The American Society of Clinical Oncology reported gains in treatments for nearly every form of cancer but said cures remain elusive at its annual conference in Chicago this week.

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 [of dollars spent] … 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 Thomas's frustration. The top achievements reported at the conference, which ended Tuesday, added an average of just two to six months of life. One pricey drug made headlines merely for delaying the stage at which ovarian cancer gets 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 melanoma might be more significant than they appear.

Reasons 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 of one such drug: Crizotinib, which is aimed at only four per cent of lung cancer patients. More than 90 per cent 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.

The hope is that companies develop enough of these specialized treatments so that, eventually, every cancer patient will have some treatment available that works for their specific manifestation of the disease.

Another finding reported at the conference was that smaller, focused studies seem to be getting quicker results. Pfizer's test of Crizotinib will need only 318 patients and will be finished early next year. The company will also test the drug earlier in the course of the illness rather than as a last-ditch option.

"You don't really need big trials if it works so well," said Dr. Roy Herbst, chief of the lung cancer division at the University of Texas M.D. Anderson Cancer Center in Houston.

Also, the group of patients who stand to benefit from the drug trial can be identified in advance, Herbst said.

Combination drug treatments

In another drug trial discussed at the conference, all 66 participants testing a drug combination for the blood disease multiple myeloma saw the amount of cancer present in their body reduced by at least half.

Having 100 per cent of trial participants respond to a drug is unheard of for any type of cancer and would not have been possible 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 myeloma research.

The combination of Takeda Pharmaceutical Co.'s drug Velcade, Celgene Corp.'s Revlimid and the chemotherapy mainstay dexamethasone enabled more than half of the patients in the study to put off — and perhaps avoid — having to get a bone marrow transplant, a harsh and risky treatment for the disease.

Another positive trend in cancer research has been comparison testing 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 combination treatment extended survival an average of six months in high-risk cases, and the oncology society said it could become a new standard of care.

"We're asking questions that should have been answered decades ago," said Dr. Len Lichtenfeld, deputy chief medical officer of the American Cancer Society.

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 Co.'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.

Eisai Inc.'s Eribulin, derived from a sea sponge, improved survival for women with advanced breast cancer and could fill some key treatment gaps.

It comes "at a time when many of us thought there weren't new chemotherapy drugs being developed," because of all the focus on gene-targeting drugs, said Dr. Eric Winer, breast cancer chief at Dana-Farber. "This may be one of the last ones."