Researchers show that adding a new chemotherapy drug called gemcitabine (Gemzar) to standard paclitaxel (Taxol) chemotherapy improves survival by several months for women with advanced breast cancer. This treatment regimen is approved in the same year, for women whose cancer persists despite other forms of chemotherapy.

The FDA approves the drug letrozole (Femara), the first in a new class of drugs called aromatase inhibitors that block an enzyme the body needs to make estrogen (estrogen fuels the growth of some breast cancers). The drug is first approved for long-term use in post-menopausal women who have completed five years of tamoxifen (Novaldex) treatment, based on studies showing letrozole reduces the risk of breast cancer recurrence and spread even more than tamoxifen alone. In 2005, letrozole is also approved as an initial therapy following surgery for post-menopausal women.

In the same time period, additional trials show that aromatase inhibitors, including letrozole and similar drugs like anastrazole (Arimidex), also improve survival and alleviate the symptoms of cancer for post-menopausal women with advanced breast cancer.

A large European study shows that a single dose of the chemotherapy drug carboplatin (Paraplatin, Paraplat), following surgical removal of the cancerous testicle, lowers the risk of cancer recurrence and may reduce the risk of cancer developing in the opposite testicle. This finding results in a new treatment option for men with early-stage testicular cancer, potentially sparing them from standard radiation therapy, which is highly effective but is associated with an increased risk of developing a second cancer in another organ later in life.

Studies show that dose-dense chemotherapy – giving a combination of chemotherapy drugs (doxorubicin, cyclophosphamide and paclitaxel) for early-stage breast cancer every two weeks instead of every three weeks – slowed cancer growth by 26 percent and extended survival by 31 percent without increasing treatment-related side effects.

Scientists show that adding two additional drugs (ifosfamide and etoposide) to the standard four-drug combination chemotherapy regimen (doxorubicin, vincristine, cyclophosphamide and dactinomycin) significantly increases five-year survival rates in patients with early-stage Ewing sarcoma (a form of bone cancer, that most often occurs in the legs, spine, ribs, or pelvis). This new combination soon becomes the standard treatment.

In several large, randomized studies, researchers demonstrate conclusively that high-dose chemotherapy with supportive stem-cell or bone marrow transplantation does not improve survival among women with advanced breast cancer or earlier-stage cancer. These results immediately change practice. (Based on the results of earlier small-scale studies, the approach came into widespread use for both advanced and early-stage breast cancer patients – well before large, randomized clinical trials were conducted.) The approach involves administering extremely high doses of chemotherapy to fight the cancer, which had been used successfully in other cancers such as lymphoma and leukemia. However, because such high doses destroy bone marrow, they are fatal if not supported by bone marrow transplantation or stem cell support, which repopulate these vital cells. The negative trial results underscore the importance of confirming preliminary data from uncontrolled pilot trials in more definitive phase III studies.