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.

But some of the victories reported this week against breast and prostate cancer, leukemia and the deadly skin cancer 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 Inc. 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.

• 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 combination of Takeda Pharmaceutical Co.’s Velcade, Celgene Corp.’s Revlimid and the chemotherapy mainstay dexamethasone allowed more than half of patients to delay and perhaps avoid a bone marrow transplant.

• 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 treatments against each other or together. A Canadian study found that combo treatment extended survival an average of six months in high-risk cases.

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