Survival by stage at diagnosis indicates the probability of surviving for a specified time-period depending on the extent of the cancer (stage) at diagnosis. To assist in interpreting the data, some of the findings in the following sections are grouped into:
- Early stage cancers (stage 1 and 2) – restricted to the local area of origin of the cancer;
- Locally advanced cancers (stage 3) – cancers which have spread locally; and
- Metastatic cancers (stage 4) – cancers which have spread to distant sites.
The stage at diagnosis for colorectal cancer has been derived from data sources that are routinely accessible to all population-based cancer registries. These data are intended to be used for broad population-based analyses, and not to guide care of an individual.
The data showed that for colorectal cancers diagnosed in 2011, cases were relatively evenly distributed across each stage category:
- Early stage cancers (stage 1 and 2) accounted for almost half (46%) of incident cases.
- Stage 1 cancers accounted for 22% of cases (3,098 cases);
- Stage 2 cancers accounted for 24% of cases (3,399 cases).
- Locally advanced cancers (stage 3) accounted for 24% of cases (3,299 cases).
- Metastatic cancers (stage 4) accounted for 18% of cases (2,474 cases).
- It was not possible to determine stage at diagnosis for 12% of cases (unknown stage; 1,723 cases).
More information on the distribution of stage at diagnosis can be accessed through the ‘Distribution of cancer stage’ measure.
Relative survival by RD-stage at diagnosis for colorectal cancers diagnosed in 2011
Relative survival for all colorectal cancers
Survival for people diagnosed with colorectal cancer in 2011 generally decreased with increasing time from diagnosis at:
- 86% at 1 year from diagnosis;
- 75% at 3 years from diagnosis;
- 70% at 5 years from diagnosis.
Although these data provide insights into survival for people diagnosed with colorectal cancer, it is also important to examine how survival differs by the extent to which a cancer has spread when first diagnosed.
Relative survival by RD-stage for all colorectal cancers
Examining relative survival by stage at diagnosis showed that survival was high for people diagnosed with early stage colorectal cancers and survival remained high up to 5 years from diagnosis. Cancers diagnosed at stage 3 and 4 had progressively lower survival in subsequent years from diagnosis compared to early stage cancers. Survival by stage at diagnosis is examined in more detail in the following sections.
Relative survival for early stage colorectal cancers (all persons)
For people diagnosed with early stage cancers (stage 1 and 2), survival remained high up to 5 years from diagnosis.
Survival for people diagnosed with:
- Stage 1 cancers was 99% at 1, 3 and 5 years from diagnosis;
- Stage 2 cancers decreased from 96% to 93% between 1 and 3 years from diagnosis. Survival decreased further to 89% at 5 years from diagnosis.
Relative survival for advanced colorectal cancers (all persons)
Survival was lower for people diagnosed with advanced cancers, particularly for cancers diagnosed as metastatic (stage 4). Survival also decreased with increasing time from diagnosis for stage 3 and 4 cancers.
Survival for people diagnosed with:
- Locally advanced cancers (stage 3) decreased from 94% to 79% between 1 and 3 years from diagnosis. Survival decreased further to 71% at 5 years from diagnosis;
- Metastatic cancers (stage 4) decreased from 49% to 23% between 1 and 3 years from diagnosis. Survival decreased further to 13% at 5 years from diagnosis.
Relative survival by stage at diagnosis, sex and age in 2011
Relative survival by sex for colorectal cancers
For colorectal cancer, survival by stage at diagnosis was similar for males and females.
For stage 1 cancers, survival was high (at least 97%) for both males and females at 1, 3 and 5 years from diagnosis.
For stage 2 cancers, survival was similar for males and females at 1 year (96% compared to 97%), 3 years (92% compared to 93%) and 5 years (88% compared to 90%) respectively.
For locally advanced cancers (stage 3), survival was similar for males and females at 1 year (94% compared to 93%), 3 years (80% compared to 78%) and 5 years (71% for both).
For metastatic cancers (stage 4), survival was similar for males and females at 1 year (51% compared to 48%), 3 years (24% compared to 22%) and 5 years (13% compared to 14%).
Relative survival by age for colorectal cancers
The analysis in the following section examines overall patterns in relative survival across age groups where there were sufficient numbers for reporting purposes. The overall trend showed a lower survival with increasing age for cancers diagnosed at stage 3 and 4. Guidance for interpreting the data can be found in the ‘About the Data’ tab.
