CHICAGO — Doctors reported gains against nearly every form of cancer at a conference that ended this week. Yet when Will Thomas heard about an advance against prostate cancer, he wanted to know just one thing: "Is it a cure?"

"I see billions and billions done on research, and it's all for treatment," said the Alabama man who has several friends with the disease. "When will they cure it?"

Many people share his frustration. The top achievements reported at the American Society of Clinical Oncology added an average of just two to six months of life. One pricey drug made headlines merely for delaying the time until ovarian cancer got worse.

Progress has always been slow for cancer treatment. New therapies are tested on people who are so sick and out of options that any extension of life is considered a success. A cure is not usually possible.

But some of the victories reported this week against breast and prostate cancer, leukemia and the deadly skin cancer called melanoma may be larger than they appear.

These trends offer reason for optimism:

• Newer drugs seem to be making a bigger difference for small, specific groups of patients, as companies develop treatments that more precisely target genes behind subtypes of cancer.

Pfizer rushed into late-stage testing one such drug: crizotinib, which is aimed at only 4 percent of lung cancer patients. More than 90 percent of them responded to the drug in initial tests. High response rates also have been reported for other novel drugs for melanoma and breast cancer driven by certain genes.

• Quicker answers from smaller, focused studies. Pfizer's test of crizotinib will need only 318 patients and will be finished early next year. It also will test the drug earlier in the course of illness rather than as a last-ditch option.

"You don't really need big trials if it works so well," and the group of patients who stand to benefit can be identified in advance, said Dr. Roy Herbst, lung cancer chief at the University of Texas M.D. Anderson Cancer Center in Houston.

• Big gains from novel combinations. All 66 patients testing a drug combo for the blood disease multiple myeloma saw a reduction in the amount of cancer they had by at least half. A 100 percent response rate is unheard of for any cancer and would not have occurred if two drugmakers had not teamed up to test their treatments together instead of against each other, said Dr. Paul Richardson of Boston's Dana-Farber Cancer Institute, who led the research.

The combo of Takeda Pharmaceutical's Velcade, Celgene's Revlimid and the chemotherapy mainstay dexamethasone allowed more than half of patients to delay and perhaps avoid a bone-marrow transplant — a harsh and risky treatment for the disease.

• Comparison tests of long-used treatments. For decades, men with cancer that has spread beyond the prostate have been given hormone treatments with or without radiation, yet only a few studies have tested these against each other or together. A Canadian study found that combo treatment extended survival an average of six months in high-risk cases.

• Building on success. Since it was approved in 2003, the Novartis drug Gleevec has been the closest thing to a cure for any cancer. It has transformed chronic myeloid leukemia from a nearly-always fatal disease to one now manageable with a daily pill.

Yet a second-generation drug from Novartis — Tasigna — and Bristol-Myers Squibb's Sprycel did even better than Gleevec as initial treatment for those who are newly diagnosed, studies found. Sprycel and Tasigna are used now only when people fail on Gleevec.

• New drugs from surprising sources. Eisai's eribulin, derived from a sea sponge, improved survival for women with advanced breast cancer and could fill some key treatment gaps.

• More hope that drugs for other conditions also can fight cancer. The Novartis bone-building drug Zometa improved survival for people with multiple myeloma in one study. Earlier research suggested it might help against breast cancer.

• Gentler treatments. More of the drugs being developed today are pills rather than infusions. Shorter, more focused radiation treatments are showing promise.

One issue is not improving: cost.

Personalized medicine will advance cancer care, said Dr. John Mendelsohn, president of the M.D. Anderson Cancer Center and head of a recent government panel on cancer research. But it will not be cheap, he said.