What PhenoAge measures in cancer patients
In a preprint involving 3,067 surgical cancer patients, PhenoAge acceleration predicted survival no better than a simple blood-test sum and increased with tumor stage in three of four cancer groups.
What PhenoAge measures in cancer patients
In 3,067 patients who underwent tumor removal, a simple sum of eight blood measurements predicted survival at least as well as PhenoAge acceleration, the amount by which calculated PhenoAge exceeds chronological age. The authors replaced the formula’s weights with +1 or −1, preserving their signs, and excluded age from the sum.
This result comes from a preprint, a manuscript that has not yet undergone peer review. Aging researcher Morgan Levine and colleagues introduced PhenoAge in 2018. The formula combines chronological age with nine blood measurements to express mortality risk in years. A value of 55 in a 50-year-old corresponds to the mortality risk of an average 55-year-old.
The new study used eight measurements because C-reactive protein was rarely measured before surgery. It included patients with colon, kidney, lung, and breast cancer who had received no drug treatment before surgery.
The effects of cancer itself complicate interpretation: tumors cause inflammation and wasting, which alter the blood measurements in the formula. PhenoAge acceleration increased with T stage, a measure of tumor size and local extent, in colon, kidney, and lung cancer. The correlations ranged from 0.14 to 0.20. In breast cancer, the correlation was weaker, at 0.06, but stage also varied little: 519 of 525 tumors were T1 or T2.
The association between PhenoAge and survival in these patients may therefore partly reflect the systemic effects of the tumor. And because the sum with weights of +1 and −1 predicted survival at least as well, the formula’s original weights added no predictive value in these groups. The authors allow that PhenoAge may also capture aging, but studying that contribution requires separating it from the effects of cancer and treatment.
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Sources
[1] doi.org
[2] journals.plos.org
[3] nature.com
[4] t.me
This item tests the interpretation of PhenoAge in a specific clinical setting and gives readers a concrete reason to open the Eternal Search page for Morgan Levine, who introduced the measure with colleagues in 2018.