Cancer survival studies should treat questions about how well people are surviving with the same importance as how long: putting quality of life on an equal footing with survival years, say researchers writing in a scientific journal this month.

Effective and reliable quality of life measures offer increasingly valuable information for cancer patients and their doctors when they discuss treatment options, their potential consequences and the likely rehabilitation needs, write Drs Paul B. Jacobsen and Heather S. Jim, of the Department of Health Outcomes and Behavior at the Moffitt Cancer Center in Tampa, Florida, in the October issue of Cancer Epidemiology, Biomarkers and Prevention.

Quality of life is often as keenly discussed as cancer survival in years, and has a number of important applications in research on cancer survivorship.

But just how to measure quality of life for cancer survivors is still being developed, say the authors, who give an overview of how quality of life is defined and constructed as a scientific measure, and the ways it is commonly used in research involving adult cancer survivors.

In conclusion, they offer several priorities for future research, including how quality of life should be measured, in whom, and how such measures should be used by clinicians caring for cancer survivors.

They write:

“Assessment of quality of life in cancer patients can be tailored through the use of measures specific to a particular disease, treatment, or end point on the cancer continuum”.

The authors describe how observational studies use quality of life measures to characterize and quantify problems that patients experience during and after cancer treatments, as well as the time elapsed since treatment was completed.

“This information can be used to inform patients of the expected consequences of specific treatments and to help identify their rehabilitative needs,” says Jacobsen in a statement.

Randomized controlled trials also use quality of life measures to evaluate and compare the impact of different treatments, or to compare ways of improving patient wellbeing. Using this measure as “an endpoint in studies can be useful in identifying which treatments yield the best quality of life for cancer survivors,” Jacobsen adds.

Another way that quality of life assessment is used is to evaluate the quality of care that patients receive.

There are different ways to collect this information, reflecting the rather broad-ranging nature of the concept “quality of life”. As Jim explains:

“Quality of life is a multidimensional construct about functioning – from physical to social – and is most often assessed by self report, either by interview or questionnaire.”

“However, some research suggests that patients may be less likely to report poor quality of life in response to an interview as compared to a questionnaire,” she adds.

Altogether, Jacobsen and Jim evaluate nearly 20 commonly used ways of measuring quality of life in studies of cancer patients and survivors.

One such measure they review is the Quality of Life in Adult Cancer Survivors (QLACS), which they say, like many existing cancer-specific measures, is concerned with capturing the after-effects of diagnosis and treatment, but “may not adequately assess problems that can persist long after treatment, such as pain, fatigue, cognitive difficulties, sexual difficulties and body image concerns,” says Jim.

The Patient-Reported Outcomes Measurement Information System (PROMIS) initiative, offers greater consistency, write the authors.

PROMIS began in 2004 with six primary research sites and a statistical coordinating center. Funded by the National Institutes of Health (NIH), the system develops, validates and standardizes measurement tools for self-reporting a range of conditions, including cancer.

Jacobsen and Jim also note that too much cancer survivorship research uses “convenience sampling” at a single recruitment site, and such studies often use samples that are too small.

Jacobsen says we need more studies that use much larger groups of cancer survivors recruited from several different sites, or even usie population-based ways of creating and recruiting samples.

He and Jim note that the “marked increase” in published studies on quality of life for cancer survivors suggests a growing and widespread acknowledgement that such a measure is important and valuable in cancer research.

But, if the field is to develop and progress, important issues need to be addressed, says Jacobsen:

“Most important among these is how quality of life is to be measured, in whom it is measured, and what uses are made of quality of life data.”

Written by Catharine Paddock PhD