Background: Local radiation therapy (RT) can provide pain relief and reduce bleeding resulting from pleural or peritoneal dissemination of primary tumors. However, the optimal RT exposure dose for such tumors is unclear and the response rate is unknown. In this study, we examined the effectiveness of palliative RT for pleural or peritoneal disseminated tumors to determine the optimal dose in these patients.
Methods: The data of 22 patients with pleural- or peritoneal-disseminated tumors who were treated with local RT at our institution between 2011 and 2019 were retrospectively reviewed.
Results: Among these patients, 9 (40.9%) had pleural tumors, 13 (59.1%) had peritoneal tumors and 2 had tumors in the peritoneum and umbilicus. The most common primary tumors were lung (22.8%) and pancreatic cancer (18.2%). RT was mainly administered for pain alleviation (72.7%). Three patients (13.6%) received RT for hemostasis. Thirteen patients (59.1%) received a regimen of 30 Gy/10 fractions (fr), with the total dosage for all patients ranging from 27 to 56 Gy. No grade 2 or higher RT-related adverse events occurred. Three and four patients obtained complete and partial responses, respectively. The timing of the measurement of response to pain relief ranged from 0 to 232 (median, 21) days upon completion of RT. Overall response to pain relief occurred in nine of 16 patients (56.3%) with pain before RT. Hemostasis was confirmed in 2 of the 3 patients (66.7%) with bleeding before RT. Twelve of 20 (60%) patients with symptoms before RT responded to RT. Disease-specific survival (DSS) time after RT ranged from 1 to 656 (median, 106) days.
Conclusions: Prompt palliative administration of RT to patients with advanced disease to alleviate pain from disseminated tumors may achieve therapeutic efficacy.
Keywords: Radiation therapy (RT); peritoneal dissemination; pleural dissemination.