I’ve been reading up a bit on the expected pathology reports for post-mastecotomy after neoadjuvant chemotherapy (that is, what should I be hoping for in the pathology after chemo – and what does that mean?).

To start with my new term for the day is “pathological complete response” or pCR – this indicates the degree to which the chemotherapy treatment has killed the cancer. According to Cortazer et al (2014), you are considered to have a pathological complete response if:

• absense of invasive cancer or in-situ cancer in breast or the axillary nodes (ypT0 ypN0)
• absence of invasive cancer in breast or axillary notes but in-situ is present (ypT0/is ypN0)
• absence of invasive cancer in breast but in-situ and nodal involvement (ypT0/is)

Note that definitions for pCR are not consistent – so each study defines it for their own analysis. For those in the analysis with the same type of tumor I have (based upon my most aggressive tumor which is IDC ER/PR+ HER2- grade 3) the pathological complete response rate is 16.2 % (95% Confidence interval – so 13-4-19.3). This means that I can expect about a 16% chance of having a complete pathological complete response. This takes into account everyone with the same type of cancer, but doesn’t separate out those who had clinical indications of node involvement prior to surgery/chemo. Of those who had no clinical indication of nodal involvement regardless of cancer type the numbers are 18.8 % (95% CI 17.9-19.8). So I’m hoping for the higher number, since I don’t have any indicators of node involvement.

The research says that for the type of tumor that I have, if I have a pathological complete response then it is a good indicator of my overall survival.  The studies don’t say anything about survival if you don’t achieve pathological complete response. The purpose of the two studies I looked at was to determine when/if pathological complete response was a good indicator of disease free survival. The answer for my type of cancer is yes – if the pathology comes back with pCR then that is a good indicator of disease free survival.

Note that it takes along time for a study to be published – so this study published in 2014 is based upon patients that were treated between 1990 – 2011.

The second study that uses more categorization and is more detailed. It gives me a higher likelihood of achieving pCR (11.2 % ypT0 ypN0, 15.4% ypT0/is ypN0, 17.6% ypT0/is ypN0/+). The one quote which is interesting is “subgroups with highly proliferating tumors, pCR can discriminate between patients with good and poor prognosis accurately” (von Minckwitz et al., 2012, p.1802).

So, I now know what I should be hoping for when the pathology comes back after my bilateral mastectomy surgery.

The one thing this exercise is telling me is that I really want to know the pathology from my bilateral mastectomy before I commit to the DIEP flap surgery. This has me leaning towards a skin sparing mastectomy with immediate reconstruction with tissue expanders. This means that if I want the DIEP surgery later, I can have it. Or I can have the expanders removed and skin cleaned up if I don’t want it. It leaves the doors open for reconstruction or not – and the decision will likely depend on prognosis. If I’m going to live a long healthy life post breast cancer, then the DIEP surgery is a worth-while investment in my time and physical energy. If the prognosis is not so great, then I’d rather be done with the surgeries and get on with living.

Reference

Cortazar, P., Zhang, L., Untch, M., Mehta, K., Costantino, J. P., Wolmark, N., . . . Valagussa, P. (2014). Pathological complete response and long-term clinical benefit in breast cancer: the CTNeoBC pooled analysis. The Lancet. Retrieved from http://www.rits.onc.jhmi.edu/dbb/custom/A1/files/12/pCR_Cortazar.pdf

von Minckwitz, G., Untch, M., Blohmer, J. U., Costa, S. D., Eidtmann, H., Fasching, P. A., . . . Loibl, S. (2012). Definition and impact of pathologic complete response on prognosis after neoadjuvant chemotherapy in various intrinsic breast cancer subtypes. J Clin Oncol, 30(15), 1796-1804. doi:10.1200/JCO.2011.38.8595