lesions being on the same side of the diaphragm; Stage III disease as involving ≥2 lymphatic regions that are on opposite sides of the diaphragm; and Stage IV disease as disseminated lesions that are found to be in ≥1 non-lymphatic organs. Response-based prognosis: FL patients whose disease progresses within 24 months of initiating treatment with chemotherapy and immunotherapy versus patients whose disease does not progress within 24 months are predicted to have 5 year survival rates of 50-74% versus ~90%, respectively. The prognosis and treatment for the specific presentations of typical FL cases (see above sections for the prognoses and treatment recommendations for primary gastrointestinal tract FL, predominantly diffuse FL with 1p36 deletion, pediatric-type FL, and primary FL of the testis) that are in common use are as follows: In situ follicular lymphoma ISFL is a benign condition that may be reevaluated periodically to detect the rare cases of it which progress to FL; otherwise ISFL is not treated. Localized follicular lymphoma In 10-20% of cases, FL appears limited to single radiation field, does not involve the bone marrow, and is therefore regarded as localized early-stage FL. In these cases, which are sometimes classified as Ann Arbor stage I (i.e. disease limited to a single restricted region) or stage II (i.e. disease restricted to two sites that are on the same side of the diaphragm), radiation therapy achieves 10 year overall survival rates of 60-80% and median overall survival times of 19 years. It seems likely that many of the relapses in these cases are due to undetected disease outside of the radiation field at the time of radiation treatment. The use of PET/CT imaging is strongly recommended to insure that the FL is localized. In any case, the excellent results achieved with radiation therapy strongly support its use in localized disease. The use of an immunotherapeutic agent such as Rituximab alone or in combination with a chemotherapeutic regimen such as CVP (i.e. cyclophosphamide, vincristine, prednisone and rituximab) in cases of localized, early-stage disease may be appropriate choices for some of these early-stage patients. However, the latter approach is recommended for cases of localized disease in which the disease extends beyond a single field: 56% of patients treated in this manner had progression-free survival at 10 years while patients treated with other regimens had progression free survivals of 41%. Nonetheless, overall survival did not differ between the two groups. Asymptomatic