Does Hypergammaglobulinemia Predispose to Secondary Solid Tumors in Patients with Chronic Lymphocytic Leukemia?.

Background:Occurrence of second hematological malignancies in patients with chronic lymphocytic leukemia (CLL) is well known but development of secondary solid tumors has not been well documented. Isolated case reports indicate, CLL patients may have a predisposition to develop solid tumors. There is not enough literature available to support this hypothesis. We here intend to study the incidence of secondary solid tumors in CLL patients with regard to their treatment and immunoglobulin levels.

Methods: We reviewed the medical records of 323 CLL patients over the last 20 years at Veteran Affairs Medical Center, Kansas City. Broadly the patients were divided into two groups; the group who received chemotherapy for CLL(74/323) versus the group who did not receive treatment (249/323) and their median immunoglobulin levels were also documented. Patients who developed secondary hematological malignancies were excluded from this study.

Results: The overall incidence of solid tumors was found to be 14.8% (48/323). In the chemotherapy treated CLL, the incidence of solid tumors was 18%(14/74) as compared to 13.6% (34/249) in the non-therapeutic group(P value 0.12). The most common malignancies noted were gastro-intestinal malignancies, genitor-urinary tumors and skin cancers including melanomas. Interestingly CLL patients who developed secondary solid tumors had a higher median IgG levels (1010 g/L) when compared to those who did not develop secondary tumors (738 g/L, P value <0.003)

Conclusion: Our study shows that there is a higher overall incidence of secondary solid tumors in patients with CLL when compared with incidence in the general population. There is no significant increase in the incidence of therapy related solid tumors in CLL patients. Upward drift in immunoglobulin levels should raise a suspicion for diagnosis of secondary solid tumors in patients with CLL. More studies are warranted to confirm this finding.