Surgical Treatment of Ductal Carcinoma In Situ

• The diagnosis of DCIS is followed by the surgical treatment with:
  • Breast-conserving surgery:
    • Also referred to as:
      • Segmental mastectomy
      • Partial mastectomy
      • Lumpectomy
      • Quadrantectomy
      • Wide local excision
  • Mastectomy:
    • Total or simple mastectomy
    • Skin sparing mastectomy
    • Nipple sparing mastectomy
• Most patients who undergo breast-conserving surgery:
  • Receive postoperative radiation therapy:
    • To improve local control
• Postoperative endocrine therapy:
  • With tamoxifen or an aromatase inhibitor:
    • Should also be considered for those patients whose tumors are:
      • Hormone (estrogen and / or progesterone) receptor positive
• Mastectomy Versus Breast-conserving Therapy:
  • Historically:
    • DCIS was treated with mastectomy
  • The rationale for performing total mastectomy in patients with DCIS was:
    • Based on the high incidence of:
      • Multifocality
      • Multicentricity:
        • The reported incidence of multicentricity may depend on the extent of the pathologic review and therefore varies from 18% to 60%
      • As well as on the risk of occult invasion associated with the disease:
        • The incidence of microinvasion in DCIS varies according to the size and extent of the index lesion:
          • Lagios et al. (1989):
            • Reported a 2% incidence of microinvasion in patients with DCIS measuring less than 25 mm in diameter, compared with a 29% incidence of microinvasion in those with lesions larger than 26 mm
            • The incidence of microinvasion is also higher in patients with high-grade or comedo-type DCIS with necrosis and in patients with DCIS who present with a palpable mass or nipple discharge
  • Thus, mastectomy remains the standard with which other proposed therapeutic modalities are compared:
    • However, in patients with DCIS, there are no prospective trials comparing outcomes after mastectomy with those after breast-conserving surgery
  • A retrospective review by Balch et al. (1993):
    • Documented a:
      • Local relapse rate of 3.1% and a mortality rate of 2.3% after mastectomy for DCIS
  • The cancer-related mortality rate following mastectomy for DCIS was:
    • 1.7% in a series reported by Fowble (1989)
    • Ranged from 0% to 8% in a review by Vezeridis and Bland (1994)
• In one of the largest studies comparing breast-conserving therapy with mastectomy, Silverstein et al. (1992):
  • Examined 227 cases of DCIS without microinvasion
  • In this nonrandomized study:
    • Patients with tumors smaller than 4 cm with microscopically clear margins:
      • Underwent breast-conserving surgery and radiation therapy
    • Whereas patients with tumors larger than 4 cm or with positive margins:
      • Underwent mastectomy
  • The rate of disease-free survival at 7 years was:
    • 98% in the mastectomy group compared with 84% in the breast-conserving surgery group (P = 0.038)
  • With no difference in overall survival rates
• In a meta-analysis, Boyages et al. (1999):
  • Reported a recurrence rate of:
    • 22.5% – following breast-conserving surgery alone
    • 8.9% – following breast-conserving surgery with radiation therapy
    • 1.4% – mastectomy
  • In patients who underwent breast-conserving surgery alone:
    • Approximately 50% of the recurrences were invasive cancers
  • Although recurrence rates are higher in patients who undergo breast-conserving surgery than in patients who undergo mastectomy:
    • No survival advantage:
      • Has been shown for patients treated with mastectomy’s
• Technique of Breast-conserving Surgery:
  • The goal of breast-conserving surgery is to:
    • Remove all suspicious calcifications and obtain negative surgical margins:
      • SSO / ASCO consensus guidelines recommend a 2 mm margin
  • Because DCIS is usually nonpalpable:
    • Breast-conserving surgery can be performed with mammographically or sonographically guided placement of a localizing wire or radioactive seed:
      • Seed localization of nonpalpable breast lesions is increasingly used in US and through multidisciplinary collaboration with surgeons, radiologists, and pathologists:
        • Has the advantage of allowing a less obtrusive marker to be placed at a time that is uncoupled from the time of surgery
      • At most centers where seed localization is performed:
        • An I-125 radioactive seed is placed by a radiologist within the area of disease:
          • In much the same way wire localization has historically been performed
