Ductal carcinoma in situ: Clinical sciences

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Introduction0:00–0:32

Ductal carcinoma in situ, or DCIS, previously known as intraductal, noninvasive, or non-infiltrating carcinoma, refers to a neoplastic lesion within the mammary ductal system that hasn’t yet invaded through its basement membrane into the surrounding tissues.
If there’s evidence of basement membrane invasion, then the lesion is upstaged to invasive carcinoma. When assessing a patient with signs and symptoms consistent with DCIS, the first step is to obtain a focused history and physical exam.

Initial assessment DMT 0-10:32–2:16

Sometimes, a patient may present after noticing a breast lump or even nipple discharge. However, the majority of patients will not have historical or physical exam findings, and they’ll be discovered on routine mammogram screening, which shows a lesion that may or may not have microcalcifications.
Be sure to ask about risk factors, such as a personal or family history of breast cancer, prior diagnosis of atypical ductal hyperplasia, early menarche or late menopause, and nulliparity or first birth after the age of 30.
Additional risk factors include age greater than 40, a known history of dense breast tissue, and more than five years of hormone replacement therapy.
On the flip side, physical exam findings might include a palpable breast mass or changes in the appearance of the nipple or skin.
Keep in mind that most patients won’t present with any physical exam findings.Here’s a clinical pearl! Biologically male patients and those who identify as transgender or non-binary are also at risk for breast cancers, so it’s important to screen them, especially as these populations frequently go underdiagnosed.

Mammogram DMT 1-22:16–3:05

Okay, now that we have our history and physical exam, let’s move on to some imaging. The next step is to obtain a diagnostic mammogram.
Unlike a screening mammogram, which is used on asymptomatic patients, diagnostic mammograms are performed in patients with evidence of disease, either in the history and physical, or with a prior abnormal screening mammogram, and involves more comprehensive imaging for a more thorough visualization of the breasts than a screening mammogram.
If imaging doesn’t reveal any suspicious findings, or if findings are confirmed to be radiographically benign in appearance, then you should continue current screening mammogram recommendations.

Suspect DCIS3:05–5:53

Alright, let’s talk about potential findings in our diagnostic mammogram. You may see microcalcifications, which are small deposits of calcium clusters that appear radiopaque on imaging; these are suggestive of pathology in the mammary ductal system, and can indicate the presence of neoplastic changes.
There are certain shapes and patterns of microcalcifications that can indicate DCIS, and in order of increasing suspicion, these patterns include coarse heterogeneous, amorphous, fine pleomorphic, and fine linear or fine branching calcifications.
Other imaging findings can include a soft tissue mass, or an area of architectural distortion. Although none of these image findings are pathognomonic for DCIS, they should raise your suspicion for malignancy.
Here’s a clinical pearl! Breast findings on imaging can be categorized with a standardized system called BI-RADS, which stands for Breast Imaging-Reporting and Data System.
The imaging findings are assigned into categories labeled as 0 to 6. First, 0 means incomplete, which needs additional imaging or comparison with previous images if available.
Next, 1 is negative, meaning that mammography is normal, with no findings like masses or calcification; while 2 indicates findings are completely benign, meaning that mammography reveals findings with no probability of malignancy; a category of 0, 1, and 2 can only be used when undergoing routine screening.
On the other hand, 3 is probably benign, meaning that mammography may reveal a finding with minimal malignant potential of less than 2%, so these patients should get follow-up imaging.
Next, 4 is suspicious for malignancy, meaning that mammography may reveal a finding with malignant potential between 2 to 94%, where biopsy will likely be indicated.
Then, a category of 5 is highly suspicious of malignancy, with malignant potential over 95%. Lastly, 6 is known malignancy that has been proven with biopsy, and requires definitive management with surgery, chemotherapy, or radiation.
Okay, after imaging, the next step is to get a core needle biopsy for pathology, which may help us confirm DCIS. Here’s a clinical pearl!

