This was based upon tumors less than 3cm in size and because of eligibility criteria only 453 patients were ultimately analyzable. Of patients to be observed only 180 did not receive any additional treatment while 34 did receive chemotherapy and 5 received other treatment. Overall 202 patients did not receive any adjuvant or additional chemotherapy. Disease-free survival means the patient is both alive and has no cancer. Statistical analysis shows this was a meaningful difference, thus revealing a benefit to women receiving chemotherapy.
Survival simply means the patient is alive - either with or without cancer.
Here again statistical analysis showed benefit of receiving chemotherapy. Authors evaluated to determine which groups benefited and chemotherapy indeed was beneficial for estrogen receptor positive and negative breast cancer patients with a tumor that measured 3cm or greater. Chemotherapy was also beneficial in estrogen receptor negative cancers. The authors found no difference in overall survival or disease-free survival with estrogen receptor negative cancers that were less than 3cm in diameter. Also, the survival rate was better in the group receiving chemotherapy.