The Influence Of Accrual Volume And National Cancer Institute-Comprehensive Cancer Center (Nci-Ccc) Designation On Outcome For The Rtog 91-11 Intergroup Trial For Laryngeal Preservation

For non-surgical cancer treatment, the influence of patient volume on outcomes is not well defined. In contrast, for complex oncologic surgery results are influenced by volume. Higher frequencies are associated with lower perioperative morbidity and mortality rates. This analysis was undertaken to ascertain if frequency of patient accrual or NCI-CCC designation influenced disease outcome for patients entered into a phase III laryngeal perservation trial. RTOG 9111 compared radiation therapy (RT) given with concurrent chemotherapy (CT), RT alone and induction CT followed by RT. There were 2 comparisons made based on accrual and institution type. Those in the top 1/3 for total accrual were high accruers (HA) compared to those in the bottom 1/3 who or low accruers (LA). NCI-CCC institutions were compared with non-NCI-CCC institutions. Endpoints were eligibility rate, time to laryngectomy (TTL), time to local failure (TTLF), and overall survival (OS). Hazard ratios (HR) and 95% confidence intervals (CI) comparing patient subgroups were estimated using Cox proportional hazards models with assigned treatment as fixed covariate, and were defined such that HR<1 indicated decreased risk for HA or NCI-CCC. 547 patients were entered and 515 were analyzed. The 7 HA institutions entered 176 cases (range 17 to 53; mean 25.1; median 18). The 117 LA institutions entered 196 cases (range 1 to 4; mean 1.7; median 1). The remaining 175 patients were treated at 21 institutions (range 5 and 14 patients; mean 8.3; median 8) but are not included in the models. 24 NCI-CCC accrued 213 patients (range 1 to 53 patients; mean 8.9; median 3.5). The other 121 institutions accrued 334 (range 1 to 18 patients; mean 2.8; median 1). HA and NCI-CCC subgroups had a higher percentage of eligible patients, but neither reached statistical significance at the 0.05 level [(HA vs. LA: 96.6% vs. 92.9%; p = 0.17) (NCI-CCC vs. non-NCI-CCC: 96.7% vs. 92.5%; p = 0.06)]. There were no statistically significant differences detected, or even any large differences estimated that approached statistical significance, for any endpoint for either comparison. Table 1 shows the estimated HR and 95% CI for all comparisons. No difference was found in eligibility, TTL, TTLF and overall survival for any comparison (p > .05). This supports a comparable outcome for non-surgical laryngeal preservation therapy regardless of accrual or NCI-CCC status. We conclude this treatment is translatable among centers if protocol guidelines are followed and appropriate quality oversight through the cooperative group is maintained.Tabled 1EndpointComparisonHR95% CIp-valueTTLHA vs. LA1.090.74, 1.610.66TTLNCI-CCC vs. non-NCI-CCC1.010.73, 1.400.96TTLFHA vs. LA0.870.63, 1.220.42TTLFNCI-CCC vs. non-NCI-CCC0.850.65, 1.130.26OSHA vs. LA0.840.63, 1.110.21OSNCI-CCC vs. non-NCI-CCC0.910.72, 1.160.45 Open table in a new tab