Fig 2.

Personalized survival effects of extent of resection (EOR) of gadolinium-enhancing (T1) tumor or adjuvant therapy as individual covariates. These figures illustrate how to use survival versus EOR curves (Fig 1B) or survival versus adjuvant therapy curves (Fig 1C) to estimate the personalized survival effects of changes in these modifiable covariates. (A and B) Survival implications of 75% (gray) versus 95% (black) EOR in two different patients. (A) The estimated incremental survival benefit of a more aggressive resection in a hypothetical young (age, 40 years), high-functioning (Karnofsky performance score [KPS], 100) patient is calculated at 135 days. (B) In contrast, a similar calculation in a hypothetical patient who is elderly (age 84 years) and debilitated (KPS, 60) has the same incremental survival benefit at only 55 days. These curves illustrate the importance of patient-specific covariates in the relationship between survival and EOR, and they can inform surgeons of the potential advantages of a more aggressive resection. This, in turn, provides better information on which patient-specific decisions regarding the risk/benefit balance of more aggressive surgical resections can be based. (C and D) Survival implications of alternative adjuvant therapy strategies in two different patients. (C) The estimated incremental survival benefit of adjuvant temozolomide alone (TMZ) versus adjuvant temozolomide plus radiotherapy (XRT) in a hypothetical young (age, 40 years), high-functioning (KPS, 100) patient is calculated at 200 days. (D) In contrast, a similar calculation in a hypothetical patient who is elderly (age 84 years) and debilitated (KPS, 60) results in an incremental survival benefit of only 90 days. These curves illustrate the importance of patient-specific covariates in the survival advantages of adjuvant therapy, and they can inform oncologists of the potential advantages of more aggressive adjuvant therapy. This, in turn, provides better information on which patient-specific decisions regarding the risk/benefit balance of the ideal, patient-specific adjuvant therapy strategy can be based. These curves also show that the survival effects of both EOR and adjuvant therapy vary with patient-specific covariates. This may have implications for the design, analysis, and interpretation of future trials that incorporate surgery, TMZ, or XRT as part of the glioblastoma management strategy being studied.