      • The seed is localized intraoperatively using a gamma probe placed on the appropriate setting to detect radioactive decay for the seed’s isotope label, and the surrounding tissue is excised
      • Resection of the seed, lesion, and previously placed clip:
        • Are confirmed intraoperatively by pathologic and radiologic review
      • Nonradioactive methods of seed localization including ultrasound and magnetic seeds are also available
  • Intraoperative orientation of the specimen:
    • With two or more marking sutures is critical for margin analysis
    • In addition, specimen radiography is essential:
      • To confirm the removal of all microcalcifications
    • In patients with extensive calcifications:
      • Bracketing of the calcifications with two or more seeds or wires may assist in the excision of all suspicious calcifications
  • After whole-specimen radiography:
    • The specimen should be inked and then serially sectioned for pathologic examination to evaluate the margin status and extent of disease
  • Chagpar et al. (2003):
    • Demonstrated that intraoperative margin assessment with the use of sectioned-specimen radiography:
      • Enabled reexcisions to be performed at the same surgery if the microcalcifications extended to the cut edge of the specimen:
        • Minimizing the need for second procedures for margin control
    • After margins are deemed adequate intraoperatively:
      • The boundary of the resection cavity is marked with radiopaque clips to aid in the planning of postoperative radiation therapy and to facilitate mammographic follow-up
  • The goal of breast-conserving surgery is to:
    • Obtain tumor-free margins
  • A detailed pathologic study of DCIS, reported by Holland et al. (1990):
    • Demonstrated that up to 44% of lesions extended more than 2 cm further on histologic examination than that estimated by mammography:
      • However, in most women, a 1- to 2-cm margin around the lesion is not feasible since the cosmetic result would be poor
  • A new guideline put out by three national cancer organizations says that:
    • 2 mm (about one-eighth of an inch) clean margins should be the standard for women diagnosed with ductal carcinoma in situ (DCIS) treated with lumpectomy and whole-breast radiation
    • The guideline was published online on Aug. 15, 2016 by the:
      • Journal of Clinical Oncology. Read “Society of Surgical Oncology–American Society for Radiation Oncology–American Society of Clinical Oncology Consensus Guideline on Margins in Breast Conserving Surgery with Whole Breast Irradiation in Patients with DCIS
    • In 2015 a multidisciplinary panel was convened by the American Society of Clinical Oncology, the American Society for Radiation Oncology, and the Society of Surgical Oncology to review a meta-analysis and other literature concerning margin width and ipsilateral breast tumor recurrence (IBTR) in patients with DCIS undergoing breast-conserving therapy (Morrow, 2016):
      • The meta-analysis included 20 studies with 7,883 patients and 865 IBTRs with a median follow-up of 78.3 months
      • The panel reported that positive margins:
        • Were associated with a twofold increased risk of IBTR compared with patients who had negative margins
      • They also reported that margins of at least 2 mm were associated with a lower risk of IBTR compared with narrower margins
      • Patients treated with wide local excision alone without radiation therapy:
        • Had substantially higher rates of IBTR compared with patients undergoing wide local excision and whole breast irradiation regardless of the margin width
      • Rates of IBTR and contralateral breast cancer:
        • Were reduced in patients who received tamoxifen, however:
          • There was no significant impact on IBTR in patients with negative margins when compared with patients receiving placebo
      • The panel concluded that a 2-mm margin was adequate in patients undergoing breast-conserving surgery and whole breast irradiation for DCIS:
        • Clinical judgment should be utilized in deciding on the need for reexcision in patients with margins less than 2 mm.
  • The 2016 guidelines of the National Comprehensive Cancer Network (NCCN) dictate that close (less than 1 mm) margins are inadequate for DCIS and should be reexcised:
    • But for patients in whom the border of disease is the fibroglandular boundary (i.e., chest wall) or skin:
      • Radiation with a boost to the surgical scar is an acceptable alternative to reexcision

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