PURPOSE: The optimal timing,dose&volume of thoracic radiation therapy (TRT) for patients (pts) with LS-SCLC remain ongoing issues. A ‘98-’99 USA RT Patterns-of-Care-Study (PCS) showed that only 6% of pts were treated with twice-daily (BID)-RT to 45Gy and only 22% received prophylactic-cranial-irradiation (PCI) (JCO 21:4553-9,2003). The purpose of this study was to evaluate the ‘06-’07 patterns-of-practice for LS-SCLC among radiation oncology (radonc) members of American-Society-of-Therapeutic-Radiology & Oncology (ASTRO).
METHODS: Study questionnaires were designed by a panel of 8 board-certified radoncs. The survey was sent through email to physician ASTRO-members in 9/06 with results collected 4/07. Of 800 responses, 425 were from the USA (of whom 51 specialized in thoracic-RT by self-report) and 59 from Canada. Chi-square testing was used with two-sided p-value 0.05 considered significant.
RESULTS: Of all respondents (N=800), 39% reported they would start TRT immediately (chemo cycle-1) vs 29% with cycle-2. Immediate-TRT was highest among USAradoncs (51%), particularly thoracic-RT USA radoncs (59%), vs only 12% for Canadian radoncs (of whom 70% would start TRT with cycle-2 for “logistic reasons”); p-value <0.001 for USA vs Canadians. Overall, 22% of all radoncs supported a BID-RT regimen (to 45Gy) vs 33% for once-daily (qd) RT (to 60-70Gy) vs 27% for 1.8-2Gy qd to 50-54Gy vs 6% for 2.67Gy qd to 40Gy. BID-RT (to 45Gy) was most highly recommended by USAradoncs (28%), particularly thoracic-RT USA radoncs (59%) vs only 5% among Canadian radoncs (of whom 44% recommended 40Gy at 2.67Gy qd); p-value <0.001 for USA vs Canadians. Most radoncs recommended treating “high-risk nodal regions” (49-50%) vs broader elective-nodal regions (21-30%) vs gross-tumor-volume only (18-28%). >=95% of all radoncs recommended PCI for patients with a complete or good-partial response to initial chemoRT.
CONCLUSION: Compared to the ‘98-’99 PCS-study, this survey suggests a shift towards dramatically higher use of PCI (>=95%) and more intensive (and earlier) TRT, as supported by evidence-based-medicine. Important differences still exist, though, re:RT dose/fractionation (fx) and timing of TRT between USA and Canadian radoncs.
CLINICAL IMPLICATIONS: A newly funded USA Quality-in-RadOnc-Research(QRRO) survey of actual treatment delivered should verify if these recommended changes are indeed being implemented. As well, a landmark intergroup phase III RT dose/fx trial is actively under development.
DISCLOSURE: Benjamin Movsas, No Financial Disclosure Information; No Product/Research Disclosure Information