Primary testicular lymphoma: the site matters

Long-term outcome of primary endocrine non-Hodgkin lymphomas: does the site make the difference?

AIM

Primary lymphomas of endocrine glands are extremely rare. Our study adds more data to the few published series regarding the incidence, clinical characteristics, management and overall survival (OS) by comparing the various diffuse large B-cell endocrine lymphomas. Moreover, it contributes to a better understanding of these neoplasms and provides concepts for future research.

METHODS

We retrospectively evaluated the clinical profile and the patterns of outcome among patients who were treated in our center with the diagnosis of aggressive, B-cell, primary endocrine lymphoma.

RESULTS

Between May 1980 and December 2011, 450 patients were diagnosed as primary extranodal non-Hodgkin lymphomas. Among them, 18 cases (4%) were primary testicular lymphoma (PTL), 8 cases (2%) were primary thyroid lymphoma (PTHL) and 4 cases (1%) were primary adrenal lymphoma (PAL). The therapeutic approaches employed were variable, including mainly chemotherapy in combination with radiotherapy and surgery. The median OS for the patients with PTL and PAL was 27 and 6 months, respectively. Better outcome was observed in patients with PTHL for whom the median OS has not been reached yet, whereas the PAL group had the worst prognosis.

CONCLUSIONS

The discrepancies in the outcome among endocrine lymphomas could be partly attributed to their biologic variability, which might be determined by the initial site involved. We conclude that treatment decisions should be made according to a multi-disciplinary approach to avoid unnecessary surgery. Existing treatment strategies for PTL and PAL fail to provide long-term survival, rendering the application of novel therapeutic approaches essential.

Primary testicular lymphoma

Primary testicular non-Hodgkin lymphoma (PTL) comprises around 9% of testicular cancers and 1-2% of all non-Hodgkin lymphomas. Its incidence is increasing and it primarily affects older men, with a median age at presentation of around 67 years. By far the most common histological subtype is diffuse large B-cell lymphoma, accounting for 80-90% of PTLs. Most patients present with a unilateral testicular mass or swelling. Up to 90% of patients have stage I or II disease at diagnosis (60 and 30%, respectively) and bilateral testicular involvement is seen in around 35% of patients. PTL demonstrates a continuous pattern of relapse and propensity for extra-nodal sites such as the central nervous system and contralateral testis. Retrospective data have emphasised the importance of prophylactic radiotherapy in reducing recurrence rates within the contralateral testis. Recent outcome data from the prospective IELSG-10 trial have shown far better progression-free and overall survival than historical outcomes. This supports the use of orchidectomy followed by Rituximab- cyclophosphamide, doxorubicin, vincristine and prednisolone (R-CHOP), central nervous system prophylaxis and prophylactic radiotherapy to the contralateral testis with or without nodal radiotherapy in patients with limited disease. Central nervous system relapse remains a significant issue and future research should focus on identifying the best strategy to reduce its occurrence. Here we discuss the evidence supporting combination chemotherapy and radiotherapy in PTL.