Purpose: To describe changes in pulmonary function and subjective dyspnea over time in patients who received bleomycin-based chemotherapy for Hodgkin’s disease (HD) and to identify predictors for decline in pulmonary function and subjective dyspnea after HD therapy
Methods: 52 patients with newly-diagnosed classical HD receiving bleomycin-based chemotherapy with or without mediastinal radiation therapy were enrolled. Patients underwent baseline pulmonary function tests (PFTs), and completed the Pulmonary Functional Status and Dyspnea Questionnaire (PFSDQ-M) pre-treatment. The PFSDQ-M is a 40-item, validated questionnaire measuring the 3 areas of dyspnea, fatigue and activity. The scores range from 0–10, with higher scores representing worse health status. The PFTs and PFSDQ-M were repeated at 1 month, 6 months, 1 year and 2 years post-treatment. Other information collected were number of cycles of bleomycin, radiation dosimetric parameters, and smoking history. This report is based on the 33 patients who had completed treatment and had at least follow-up at 1 month post-treatment. 19 patients received chemotherapy alone and 14 received combined modality therapy. Three-dimensional radiation planning was used and lung dose-volume histograms were generated. Wilcoxon rank sum tests were used to compare the baseline and 1-month objective and subjective lung function results, and to determine whether the addition of radiation therapy to chemotherapy, and among patients who received combined modality therapy, whether the percentage of lung volume receiving 20 Gray (V20), contribute to the changes. A general linear model was used to identify predictors for decline in percentage of predicted carbon monoxide diffusing capacity (%DLCO) at 1 month.
Results: At baseline, the median %DLCO was 94% (range: 53–139%). At 1 month post treatment, it was significantly lower at 82% (range: 46–133%) (p=0.0003). Decline in %DLCO at 1 month was not significantly predicted by the addition of mediastinal irradiation (p=0.84), number of cycles of bleomycin (p=0.6), and smoking history (p=0.14), but it was significantly predicted by the baseline %DLCO, with a lower baseline %DLCO associating with less decline in %DLCO (p=0.03). However, the baseline %DLCO also significantly correlated with treatment, with 72% of patients who received chemotherapy alone having a baseline %DLCO =< 94% (median), compared with 23% of patients treated with combined modality therapy (p=0.011). The median general dyspnea and fatigue scores pre-treatment were 0 (range: 0–6) and 2 (range: 0–7), respectively, and remained the same at 1 month post-treatment. For the 14 patients treated with combined modality therapy, the median V20 was 31.5 % (range: 12–36%). There was no significant effect of V20 on the decline in %DLCO or changes in general dyspnea and general fatigue scores at 1 month. Conclusions: Preliminary results of this study showed significant decline of %DLCO at 1 month post-treatment, but no significant changes in subjective dyspnea and fatigue. None of the treatment-related variables significantly predicted for changes in the pulmonary function at 1 month. The baseline %DLCO was negatively associated with decline in %DLCO, which may be due to response of the mediastinal disease to treatment. However, this association may be confounded by the type of treatment received. Further follow-up is needed to determine the long-term effect of the treatment on lung function.