STANFORD, Calif., Aug. 26 (UPI) -- Chemotherapy is part of most cancer treatment regimens because it can kill cancer cells, but the drugs carry significant side effects and in many cases more is not better, as researchers found in a recent study of bone cancer patients.
Adding two chemotherapy drugs to the standard three-drug treatment plan for osteosarcoma did not improve patient outcome in a multi-year, international study, researchers report in The Lancet Oncology.
Osteosarcoma is somewhat rare, with about 600 patients per year in the United States, most of whom are teenagers. The average age of patients, combined with the difficulty of treatment, has researchers looking for ways to improve outcomes -- survival rates from the disease have remained around 60 percent for the last 25 years.
Researchers sought to compare two treatment regimens for the disease. The standard, called MAP, combines the drugs methotrexate, doxorubicin and cisplatin, and is generally used before and after surgery to remove the tumor. The second regimen, MAPIE, adds two more chemotherapy drugs, ifosfamide and etoposide.
Where more drugs can often hit a disease harder and help patients, the researchers report no difference in survival time after surgery to remove tumors -- but patients experienced more side effects.
"The important message from this data is that adding these two drugs does not improve the outcomes of patients who have poor responses to the initial chemotherapy," Dr. Neyssa Marina, a professor of pediatrics at Stanford University's School of Medicine and lead author of the study, said in a press release. "The drugs shouldn't be added. With them, patients experience more toxicity and more second malignancies."
For the study, researchers registered 2,260 osteosarcoma patients between April 2005 and June 2011, identifying 618 from 17 countries who were treated initially with MAP, had surgery to remove their tumors and appeared to have poor response to treatment. The expectation when removing a bone cancer tumor is for it to be at least 90 percent dead, with anything less suggesting ineffective treatment and worse prognosis for the disease.
The researchers split the 618 patients into two groups, giving 310 MAP and 308 MAPIE treatment after surgery, following the patients for about five years to measure "event-free survival," or whether they had recurrence of cancer, a second cancer or died.
Overall, researchers saw about the same level of survival and health event between patients in the two groups, but those receiving MAPIE patients experienced additional side effects from their treatment.
"This trial matters because, in the past, we were treating a lot of patients with these drugs without realizing that they weren't helping," Marina said.