By Lynda Williams, medwireNews Reporter
medwireNews: Women who do not undergo surgery within 6 months of being diagnosed with ductal carcinoma in situ (DCIS) have an 11% risk of developing ipsilateral breast cancer over the following 8 years, indicates research published in The BMJ.
“Surgery remains universally recommended for patients with a new diagnosis of DCIS to prevent future invasive cancer”, explain Eun-Sil Shelley Hwang (Duke University Medical Center, Durham, North Carolina, USA) and colleagues, and therefore “the natural history of DCIS in the absence of excision is largely unknown.”
To investigate further, the team reviewed the medical records of 1780 women aged a median of 63 years who were diagnosed with primary DCIS by needle biopsy. None of the patients underwent surgery or radiotherapy within 6 months of their DCIS diagnosis and they were free from invasive breast cancer at this time point. Overall, 38% underwent surgery after this time, with 63% of lumpectomies and mastectomies reported occurring 6–12 months after diagnosis, and 25% received endocrine therapy.
The majority of the women were White (70%) or Black (22%) and 33% had at least one comorbidity. Of the 1533 women whose tumours had a known grade, 59% had low-to-intermediate grade disease and 88% had hormone receptor-positive disease.
Over a median follow-up of 53.3 months, 6.5% of the 1780 women were diagnosed with ipsilateral invasive breast cancer and 1.6% died from breast cancer. This gave an 8-year cumulative incidence of 10.7% and a disease-specific survival probability of 96.4%.
Of note, the 8-year incidence of ipsilateral breast cancer rose to 11.6% for women who did not undergo initial surgery within 9 months of diagnosis and 12.1% for those whose first surgery was at least 12 months after surgery.
“For context, the 10 year cumulative incidence of ipsilateral invasive cancer in women with atypia—a benign diagnosis for which the treatment recommendation is close monitoring—has been reported to be between 6% and 13%”, Hwang and co-authors comment.
The team also calculated the 5-year risk of ipsilateral invasive breast cancer among 11,783 women who had undergone breast-conserving surgery within 6 months of DCIS diagnosis to be 1.4%, rising to 3.4% when considering the risk of any ipsilateral cancer including DCIS.
Overall, 650 women were classified as low risk for ipsilateral invasive disease, defined as being aged at least 40 years old, having an imaging-detected diagnosis, having nuclear grade I/II disease and being hormone receptor-positive. A further 833 women who did not meet all four criteria were classified as high risk and 297 were not classified.
Analysis showed that low-risk women had a significantly lower 8-year rate of ipsilateral invasive breast cancer than their high-risk peers, at 8.5% versus 13.9%, and this translated to a better disease-specific survival probability (98.1 vs 94.4%).
“The variability in outcomes between women with low risk and high risk DCIS emphasizes the need for accurate risk stratification tools in women with a diagnosis of DCIS”, the researchers say.
“For patients at an elevated risk of invasive progression, offering them timely surgery and adjuvant therapy is important. At the other end of the risk spectrum, select patients may benefit from de-escalation of treatment.”
While acknowledging that the study is not adequate to “change practice”, the team concludes that the data indicate “DCIS should not be categorically regarded as ‘cancer,’ with the attendant fears of cancer dissemination and death”, and suggest that for low-risk women who may have to delay surgery for other medical reasons, “an active monitoring approach is not likely to pose undue oncologic dangers.”
Writing in an accompanying editorial, Nehmat Houssami (University of Sydney, New South Wales, Australia) agrees that “[t]his important study provides evidence that risk of progression to, and prognostic features of, ipsilateral breast cancer differ between low risk and high risk DCIS when surgery is omitted and can inform evaluations of de-escalation of DCIS treatment.”
He adds, however, that “it does not provide evidence negating benefit from surgical excision of low risk DCIS.”
The editorialist concludes that “[l]ong term outcomes showing the safety of active surveillance alone for DCIS [in ongoing prospective trials] are needed before omission of surgery can be routinely offered for low risk DCIS.”
medwireNews is an independent medical news service provided by Springer Healthcare Ltd. © 2025 Springer Healthcare Ltd, part of Springer Nature
BMJ 2025; doi:/10.1136/bmj-2024-083542
BMJ 2025; doi:10.1136/bmj.r1423
https://pubmed.ncbi.nlm.nih.gov/40628457/
https://pubmed.ncbi.nlm.nih.gov/40645645/
Keywords: breast cancer, ductal carcinoma in situ, surgery