Hematologic recovery after central lymphatic irradiation for patients withstage I-II follicular lymphoma

BACKGROUND. The authors previously reported that central lymphatic irradiat ion (CLI) can induce molecular remission in patients with Stage I-III folli cular lymphoma, as measured by polymerase chain reaction analysis for t(14; 18) (q32;q21). Hematologic to)toxicity has been considered a major conseque nce of CLI. This study was undertaken to analyze the patterns of hematologi c recovery after CLI. METHODS. Thirty-three patients with Stage I-III follicular lymphoma. were t reated with CLI between January 1993 and February 1998. CLI consisted of ir radiation to mantle, upper two-thirds of abdomen, and pelvic fields. Each f ield was treated to 30.0-30.6 grays (Gy) at 1.5-1.8 Gy per fraction, with a boost to 36.0-39.6 Gy at the same rate to the sites of macroscopic disease . A break of approximately 4 weeks was given after treatment of each field. Twenty-four patients who were followed for a minimum of I year from the en d of CLI form the basis of this analysis. Fourteen patients were male. Thre e patients had Stage I disease, 6 patients had Stage II disease, and 15 pat ients had Stage III disease. The International Prognostic Index IPI) for ma lignant lymphoma. was 0 for 5 patients, I for 13 patients, and 2 for 6 pati ents. The Eastern Cooperative Oncology Group performance status was 0 for 2 1 patients and 1 for 3 patients. The median values for their pretreatment c haracteristics were as follows: age, 60 years (range, 34-73 years); height, 173 cm (range, 155-193 cm); weight, 79 kg (range, 57-107 kg); body surface area (BSA), 1.95 m(2) (range, 1.61-2.31 M-2); bone marrow cellularity, 27% (range, 2-75%), platelet count, 233, 000/mm(3) (range, 139,000-339,000/mm(3 )), white blood cell (WBC counts, 6400/mm(3) (range, 4200-10,900/mm(3)); an d hemoglobin, 14.5 mg/dL (range, 11.8 -16.6 mg/dL The median duration of CL I was 159 days (range, 137-345 days). Ten patients had cardiovascular disea se. The number of sites receiving a boost dose of greater than or equal to 36.0 Gy was 0 sites in I patient, 1 site in 6 patients, 2 sites in 11 patie nts, 3 sites in 5 patients, and 4 sites in 1 patient. The platelet, hemoglo bin, and WBC counts were followed every 3 months after completion of CLI. T hese counts were normalized to the pretreatment counts for statistical anal yses. Univariate and multivariate analyses were per-formed to investigate t he correlations between patient factors and hematologic status at 1 year po sttreatment. Pearson correlation analysis was used for the continuous facto rs (patient age, height, weight, BSA, bone marrow cellularity, and duration of CLI), and the Mann-Whitney test was used for categoric factors (IPI, ge nder, performance status, stage, number of sites receiving greater than or equal to 36.0 Gy, and presence or absence of cardiovascular disease). RESULTS. There was continued recovery, essentially approaching the pretreat ment levels, over 3 years for platelet, WBC, and hemoglobin counts. Factors that were associated significantly with normalized platelet counts at 1 ye ar by univariate analyses were age (P = 0.015) and cardiovascular disease ( P = 0.041). Age was the only significant factor by multivariate analyses, w ith older patients having lower platelet counts at 1 year posttreatment. No factors were found that were associated significantly with 1-year normaliz ed WBC or hemoglobin levels by either univariate or multivariate analyses. CONCLUSIONS. All three of the hematologic components (platelets, IVBC, and hemoglobin) essentially recover after patients undergo CLI over a 3-year pe riod. Older age was the only significant adverse factor that affected the p latelet recovery, as detected by multivariate analysis. (C) 2001 American C ancer Society.