Core needle biopsy DMT 2-35:53–7:14

Core needle biopsy is the standard way to obtain breast tissue for histology, and surgical excisional biopsy is generally not recommended.
However, in rare cases, excisional biopsy is still performed. A couple of examples include a prior non-diagnostic sample from a core needle biopsy, or unsuitable anatomy, like a lesion that’s too close to the skin, too close to the chest wall, or right next to a breast implant.
These biopsies can be tricky, as the lesions in DCIS are not always palpable, meaning a radiologist will need to help localize the lesion for the surgeon to excise.
Okay, if the core needle biopsy doesn’t show evidence of neoplastic epithelial cells, then you may consider an alternative diagnosis.
However, if the biopsy shows neoplastic epithelial cells that arise from ductal tissue, and they don’t invade through the surrounding basement membrane, you can diagnose DCIS.
Alright, now that we have a tissue diagnosis, let’s talk about next steps. Remember, DCIS by definition is a group of neoplastic epithelial cells that have not invaded the basement membrane and surrounding tissues, so, you do not need more imaging to look for distant spread.Here’s a clinical pearl!

Staging7:14–8:49

Cancer staging is based on the TNM system, which stands for Tumor size and extent, spread to lymph Nodes, and Metastasis or spread to distant parts of the body.
The treatment depends on the stage of the tumor. DCIS is considered TisN0M0, also known as Stage 0 breast cancer, to indicate that it is a local malignancy without lymph node involvement or metastasis.
Once you have tissue diagnosis and TNM staging, the next step is to establish estrogen receptor status, which will help direct future therapies.
Additionally, some patients should meet with a genetic counselor to consider testing for inherited genetic mutations. Candidates for testing can be identified with evidence-based risk assessment tools and may include patients who are younger than 45, who have strong family histories of certain cancers, or who have a personal history of prior malignancy, such as ovarian cancer.
Let’s move on to DCIS management. Begin by consulting the surgery team.

DCIS management8:49–11:26

Surgical options include breast-conserving therapy, which involves a partial mastectomy; or simple mastectomy with or without breast reconstruction.
If the patient has breast-conserving surgery, they will need additional radiation therapy as that is the only way to give them the same benefit as with a complete mastectomy.In general, patients can choose between surgical options according to their personal goals, but there are a few contraindications for breast-conserving therapy in DCIS to take into consideration.
For patients who have a multicentric disease, separated by a significant distance, breast-conserving therapy is a relative contraindication.
Also, if the patient’s resection-to-breast-size ratio is cosmetically unacceptable, or if standard 2 mm resection margins are not possible, simple mastectomy should be performed.
If the patient has a simple mastectomy, they should also have a sentinel lymph node biopsy, meaning a biopsy of the first draining lymph node from the neoplastic lesion.
This is because some patients whose initial biopsy indicates DCIS may actually have an invasive breast cancer, which may not be discovered until the mastectomy specimen is examined in pathology.
However, because a mastectomy alters the natural lymphatic drainage of the breast and removes significant tissue, obtaining a sentinel lymph node biopsy in a separate surgery from the mastectomy becomes almost impossible.
Another consideration is the presence of hormone receptors, especially for estrogen. Lesions without estrogen receptors are at a higher risk of recurrence; while lesions with estrogen receptors can be treated with a selective estrogen receptor modulator, or SERM, such as Tamoxifen.
If Tamoxifen is contraindicated, like in patients who had a prior deep vein thrombosis or pulmonary embolism, then an aromatase inhibitor, like Anastrozole, can be used.
Finally, these patients will require routine post-treatment surveillance of both the affected and the unaffected breast, as some patients might develop malignancy in the unaffected breast.
Okay, finally, let’s go all the way back to our core needle biopsy results. If you see that the neoplastic epithelial cells from the breast ducts have invaded through their basement membrane, you should diagnose invasive ductal carcinoma and pursue surgical consultation for appropriate management.

Invasive ductal carcinoma management DMT 3-411:26–11:49

Alright, as a quick recap… DCIS is a neoplastic lesion within the mammary ductal system that hasn’t invaded through its basement membrane.

Review11:49–12:56

Some patients may present after noticing a breast lump or nipple discharge, but most patients are asymptomatic and present after an abnormal screening mammogram.
To diagnose DCIS, start with a diagnostic mammogram, and if the patient has evidence of any suspicious findings, proceed with a core needle biopsy.
If pathology is consistent with DCIS, surgical options include breast-conserving therapy or simple mastectomy, with a sentinel node biopsy.
Patients who underwent breast-conserving therapy require postoperative radiation therapy as well. Other therapies depend on the patient’s estrogen receptor status, and include Tamoxifen or Anastrozole.
Finally, make sure to continue routine post-treatment surveillance, including scheduled physical exams and mammograms.
Ductal carcinoma in situ: Video, Causes, Symptoms | Osmosis