Estimation Of Network Link Loss Rates Via Chaining In Multicast Trees

Of increasing importance is estimation of internal link parameters in communications networks. Multicast probes are a way to gather statistics about internal links from edge node measurements. The problem of estimating link loss probabilities for a multicast distribution tree is examined here. Our model assumes loss statistics are distributed to session participants by a network protocol such as RTCP. We propose a decentralized algorithm for ML estimation of the link loss probabilities in a chain of nodes rooted at the source node of the multicast distribution tree and terminating at a given leaf. An expression for the Cramer-Rao bound and an approximate form for the probability distribution function of the estimator are given. The performance of the algorithm is evaluated using computer simulations for a bottleneck detection application

Vinorelbine plus cisplatin versus docetaxel plus gemcitabine in advanced non-small-cell lung cancer: A phase III randomized trial

Purpose To compare the activity and tolerability of docetaxel/gemcitabine (DG) and vinorelbine/cisplatin (VC) combinations in chemotherapy-naive non-small-cell lung cancer (NSCLC) patients. Patients and Methods Patients with advanced NSCLC were randomly assigned to receive either DG (gemcitabine 1,000 mg/m(2) [days 1 and 8] plus docetaxel 100 mg/m(2) [day 8]) or VC (vinorelbine 30 mg/m(2) [days 1 and 8] plus cisplatin 80 mg/m(2) [day 8]) and prophylactic recombinant human granulocyte colony-stimulating factor (150 mu g/m(2) subcutaneously [day 9 through 15]) every 3 weeks. Results A total of 413 randomly assigned patients were analyzed for response and toxicity (DG, n = 197; VC, In = 192). Median survival was 9.0 and 9.7 months (P = .965) for DG and VC arms, respectively; the corresponding 1-year survival rates were 34.3% and 40.8%, respectively. Overall response rate was 30% (95% CI, 23.9% to 36.3%) and 39.2% (95% CI, 32.5% to 45.9%; P = .053) for DG and VC, respectively. Toxicity was as follows (DG v VC): grade 2 to 4 anemia, 34% v 55% (P = .0001); grade 3 to 4 neutropenia, 16% v 37% (P = .0001); febrile neutropenia, 6% v 11% (P = .009); and grade 3 to 4 nausea and vomiting, 1% v 15% (P = .003). Nephrotoxicity occurred in 8% and ototoxicity in 2% of VC-treated patients. There were five and six treatment-related deaths in the DG and VC arms, respectively. Quality of life was improved in DG but not in VC patients. Conclusion Although the two regimens produced comparable overall survival, the DG regimen had a better toxicity profile. Therefore, DG could be used in the first-line setting of advanced NSCLC, especially for patients who cannot tolerate cisplatin

Cisplatin-etoposide alternating with topotecan in patients with extensive stage small cell lung cancer (SCLC) - A multicenter phase II study

Purpose: In order to investigate the feasibility of a potentially non-cross resistant drug regimen, we alternated cycles of cisplatin-etoposide with topotecan as front-line treatment in patients with extensive stage small cell lung cancer (SCLC). Patients and Methods: Thirty-six previously untreated patients with extensive stage SCLC received cisplatin 75 mg/m(2) IV on day I and etoposide 100 mg/m(2) IV on days 1-3 on cycles one, three, five and seven and topotecan 1.5 mg/m(2) IV on days 1-5 on cycles two, four, six and eight. Cycles were repeated every 21 days. Patients’ median age was 60 years and performance status (WHO) was 0 for 13, 1 for 20 and 2 for three patients. All patients were evaluable for response and toxicity. Results: Five (14%) patients achieved a complete response and 18 (50%) a partial response for an overall response rate of 64% (95% confidence interval: 48.2-79.6%). After a median follow up of 10 months, the median duration of response was 5.5 months, the time to tumor progression 8 months and the probability of 1-year survival 48.9%. A total of 126 cycles of cisplatin-etoposide and 117 cycles of topotecan were administered with a median number of 4 cycles/patient for each regimen. There were no toxic deaths. Treatment delays due to toxicity occurred in 13 (10%) cycles after cisplatin-etoposide and 16 (14%) cycles after topotecan while doses were reduced in seven (6%) and five (4%) cycles, respectively. Grade 3-4 neutropenia, thrombocytopenia and febrile neutropenia complicated 13, 1 and 3% of cisplatin-etoposide cycles and 28, 6 and 1% of topotecan, respectively. Non-hematologic toxicity was mild. The delivered dose intensity was 96% for cisplatin and etoposide and 98% for topotecan. Conclusions: The alternating administration of cisplatin-etoposide and topotecan is a feasible, active and well-tolerated regimen in patients with extensive stage SCLC. (C) 2002 Elsevier Science Ireland Ltd. All rights reserved