Stereotactic Body Radiotherapy versus Low Dose Rate Brachytherapy for Localised Prostate Cancer: a Cost-Utility Analysis

AIMS

To conduct a cost-utility analysis comparing stereotactic body radiotherapy (SBRT) with low dose rate brachytherapy (LDR-BT) for localised prostate cancer (PCa).

MATERIALS AND METHODS

A decision-analytic Markov model was developed from the healthcare payer perspective to simulate the history of a 66-year-old man with low-risk PCa. The model followed patients yearly over their remaining lifetimes. Health states included 'recurrence-free', 'biochemical recurrence' (BR), 'metastatic' and 'death'. Transition probabilities were based on a retrospective cohort analysis undertaken at our institution. Utilities were derived from the literature. Costs were assigned in 2015 Canadian dollars ($) and reflected Ontario's health system and departmental costs. Outcomes included quality-adjusted life years (QALYs), costs and incremental cost-effectiveness ratios. A willingness-to-pay threshold of $50 000/QALY was used.

RESULTS

SBRT was the dominant strategy with 0.008LYs and 0.029QALYs gained and a reduction in cost of $2615. Under base case conditions, our results were sensitive to the BR probability associated with both strategies. LDR-BT becomes the preferred strategy if the BR with SBRT is 1.3*[baseline BR_SBRT] or if the BR with LDR-BT is 0.76*[baseline BR_LDR-BT]. When assuming the same BR for both strategies, LDR-BT becomes marginally more effective with 0.009QALYs gained at a cost of $272 848/QALY.

CONCLUSIONS

SBRT represents an economically attractive radiation strategy. Further research should be carried out to provide longer-term follow-up and high-quality evidence.

The effects of forest canopy shading and turbulence on boundary layer ozone

The chemistry of the Earth's atmosphere close to the surface is known to be strongly influenced by vegetation. However, two critical aspects of the forest environment have been neglected in the description of the large-scale influence of forests on air pollution: the reduction of photolysis reaction rates and the modification of vertical transport due to the presence of foliage. Here we show that foliage shading and foliage-modified vertical diffusion have a profound influence on atmospheric chemistry, both at the Earth's surface and extending throughout the atmospheric boundary layer. The absence of these processes in three-dimensional models may account for 59–72% of the positive bias in North American surface ozone forecasts, and up to 97% of the bias in forested regions within the continent. These processes are shown to have similar or greater influence on surface ozone levels as climate change and current emissions policy scenario simulations.

Fully quantifying the influence of vegetation on atmospheric chemistry remains challenging. Here, the authors show that forest canopy shading and turbulence significantly modify air pollution throughout the atmospheric boundary layer, and must be taken into account in models of the atmosphere.

Canadian consensus: inhibition of ALK-positive tumours in advanced non-small-cell lung cancer

Anaplastic lymphoma kinase (alk) is an oncogenic driver in non-small-cell lung cancer (nsclc). Chromosomal rearrangements involving the ALK gene occur in up to 4% of nonsquamous nsclc patients and lead to constitutive activation of the alk signalling pathway. ALK-positive nsclc is found in relatively young patients, with a median age of 50 years. Patients frequently have brain metastasis. Targeted inhibition of the alk pathway prolongs progression-free survival in patients with ALK-positive advanced nsclc. The results of several recent clinical trials confirm the efficacy and safety benefit of crizotinib and ceritinib in this population. Canadian oncologists support the following consensus statement: All patients with advanced nonsquamous nsclc (excluding pure neuroendocrine carcinoma) should be tested for the presence of an ALK rearrangement. If an ALK rearrangement is present, treatment with a targeted alk inhibitor in the first-line setting is recommended. As patients become resistant to first-generation alk inhibitors, other treatments, including second-generation alk inhibitors can be considered.