Competing risks survival of older patients with metastatic cutaneous melanoma: a SEER population-based study

Mortality from metastatic cutaneous melanoma is substantially heterogeneous as reflected in three distant metastatic (M1) subtypes with metastasis to skin, subcutaneous tissue, or distant lymph nodes (M1a), conferring nearly half the risk of death compared with distant visceral metastasis (M1c). It remains unknown whether older patients experience the survival benefit from the M1a subtype given a higher overall mortality risk. Surveillance, Epidemiology, and End Result data were retrieved from 1878 metastatic melanoma patients, from 2005 to 2009, with follow-up through 2011. Hazard ratios (HRs) for 2-year overall survival were estimated for M1 subtypes among older (≥65) and younger (<65) patients. Proportional subdistribution hazard ratios (SHRs) were calculated for melanoma-specific and competing risk mortality. For both older and younger patients, worse overall survival was observed for the M1c compared to the M1a subtype [HR: 2.65, 95% confidence interval (CI): 2.02-3.49; and, SHR: 3.36, 95% CI: 2.56-4.41; respectively]. For competing mortality, older compared to younger patients had increased risk in the M1a and M1b subtypes (SHR: 6.07, 95% CI: 1.94-19.0, and SHR: 2.34, 95% CI: 1.08-5.05, respectively). Conversely, when examining melanoma-specific mortality, older patients had decreased risk in M1a and M1b subtypes (SHR: 0.28, 95% CI: 0.14-0.53, and SHR: 0.60, 95% CI: 0.38-0.94, respectively) compared to those under 65 years. The persistent prognostic advantage of M1a among older patients should be considered when calculating the risk-benefit ratio for treatment. Prior reports of a protective effect of older age on melanoma-specific mortality, when based on traditional competing risks analyses, might be explained as an artifact of increased competing mortality risk.

Histogram analysis of apparent diffusion coefficient within enhancing and nonenhancing tumor volumes in recurrent glioblastoma patients treated with bevacizumab

While patients with recurrent glioblastoma receiving anti-angiogenic therapy demonstrate significant response rates, the benefit on patient survival is less clear. We assessed whether histogram analysis of diffusion weighted MRI can stratify for progression-free and overall survival. Baseline and 3-6 week post-treatment MRI exams of 91 patients with recurrent glioblastoma treated with bevacizumab were retrospectively evaluated. Histograms of apparent diffusion coefficient (ADC) within the volume of contrast enhancing and nonenhancing T2/FLAIR lesions were analyzed using curve-fit analysis. Overall survival (OS) and progression-free survival (PFS) were assessed using ADC parameters in a Cox proportional hazards model adjusted for clinical variables. Baseline ADC(L)/ADC(M) within nonenhancing T2/FLAIR volume (> or ≤0.64) can stratify OS (HR = 2.24, p = 0.002) and PFS (HR = 1.90, p = 0.005). %ADC(H) within enhancing T1+C volume (> or ≤25 %) can also stratify OS (HR = 0.59, p = 0.034) and PFS (HR = 0.56, p = 0.01). Stratification of patient survival can be improved by merging these two ADC parameters into a single combined ADC factor (HR = 0.17, p < 0.0001). The median OS ratio of patient groups stratified by this combined factor was 2.03, larger than median OS ratio when stratifying by either %ADC(H) within T1+C volume alone (1.3) or ADC(L)/ADC(M) within T2/FLAIR alone (1.86). ADC histogram analysis within both enhancing and nonenhancing components of tumor can be used to stratify for PFS and OS in patients with recurrent glioblastoma.

Boosting enrolment in clinical trials: validation of a regional network model

BACKGROUND

Clinical trials of stroke therapy have been hampered by slow rates of enrolment.

PURPOSE

Our purpose is to validate a previously developed model for accelerating enrolment in clinical trials by replicating it at new locations. The model employs coordinators who travel from a host institution to enrol participants from a network of participating hospitals. Active surveillance assures identification of all eligible patients.

METHODS

Among 70 U.S. investigators participating in National Institutes of Health-funded trial of stroke prevention, five investigators were invited to develop local identification and outreach networks (LIONs). Each LION comprised a LION coordinating centre servicing multiple hospitals. Hospitals provided names of patients with stroke or transient ischaemic attack to researchers at the LION coordinating centre who initiated contact; patients were offered home visits for consent and randomization. Outcomes were feasibility, enrolment, data quality, and cost.

