This article is more than 5 years old. Information may no longer be current.
Study results guide decisions about local therapy for breast cancer
Click Here to Manage Email Alerts
Agarwal and colleagues analyzed the SEER database from 1998 to 2008 to address a common question posed by many patients: “Wouldn’t it be better to have my breasts removed to prevent recurrence?”
In the SEER database, they compared breast conservation therapy with mastectomy alone or mastectomy with radiation therapy. Instead of just focusing only on OS, they looked closely at breast cancer-specific survival. To avoid the bias of surgeons choosing mastectomy for larger tumors, only early-stage breast cancer (tumors <4 cm and those with fewer than three positive nodes) were evaluated. The database contained more than 130,000 patients, 70% of whom received breast conservation therapy.
When matched for tumor size and lymph node status, the researchers found that breast conservation therapy was associated with superior survival to mastectomy. For all patients, the hazard ratio for breast cancer-specific survival after mastectomy was 1.82 (95% CI, 1.73-1.91) compared with breast conservation therapy. Although larger tumors and lymph node involvement conferred worse breast cancer-specific survival, breast conservation therapy was the superior modality compared with both mastectomy and mastectomy with radiation.
Douglas Yee
Because the SEER database does not contain information on tumor biologic parameters or consistent description of adjuvant therapy, these important determinants of breast cancer outcomes could not be evaluated when examining survival rates. However, if different rates of systemic therapy accounted for the improvement in breast cancer-specific survival, then it would have to be assumed that patients who underwent breast conservation therapy received adjuvant therapy at a higher rate than those who underwent mastectomy.
This supposition does not seem supported by current practice; decisions about administration of adjuvant therapy are mostly independent of the type of surgery and more dependent on tumor size and lymph node status. For example, patients with larger tumors (>2 cm to 4 cm) almost always receive adjuvant therapy, yet breast conservation therapy still had an improved survival rate compared with mastectomy. These data are consistent with results of a study by Hwang and colleagues published last year in Cancer (Hwang ES. Cancer. 2013;119:1402-1411). In that study, the researchers reported improved survival for breast conservation therapy compared with mastectomy in a California population.
To address the question about risk for recurrence in different biological subtypes, Gangi and colleagues examined breast conservation therapy results from 20 surgeons operating at a single hospital. During 12 years, they performed more than 1,800 breast conservation therapy surgeries. They could find no risk for local recurrence for any intrinsic subtype. Although triple negative breast cancer had a worse rate for distant recurrence, this observation is consistent with the biological properties of the disease.
Taken together, these studies help guide decisions for women making choices about local therapy for breast cancer. We can reassure patients about breast conservation therapy and breast cancer-specific survival when compared with mastectomy. Although a biological explanation for the reason that breast conservation therapy appears superior to mastectomy in the SEER database, the data favor breast conservation therapy over mastectomy for breast cancer-specific survival in early-stage breast cancer. We also can reassure patients that the intrinsic subtype does not appear to influence risk for local recurrence. Thus, breast conservation therapy remains the treatment of choice for early-stage breast cancer.
For more information:
Douglas Yee, MD, is a professor of medicine and pharmacology and director of the Masonic Cancer Center at the University of Minnesota. He also is a HemOnc Today Editorial Board member. He can be reached at Masonic Memorial Building, 424 Harvard St. SE, First floor, Minneapolis, MN 55455.
Disclosure: Yee reports no relevant financial disclosures.