Algumas drogas conseguem inibir crescimento de células cancerosas por mais tempo

Mieloma

Study Finds Certain Drugs Can Keep Some Forms of Cancer in Remission Longer

Using certain anticancer drugs for years at a time can help keep some types of cancer in remission longer, doctors reported Thursday.

In another finding, researchers said they had made progress on a long-sought goal — developing a way to screen healthy women for ovarian cancer, potentially catching tumors before they become virtually incurable.

The research findings were among more than 4,000 that will be presented next month at the annual meeting of the American Society of Clinical Oncology. Among the others: a randomized trial showing that twice-a-week yoga sessions can help cancer survivors sleep better and reduce their fatigue.

The studies on longer cancer treatment involve what is called maintenance therapy. It is a strategy for making cancer into a chronic disease like diabetes or hypertension, held in check by continuous use of medicines.

Typically, cancer patients stop taking antitumor drugs once their tumors have shrunk or the disease goes into remission. They do not resume taking drugs until the tumor starts growing again.

In one study of about 600 patients that was made public on Thursday, use of the drug lenalidomide after stem-cell transplant sharply cut the recurrence of multiple myeloma, a cancer of the bone marrow. After three years, 68 percent of the patients who took the drug were free of disease progression, compared with 35 percent of those who got the placebo. “This is of major clinical importance for patients,” Michel Attal of Purpan Hospital in Toulouse, France, the lead author of the study, said in a telephone news conference.

Another study found that two years of maintenance therapy with the drug rituximab cut the risk of cancer recurrence in half among patients with follicular lymphoma, a type of non-Hodgkin’s lymphoma.

The trial involved about 1,000 patients who responded to initial treatment with rituximab plus chemotherapy. Those who continued to get an infusion of rituximab every eight weeks had a relapse rate of 18 percent after about two years. Those who stopped taking the drug after the initial response had a relapse rate of 34 percent.

Neither study has shown yet that maintenance therapy allows people to live longer. For both multiple myeloma and lymphoma, people can live a decade or more after diagnosis. Long-term use of the drugs could cause side effects and is expensive. Two years of maintenance therapy with rituximab, which is sold by Genentech as Rituxan, costs about $50,000. Lenalidomide, sold by Celgene as Revlimid, costs more than $6,000 a month.

Regarding ovarian cancer, doctors have long been searching for the ovarian cancer equivalent of mammography — a way to catch tumors early enough that they are treatable. A big challenge is that ovarian cancer is very rare. That raises the risk of false positives, which would subject many women to needless surgery.

Researchers at the University of Texas MD Anderson Cancer Center say the answer might lie not in some new test but an old one — a test that measures the amount of a protein called CA-125 in the blood. That test is now used to detect recurrence of ovarian cancer but has not been a reliable marker for detecting an initial occurrence of the disease. But the researchers tried to overcome this by following changes in CA-125 over time.

The study involved more than 3,200 healthy, postmenopausal women, who were given a risk score calculated from the CA-125 result and their age.

Those with low risk scores were told to come back a year later for another CA-125 test, and those with intermediate scores were told to come back in three months. Those with the highest risk were referred for transvaginal ultrasound, with possible surgery after that. Over a nine-year period, only eight women underwent surgery. Three were found to have invasive cancers that were caught early enough to treat. Two had borderline cancers, and three did not have cancer.

The researchers said this was encouraging in terms of avoiding unnecessary surgeries. The screening failed to detect two borderline cancers but did not miss any invasive ones.

Still, Dr. Karen Lu, lead author of the study, said the results were “not practice-changing at this time” because it is not known whether the screening strategy would save lives. A study involving more than 200,000 women to answer that question is now under way in Britain, with results expected around 2015.

One of the authors of the study, Dr. Robert Bast, is a co-inventor of the CA-125 test and receives royalties on its use.

The yoga trial, led by researchers at the University of Rochester, randomized 410 survivors of early-stage cancers who reported problems with sleep after their treatment had finished. Half the patients went to a yoga session twice a week for four weeks, and the rest did not. Based on questionnaires, those who did yoga had a bigger improvement in sleep and a reduction in fatigue.