Omitting Radiation Therapy in Ductal Carcinoma In Situ

  • A survey (Jagsi, 2010):
    • Demonstrated that 95% of women with breast cancer and strong indications for post-lumpectomy radiation:
      • Went on to receive it:
        • But rates of post-lumpectomy radiation therapy use have been shown to vary:
          • Depending on the region of the country that the patient lives in
          • The age of the patient
          • The disease being treated (DCIS vs Invasive Disease)
  • Among patients who undergo BCT for DCIS:
    • Only 50% are estimated to receive adjuvant radiation
  • Many patients choose mastectomy over breast-conserving surgery for DCIS:
    • Because they are not able or willing to complete 6 weeks of daily radiation therapy:
      • Secondary to social or health considerations
  • Other patients who are candidates for breast-conserving surgery:
    • Choose to undergo a mastectomy:
      • Because of concerns about postradiation complications
  • Breast-conserving surgery alone (i.e., without radiation therapy):
    • May be sufficient in a select subgroup of patients with DCIS
  • Initial data that supported the use of breast-conserving surgery alone in the treatment of DCIS came from a study by Lagios et al. (1989):
    • In which 79 patients with mammographically detected DCIS underwent margin-negative excision alone
    • After a follow-up time of 124 months:
      • The local recurrence rate was 16% overall, specifically:
        • 33% for the subgroup of patients with high-grade lesions and comedo necrosis versus only 2% for the patients with low- or intermediate-grade lesions
  • The USC / VNPI score can be a helpful tool in clinical decision making:
    • But even though margin width is an independent prognostic factor for recurrence using the USC / VNPI score:
      • It is unlikely that margin width alone can identify the patients with DCIS treated with breast conservation for whom radiation therapy can be safely omitted
  • In a retrospective analysis of 469 patients with DCIS who underwent breast conservation with margins that were at least 10 mm, Silverstein et al. (1999):
    • Did not detect a lower recurrence rate:
      • When postoperative radiation therapy was employed
  • In contrast, even on reanalysis of the NSABP B-17 data:
    • All patient cohorts benefited from radiation therapy:
      • Regardless of the clinical or mammographic tumor characteristics
  • Furthermore, Wong et al. (2003, 2014):
    • Reported the early termination of a prospective single-arm trial conducted at the Dana-Farber / Harvard Cancer Center:
      • In which radiation therapy was omitted in patients with grade 1 to 2 DCIS that was no more than 25 mm and excised with 10 mm or greater margins:
        • At a median follow-up of 3.3 years:
          • The number of local recurrences observed was 2.5% per patient-year:
            • Corresponding to a 5-year rate of 12.5%
  • In 2010, Rudloff and colleagues at Memorial Sloan Kettering Cancer Center:
    • Published a multivariable nomogram:
      • To estimate risk for local recurrence in women with DCIS treated with breast-conserving surgery
    • The nomogram incorporates commonly available factors that have previously been shown to affect risk of ipsilateral breast tumor recurrence, these include:
      • Age at diagnosis
      • Family history
      • Type of patient presentation:
        • Radiologic or clinical
      • Nuclear grade
      • Necrosis, margins
      • Number of excisions
      • Receipt of radiation and / or adjuvant endocrine therapy
    • The nomogram calculates an actual, individualized estimate of absolute risk of ipsilateral breast tumor recurrence at 5 or 10 years:
      • Which can be weighed against the use of available adjuvant treatment options
  • There are two large, prospective, observational studies:
    • Designed to investigate the role of observation versus radiation therapy after breast-conserving therapy in patients with DCIS
    • As mentioned earlier, Wong and colleagues at Harvard:
      • Conducted a single-arm, phase III observational study examining long-term outcomes in women with small (≤ 2.5 cm), low- and intermediate-grade DCIS who were treated with lumpectomy and margins ≥ 1 cm and did not receive adjuvant tamoxifen or radiation:
      • With a median follow-up of 11 years:
        • 13% (19 of 143) of patients experienced local recurrence:
          • Approximately two-third of which were DCIS
    • In the Eastern Cooperative Oncology Group–American College of Radiology Imaging Network (ECOG-ACRIN; formerly known as the Eastern Cooperative Oncology Group) Cancer Research Group E5194 study:
      • Patients with low- or intermediate-grade DCIS smaller than 25 mm (cohort 1), or high-grade DCIS smaller than 10 mm (cohort 2), with excisional margins of at least 3 mm, underwent breast-conserving surgery without radiation therapy:
        • 30% of patients received tamoxifen
      • At 12 years:
        • 14.4% of the participants in cohort 1 experienced an in-breast even while 24.6% of those in cohort 2 experienced an in-breast event (p = 0.0003), and this difference was driven by a statistically significant difference (p = 0.02) in noninvasive recurrence
        • In addition, membership in cohort 2 and larger tumor size were both found to be associated with increased likelihood of recurrence (Solin, 2015)
  • Finally, in patients over 70:
    • There is increasing evidence that radiation therapy:
      • Depending on the aggressiveness of the DCIS and the expected life expectancy of the patient:
        • Can be omitted on a case-by-case basis

#Arrangoiz #BreastSurgeon #CancerSurgeon #SurgicalOncology #Surgeon #Teacher #BreastCancer #BreastExpert #MSMC #MountSinaiMedicalCenter #Miami #Mexico #DCIS #DuctalCarcinomaInSitu #OmissionofRadiation

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