RESULTS

Five LIONs varied in size from two to eight hospitals. All 24 hospitals we approached agreed to participate. The average monthly rate of enrolment at the research sites increased from 1.4 participants to 3.5 after expanding from a single institution model to the LION format (mean change = 2.1, range 0.9-3.7). Monthly performance improved over time. Data quality was similar for LIONs and non-LION sites, except for drug adherence which was lower at LIONs. The average cost to randomize and follow one participant during the study interval was 2.4 times the cost under the per-patient, cost-reimbursement strategy at non-LION sites. The cost ratio declined from 3.4 in year one to 1.8 in year two.

LIMITATIONS

The LION strategy requires unprecedented collaboration and trust among institutions. Applicability beyond stroke requires confirmation.

CONCLUSION

LIONs are a practical, reproducible method to increase enrolment in trial research. Twelve months were required for the average site to reach its potential. The per-participant cost at LIONs was higher than conventional sites but declined over time.

High dose baclofen is neuroprotective but also causes intracerebral hemorrhage: a quantal bioassay study using the intraluminal suture occlusion method

Agonists of the GABA-A receptor are neuroprotective after experimental stroke, but studies of GABA-B agonists have contradicted each other. To further investigate whether GABA-B agonists may be neuroprotective, we devised a quantal bioassay using the intraluminal occlusion method of inducing reversible cerebral ischemia. Subjects underwent middle cerebral artery occlusion for varying amounts of time, ranging from 5 to 90 min. Behavioral outcome was measured 48 h later with a quantal observational scale: score of abnormal given for any one of asymmetric forepaw flexion on tail lift, asymmetric grip, circling, reduced exploration, seizures, or death. To the grouped response data the logistic equation was used to find the ED50, the duration of occlusion that caused one-half of the subjects to be abnormal. To find the potency ratio for each drug, we divided the ED50 for treatment by that for vehicle. We administered baclofen, a GABA-B agonist, intraperitoneally 5 min after the onset ofischemia. Baclofen (20 mg/kg) was neuroprotective (potency ratio of 3.0, P < 0.05), but a lower dose (10 mg/kg) was not. However, both doses of baclofen caused significantly more intracerebral hemorrhages than control. In awake animals, both baclofen doses caused significant increases in mean arterial pressure, but no changes in other cardiorespiratory variables. The glutamate antagonist MK-801, the GABA-A agonist muscimol, and hypothermia were all protective using the bioassay (potency ratios ranging from 1.5 to 3.0). We conclude that although baclofen (20 mg/kg) may be neuroprotective, its utility is complicated by postischemic hypertension and cerebral hemorrhages.

A rapid, reliable, and valid method for measuring infarct and brain compartment volumes from computed tomographic scans

BACKGROUND AND PURPOSE

Clinical stroke trials require objective and reproducible end point variables. Morphometry of cerebral structures, including infarct volume, provides numerical measures that represent the amount of tissue damaged and potentially salvaged by therapy. However, morphometry may be time-consuming and labor-intensive, and it requires standardization across multiple centers, which may be difficult to achieve in large multicenter trials. We developed a brain morphometry method that is unbiased, rapid, reliable, and based on well-accepted stereological techniques. We now extend this method to analysis of routine computed tomographic (CT) scans such as might be obtained during a clinical stroke trial.

METHODS

We studied CT scans from 18 stroke patients and 14 asymptomatic control patients obtained over 5 years at the San Diego Veterans Administration Medical Center. Three observers independently measured the volume of the cranial vault, cerebrum, cortex, white matter, deep gray structures, ventricle, sulcal cerebrospinal fluid space, visible infarction, and cerebellum/brain stem.

RESULTS

The two patient groups were well matched demographically. The intracranial volume of 1400 +/- 40 mL in control subjects was not different from the 1311 +/- 41 mL in patients. Cerebral volume was 1250 +/- 36 mL compared with 1070 +/- 36 mL (control subjects versus patients, P < .001), and infarction volume was 55 +/- 16 mL in patients. For all structures, intraclass correlation coefficients among the observers ranged from 0.87 to 0.03; the best agreement was found for lesion, ventricle, and intracranial volume. White matter and cortex volume predicted the National Institutes of Health Stroke Scale score but not the late outcome scores on the Barthel Index or Rankin Scale. Each scan required 70 to 90 minutes for analysis.

CONCLUSIONS

We developed a stereological method for cerebral morphometry from CT scans that is reliable, rapid, and simple. The measurements are unbiased, can be made on slices of any known thickness, and are independent of machine variables. Our results are remarkably similar to values obtained with more labor-intensive methods. This method should be of use in large-scale, multicenter trials of stroke therapy.