MIPI
MIPI is basically a risk score calculated based on age, performance status, lactate dehydrogenase levels, and white cell count, she said.
MIPI less than 5.70 indicates low risk, MIPI of 5.70-6.2 is considered intermediate risk, and MIPI greater than 6.2 is considered high risk. High-risk patients who were transplanted in one study had a median overall survival of about 2.8 years and a median time to treatment failure of 1.4 years (J Clin Oncol. 2014 May 1;32[13]:1338-46). Even among patients under age 65 with high risk, the median time to treatment failure was 2 years, she said.
“So I do wonder, are we really helping these patients by transplanting them?” she added. “Similarly, the low-risk patients had a median time to treatment failure of 6 years; I wonder if they didn’t need a transplant.”
Biology
Ki-67 protein, a cellular marker for proliferation, is another important prognostic factor. A European Mantle Cell network study showed that median overall survival for patients with a Ki-67 proliferation index of less than 30% was not reached, and 5-year survival was 75%. At the same time, the median overall survival (OS) for those with Ki-67 proliferation index of 30% or greater was just 3.4 years, and 5-year OS was only 41% (J Clin Oncol. 2016 Apr 20;34[12]:1386-94).
The prognostic effect was independent of induction treatment, Dr. Blum said.
Combining MIPI and the Ki-67 index (MIPI-C) provides further value in defining a very high-risk group; those with both high MIPI and high Ki-67 had a median overall survival of only 1.5 years, and those with both, but who were under age 65, had median OS of only 1.7 years.
Histology
Patients with blastoid MCL variants were shown in that same study to have median OS of about 2.8 years, compared with 8 years in those with nonblastoid variants. The 5-year OS and progression-free survival (PFS) for blastoid variants were 35% and 29%, respectively, and for nonblastoid variants were 68% and 44%, respectively.
“But when you look at this with respect to the Ki-67 – so those patients that were called nonblastoid, that had a high Ki-67 index – their median overall survival is still lower at 5 years,” she said, noting that median OS was not reached in blastic variant (low-Ki-67) patients. “So it seems like the prognostic effect of cytology is largely explained by the Ki-67 index.”
In terms of karyotype, several studies have shown that complex karyotype is associated with poorer outcomes. One recent multicenter study of 274 patients showed that median OS in 53 patients with at least three cytogenetic abnormalities versus the remaining patients was 4.5 years vs. 11.6 years, and median PFS was 1.9 vs. 4.4 years (Cancer. 2018 Jun 1;124[11]:2306-15).
TP53 deletions (which affect about 20% of MCL patients) and mutations (which affect about 10%), are also useful prognostic factors, she said, noting that each is associated with inferior outcomes, and in one study patients with both appeared to have the worst outcomes (Blood. 2017;130:1903-10).
Another study showed that high TP53 staining (greater than 50% positive) is also associated with inferior outcomes, including reduced time to treatment failure and lower overall survival (Blood. 2018;131:417-20).
Finally, the most important factor is the patient’s wishes, Dr. Blum said, noting that she has “a lot of long discussions with these patients.”
“I consider all of these factors with each patient that I see with mantle cell,” she said.
Dr. Blum is a consultant for Acerta, AstraZeneca, and Molecular Templates and has received research funding from Acerta, AstraZeneca, Celgene, Cephalon, Immunomedics, Janssen, Merck, Millennium, Molecular Templates, Novartis, Pharmacyclics, and Seattle Genetics.