Results highlight areas for more improvement.
Before bone marrow and stem cell transplants became standard therapies, hardly anyone survived blood cancers.
A 2010 study shows 80 percent of patients who have transplants and survive their first five years go on to survive for at least another 15 years.
It's a remarkable achievement, one that could not have been imagined for such deadly cancers more than three decades ago, before Dr. E. Donnall Thomas and his Hutchinson Center team developed clinical therapies to treat them.
We have gone a long way in helping patients live longer lives. But the study, reported in the Journal of Clinical Oncology, also shows that survivors continue to have a lower life expectancy than the general population. In the general population, people who are now 20 years old would be expected to live to an average age of about 77 years, and people who are now 60 years old would be expected to live to an average age of about 80 years, not counting the differences between men and women.
As a group, transplant patients have not lived as long as the general population. Based on results of the study, a group of five-year survivors who are now 20 years old would be expected to live to an average age of about 60 years, and a group of five-year survivors who are now 60 years old would be expected to live to an average age of about 74 years.
Dr. Paul Martin, who led the team of researchers responsible for the study, cautioned that the results do not mean that the lifetime of any given individual will be cut short. Life expectancy also depends on many other factors, including genetics and lifestyle choices. "It's important to remember that these results are mathematical averages," he said.
Martin emphasized that the comparison with life expectancy of the general population is not completely fair, since most people in the general population have not had a life-threatening disease. The study noted that long-term survival was better for patients with acute myeloid leukemia who had a transplant than for those who had conventional chemotherapy.
The findings of the study also underscore the importance of the ongoing work at the Center to improve patients' lives, and the continued relevance of the Long-Term Follow-Up Program, which provides life-long monitoring and care of patients following a bone marrow or stem cell transplant.
Surviving for five years without cancer recurrence is sometimes considered as an informal benchmark suggesting that the cancer might be cured permanently.
"However, this success does not mean that the effects of the disease and treatments are gone. The new analysis confirms that risks of relapse and other problems can persist beyond the five-year milestone," Martin said.
"As an ideal, physicians would like to have treatments that could cure malignant diseases and restore life expectancy to what it would have been if patients had never had cancer," Martin said. "From that perspective, the results might seem gloomy, but when it comes to treating cancer, the results are actually very good. Of course, we would like to make the results even better. In fact, our treatments have improved during the past 40 years, suggesting that outcomes in the future will be better.
"The transplant process involves a long series of steps. Getting through the first few months is the major challenge for new patients. Recovery after a transplant takes years," Martin said.
"Information from this study is important for all patients, but especially for those who are approaching survival for five years after the transplant and wondering, 'What comes next?' The message for everyone is that risks persist for many years after a transplant. Nonetheless, the extra years gained from a successful transplant give patients opportunities to reach important goals, such as finishing a college degree, getting married, seeing children grow up, and reaching other important goals in life."
Dr. Mary Flowers, the medical director for the LTFU clinical service program, said it was important to put the study in perspective.
"The good news is that 80 percent of the patients in the study survived for at least another 15 years. This is wonderful," said Flowers, who cautioned that a statistical finding should not be translated to individual patients.
"The results are an average. We cannot know how long anyone is going to live. Some people live longer than average, while others have lives that are shorter than average. This is true for everyone."
The study, Flowers said, underscores for patients the tremendous importance of maintaining a healthy lifestyle and having regular medical checkups that include cancer screening appropriate to their age and sex.
For starters, patients can do simple things that are actually very important to their overall health: get regular exams, treat infections promptly, get flu shots every year and other vaccinations as recommended, have teeth cleaned as needed after all immunosuppressive treatment has ended, avoid smoking, and have regular cancer screening tests.
A healthy lifestyle also includes regular exercise. As always, consult your doctor before starting any physical activity.
Because he went through a transplant, Michael Rubin, a Hutchinson Center employee, said he knows it's his duty to stay vigilant.
"I'm already exercising for heart and bone health, seeing my dermatologist twice a year, getting screened for colon and prostate cancer and answering my Long-Term Follow-Up annual surveys," he said.
"Now I'll just have to accelerate my plans for fun trips and experiences, take risks, live with no regrets-something you don't have to be a BMT survivor to do."
"While I'd have preferred a finding of equal or greater longevity, I'm grateful for the years I've lived post-transplant," Rubin said.
"In my head, I know not to apply statistics to my own life, but I'm sure this will reinvigorate my efforts to live a healthy life—to ward off the effects of things that are within my control."
The study looked at 2,574 transplant patients who had survived for at least five years, including some who had been followed for as long as 36 years after the transplant. The long-term follow-up program at the Center made it possible for the first time to estimate the effects of higher death rates on overall life expectancy. The shorter life expectancy is related to combined effects of the pretransplant disease, its treatment before the transplant, and the transplant itself.
More specific research to identify risk factors for early death needs to be done, according to Martin. For example, one of his colleagues, Dr. Eric Chow, is examining factors that might increase the risk of cardiovascular deaths in transplant patients.
"If efforts like this are successful, we would try to identify interventions that could decrease the risk of such complications," Martin said.
He also pointed out that other colleagues are working to develop new treatments for some of the immunological complications that can occur after transplantation.
Hematopoietic cell transplantation has been used to treat hematologic malignancies for more than 40 years. The process of replacing a person's diseased bone marrow with donor cells was refined and developed into a clinical therapy at the Hutchinson Center and earned a 1990 Nobel Prize for physiology or medicine for Thomas, who led the pioneering work.
More than 800,000 people worldwide have had transplants and about 60,000 people each year undergo the complex treatment at centers around the globe.
The study, "Life Expectancy in Patients Surviving More Than Five Years After Hematopoietic Cell Transplantation," was funded by the National Cancer Institute and the National Heart, Lung and Blood Institute of the National Institutes of Health.