For stage 1 cancers, survival was similar across all age groups at 1 year (between 98% and 100%), 3 years (between 97% and 99%) and 5 years from diagnosis (between 95% and 100%).
Stage 2 cancers, survival varied across all age groups at 1 year (between 92% and 100%), 3 years (between 90% and 99%), and 5 years from diagnosis (between 84% and 95%).
For locally advanced cancers (stage 3):
- Survival generally decreased with increasing age for people:
- In age groups between 50 and 85 years and over from 99% to 81% at 1 year from diagnosis;
- In age groups between 45 and 85 years and over from 90% to 62% at 3 years from diagnosis;
- In age groups between 45 and 85 years and over from 83% to 56% at 5 years from diagnosis.
For metastatic cancers (stage 4):
- Survival generally decreased with increasing age for people:
- In age groups between 45 and 85 years and over from 80% to 15% at 1 year from diagnosis;
- In age groups between 45 and 84 years from 45% to 11% at 3 years from diagnosis.
- In age groups between 45 and 79 years from 27% to 12% at 5 years from diagnosis.
Similar patterns of survival were apparent in both sexes when examining sex-specific relative survival by stage at diagnosis across age groups for males and females.
Relative survival by age (<50 years and ≥50 years age groups)
This section examines patterns in relative survival for people aged 50 years and over compared to people aged less than 50 years. A similar proportion of cases (between 10% and 13% of cancers) were not able to be staged for both age groups.
- People aged 50 years and over when diagnosed:
- Accounted for 93% of cases eligible for staging;
- Had a similar proportion of cases diagnosed at stage 1, 2 and 3 (with 22%, 25% and 23% of cases respectively) and a slightly lower proportion of stage 4 cancers (17%).
- People aged less than 50 years when diagnosed:
- Accounted for a low proportion of cases overall (7%), with the proportions of cancers generally increasing with increasing stage;
- Had around two in five cases (39%) diagnosed at an early stage (stage 1, 20%; stage 2, 19%) whilst more advanced cancers each accounted for 51% of cases (stage 3, 26%; stage 4, 25%).
For early stage and locally advanced colorectal cancers (stage 1-3), survival by stage at diagnosis was similar between these two groups at 1, 3 and 5 years from diagnosis.
For metastatic cancers (stage 4), those aged 50 years and over had a much lower survival than those aged less than 50 years:
- 47% compared to 72% at 1 year from diagnosis;
- 21% compared to 38% at 3 years from diagnosis;
- 13% compared to 22% at 5 years from diagnosis.
Observed survival by stage at diagnosis and remoteness area in 2011
For examination of survival by remoteness area, the data apply to observed rather than relative survival due to an absence of life tables. More information can be found in the ‘About the Data’ tab.
For colorectal cancers, observed survival by stage at diagnosis was generally similar across remoteness areas for early stage cancers (stage 1 and 2).
For locally advanced cancers (stage 3), there was a small but significant difference in observed survival between people living in Inner and Outer Regional areas compared to those living in Major Cities at 1 year (89% compared to 92%) and 3 years from diagnosis (70% compared to 75%).
For metastatic cancers (stage 4), there was a small but significant difference in observed survival in observed survival between people living in Inner and Outer Regional areas compared to those living in Major Cities at 3 years from diagnosis (17% compared to 23%). For stage 4 cancers, observed survival was not reported for Remote and Very Remote areas at 3 and 5 years from diagnosis due to small numbers.
Similar patterns were apparent in both sexes when examining 1, 3, and 5-year observed survival by stage at diagnosis for people living in different remoteness areas.
Observed survival by stage at diagnosis and socioeconomic status (SES) area in 2011
For examination of survival by SES areas, the data apply to observed rather than relative survival due to an absence of life tables. More information can be found in the ‘About the Data’ tab.
For colorectal cancers, observed survival by stage at diagnosis was generally similar across SES areas at 1, 3 and 5-years from diagnosis for people diagnosed with early stage or metastatic cancers (stage 1, 2 and 4).
For locally advanced cancers (stage 3), there was a small but significant difference in observed survival between people living in the:
- Highest SES areas (SES5, 95%) compared to lower SES areas (SES1-4, between 89% and 91%).
- Highest SES areas (SES5, 77%) compared to the lowest SES areas (SES1, 69%).
Similar patterns were apparent in both sexes, when examining 1, 3, and 5-year observed survival by stage at diagnosis for people living in different SES areas.
Observed survival by stage at diagnosis and Indigenous status in 2011
Analyses of survival by stage were not undertaken by Indigenous status due to small numbers.