People who have had surgery to remove pancreatic cancer may benefit from better survival time, without the disease progressing, if they are treated with the drug gemcitabine for 6 months after surgery, a study has shown.
The randomized trial investigated treatment with gemcitabine (a chemotherapy drug marketed in the US under the brand name Gemzar) given in addition to surgery, comparing this with observation alone, and the results are published in the journal JAMA.
The authors conclude that treatment with adjuvant gemcitabine for 6 months "leads to a 24% improvement in overall survival."
The researchers found a statistically significant improvement in the overall absolute numbers of people surviving 5 years - 20.7% of patients given gemcitabine versus 10.4%, an improvement in absolute survival rate of 10.3% over observation alone.
There was also a slight improvement in the 10-year absolute survival rate, of 4.5%. Of the patients taking gemcitabine, 12.2% lived another 10 years, compared with 7.7% who only received observation.
In their introduction to the study, the authors say:
"Pancreatic cancer is a disease with a poor prognosis, mainly because of the inability to detect the tumor at an early stage, its high potential for early dissemination, and its relatively poor sensitivity to chemotherapy or radiation therapy."
The authors add that the "overall mortality-to-incidence ratio is almost 98%." Only a minority of patients have a localized disease that raises the prospect of cure by surgical tumor resection.
Even after complete surgical removal, "the vast majority of the patients relapse within 2 years, leading to a 5-year survival rate of less than 25%."
Increased disease-free survival after 6 months
Helmut Oettle, of the Berlin university hospital Charité in Germany, and colleagues conducted follow-up of a randomized trial that previously reported an improvement in disease-free survival with gemcitabine as an adjuvant therapy alongside surgery. The follow-up was designed to find out if this treatment improved overall survival rates as well as freedom from disease progression.
Patients with pancreatic cancer completely removed by surgery (as determined "macroscopically" - by the unaided eye) entered the study between July 1998 and December 2004 across 88 hospitals in Germany and Austria.
Follow-up ended in September 2012, when a total of 354 patients had been analyzed, with 308 (87%) showing cancer relapse.
The median (midpoint) period of survival without any progression of disease in the study was:
- 13.4 months in the treatment group
- 6.7 months in the observation group.
There was also a statistically significant difference in overall survival between the study groups, with a median of:
- 22.8 months in the gemcitabine group
- 20.2 months in the observation group.
"[These] data show that among patients with macroscopic complete removal of pancreatic cancer, the use of adjuvant gemcitabine for 6 months compared with observation resulted in increased overall survival as well as disease-free survival. These findings support the use of gemcitabine in this setting," the authors conclude.
Cancer of the pancreas almost always lethal
The authors cite a study by other researchers finding that pancreatic cancer is responsible for 227,000 deaths worldwide every year, and is the eighth most common cause of death from cancer.
The global cancer statistics paper, published in the American Cancer Society journal CA, notes a "very poor prognosis," with 98% of diagnoses leading to death.
Gemcitabine-based chemotherapy is standard treatment for advanced pancreatic cancer, but its effect on survival after surgery had not shown before, the authors say, adding: "No consensus has been reached on a standard treatment approach for additional therapy."
The trial results are applicable to general clinical practice "not only for Austria and Germany but for many other countries as well," the authors say, because of the design of the study. The CONKO-001 trial was community-based and designed to be applicable to community oncologists who do not have the "uniform standards for surgery and centralized pathology review" seen in academic centers.
The researchers are continuing their studies into gemcitabine, running trials that investigate combination with other drugs.
In other recent pancreatic cancer news, a link with high-fat, high-calorie diet has been found in a study involving mice published in the journal Cancer Prevention Research in October 2013.