Analysis of radiotherapy optimization regimens after modified radical mastectomy.

OBJECTIVE: Concomitant chemo-radiotherapy after modified radical mastectomy for breast cancer is an effective means of achieving high survival rates. In this study different radiotherapy optimization regimens are compared to assess their effectiveness and toxicity rates.

PATIENTS AND METHODS: 112 patients with modified radical mastectomy participated, and were randomly assigned to one of three groups, all receiving adjuvant chemotherapy for 4-6 weeks prior to radiotherapy: group A received intensity modulated radiotherapy (radiation dose (DT) 50 Gy, 2.0 Gy/fraction, 25 times, during the course of 33-35 days); group B received concurrent radio chemotherapy and intensity modulated radiotherapy; and group C adopted concurrent radio chemotherapy and hypofractionation (DT of 42.56 Gy, 2.66Gy/fraction, 16 times, during the course of 22-24 days) with 37 cases. The occurrence of acute and chronic radiation injuries, the cancer recurrence and the survival rates were compared, and a dose volume histogram (DVH) was created.

RESULTS: The total prevalence and survival rates of Group C were significantly better than those of the other two groups (p ≤ 0.05); in spite of the fact that the local recurrence and distant metastasis rates separately were all statistically the same (p ≥ 0.05). Also, the total radiation injury occurrence of group C was significantly lower (p < 0.05); but no significant differences were found when singling out acute and chronic injury occurrences or injury severity between the three groups. The values of V5, V10, V20 and V30 increased gradually in all of the groups, and V5 and V10 in Group C were higher than those in the other two groups, but the comparison between V20 and V30 yielded no statistically significant differences.

CONCLUSIONS: Based on these results, the concurrence of hypo-fractionation radiotherapy and chemotherapy may be an effective and safe approach for cancer treatment after modified radical mastectomy, and larger studies are warranted given the convenience of the method.