Being told there is more than one tumor in the same breast often brings an immediate fear: that the cancer is more advanced, and that the whole breast has to be removed. Neither is automatically true. Multifocal and multicentric breast cancer are descriptions of where the tumors sit, not of how far the cancer has spread, and a prospective trial has shown that many women with two or three tumors in one breast can safely keep it. This article explains the difference between multifocal and multicentric breast cancer, how it is diagnosed, when breast conserving surgery is still an option, and how surgeons find each tumor.
Both terms describe more than one separate tumor in the same breast. The difference is the distance between them.
Definitions are not used in exactly the same way everywhere, and some hospitals use a set distance between tumors rather than quadrants. Clinical trials increasingly use one umbrella term, multiple ipsilateral breast cancer, which simply means more than one cancer in the same breast. Whichever term is on your report, the practical question is the same: can all of the tumors be removed with clear margins while leaving a breast that looks and feels acceptable?
A second or third tumor is often found during the workup of the first. A mammogram or ultrasound shows one suspicious area, a biopsy confirms cancer, and further imaging then shows more. Breast MRI is particularly sensitive and is the test most likely to reveal additional areas, which is one reason MRI is commonly used before surgery when more than one tumor is suspected.
Every additional suspicious area that would change the operation is usually biopsied as well. Imaging alone cannot tell a second cancer from a benign finding, and the decision between keeping and removing the breast should not rest on a finding that has not been confirmed. At each biopsy a small marker is normally left behind, so that every confirmed tumor has its own reference point. How biopsy markers work is explained in Clip Marker in Breast Cancer.
For staging, the size of the largest tumor determines the T category, and the letter m is added to show that there is more than one. Having several tumors does not in itself move the cancer into a later stage.
For a long time, more than one tumor in a breast was considered a reason for mastectomy, mainly out of concern that cancer would come back in the breast more often after a lumpectomy. That advice was based on older, mostly retrospective data, in an era before MRI and modern radiation techniques.
The ACOSOG Z11102 trial tested the question prospectively. Women aged 40 or older with two or three biopsy-proven cancers in the same breast had lumpectomies with negative margins, followed by whole breast radiation with an extra boost dose to every lumpectomy bed. In 204 eligible patients followed for a median of more than five years, the 5-year rate of local recurrence was 3.1 percent, well below the 8 percent threshold the investigators had set as clinically acceptable (Boughey and colleagues, Journal of Clinical Oncology, doi: 10.1200/JCO.22.02553). An exploratory analysis found that the small group without a preoperative MRI had a much higher local recurrence rate, which supports MRI as part of the workup when breast conserving surgery is planned.
So breast conserving surgery is now a reasonable option for many people with two or three tumors, particularly when the tumors are relatively small compared with the breast. Mastectomy remains the better choice for some, for example when there are many tumors, when they are spread widely across the breast, when clear margins are unlikely, or when the patient prefers it. The general trade offs are covered in Lumpectomy vs Mastectomy. Where a larger volume of tissue has to be removed, oncoplastic techniques can reshape the breast in the same operation, as explained in Oncoplastic Breast Surgery.
When the tumors are close together, as in many multifocal cancers, they can often be removed in one piece of tissue through a single incision. When they are in different quadrants, as in multicentric cancer, the surgeon usually performs two or three separate lumpectomies, sometimes through separate incisions, in the same operation.
Each specimen is checked by the pathologist for clear margins, and the same rules apply as for a single tumor, explained in Surgical Margins in Breast Conserving Surgery. Radiation follows, with a boost to each place where a tumor was removed. That is why a clearly marked tumor bed matters even after the cancer is gone, a point explained in Radiation After Lumpectomy and Tumor Bed Localization.
The lymph nodes are assessed in the same way as for a single tumor. For most patients with clinically normal nodes, that means a sentinel lymph node procedure, described in Sentinel Lymph Node Dissection.
Here lies a practical challenge that rarely gets mentioned. Many multifocal and multicentric cancers are found on imaging and cannot be felt, so the surgeon needs a guide to each one. With wire localization, that means a separate wire for each tumor, all placed on the morning of surgery and all protruding from the breast until the operation. Where a cancer extends over a longer area, for example a band of calcifications, two markers can be placed at either end of it. This is called bracketing, and it shows the surgeon where the excision should start and end.
Wire-free localization with markers placed in advance removes the morning wire placement and the protruding wires, which makes a difference when more than one wire would otherwise be needed. Whatever method your hospital uses, it is worth asking how each tumor will be identified during the operation, and how the team will confirm that every one of them has been removed. The available approaches are compared in Preoperative Localization in Breast Surgery and Seed Localization vs Wire-Guided.
Not necessarily. Having more than one tumor describes where the cancer is in the breast. How aggressive it is depends mainly on the biology of the tumors, such as grade, hormone receptor and HER2 status, and on the size of the largest tumor and whether the lymph nodes are involved. Studies on whether multiplicity itself affects prognosis have reached different conclusions.
No. Metastatic breast cancer has spread to other parts of the body, such as the bones, liver or lungs. Multifocal and multicentric cancers are confined to one breast, possibly with lymph nodes involved, and are treated with the aim of cure.
Often, yes. When the tumors are close together they can usually be removed in one excision. The ACOSOG Z11102 trial showed a low local recurrence rate after breast conserving therapy in women with two or three tumors in the same breast, provided margins were clear and radiation with a boost to each lumpectomy bed followed.
An MRI is commonly recommended when breast conserving surgery is being considered, because it is the most sensitive test for finding additional tumors. In the Z11102 trial, local recurrence was much more frequent in the small group of patients who did not have a preoperative MRI.
The stage is based on the largest tumor, with the letter m added to the T category to show there is more than one. Lymph node involvement and the biology of the tumor are also part of the stage.
That depends on the biology of the cancer and on lymph node involvement, in the same way as for a single tumor. Having more than one tumor does not by itself mean chemotherapy is needed.
Every tumor that cannot be felt needs to be found precisely, and with more than one tumor in the breast that matters more, not less. Sirius Medical developed the Pintuition® system for wire-free localization of non-palpable lesions. The Pintuition Marker® is a non radioactive, permanent magnetic marker that is cleared for long-term placement in soft tissue, so it can be placed well before surgery instead of with a wire on the morning of the operation. During surgery, GPSDetect™ technology gives the surgeon real-time distance and direction to the marker, and TargetLOC™ confirms when the probe is directly above it. The signal is not lost in blood, fluid or hematoma and cannot be deactivated by electrocautery.
In the first 200 cases at a French cancer center, reported by Ceccato and colleagues in Scientific Reports (doi: 10.1038/s41598-025-88430-5), every targeted lesion was excised and 39.5 percent of markers were placed 2 to 29 days before surgery. A Stanford comparison with an alternative wireless technique, published by Chinn and colleagues in Annals of Surgical Oncology (doi: 10.1245/s10434-025-18354-x), found a median operating time of 37 minutes versus 50 minutes. Elisabeth TweeSteden Hospital in the Netherlands has performed more than a thousand Pintuition® guided procedures.
Learn how Pintuition® can support precision, workflow efficiency and reliable excision in breast cancer surgery. Request demo or explore the clinical overview for more information.
Disclaimer
This article is intended for informational purposes only and should not be considered medical advice. Clinical decisions should always be made by qualified healthcare professionals based on individual patient needs and current guidelines.