Relapse of primary CNS lymphoma after more than 10 years in complete remission

Can exercise-related improvements in immunity influence cancer prevention and prognosis in the elderly?

Cancer incidence increases with advancing age. Over 60% of new cancers and 70% of cancer deaths occur in individuals aged 65 years or older. One factor that may contribute to this is immunosenescence - a canopy term that is used to describe age-related declines in the normal functioning of the immune system. There are multiple age-related deficits in both the innate and adaptive systems that may play a role in the increased incidence of cancer. These include decreased NK-cell function, impaired antigen uptake and presentation by monocytes and dendritic cells, an increase in 'inflammaging', a decline in the number of naïve T-cells able to respond to evolving tumor cells, and an increase in functionally exhausted senescent cells. There is consensus that habitual physical exercise can offer protection against certain types of cancer; however the evidence linking immunological mechanisms, exercise, and reduced cancer risk remain tentative. Multiple studies published over the last two decades suggest that exercise can mitigate the deleterious effects of age on immune function, thus increasing anti-cancer immunity. The potential ameliorative effect of exercise on these mechanisms include evidence that physical activity is able to stimulate greater NK-cell activity, enhance antigen-presentation, reduce inflammation, and prevent senescent cell accumulation in the elderly. Here we discuss the role played by the immune system in preventing and controlling cancer and how aging may retard these anti-cancer mechanisms. We also propose a pathway by which exercise-induced alterations in immunosenescence may decrease the incidence of cancer and help improve prognosis in cancer patients.

Relapse of primary central nervous system lymphoma 13 years after high-dose methotrexate-based polychemotherapy

We report a now 74-year-old patient who was successfully treated with a methotrexate (MTX)-ssbased polychemotherapy protocol (Bonn protocol) for primary central nervous system lymphoma (PCNSL) in 1996. When presenting with an unusually late relapse after 13 years of tumor-free survival the diagnosis was made on the basis of clinical and radiological criteria. In the context of the very limited treatment options for recurrent PCNSL, it is reassuring that the re-application of high dose-MTX-based polychemotherapy, including intraventricular treatment, again succeeded in a sustained complete response with still low neurotoxicity.

Late relapse in primary central nervous system lymphoma: clonal persistence

Recurrence of primary central nervous system lymphoma (PCNSL) after initial diagnosis and treatment occurs within 2 years in most patients, and relapse after 5 years is rare. We evaluated late relapse in our PCNSL population. We identified 10 patients from our database of 378 patients (268 achieved a complete response and 230 had relapse) with PCNSL who had relapse ≥5 years after initial diagnosis. At initial diagnosis, their median age was 47 years; all patients had brain involvement and achieved a complete response to initial therapy (9 received high-dose methotrexate). Median time to first relapse was 7.4 years (range, 5.2-14.6 y). Eight patients had relapse in the brain, 1 had ocular relapse, and 1 had a systemic relapse. The histologic specimens at initial diagnosis and relapse were examined for clonal rearrangement in 3 patients; 1 had the identical clone at initial diagnosis and relapse 13.8 years later, and the other 2 were uninformative. All patients received salvage therapy (9 received systemic therapy and 1 received intraocular chemotherapy. Nine patients achieved a complete response to salvage therapy and 1 achieved a partial response. Four patients had relapse a second time. The median progression-free survival after first relapse was 31 months (range, 7.9-82.4). Late relapses accounted for 4% of all recurrences (10 of 230 patients) in our PCNSL population. Long-term persistence of the PCNSL clone was observed in one patient. Patients with late relapses have a good response to salvage therapy and prolonged survival.

Immune escape mechanisms of intraocular tumors

The notion that the immune system might control the growth of tumors was suggested over 100 years ago by the eminent microbiologist Paul Ehrlich. This concept was refined and expanded by Burnet and Thomas 50 years later with their articulation of the "immune surveillance" hypothesis. In its simplest form, the immune surveillance hypothesis suggests that neoplasms arise spontaneously and express novel antigens that are recognized by the immune system, which either eliminates the tumors or restrains their growth. Within the eye, immune responses are controlled and sometimes profoundly inhibited - a condition known as immune privilege. Immune privilege in the eye is the result of a complex array of anatomical, physiological, and immunoregulatory mechanisms that prevent the induction and expression of many immune responses. Tumors arising in the eye would seem to have an advantage in evading immune surveillance due to ocular immune privilege. Uveal melanoma, the most common and malignant intraocular tumor in adults, not only benefits from the immune privilege of the eye but also has adopted many of the mechanisms that contribute to ocular immune privilege as a strategy for protecting uveal melanoma cells once they leave the sanctuary of the eye and are disseminated systemically in the form of metastases. Although the immune system possesses a battery of effector mechanisms designed to rid the body of neoplasms, tumors are capable of rapidly evolving and countering even the most sophisticated immunological effector mechanisms. To date, tumors seem to be winning this arms race, but an increased understanding of these mechanisms should provide insights for designing immunotherapy that was envisioned over half a century ago, but has failed to materialize to date.

Immune-mediated dormancy: an equilibrium with cancer

This brief review discusses the role of the immune system in tumor development, covering a history of cancer immunity and a summary of the concept of cancer immunoediting, including its three phases: elimination, equilibrium, and escape. The latter half of this review then focuses specifically on the equilibrium phase, making note of previous work, suggesting that immunity might maintain cancer in a dormant state, and concluding with a description of a tractable mouse model unequivocally demonstrating that immunity can indeed hold preformed cancer in check. These findings form a framework for future studies aimed at validating immune-mediated cancer dormancy in humans with the hopes of devising new, immunotherapeutic strategies to treat established cancer.