Mastectomy May Be Overused, Analysis Shows
A re-analysis of data from the NeoALTTO trial found that women whose tumors disappeared after neoadjuvant, or pre-surgery, treatment, were just as likely to have mastectomy as they were to have lumpectomy.
The results, presented at the 2012 European Society for Medical Oncology (ESMO) Congress, have not yet been published in a medical journal.
Background and Reason for the Study
In some situations, women with early-stage breast cancer can have lumpectomy, surgery to remove the tumor and a small margin of healthy tissue around it, to preserve as much of their natural breast as possible. Lumpectomy is sometimes referred to as breast-conserving surgery. Lumpectomy is not always possible and doctors will suggest a mastectomy instead. In mastectomy, the whole breast is removed.
A group of international researchers re-analyzed data from the NeoALTTO trial to find out what factors led to the choice of surgery women had, especially after neoadjuvant treatment with chemotherapy eliminated the cancer.
Published in The Lancet in February 2012, the NeoALTTO trial tested the effect of the anti-HER2 therapies lapatinib (Tykerb), trastuzumab (Herceptin), or a combination of the two in treating HER2 positive early breast cancer when combined with the chemotherapy paclitaxel (Taxol).
The 455 participants in three arms received six weeks of lapatinib alone, trastuzumab alone, or lapatinib plus trastuzumab, all followed by 12 weeks of weekly paclitaxel before they had surgery. The main endpoint was pathological complete response (pCR), or no evidence of invasive cancer at the time of surgery.
Overall, NeoALTTO found that participants given the combination were more likely to reach pCR than the other two groups, with 51.3 percent showing no sign of cancer versus 29.5 percent (trastuzumab alone) and 24.7 percent (lapatinib alone).
The research presented at ESMO looked at results from the 429 women who underwent breast surgery. They found:
- 37 percent of participants achieved pCR
- 57 percent of participants had mastectomy
- 43 percent of participants had lumpectomy
- No matter the rate of pCR for the treatment arm, only around 40 percent of women had lumpectomy (42.9 percent with lapatinib alone, 38.9 percent with trastuzumab alone, 41.4 percent with combination therapy)
- Mastectomy was more likely in women under 50, in women who received treatment in developing countries, if the tumors were large (more than 5 centimeters) or multicentric (in many places in the breast), or estrogen receptor-negative
- All women with lobular cancer had mastectomy
Researchers believe these results show that in some cases, women may have had a mastectomy when breast-conserving surgery might have been an option. In particular, 51.3 percent of participants in the combination arm showed no evidence of invasive disease at the time of surgery, but only 41.4 percent had conserving surgery.
Tumor characteristics before neoadjuvant treatment tended to determine the type of surgery given, rather than the response of the cancer to neoadjuvant treatment.
What This Means for You
This analysis suggests some women may not be offered, or choose, breast-conserving surgery, even after neoadjuvant treatment eliminates the cancer. Previous research shows no differences in survival between neoadjuvant and adjuvant chemotherapy, so more research is needed on how women and doctors choose surgery before these data will impact breast cancer treatment.
The international nature of the NeoALTTO trial naturally involves differences in perspectives on the use of neoadjuvant treatment; therefore, where participants were treated may have impacted the type of surgery they received.
If you have a choice of surgery, talk with your doctor about the risks and benefits. For questions to consider, download a copy of our Guide to Understanding Treatment Decisions.
Criscitiello, C., Azim Jr., H.A., et al: The Discrepancy Between High Pathological Complete Response (PCR) Rate and Low Breast Conserving Surgery (BCS) Following Neoadjuvant Therapy: Analysis from the NeoALTTO Trial. Presented at the 37th European Society for Medical Oncology (ESMO) Congress on September 30, 2012. Vienna, Austria.