Adjuvant Chemotherapy Improves Survival in Women With Recurrent Breast Cancer

Stefan Aebi, MD

Adjuvant chemotherapy improved survival rates in women with isolated local or regional breast cancer recurrence, according to results from the CALOR trial presented by Stefan Aebi, MD, at the 2012 San Antonio Breast Cancer Symposium (SABCS). Aebi, head of the division of Medical Oncology at Luzerner Kantonsspital in Luzern, Switzerland, said the greatest benefit was observed in patients with estrogen receptor (ER)—negative disease.

Aebi and colleagues from the Breast International Group, the National Surgical Adjuvant Breast and Bowel Project, and the International Breast Cancer Study Group randomized 162 patients (median age, 56 years) with recurrent tumors to chemotherapy (n = 85) or no chemotherapy (n = 77). “The choice of chemotherapy was determined by the patient’s treating oncologist based on her prior therapy,” Aebi said. A minimum of four cycles of a multidrug chemotherapy regimen was recommended.

Patients were evenly distributed between the two trial arms in terms of location of recurrence (breast, chest wall/mastectomy scar, or lymph nodes), ER status, and menopause status. Sixty-eight percent and 58% of patients in the control and treatment arms, respectively, had prior adjuvant chemotherapy. The median time between patient surgeries for primary and recurrent disease was 5 years in the treatment group and 6 years in the control group.

At 4.9 years’ follow-up, the overall survival (OS) rate for patients receiving adjuvant chemotherapy was 88% versus 76% in the control arm (hazard ratio [HR] = 0.41; 95% CI, 0.19-0.89; P = .02). Five-year disease-free survival (DFS) rates were 69% and 57% with and without chemotherapy, respectively (HR = 0.59; 95% CI, 0.35-0.99; P = .046). The data remained statistically significant in statistical analyses controlling for recurrent disease location, ER-status, prior adjuvant chemotherapy, and interval between primary and recurrent surgeries.

In women with ER-negative disease, 5-year DFS was 67% in the treatment arm versus 35% in the control group (HR = 0.32; 95% CI, 0.14-0.73; P = .007). Five-year OS in ER-negative patients was 79% with adjuvant chemotherapy versus 69% without (HR = 0.43; 95% CI, 0.15-1.24; P = .12).

DFS at 5 years in patients with ER-positive recurrent tumors was 70% and 69%, respectively, with and without treatment (HR = 0.94; 95% CI, 0.47-1.89; P = .87). OS rates were 94% and 80%, respectively (HR = 0.40; 95% CI, 0.12-1.28; P = .12). Aebi commented that the ER-positive data are not yet mature. “When I say now that we found no statistically significant benefit in the ER-positive group, this does not mean that it will stay this way with further follow-up. We need to observe these patients for a longer period of time.”

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Dr Stefan Aebi on Adjuvant Chemo in Recurrent Breast Cancer

Regarding side effects, Aebi said nothing abnormal was observed in the treatment arm. “Toxicity-wise, we observed what is expected from these chemotherapies.”

Aebi said the next step with his research in this setting is unclear, as patient recruitment for clinical studies has been difficult. “You’ve seen that recruitment for [the CALOR] trial was very challenging. So, at the moment, we are still struggling with how to follow up this trial. We have to be realistic and find out a way to go on that is acceptable to patients and clinicians, so that we do not run into the same problem. This is still an unresolved challenge.”

Aebi S, Gelber S, Láng I, et al. Chemotherapy prolongs survival for isolated local or regional recurrence of breast cancer: the CALOR trial (Chemotherapy as Adjuvant for Locally Recurrent breast cancer; IBCSG 27-02, NSABP B-37, BIG 1-02). Presented at: 2012 CTRC-AACR San Antonio Breast Cancer Symposium; December 4-8, 2012; San Antonio, Texas. Abstract S3-2.

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