Timing of Postoperative Radiation Therapy

In a randomized trial, patients received one of the following regimens:[27][Level of evidence A1]The following results were observed:

In a randomized trial, patients received one of the following regimens:[27][Level of evidence A1]The following results were observed:

Chemotherapy first (n = 122), consisting of cyclophosphamide, methotrexate, fluorouracil (5-FU), and prednisone plus doxorubicin repeated every 21 days for four cycles, followed by breast radiation.

In a randomized trial, patients received one of the following regimens:[27][Level of evidence A1]The following results were observed:

Breast radiation first (n = 122), followed by the same chemotherapy.

In a randomized trial, patients received one of the following regimens:[27][Level of evidence A1]The following results were observed:

With a median follow-up of 5 years, OS was 73% for the radiation-first group and 81% for the chemotherapy-first group (P = .11).

In a randomized trial, patients received one of the following regimens:[27][Level of evidence A1]The following results were observed:

The 5-year crude rate of first recurrence by site was 5% in the radiation-first group and 14% in the chemotherapy-first group for local recurrence and 32% in the radiation-first group and 20% in the chemotherapy-first group for distant or regional recurrence or both. This difference in the pattern of recurrence was of borderline statistical significance (P = .07).

In a randomized trial, patients received one of the following regimens:[27][Level of evidence A1]The following results were observed:

Further analyses revealed that differences in recurrence patterns persisted for most subgroups except for those who had either negative tumor margins or one to three positive lymph nodes. For these two subgroups, sequence assignment made little difference in local or distant recurrence rates, although the statistical power of these subgroup analyses was low.

In a randomized trial, patients received one of the following regimens:[27][Level of evidence A1]The following results were observed:

Potential explanations for the increase in distant recurrence noted in the radiation-first group are that chemotherapy was delayed for a median of 17 weeks after surgery, and that this group received lower chemotherapy dosages because of increased myelosuppression.

Two additional randomized trials, though not specifically designed to address the timing of radiation therapy and adjuvant chemotherapy, do add useful information.

Two additional randomized trials, though not specifically designed to address the timing of radiation therapy and adjuvant chemotherapy, do add useful information.

In the NSABP-B-15 trial, patients who had undergone breast-conserving surgery received either one course of cyclophosphamide, methotrexate, and 5-FU (CMF) (n = 194) followed by radiation therapy followed by five additional cycles of CMF, or they received four cycles of doxorubicin and cyclophosphamide (n = 199) followed by radiation therapy.[28][Level of evidence A1]

Two additional randomized trials, though not specifically designed to address the timing of radiation therapy and adjuvant chemotherapy, do add useful information. › In the NSABP-B-15 trial, patients who had undergone breast-conserving surgery received either one course of cyclophosphamide, methotrexate, and 5-FU (CMF) (n = 194) followed by radiation therapy followed by five additional cycles of CMF, or they received four cycles of doxorubicin and cyclophosphamide (n = 199) followed by radiation therapy.[28][Level of evidence A1]

No differences in DFS, distant DFS, and OS were observed between these two arms.

Two additional randomized trials, though not specifically designed to address the timing of radiation therapy and adjuvant chemotherapy, do add useful information.

The International Breast Cancer Study Group trials VI and VII also varied the timing of radiation therapy with CMF adjuvant chemotherapy and reported results similar to NSABP-B-15.[29]