Pulmonary Radiotherapy Can Usually Be Omitted for Nephroblastoma and Pulmonary Metastases

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For the majority of patients with nephroblastoma and pulmonary metastases, pulmonary radiotherapy can be omitted and the patients will still have a relatively good outcome, according to a study published in the Journal of Clinical Oncology. “The rationale of omitting pulmonary [radiotherapy] for the majority of the patients is prevention of midterm and long-term morbidity, such as exercise-induced dyspnea, interstitial pneumonia, diminished lung volumes, and other respiratory disorders,” the researchers explained.

The current treatment strategy for nephroblastoma, the most frequent common renal tumor of childhood, consists of neoadjuvant chemotherapy, nephrectomy, postoperative chemotherapy, and sometimes radiotherapy, according to the International Society of Pediatric Oncology. Different strategies have been used for treating pulmonary metastases, ranging from the routine use of pulmonary radiotherapy for metastases detected on conventional pulmonary x-ray to using radiotherapy only in cases of persistent nodules or high-risk histology.

Study Details

The current study involved 1,170 patients (aged 6 months to 18 years), including 234 with pulmonary metastases. Patients were treated with preoperative chemotherapy consisting of 6 weeks of vincristine, dactinomycin, and epirubicin or doxorubicin. “Chest CT was repeated at the time of nephrectomy to assess the response of the pulmonary nodules, and postoperative chemotherapy was adapted according to the results of CT,” the authors noted.

Patients who achieved complete remission received three-drug postoperative chemotherapy. In cases of persisting pulmonary nodules, metastasectomy was performed if feasible, and if complete remission was achieved, followed by the same three-drug regimen. Patients who did not achieve complete remission were switched to a high-risk regimen and assessed at week 11. Radiotherapy was mandatory for those not obtaining complete remission.

“Of the 220 patients with [pulmonary metastases] and complete data, 185 patients (84%) were in [complete remission] postoperatively,” the authors stated. In addition, 148 patients (67%) were in complete remission after preoperative chemotherapy only and 37 patients (17%) were considered for metastasectomy. The high-risk protocol was required for 35 patients (16%) who had multiple inoperable pulmonary metastases. “Only 14% of patients received pulmonary [radiotherapy] during first-line treatment,” the authors noted.

Key Results

The 5-year event-free survival rate for patients with pulmonary metastases was 73% (95% CI = 68%–79%), and the 5-year overall survival rate was 82% (95% CI = 77%–88%). “Five-year [overall survival] was similar for patients with local stage I and II disease (92% and 90%, respectively) but lower for patients with local stage III disease (68%; P < .001). Patients in [complete remission] after chemotherapy only and patients in [complete remission] after chemotherapy and metastasectomy had a better outcome than patients with multiple unresectable [pulmonary metastases] (5-year [overall survival], 88%, 92%, and 48%, respectively; P < .001),” the researchers reported.

“Given the current results, we conclude that the majority of patients with nephroblastoma and [pulmonary metastases] can obtain a long-term [complete remission] without pulmonary [radiotherapy],” the authors stated. “By adopting this strategy, we observed a 5-year [event-free survival] of 73% and a 5-year [overall survival] of 82%. These survival data are similar to the 4-year recurrence-free survival rate of 77% and [overall survival] rate of 81% reported in patients with lung metastases only and treated with regimen DD-RT (a combination of vincristine, dactinomycin, doxorubicin, and radiotherapy).” ■

Verschuur A, et al: J Clin Oncol 30:3533-3539, 2012.