Role of radiotherapy to bulky sites of advanced Hodgkin lymphoma treated with ABVD: final results of FIL HD0801 trial.

The role of consolidation radiotherapy (RT) for bulky lesions is controversial in patients with advanced-stage Hodgkin lymphoma who achieve complete metabolic response (CMR) after doxorubicin, bleomycin, vinblastine, dacarbazine (ABVD)-based chemotherapy. We present the final results of the Fondazione Italiana Linfomi HD0801 trial, which investigated the potential benefit of RT in that setting. In this phase 3 randomized study, patients with a bulky lesion at baseline (a mass with largest diameter ≥5 cm) who have CMR after 2 and 6 ABVD cycles were randomly assigned 1:1 to RT vs observation (OBS) with a primary endpoint of event-free survival (EFS) at 2 years. The sample size was calculated estimating an EFS improvement for RT of 20% (from 60% to 80%). The secondary end point was progression-free survival (PFS). One hundred sixteen patients met the inclusion criteria and were randomly assigned to RT or OBS. Intention-to-treat (ITT) analysis showed a 2-year EFS of 87.8% vs 85.8% for RT vs OBS (hazard ratio [HR], 1.5; 95% confidence interval [CI], 0.6-3.5; P = .34). At 2 years, ITT-PFS was 91.3% vs 85.8% (HR, 1.2; 95% CI, 0.5-3; P = .7). Patients in CMR randomly assigned to OBS had a good outcome, and the primary end point of a 20% benefit in EFS for RT was not met. However, the sample size was underpowered to detect a benefit of 10% or less, keeping open the question of a potential, more limited role of RT in this setting. This trial was registered at www.clinicaltrials.gov as #NCT00784537.

Variability in floral scent in rewarding and deceptive orchids: the signature of pollinator-imposed selection?

BACKGROUND AND AIMS: A comparative investigation was made of floral scent variation in the closely related, food-rewarding Anacamptis coriophora and the food-deceptive Anacamptis morio in order to identify patterns of variability of odour compounds in the two species and their role in pollinator attraction/avoidance learning. METHODS: Scent was collected from plants in natural populations and samples were analysed via quantitative gas chromatography and mass spectrometry. Combined gas chromatography and electroantennographic detection was used to identify compounds that are detected by the pollinators. Experimental reduction of scent variability was performed in the field with plots of A. morio plants supplemented with a uniform amount of anisaldehyde. KEY RESULTS: Both orchid species emitted complex odour bouquets. In A. coriophora the two main benzenoid compounds, hydroquinone dimethyl ether (1,4-dimethoxybenzene) and anisaldehyde (methoxybenzaldehyde), triggered electrophysiological responses in olfactory neurons of honey-bee and bumble-bee workers. The scent of A. morio, however, was too weak to elicit any electrophysiological responses. The overall variation in scent was significantly lower in the rewarding A. coriophora than in the deceptive A. morio, suggesting pollinator avoidance-learning selecting for high variation in the deceptive species. A. morio flowers supplemented with non-variable scent in plot experiments, however, did not show significantly reduced pollination success. CONCLUSIONS: Whereas in the rewarding A. coriophora stabilizing selection imposed by floral constancy of the pollinators may reduce scent variability, in the deceptive A. morio the emitted scent seems to be too weak to be detected by pollinators and thus its high variability may result from relaxed selection on this floral trait.

Evidence for pollinator sharing in Mediterranean nectar-mimic orchids: absence of premating barriers?

Pollinator specificity has traditionally been considered the main reproductive isolation mechanism in orchids. Among Mediterranean orchids, however, many species attract and deceive pollinators by mimicking nectar-rewarding plants. To test the extent to which deceptive orchid species share pollinators, we collected and identified hemipollinaria-carrying insects, and used ribosomal sequences to identify the orchid species from which hemipollinaria were removed. We found that social and solitary bees, and also flies, carried hemipollinaria belonging to nine orchid species with different degrees of specialization. In particular, Anacamptis morio, Dactylorhiza romana and Orchis mascula used a large set of pollinator species, whereas others such as Orchis quadripunctata seemed to be pollinated by one pollinator species only. Out of the insects with hemipollinaria, 19% were found to carry hemipollinaria from more than one orchid species, indicating that sympatric food-deceptive orchids can share pollinators. This sharing was apparent even among orchid sister-species, thus revealing an effective overlap in pollinator sets among closely related species. These results suggest varying degrees of pollinator specificity in these orchids, and indicate that pollinator specificity cannot always act as the main isolation mechanism in food-deceptive temperate orchids.