Therapy Options for Primary Pulmonary NHL?
A 69-year-old postmenopausal woman presented with incidental findings of a follicular lymphoma of the mid-lobe of the right lung. Three adjacent nodes were examined: 1 was negative and 2 showed minimal evidence of follicular (small-cell) lymphoma. Neither CT scan with contrast nor PET demonstrated involvement of the bowel, liver, or spleen. Bone marrow biopsy was negative. What would you suggest as a course of therapy?

This is a case of a 69-year-old woman with follicular small-cell lymphoma localized in one of the lung lobes, in whom extensive search did not reveal any other involved sites.

Involvement of the lung with non-Hodgkin's lymphoma (NHL) usually occurs with disease present elsewhere in a generalized process. Primary lung NHL occurs rarely, comprising only 1% of extranodal lymphomas. In this case, we're dealing with a low-grade lymphoma, and primary NHL representing low-grade, intermediate-grade, and mucosa-associated lymphoid tissue (MALT) type have all been described in the literature. The risk of primary lymphoma involving the lung is higher in patients with immunodeficiency states, such as those with AIDS and those on immunosuppressive therapy following organ transplantation, where the lung may be the most common organ involved following the CNS.

Primary pulmonary NHL typically presents as multiple parenchymal nodular lesions. In the above case, the disease is localized, an important factor affecting the choice of therapy. The majority of the patients with low-grade lung lymphoma have MALT subtype. This is highly radiation-sensitive tumor, requiring relatively low doses for cure. For example, the common MALT lymphoma of the stomach has a very high cure rate following a dose of 30 Gy or less, which would be well tolerated if delivered to a limited lung volume. Low-grade lymphoma that is not MALT may be controlled locally by 30-36 Gy in 15-20 daily fractions.

No chemotherapy would be advised in conjunction with irradiation, as there is no evidence that chemotherapy affects the survival of patients with low-grade lymphomas. Cordier and colleagues reported a very high rate of tumor control in localized lung lymphoma following surgical excision. However, local radiotherapy is expected to achieve similar results with less morbidity. On the other hand, chemotherapy or antilymphoma antibodies would be appropriate in symptomatic patients with multiple involved lung sites, where radiation to extensive lung volumes would be prohibitive.