Effect of adjuvant chemotherapy on survival of patients with stage III colon cancer diagnosed after age 75 years.

PURPOSE: Few patients 75 years of age and older participate in clinical trials, thus whether adjuvant chemotherapy for stage III colon cancer (CC) benefits this group is unknown. METHODS: A total of 5,489 patients ≥ 75 years of age with resected stage III CC, diagnosed between 2004 and 2007, were selected from four data sets containing demographic, stage, treatment, and survival information. These data sets included SEER-Medicare, a linkage between the New York State Cancer Registry (NYSCR) and its Medicare programs, and prospective cohort studies Cancer Care Outcomes Research and Surveillance Consortium (CanCORS) and the National Comprehensive Cancer Network. Data sets were analyzed in parallel using covariate adjusted and propensity score (PS) matched proportional hazards models to evaluate the effect of treatment on survival. PS trimming was used to mitigate the effects of selection bias. RESULTS: Use of adjuvant therapy declined with age and comorbidity. Chemotherapy receipt was associated with a survival benefit of comparable magnitude to clinical trials results (SEER-Medicare PS-matched mortality, hazard ratio [HR], 0.60; 95% CI, 0.53 to 0.68). The incremental benefit of oxaliplatin over non-oxaliplatin-containing regimens was also of similar magnitude to clinical trial results (SEER-Medicare, HR, 0.84; 95% CI, 0.69 to 1.04; NYSCR-Medicare, HR, 0.82, 95% CI, 0.51 to 1.33) in two of three examined data sources. However, statistical significance was inconsistent. The beneficial effect of chemotherapy and oxaliplatin did not seem solely attributable to confounding. CONCLUSION: The noninvestigational experience suggests patients with stage III CC ≥ 75 years of age may anticipate a survival benefit from adjuvant chemotherapy. Oxaliplatin offers no more than a small incremental benefit. Use of adjuvant chemotherapy after the age of 75 years merits consideration in discussions that weigh individual risks and preferences.

Comparative effectiveness of oxaliplatin vs non-oxaliplatin-containing adjuvant chemotherapy for stage III colon cancer.

BACKGROUND: The addition of oxaliplatin to adjuvant 5-fluorouracil (5-FU) improves survival of patients with stage III colon cancer in randomized clinical trials (RCTs). However, RCT participants are younger, healthier, and less racially diverse than the general cancer population. Thus, the benefit of oxaliplatin outside RCTs is uncertain. SUBJECTS AND METHODS: Patients younger than 75 years with stage III colon cancer who received chemotherapy within 120 days of surgical resection were identified from five observational data sources-the Surveillance, Epidemiology, and End Results registry linked to Medicare claims (SEER-Medicare), the New York State Cancer Registry (NYSCR) linked to Medicaid and Medicare claims, the National Comprehensive Cancer Network (NCCN) Outcomes Database, and the Cancer Care Outcomes Research & Surveillance Consortium (CanCORS). Overall survival (OS) was compared among patients treated with oxaliplatin vs non-oxaliplatin-containing adjuvant chemotherapy. Overall survival for 4060 patients diagnosed during 2004-2009 was compared with pooled data from five RCTs (the Adjuvant Colon Cancer ENdpoinTs [ACCENT] group, n = 8292). Datasets were juxtaposed but not combined using Kaplan-Meier curves. Covariate and propensity score adjusted proportional hazards models were used to calculate adjusted survival hazard ratios (HR). Stratified analyses examined effect modifiers. All statistical tests were two-sided. RESULTS: The survival advantage associated with the addition of oxaliplatin to adjuvant 5-FU was evident across diverse practice settings (3-year OS: RCTs, 86% [n = 1273]; SEER-Medicare, 80% [n = 1152]; CanCORS, 88% [n = 129]; NYSCR-Medicaid, 82% [n = 54]; NYSCR-Medicare, 79% [n = 180]; and NCCN, 86% [n = 438]). A statistically significant improvement in 3-year overall survival was seen in the largest cohort, SEER-Medicare, and in the NYSCR-Medicare cohort (non-oxaliplatin-containing vs oxaliplatin-containing adjuvant therapy, adjusted HR of death: pooled RCTs: HR = 0.80, 95% CI = 0.70 to 0.92, P = .002; SEER-Medicare: HR = 0.70, 95% CI = 0.60 to 0.82, P < .001; NYSCR-Medicare patients aged ≥65 years: HR = 0.58, 95% CI = 0.38 to 0.90, P = .02). The association between oxaliplatin treatment and better survival was maintained in older and minority group patients, as well as those with higher comorbidity. CONCLUSION: The addition of oxaliplatin to 5-FU appears to be associated with better survival among patients receiving adjuvant colon cancer treatment in the community.

