Backgrounder for Wait times for cancer treatment

[ Press Release 2005-50 ]

This summary was developed by CIHR and is based on four separate research syntheses. Please visit the below links for a copy of the complete reports:

• Dr. William J. Mackillop (Queen's University) and team
• Dr. Marcy Winget (Alberta Cancer Board) and team
• Dr. Paul Moayyedi (McMaster University) and team
• Dr. Mark Taylor (Cancer Care Manitoba) and team

Background

In February 2005, Canada's Provincial and Territorial Ministries of Health, in partnership with CIHR's Institutes of Health Services and Policy Research, Cancer Research, and Musculoskeletal Health and Arthritis, agreed to fund research designed to inform the establishment of evidence-based benchmarks for medically acceptable wait times in select clinical areas.

Eight Canadian research teams, based in British Columbia, Alberta, Manitoba, Saskatchewan, Quebec, Nova Scotia, and Ontario, carried out research regarding wait times for three priority treatment areas: sight restoration, joint replacement, and cancer. While similar research in the areas of cardiac care and diagnostic imaging was also solicited in February, no projects focused on those areas were funded at that time.

This research was designed to inform the work of the Provincial and Territorial Ministers of Health in establishing evidence-based benchmarks for wait times for specific types of cancer treatments in Canada. Two main questions were asked:

1. What does existing research say about the relationship between clinical condition, wait times, and health outcomes or quality of life for individuals waiting for treatment?
2. What are the national or international wait time benchmarks (proposed or in use) for cancer treatment, and what research evidence (if any) are they based on?

The researchers examined evidence from the available research studies that focused on the relationship between wait times and the health of individuals while waiting for cancer treatment, or after treatment. They also reviewed national and international benchmarks for wait times for cancer treatment.

Not all types of cancer were covered, nor were all stages in the care process at which a patient might wait investigated. An individual might wait to see a specialist after having seen a GP with symptoms that would suggest cancer; might wait for diagnostic services such as blood tests, x-rays or other types of scans after seeing a specialist; or might wait for appropriate treatment after a diagnosis of cancer. Most of the research reviewed here focused on the wait between when an individual is diagnosed with cancer to the date of treatment.

Colorectal, lung, solid organ, and gastrointestinal cancer were investigated. For most of these cancers, surgery, often in combination with chemotherapy or radiotherapy, is the main treatment option. Wait times for one particular cancer treatment-radiotherapy-were also examined. Radiotherapy is used by about half of individuals with cancer, often in combination with surgery.

Challenges in researching the effect of waiting for cancer treatment

Limited conclusions about the effect of wait times on the quality and length of life among individuals who have cancer could be drawn and generalizations cannot be made across different types of cancers or treatments. The current findings are preliminary, and may change with future research.

There are particular challenges associated with cancer that have implications for developing evidence-based wait times for treatment. The most important is that cancer is not a single disease. Cancer is many diseases: breast cancer, lung cancer, colorectal cancer, prostate cancer, etc. Particular types of cancer progress differently in each individual, and in ways we can't always predict. Tumours can also be fast or slow growing, but we don't yet have reliable ways to determine this prior to treatment. This means that wait times for treatment may pose greater or lesser risks, depending on the type of cancer, and even the specific type, or stage of growth, of tumour.

Research on the effect of wait times is also particularly difficult for cancer treatment because the most important predictor of survival after the type of cancer, is the extent of disease when it is diagnosed. A group of individuals with advanced lung cancer are likely to have poorer outcomes after treatment than a group of individuals with early-stage breast cancer, regardless of wait time. This doesn't mean that wait times don't matter; only that, because of the other factors at play, it is currently very difficult to determine how much they matter.

What the research says about the effect on health of waiting for cancer treatment

• A delay in beginning radiotherapy after surgery is associated with an increased risk of cancer recurring at the primary tumour site. While evidence was found only for breast, and head and neck cancer, there is no theoretical reason, or evidence, to suggest that this would be different for other types of cancer. This risk becomes greater as the wait time increases.

• However, the basis of currently available evidence, we cannot conclude that a delay in beginning radiotherapy for breast or head and neck cancer necessarily increases the risk of the primary cancer spreading to other parts of the body, or the risk of death.
• Treatment for lung cancer often involves surgery or chemotherapy to reduce tumour size, followed by radiotherapy. However, the rate of tumour growth often increases after partial treatment. Once initial treatment begins, wait times for subsequent treatment should therefore be minimized.
• For gastrointestinal cancer, the wait between presentation at a GP's office and seeing a specialist was investigated. Common symptoms such as difficulty swallowing and weight loss are not good enough predictors of an underlying cancer to inform evidence-based wait time benchmarks for follow-up appointments with specialists or further diagnostic work.

• However, for gastrointestinal cancer, no currently available evidence pointed to an association between common diagnostic delays and poorer health outcomes.
• For solid organ cancers, no currently available evidence pointed to an association between waiting for cancer surgery and poorer health outcomes.

National or international benchmarks

• National and international benchmarks for wait times for radiotherapy recommend avoiding any unnecessary delay in beginning treatment. These benchmarks are based largely on expert clinical opinion.
• Proposed benchmarks for radiotherapy developed by the Canadian Association of Radiation Oncologists (CARO) and adopted by the Canadian Wait Time Alliance (WTA) are consistent with international benchmarks.

• Other national and international benchmarks for cancer treatment cluster around 1 to 4 weeks once cancer is diagnosed. These benchmarks have been based on expert clinical opinion.

Take-home messages

• The available scientific evidence suggests that the wait times for beginning radiotherapy for treatment for all types of cancer should be as short as possible. This is consistent with international and proposed Canadian benchmarks.
• For lung cancer, once treatment has begun, further delays in the course of treatment (e.g. radiotherapy after surgery or chemotherapy) should be as short as possible.
• Beyond these two indications, there does not currently appear to be enough scientific evidence to reasonably inform benchmarks for wait times for treatment of particular cancers at any stage of the care process. Further research will be required.