Radiotherapy capacity required in Scotland in 2015 Sara C Erridge Carrie Featherstone

Scottish RT models RT capacity required depends on  Number of new cancer patients  Types of cancer  Proportion needing RT  Fractionation schedule used  Complexity of treatments e.g. IGRT  Spare capacity to avoid waiting times /R&D etc

Scottish Models In 2005 Scottish Activity Report suggested that by 2015 potential 38% to 81% increase in machine capacity required 270,000 and 354,000 fractions Given as total number of fractions as can be delivered on variable number of machines depending on hours worked, through-put etc

Scottish Models –weaknesses Some sites no Scottish data could be identified (e.g. prostate) – we had to use NYCRIS or the Australian data Predictions of future can be affected by other factors e.g. informal PSA screening Models are just models……… some will always work better than others

Calculating demand Proportion of patients who fit into different cancer scenarios Population-based (>90% cases) Factors  Cancer type  Stage  Performance status  Co-morbidity  Patient/physician preference Difficulty

Revised models Step 1 – predicting the number of cancer patients

Data and methods Historical incidence data GRO population estimates GRO population projections Age-Period-Cohort models using software developed by the Norwegian Cancer Registry (NORDPRED) Conducted by Sam Oduro, David Brewster, Roger

Lung cancer risk varies by birth cohort Source: Swerdlow et al, 1998

Age-Period-Cohort models Model works by estimating the simultaneous influence of age, period and birth cohort on individual risk Cohort effects highly predictable Future period effects not so, e.g. new screening programme, diagnostic test

Source: GRO(S) We have consistently underestimated population growth in Scotland …

Source: GRO(S) … and most of the growth is in people aged 75+

Results (average number of new cases per annum)

Validation

Comment on results Results reasonably reliable for most of the common cancers and the total Concern about prostate cancer (period effect) We usually adopted the most conservative results from the range of model predictions Model choice is always to some extent subjective

Conclusion New cancer cases expected to increase by approximately 18% every 10 years This is mainly due to our aging population Results for Scotland compatible with those for England (33% increase from 2001 to 2020).