Disease Characteristics el pt

Are Patients Living Longer?

Date: March 2, 2024

by Chaya Venkat

If Not a Cure, At Least Longer Life?

The journal Blood has just published an article on long-term survival statistics for CLL patients. The article abstract is below – and by now you know what you have to do if you want to read the full text of the article, right?

Abstract

Blood First Edition Paper, prepublished online February 28, 2024; DOI 10.1182/blood-2007-12-129379

Trends in long-term survival of patients with chronic lymphocytic leukemia from the 1980s to the early 21st century

Hermann Brenner*, Adam Gondos, and Dianne Pulte

Division of Clinical Epidemiology and Aging Research, German Cancer Research Center, Heidelberg, Germany Weill Cornell Medical Center, New York, NY.

Although chronic lymphocytic leukemia (CLL) has remained incurable with standard treatments, newer therapeutic approaches, such as chemoimmunotherapy or stem cell transplantation bear the potential for prolonged survival. We estimated trends in age specific 5- and 10-year absolute relative survival of CLL patients in the United States from 1980-1984 to 2024-2004 from the 1973-2004 data base of the Surveillance, Epidemiology, and End Results (SEER) Program. Period analysis was employed to disclose recent developments with minimum delay. Overall, 5-and 10-year absolute survival from diagnosis increased from 54.2% to 60.2% (+6.0 percent units, p<0.0001), and from 27.8% to 34.8% (+7.0 percent units, p<0.0001), respectively. Despite a strong age gradient in prognosis, increases in 5-year absolute and relative survival over time were rather homogeneous across age groups. By contrast, increases in 10-year absolute and relative survival close to or well above 10 percent units were observed for all patients below 80 years of age at diagnosis, compared to no increase at all for older patients. Long-term survival expectations of patients with CLL have substantially improved over the past two decades except for patients aged 80 or older at the time of diagnosis. Future studies are needed to confirm and expand our findings.

This detailed statistical analysis of CLL patient survival is based on data from the SEER (Surveillance, Epidemiology, and End Results) Program. The SEER program collects population based data from cancer registries in Connecticut, New Mexico, Utah, Iowa, Hawaii, Atlanta, Detroit, Seattle-Puget Sound and San Francisco-Oakland. While it does not cover the whole of USA, SEER includes about 30 million people in its scope and therefore has pretty powerful statistical validity. Roughly 21,000 CLL patients (15 years or older) were included in this specific study, time frame was 1973 – 2024. For those of you who like to have your facts as sound-bites, here is the cheat-sheet version of the findings reported in this study.

CLL Patient Profile Over Two Decades

• The study looked at 21,000 adult patients with CLL (and no previous cancer diagnosis), over the time period of 1973 – 2024.
• The single most common age group diagnosed with CLL was 70 -79 years old. Roughly 30% of the cases registered fell into this age bracket.
• 60% of the cases were men, a statistical difference that persisted over the whole time period of the study.
• Put these two facts together, and it is hard to deny there is some truth to the often repeated and deeply annoying comment that CLL is an old man's disease. However, another way of looking at the same statistics is that a goodly percentage of the patients were younger than 70 years and fully 40% were not men. And I am dead certain all of the patients were young at heart. So there.
• Comparing the time frames 1980-84 and 2024-04, the number of registered CLL cases increased by 20%. But before you jump to conclusions, the authors point out that the number of CBC blood tests done as part of routine annual checkups has increased dramatically in the two decades between, and this may be the reason why we are now seeing more cases of CLL that would have gone undiagnosed in the earlier time frame. It is a case of looking for problems.
• Even with the higher level of routine monitoring of blood counts, the authors believe CLL is an under-reported cancer. The actual number of cases may be higher than reported by SEER. This may be due to the fact that majority of CLL patients are not treated at diagnosis. Local oncologists sending in their data to SEER registries may overlook counting patients that are in Watch & Wait mode.

Numbers of patients with CLL by age group, sex and calendar period. Source: Blood.

Survival Statistics

When all is said and done, this is what matters most to patients and their families: are our guys living any longer now than they did back in the 80's? The two graphs below are excerpted from the Blood article, and they show how survival statistics have changed from the 1980-84 time frame to 2024-04.

Ten-year relative survival curves of patients with CLL by major age groups.
Period estimates for 1980-1984 (solid lines) and 2024-2004 (dashed lines).
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Conclusions

• As you can see, survival improved between the two time periods, our guys are living longer today than they used to back in 1980's. The first graph is for patients younger than 60 at diagnosis, the second graph looks at older patients.
• But the there is no flattening of the curves in either graph. This means patients continue dying over time, there is no point at which the mortality risk of CLL goes away. It is not like all the guys who are going to die are done with it in the first few years, and the remaining bunch are long term survivors that have put this whole messy business of cancer behind them. CLL is a gift that keeps on giving - this is what makes it an incurable disease.
• I would have been interested in seeing if there was a breakout of the data for patients using new fangled stuff like monoclonal antibodies (Rituxan, Campath etc) and potentially curative mini-allo transplants. Unfortunately, the data does not go into that level of detail. There is also no breakout of survival differences between high risk patients with poor prognostics and those who are blessed with more indolent disease.
• The authors suggest that the improved survival statistics are due to (a) earlier diagnosis, (b) better supportive care, including use of prophylactic antibiotics and anti-viral medications (c) advances in modern technologies such as flow cytometry capable of identifying higher risk patients (d) improved therapy regimens.

I guess it is good to have all these statistics sorted out and available in one place. Shoot, I doubt Blood would have been interested in publishing my layperson 2 cents, but none of this comes as a huge surprise to me. How about you?