Progression-Free Survival: What Does It Mean for Psychological Well-Being or Quality of Life?

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Background

Progression-free survival (PFS) is defined as the time from random assignment in a clinical trial to disease progression or death from any cause. PFS as an outcome is of interest to a variety of disciplines, most especially, for purposes of this project, to oncologists, pharmacologists, trialists, social scientists, and other scientists with interest in designing or interpreting clinical trials. This background section addresses how PFS is used, its role as a surrogate for overall survival (OS), the challenges it presents in obtaining accurate and reproducible measurements, and finally its role as a health outcome.

Conclusion
The objective of this methods project was to address whether PFS is an outcome related to psychological well-being or QOL. There were no studies that directly addressed the question of a causal relationship between knowing PFS status and patient anxiety, depression, or psychological well-being. Due to limitations in their design, the four studies demonstrating an association between PFS and better QOL or disease symptoms were all of poor quality. Hence, there is insufficient evidence to make any conclusions about the association between PFS and QOL or related outcomes. The direct measurement of both PFS and QOL may be a practical and informative alternative when measurement of OS is unfeasible.

"PFS as an OS Surrogate for Specific Cancers
Efforts to establish PFS as a surrogate for OS in oncology trials have had variable results depending on the specific cancer. For example, several studies have shown that PFS is a valid surrogate for OS in colorectal cancer,12-15 and it has been argued that PFS is a reasonable primary endpoint for the disease on its own merit.16, 17 Similar conclusions have been reached about PFS as a surrogate for OS in first-line therapy for ovarian cancer.18-20 Expert panelists at two major workshops agreed, however, that the PFS to OS relationship with regard to ovarian cancer may be different for different patient groups or for first-line compared with second- or third-line therapy.18, 20 Contrary to the relative success of PFS as a surrogate endpoint in first-line treatment of colorectal and ovarian cancer, a strong relationship between PFS and OS has not been demonstrated in studies of metastatic breast cancer.4, 12,.....