Thanks, Caryn. I found this information which is fairly recent.

This information scares me since I'm considering delayed micro vascular flap reconstruction.

Internal Mammary Recipient Site Breast Cancer Recurrence Following Delayed Microvascular Breast Reconstruction

Anais Rosich-Medina, MB ChB, BSc, MRCS; Susan Wang; Ertan Erel, FRCS Plast; Charles M. Malata, FRCS Plast

|Disclosures

ePlasty. 2013;13

METHODS

A retrospective review of the senior author's (C.M.M.) delayed free flap breast reconstructions using the IMV as the recipient site was conducted between January 2004 and January 2011. All patients who developed local breast cancer recurrence at the site of the IMV anastomoses following DBR were identified from the paper and electronic medical records. Their demographics, reconstructive details, histology reports, reconstructive and oncology outcomes, and follow-up were reviewed. The 3 main areas of interest were (1) the time interval between mastectomy and DBR, (2) the time interval between DBR and local internal mammary recurrence, and (3) patient survival and follow-up.

DISCUSSION

The 3 patients in our case series developed local recurrence at the site of microvascular anastomosis within 10 months of their DBR, despite being disease-free for a long time following their mastectomy. In fact, one of the patients was disease-free for 10 years prior to her DBR and then presented shortly (4 months) after her reconstruction with local intercostal space recurrence. This temporal relationship between the DBRs and the recurrences therefore raises the question whether an aspect of the DBR such as the IMV dissection or general immunosuppression may have in some way stimulated the local breast cancer recurrence. Could it have activated dormant tumor cells present in the lymph nodes at the internal mammary dissection site present for instance in the IMLNs? It has previously been documented that surgical trauma and other stress factors can "activate dormant micrometastases" and this may be a potential explanation for the local recurrence in our patients.[11] It is also conceivable that breast cancer cells which had metastasized to the IMLNs and lymphatics might have been inactive prior to the reconstructive surgery but were reactivated following the reconstruction. The patient who had incidental lymph nodes harvested during vessel exposure was found not to have metastatic malignancy at the time of DBR, thus suggesting that there was no evidence of locoregional metastases at the time of DBR. This finding would suggest that surgical trauma or other stress factors during the DBR may have "re-activated dormant micrometastases," which months later caused the patient to present with local chest wall recurrence.

There have been anecdotal reports of possible links between DBR and cancer recurrence.[7,8] Most reports have focused on the possible links between immediate breast reconstruction and local recurrence.[4–5,12–15] However, a recent study comparing recurrence rates in women with delayed large flap (postmastectomy) breast reconstruction with mastectomy alone found a significantly higher risk of breast cancer recurrence following DBR.[9]Our study lends further credence to this association. Despite this, the mechanism by which DBR can influence local breast cancer recurrence remains to be elucidated.

Several theories have been proposed for the role of surgery in precipitating local breast cancer recurrence. First, the insult of major surgery may upset the delicate balance between the immune system and dormant breast cancer cells.[9] Patients with breast cancer are known to harbor micrometastases at different sites and surgical trauma may reactivate the dormant micrometastases, which could result in early local recurrence or distant metastases.[11] Second, mechanical dispersal of dormant tumor cells in the IMLNs during IMV exposure is a possibility. Disruption of metastatic growth suppression may lead to uncontrolled cancer growth in tissues where the metastatic cells had been previously suppressed and not clinically apparent. In contrast to flap reconstruction, DBR with implants did not increase breast cancer recurrence rates after reconstruction.[16] This perhaps suggests that it may not be the surgical trauma per se that may be implicated but other factors such as disruption of lymphatics.

The case series herein reported raises the question whether there may be a causal link between DBR and local recurrence following microsurgical breast reconstruction or whether our findings were coincidental. If there was a causal link, this would have important implications for the use of the internal mammary recipient site for microsurgery. For the reconstructive microvascular surgeon, this would create a dilemma whether to preferentially use this site which has multiple advantages over the subscapular-thoracodorsal vascular axis or avoid it for fear of "reactivating" recurrence.[17]

CONCLUSION
Although no generalizations can be made from our small case series, we would like to make other clinicians aware that there is a theoretical possibility of a correlation between delayed free flap breast reconstruction using the IMV as the recipient site and the onset of local breast cancer recurrence. We suggest that other clinicians with similar experience should formally report their results in the literature to generate more informative discussion.