metaplastic carcinoma

[doctorsis]

A bilateral mastectomy was recently done. The path report states: metaplastic carcinoma, 5X2.8cm, extending to within 0.5cm of inferior skin margin (closest margin). 8 lymph nodes removed including sentinel lymph node all negative. Cancer found in only one breast. The other was completely negative. The AJCC classification is:  PT2.PNO (I-).PMX. We do not understand this classification. Also there was no other tumors anywhere else. A PET and a CAT scan was done and the one tumor was it. There is a disagreement as to whether radiation and chemo should be done. We do not see the point since everything else was fine. Could you help us understand the situation better. Both the surgeon and oncologist says they have never seen this type before due to its rarity. Thank you for shedding any light on this for us.


This discussion is related to Post Whipple Cat-Scans.

[Fernando Roque, MD]

Hi.  The American Joint Committee on Cancer (AJCC) staging system for breast cancer classifies disease using three criteria: T refers to a description and size of the primary tumor, N refers to the presence or absence of metastases or cancer spread to nearby lymph nodes, and M indicates the presence or absence of metastases to distant body organs like the bones, lungs or liver.  A prefix "P" when combined with T, N, or M indicates the "pathologic staging".   This means that the staging was arrived at through pathologic examination (an examination of tissues harvested after biopsy or surgery), which is a more thorough evaluation as opposed to "clinical staging", which is an initial staging done prior to surgery/ mastectomy.

PT2 indicates a primary tumor which is between 2 - 5 centimeters in size.  The 5 x 2.8 cm mass that was removed certainly qualifies as PT2.  PN0 (I-) means that no metastases were found on microscopic examination of the 8 lymph nodes harvested. (I-) means that immunohistochemistry staining methods were employed to look for minute aggregations of metastatic cells which may have been missed out by ordinary microscopy. The negative sign after the "I" indicates that no metastases were found using this method. PMX means that distant metastatic spread has not yet been thoroughly evaluated (imaging studies of the liver, lungs and bones may have to be done first).  A classification of PT2 PN0 PMX means that the cancer is at an early stage (Stage IIA), assuming that there are no metastases to distant body organs.

For Stage IIA patients who have undergone mastectomy and who have a metaplastic histology, the NCCN (National Comprehensive Cancer Network) guidelines suggest that radiation therapy be done if the tumor is 5cm or less and the margins of resection are close (less than 1 mm).  Since the closest margin in your case is 0.5 cm or 5 mm, you have the option not to undergo radiotherapy.  The guidelines also recommend that chemotherapy after surgery be done for tumors 5 cm in size, even for those with metaplastic histology.

[doctorsis]

Thank you so very much for explaining the classification and the recommended guidelines. This is very clear and helpful.