Unintended thermal injuries from radiofrequency ablation: protection with 5% dextrose in water.

OBJECTIVE: Radiofrequency ablation of hepatic tumors can lead to thermal injury of surrounding structures. Both saline and 5% dextrose in water (D5) have been used to displace these surrounding structures before radiofrequency ablation. The purpose of this study was to determine the relative effectiveness of these two fluids for protecting the diaphragm and lung during radiofrequency ablation. MATERIALS AND METHODS: Ten female domestic swine (mean weight, 45 kg) underwent radiofrequency ablation at open surgery. Group 1 (n = 12 lesions) was pretreated with peritoneal D5 before radiofrequency ablation. Group 2 (n = 11 lesions) was pretreated with peritoneal 0.9% saline. A 2.7-mm spacer was placed between the liver surface and diaphragm in groups 1 and 2. Group 3 (n = seven lesions) served as a control group with no pretreatment regimen. Group 4, an additional control group (n = eight lesions), consisted of animals pretreated with D5 in which a larger spacer was used. After radiofrequency ablation, the animals were sacrificed and the liver, diaphragm, and lung were removed. The extent of thermal injury to the surface of each organ was recorded. RESULTS: The animals in the D5 and saline pretreatment groups experienced fewer diaphragm injuries than the control animals (D5, p = 0.02). The smallest lesions in the lung and diaphragm were in the D5 group, followed by the saline and control groups (diaphragm, p = 0.0001; lung, p = 0.13). Diaphragm lesions were significantly smaller in the D5 and saline groups than in the control group (p = 0.0001 and 0.01, respectively). CONCLUSION: Instillation of D5 into the peritoneal cavity before hepatic radiofrequency ablation decreases the risk and severity of diaphragm and lung injuries compared with no pretreatment or pretreatment with 0.9% saline in this animal model. Pretreatment with D5 may increase both the safety of and the number of patients eligible for treatment with thermal therapies.

Microwave ablation with loop antenna: in vivo porcine liver model.

PURPOSE: To determine the effectiveness of tissue ablation with a loop microwave antenna in various configurations in porcine liver tissue. MATERIALS AND METHODS: Microwave energy was applied for 7 minutes at 60 W in six porcine livers (mean weight, 68.2 kg) by using single (n = 7) or dual 2.7-cm loop microwave probes in parallel (n = 9) or orthogonal (n = 9) configurations. Volume, diameter, shape, and temperature of the zone of necrosis and the presence of viable tissue inside the loop were determined and compared by means of factorial analysis of variance. RESULTS: Mean lesion volume and maximum diameter, respectively, were 32.2 cm(3) +/- 14.4 (SD) and 4.6 cm +/- 1.4 for lesions ablated with parallel probes (parallel lesions), 29.5 cm(3) +/- 8.1 and 4.3 cm +/- 0.6 for lesions ablated with orthogonal probes (orthogonal lesions), and 6.4 cm(3) +/- 1.9 and 3.4 cm +/- 0.62 for lesions ablated with single probes (single lesions) (P <.05, single vs parallel and orthogonal lesions). Mean minimum diameter was greatest for orthogonal lesions (3.5 cm +/- 0.53; P =.017, parallel vs orthogonal lesions). Orthogonal lesions had the highest mean internal temperature (97.2 degrees C) versus parallel (91.9 degrees C) and single (60.0 degrees C) lesions. All orthogonal lesions heated to 60 degrees C in comparison to eight of nine parallel and four of seven single lesions. The mean time to reach 60 degrees C was shortest for orthogonal lesions (93.3 seconds) versus parallel (123.8 seconds) and single (263.0 seconds) lesions. Orthogonal lesions were the most spherical. Viable tissue was present in the center of five of seven single, six of nine parallel, and zero of nine orthogonal lesions. CONCLUSION: Loop microwave antennas allow precise control and effective ablation of targeted tissue, particularly in the orthogonal configuration.