Ductal Carcinoma in Situ

Introduction

DCIS is classified as a form of breast cancer that is non-invasive or pre-invasive. DCIS, or ductal carcinoma in situ, is a condition where cancer cells are confined to the breast and cannot move beyond it. However, treatment is typically recommended because if left untreated, certain DCIS cells may undergo further aberrant alterations, leading to the development of invasive breast cancer, which has the potential to spread.

What Are the Different Risk Factors?

Potential risk factors for DCIS include:

• Advancing age.

• Previous medical records of non-cancerous breast conditions, such as atypical hyperplasia.

• Hereditary predisposition to breast cancer.

• Being nulliparous.

• Maternity at an age beyond 30.

• Experiencing menarche before the age of 12.

• Experiencing the onset of menopause at the age of 55 or later.

• Genetic abnormalities that elevate the susceptibility to breast cancer, such as those occurring in the breast cancer genes BRCA1 and BRCA2.

Which Are the Methods of Pathology?

Microinvasion: It is called microinvasion (MI) when cancerous epithelial cells have broken through the basement membrane and moved into the nearby stroma to a depth of 1 mm or less. At different places along the affected duct system, this can happen as single cells or groups of cells. It can happen in a DCIS area or all over the system. Even though it can be found with all grades of DCIS, it happens most often with high-grade tumors. It might be hard to make a final diagnosis if the DCIS is high-grade and there is a lot of cancer in the lobules or if there is a lot of lymphocyte infiltration or stromal distortion.

There are usually ways to get around these problems by using more than one level of images, cytokeratin stains to show off the epithelial cells, and myoepithelial markers to show that there are cancerous cells outside the duct space. Usually, a sentinel lymph node biopsy is done when there is micro invasion, especially high-grade DCIS. In about ten percent of cases (and in some series up to 20 percent of cases), lymph node metastases, mostly micrometastases or single tumor cells, have been found.

What Are the Various Treatment Methods?

Typically, a woman diagnosed with DCIS has the option to select either breast-conserving surgery (BCS) or simple mastectomy. However, in cases where DCIS is present throughout the entire breast, a mastectomy may be a more favorable choice. Ongoing clinical trials are investigating the viability of utilizing observation as an alternative to surgery for certain women.

• Partial Mastectomy: During breast-conserving surgery (BCS), the surgeon excises the tumor along with a minimal portion of healthy breast tissue surrounding it. Lymphadenectomy is typically unnecessary in the context of breast-conserving surgery (BCS). If an area of invasive cancer is detected, it may be addressed during the initial operation. The likelihood of a region of DCIS harboring invasive cancer increases in proportion to the size of the tumor and the rate of cancer growth. When lymph nodes are extracted, it is typically performed as a sentinel lymph node biopsy (SLNB).

• Radiation Therapy: BCS is typically succeeded by radiation therapy. This reduces the likelihood of cancer recurrence in the same breast, whether as further DCIS or as an invasive carcinoma. BCS without radiation therapy is not considered a conventional treatment. However, it could be considered for older women, people with other serious health conditions, or women who had small regions of low-grade DCIS that were surgically excised with sufficient cancer-free margins.

Some women may have concerns that undergoing less comprehensive surgery could potentially increase their chance of cancer recurrence. However, the survival rates for women with early-stage cancer who undergo breast-conserving surgery (BCS) with radiation are equivalent to those who choose a mastectomy.

• Mastectomy: Mastectomy refers to the surgical removal of one or both breasts, typically as a treatment for breast cancer. A complete breast removal, known as a simple mastectomy, may be necessary in cases where the area affected by DCIS is extensive, when there are multiple separate areas of DCIS in different parts of the breast (multicentric), or when breast-conserving surgery (BCS) fails to completely remove the DCIS, leaving cancer cells in or near the surgical margins. Suppose a mastectomy is required due to any of the causes above. In that case, it is common for doctors to perform a sentinel lymph node biopsy (SLNB) simultaneously, as there is an increased likelihood of detecting invasive malignancy. If a mastectomy reveals the presence of invasive cancer in the excised tissue, the doctor will be unable to do a sentinel lymph node biopsy (SLNB) at a later time. Consequently, the doctor may need to perform a complete axillary lymph node dissection (ALND) instead.

Women undergoing a mastectomy for DCIS often do not require radiation therapy and can opt for immediate or delayed breast reconstruction.

• Postoperative Hormone Treatment: For women with hormone receptor-positive DCIS (estrogen or progesterone), a 5-year treatment plan involving Tamoxifen (for all women) or an aromatase inhibitor like Exemestane or Anastrozole (for women who have gone through menopause) after surgery can effectively reduce the likelihood of developing another DCIS or invasive cancer in either breast. If one has been diagnosed with hormone receptor-positive DCIS, it is advisable to have a detailed conversation with the doctor regarding the pros and cons of hormone therapy.

Conclusion

In summary, DCIS is an exceptionally diverse condition that, similar to its invasive alternative, is probably composed of numerous disease entities that are biologically distinct. In the future, differentiating between forms of DCIS that are more indolent and less likely to progress to invasive disease and those that are likely to recur will be a challenge. Imaging and treatment decisions will need to be tailored accordingly.