A study presented earlier this year at an ASCO meeting in Florida found similar survival rates for men with high-risk prostate cancer who received radiation and either 18 or 36 months of hormone therapy. The findings suggest the therapy, which causes significant side effects, could be given for less than the current standard of 24 to 36 months.

Another recent study out of the Duke Cancer Institute in Durham, North Carolina, found that survival odds for women with early-stage breast cancer who underwent breast-preserving surgery such as lumpectomy were as good as, or even better than, the odds for women who had mastectomies.

"We are going to see reevaluations of very successful therapies to determine whether or not we can achieve the same results using less treatment," said Dr Armand Keating, director of the hematology division at the University of Toronto and president of the American Society of Hematology.

The first-ever study showing that a type of leukemia could be cured without using chemotherapy was released in December. The Italian-German study found that a combination of a derivative of vitamin A, known as ATRA, and arsenic trioxide, a newer drug, worked as well as ATRA and chemotherapy in patients newly diagnosed with acute promyelocytic leukemia (APL).

"APL used to be one of the most dreaded strains of cancer, but with ATRA and chemo the results are very gratifying," Keating said. "Now we have two agents that are not chemo agents ... That to me is a milestone. I can't see any reason why this wouldn't become the standard of care."

A recent trial conducted in France found that omitting standard chemotherapy, which has been linked to heart damage, from the initial treatment of a type of childhood leukemia did not reduce survival outcomes.

"The nice thing is you have omitted a potentially toxic agent that contributes to morbidity and maybe mortality down the road," Keating said.

The priciest therapies are designed to take advantage of genetic mutations associated with cancer cells, some of them found only in a small percentage of patients.

A new drug for melanoma, BRAF inhibitor Zelboraf from Roche Holding AG, is designed to work by targeting a specific genetic mutation found in about half of all melanomas. Patients are first tested to see if they have it.

Pfizer's lung-cancer drug Xalkori, which targets a mutation in the ALK gene, works in about 4 percent of lung cancer patients. It also has been effective as a treatment for a rare but aggressive type of childhood lymphoma.

"We've been really trying for years to be more precise about who needs treatment ... Now we are more able to achieve it," said Swain.

(Editing by Michele Gershberg and Prudence Crowther)