The objective of the current study is to further explore this finding in additional cases.
We measured serum levels of PCBs and DDE (DDT metabolite) in samples collected before, during and after chemotherapy from 24 cases diagnosed with large B-cell lymphoma, and enrolled in an etoposide, vincristine, doxorubicin, cyclophosphamide, and prednisone clinical trial. Of 24 patients with a pre-treatment sample, 20, 18 and 15 patients gave a second, third and post-treatment sample, respectively. Changes in PCBs and DDE levels were examined over the course of chemotherapy.
Lipid levels generally increased in most, but not all, cases during treatment, with levels returning to baseline in many, but not all, following chemotherapy. For the majority of patients, both lipid-corrected and -uncorrected PCB and DDE levels increased following the initiation of chemotherapy and declined through the follow-up visit, sometimes, but not always, falling below pre-treatment levels. The median % change between the lipid-corrected pre-treatment and post-treatment levels was −20.2% for PCBs and −17.3% for DDE.
Our results are consistent with the previous report suggesting that chemotherapy alters organochlorine serum levels. As certain organochlorines (e.g., dioxins) need to be measured in large amounts of serum that can be available in case-control studies but not usually in cohort studies, the case-control approach needs to continue to be utilized. It is critical however, that case-control studies examining this hypothesis use untreated cases to avoid misclassification of pre-diagnostic exposure.