Nomogram-predicted recurrence risk may aid adjuvant chemotherapy stratification in MIBC
medwireNews: Muscle-invasive bladder cancer (MIBC) patients with a nomogram-derived 1-year recurrence probability of at least 40% are likely to benefit from adjuvant chemotherapy, suggests a retrospective study.
Plotting actual 1-year recurrence rates against nomogram-predicted rates for 950 patients with cT2–T4N0M0 MIBC treated with radical cystectomy, Filippo Pederzoli (IRCCS Ospedale San Raffaele, Milan, Italy) and colleagues found a recurrence-free survival (RFS) benefit with adjuvant chemotherapy only in patients with a predicted 1-year recurrence risk of more than 20%.
The difference became statistically significant and clinically meaningful at a predicted risk of 40%, at which point the actual 1-year rate of recurrence was 26% for those treated with adjuvant chemotherapy versus 35% for those who were not (a 9% net decrease).
The predefined nomogram was developed using data from 1067 patients from the institutional database of the San Raffaele Hospital and 3024 participants of the Retrospective International Study of Invasive/Advanced Cancer of the Urothelium (RISC) database. It incorporated surgical margin status, pathologic tumor and nodal stage, and previous neoadjuvant chemotherapy administration. Those with a predicted 1-year recurrence risk of 40% or more would have features such as positive surgical margins, a high pathologic stage, and suboptimal response to neoadjuvant chemotherapy, say the researchers.
“The possibility of quantifying the individual relapse risk and the [adjuvant chemotherapy] benefit based on [a] nomogram using readily available clinical parameters is appealing,” write Pederzoli and colleagues in European Urology.
And although the researchers did not see an effect of adjuvant chemotherapy on 1-year RFS rates in the overall population, they did note a significant survival advantage among the 60% of patients with pT3–T4 or pN1 stage disease at the time of cystectomy, with a 1-year RFS rate of 75% for those who received adjuvant chemotherapy versus 54% for those who did not. By contrast, there was no difference in the 1-year RFS rate among patients with pT0–2N0-X stage disease.
The team notes that until personalized genomic tools that can predict response to chemotherapy in vivo become readily available, “the 40% nomogram-derived threshold for [adjuvant chemotherapy] represents a more accurate and reliable benchmark than single clinical and pathological factors (e.g., evidence of lymph node involvement).”
The researchers conclude that “pending validation with data from prior randomized trials, our proposed 40% nomogram-predicted 1-yr recurrence risk could guide clinicians in stratifying patients for [adjuvant chemotherapy] therapy.”
By Catherine Booth
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