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

Difficu

lty

Revised models

Step 1 – predicting the number of cancer patients

Data and methods

Historical incidence data 1978-2007 GRO population estimates 1978-2007 GRO population projections 2008-2022 Age-Period-Cohort models using software

developed by the Norwegian Cancer Registry (NORDPRED)

Conducted by Sam Oduro, David Brewster, Roger Black @ISD

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

Figure 6 Actual and projected total population compared with previous projections, 1983-2033

0

1,000

2,000

3,000

4,000

5,000

6,000

1983 1988 1993 1998 2003 2008 2013 2018 2023 2028 2033

Year

Per

son

s ('

000s

)

Actual 2008-based 2006-based 2004-based 2003-based

Source: GRO(S)

We have consistently underestimated population growth in Scotland …

Source: GRO(S)

… and most of the growth is in people aged 75+

Actual Projected2003-2007 2013-2017 % change

All Cancer(excluding C44) 27352 32256 18Lung 4692 4691 0Kidney 717 912 27Stomach 800 741 -7Melanoma of skin 927 1350 46Leukaemia 651 811 25Colorectal 3513 4202 20Colon 2332 2748 18Rectum 1180 1453 23Brain & CNS 382 398 4Head & neck 1040 1288 24Bladder 1610 1824 13Oesophagus 832 1030 24Hodgkins 141 156 11Non-Hodgkins 916 1212 32Panceas 634 711 12Other 3152 3690 17Breast 4004 4820 20Corpus Uteri 518 610 18Cervix 285 242 -15Ovarian 623 694 11Prostate 2577 3805 48Testis 197 221 12

Results(average number of new cases per annum)

ValidationActual Projected

2003-2007 2003-2007 % differenceAll Cancer(excluding C44) 27352 28090 3Lung 4692 4481 -4Kidney 717 714 0Stomach 800 864 8Melanoma of skin 927 865 -7Leukaemia 651 767 18Colorectal 3513 3765 7Colon 2332 2458 5Rectum 1180 1307 11Brain & CNS 382 404 6Head & neck 1040 1153 11Bladder 1610 1636 2Oesophagus 832 878 5Hodgkins 141 123 -13Non-Hodgkins 916 991 8Panceas 634 623 -2Other 3152 3295 5Breast 4004 4073 2Corpus Uteri 518 505 -3Cervix 285 312 10Ovarian 623 676 9Prostate 2577 2496 -3Testis 197 234 19

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).