Concurrent administration of CMF chemotherapy and radiotherapy after breast-conserving surgery for mammary carcinomas

 

Several retrospective studies and one prospective randomized trial showed no statistically significant differences in first failure patterns and event-free survival between patients receiving chemotherapy first and those receiving radiotherapy first as adjuvant treatment after breast-conserving surgery for mammary carcinomas (1-2).

Our study was designed to test a third option, that is, concurrent radiotherapy and CMF chemotherapy in comparison to the sequence of CMF chemotherapy followed by radiotherapy. The concurrent treatment has the potential of increasing local control by reducing the overall treatment time and by exploiting the interaction between the two modalities. Naturally, the concurrent treatment could cause an increase in toxicity and a reduction in patient compliance.

Our study (Arcangeli G et al.: "A Phase III randomized study on the sequencing of radiotherapy and chemotherapy in the conservative management of early-stage breast cancer", Int J Radiat Oncol Biol Phys. 2005 Oct 11; [Epub ahead of print]) had that the concurrent administration of CMF chemotherapy and radiotherapy as adjuvant treatment provides similar local failure rates and survival and does not increase local or systemic toxicity in comparison to the sequential schedule of CMF followed by radiotherapy. However, no patient in this study had high risk for local recurrence such as infiltration of surgical margins and/or large tumor size.

The findings of this study suggest that in patients without specific risk for local recurrence, radiotherapy can be delayed up to 7 months. Conversely, concurrent treatment, with its potentially increased effectiveness for local control, could perhaps, be more appropriate to patients with high risk of local recurrence, as showed by other studies (2-3).

These suggestions, however, are strictly limited to the combination of radiotherapy and CMF chemotherapy and cannot be employed when other drugs are used.

CMF is, presently, rarely used as adjuvant chemotherapy, since it is often replaced by drug combinations, including anthracyclines and taxanes, apparently more effective than CMF in controlling micrometastases. This drugs, however, have the potential of increasing local toxicity when given concurrently with radiation (4) and therefore, additional studies, employing the chemotherapy agents more commonly used today, are necessary to confirm the validity of the treatment strategy emerged from our study.

 

References: 

  1. Recht et al. New Engl J Med 1996; 334:1356
  2. Bellon JR et al. J Clin Oncol 2005; 23:1934
  3. Bellon JR et al. Int J Radiat Oncol Biol Phys 2000; 48:393
  4. Hanna YM et al. Breast J 2005 ; 8 :149  

 

Giorgio Arcangeli

Regina Elena National Cancer Institute, Rome, Italy