Mamma Print Low Risk after mastectomy

Hi swivel2020:

I don't have relevant experience for you, but the MammaPrint test is typically used to inform the question of chemotherapy. The test result does not control loco-regional treatments (e.g., post-mastectomy radiation).

Guidelines for radiation generally differ according to type of surgery received (lumpectomy vs mastectomy) and type of disease (non-invasive versus invasive disease).

The NCCN guidelines (Version 2.2016) include a separate algorithm for post-mastectomy radiation in the setting of invasive disease (Stage I, IIA, or IIB disease OR T3, N1, M0), which takes into account nodal status, tumor size, and margin status. When post-mastectomy radiation is indicated, the radiation field would include the chest wall. In the appropriate case, additional fields could include the infra-clavicular region, supra-clavicular area, internal mammary nodes, and any part of the axillary bed at risk.

Just this month, a focused update of the 2001 guideline was issued by ASCO–ASTRO–SSO regarding post-mastectomy radiotherapy in invasive T1-T2 size tumors:

ASCO–ASTRO–SSO UPDATE (2016): http://jco.ascopubs.org/content/early/2016/09/15/JCO.2016.69.1188.full#ref-3

ASCO–ASTRO–SSO (2016): PDF version

T1 Tumor ≤ 20 mm in greatest dimension;

T2 Tumor > 20 mm but ≤ 50 mm in greatest dimension.

The focused update is discussed in this MedScape article.

MedScape (2016): http://www.medscape.com/viewarticle/868989

Registration for MedScape is free. To access without registration, google the title of the article, "New Guideline: No Single Formula for Postmastectomy RT"

Age and any relevant co-morbidities may also be considerations.

As both the medical advice regarding chemotherapy and radiation therapy involve some judgment, after you meet with your Radiation Oncologist, time permitting per your team, you may wish to seek a second opinion regarding your treatment plan.

Best,

BarredOwl

[EDIT (10/26/2016) - Unable to access any PDFs from the updated J Clin Oncol website. A PDF version of the 2016 Guideline published in the Ann. Surg. Oncol. can be accessed here (at upper right):

http://link.springer.com/article/10.1245/s10434-016-5558-8

For completeness, links to the much older prior guideline are provided:

Prior 2001 Guideline: http://jco.ascopubs.org/content/19/5/1539.full

A pdf version can be accessed at the full-text page.

Congratulations on your low mammoprint score. I hope you are recuperating nicely after your procedure. Mammoprint is correlated with recurrence but is used mostly for decisions regarding the need for chemotherapy. I agree that you do not need chemo. The fact that your lymph node was negative, tumor was luminal A, and ER/PR positive and Her 2 neu negative all suggests a favorable tumor. Radiation after mastectomy is not routine but generally considered in cases such as yours with multiple tumors and an extremely close margin. Clinical experience would suggest you have a higher risk for local recurrence (but not metastatic disease) based upon the number of tumors in your breast, the size (2cm) and close margin despite mastectomy.  I agree with the addition of radiation to your treatment regimen. Talk to your radiation oncologist to get some statistics if he has them so you can make an informed choice. I know radiation will lower your risk of recurrence. Find out if the benefit is worth the risk (implant deformity etc) to you. Some women would not proceed with radiation despite the recommendation. Good luck and take care.