After radiotherapy, do bone metastases from gastrointestinal cancers show response rates similar to those of bone metastases from other primary cancers?

PURPOSE: Reports investigating whether the response rates to palliative radiation therapy (rt) for painful bone metastases from gastrointestinal (gi) cancers are similar to rates for bone metastases from other primary cancer sites have been limited. The present study evaluated response rates for symptomatic bone metastases from gi cancers after palliative outpatient rt in the Rapid Response Radiotherapy Program (rrrp). PATIENTS AND METHODS: We identified 69 patients with bone metastases from gi primaries who received palliative rt in the rrrp clinic during 1999–2006. We extracted records for 31 of these patients during 1999–2003 from an rrrp database that used the Edmonton Symptom Assessment Scale (esas). Record for the remaining 38 patients during 2003–2006 were extracted from an rrrp database that used the Brief Pain Inventory (bpi). Eligibility criteria for encryption in the two rrrp databases and for collection of patient demographic information (age, sex, primary cancer site, and Karnofsky performance status) were identical. Response rates for this cohort of metastatic gi patients were then compared to rates for 479 patients receiving palliative rt for bone metastases from other primary cancer sites. Pain scores from the esas and bpi and data on analgesic consumption were collected at baseline and by telephone follow-up at 4, 8, and 12 weeks after rt for all patients. Complete (cr), partial (pr), and overall (cr+pr) responses were evaluated according to International Consensus Endpoints. RESULTS: Assessment of the 69 patients with metastatic gi cancers revealed cr, pr, and cr+pr rates of 18%, 42%, and 61% at 4 weeks; 22%, 35%, and 57% at 8 weeks; and 50%, 21%, and 71% at 12 weeks for evaluable patients. The 479 evaluable patients with metastatic cancer from other primary cancer sites had cr, pr, and cr+pr rates of 25%, 27%, and 51% at 4 weeks; 26%, 22%, and 48% at 8 weeks; and 22%, 29%, and 51% at 12 weeks. No statistically significant differences were observed in rt response rates for bone metastases from gi cancers than from other primary cancer sites. CONCLUSIONS: After palliative rt, bone metastases from gi cancers demonstrate response rates that are similar to rates for metastases from other primary cancer sites. Patients with symptomatic bone metastases from gi malignancies should be referred for palliative rt as readily as patients with osseous metastases from other primary cancer sites.