DCIS (Ductal Carcinoma In Situ)
Understanding your assessment and treatment
By Graeme Millar, Lead Breast Surgeon – Otago Surgical Associates
Being told you have DCIS, sometimes described as pre-cancer of the breast, can be confusing and frightening. Many patients feel unsure what this diagnosis means, whether it is cancer, and what treatment is required.
My role as a breast cancer surgeon, and the role of the wider team at Otago Surgical Associates (OSA), is to guide you carefully through this process, explain your diagnosis clearly, and tailor treatment specifically to you—delivered locally here in Dunedin and Otago.
What is DCIS?
DCIS stands for ductal carcinoma in situ. It means that abnormal cells have developed within the milk ducts of the breast, but have not spread beyond the ducts into surrounding breast tissue.
DCIS is:
Not invasive breast cancer
Not life-threatening at diagnosis
Considered a precursor to invasive breast cancer
The reason DCIS is treated seriously is that, if left untreated, some cases can progress to invasive breast cancer over time. Treatment aims to prevent this progression.
How DCIS is usually found
Most people with DCIS:
Do not feel a lump
Have no symptoms
DCIS is most commonly detected on screening mammography, where it appears as tiny calcium deposits (microcalcifications). Occasionally, it may be found during investigation of another breast concern or symptom.
Your initial assessment
Your first consultation will take place at:
Suite 6, Marinoto Clinic, Dunedin, or
My private clinic at Balclutha Hospital, held twice monthly
At this appointment, we will:
Review how the DCIS was detected
Discuss your medical and family history
Perform a chaperoned breast examination
Review all imaging and biopsy results in detail
After this, we sit down together to talk through what the diagnosis means and outline the next steps.
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Treatment is highly individualised and depends on:
The size and extent of DCIS
Grade (how abnormal the cells look)
Whether it involves one or multiple areas
Your breast size, health, and personal preferences
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Most patients with DCIS will require surgery. This may involve:
Breast-conserving surgery (lumpectomy) to remove the area of DCIS, or
Mastectomy, if the DCIS is extensive or involves multiple areas
If mastectomy is required for DCIS treatment the possibility of immediate breast reconstruction will be discussed if this is something you would like to consider
The aim is to completely remove the DCIS with clear margins.
Lymph node surgery is not routinely required for DCIS but may be recommended in selected cases if the area of DCIS is larger, particularly if a mastectomy is planned.
Our approach at Otago Surgical Associates
At OSA, DCIS care is:
Local – delivered in Dunedin and Otago
Individualised – no one-size-fits-all treatment
Multidisciplinary – involving a full breast cancer team
Supportive – recognising both the physical and emotional impact
If you have been diagnosed with DCIS, my commitment is to ensure you receive clear information, thoughtful recommendations, and compassionate care, from the initial assessment through treatment and into long-term follow-up—close to home.