Results of conservative surgery and radiation for mammographically detected ductal carcinoma in situ (DCIS)

Purpose: The role of conservative surgery and radiation for mammographically detected DCIS is controversial. In particular, there is a paucity of data for outcome with radiation in a group of patients comparable to those treated with local excision and surveillance (mammographically detected DCIS ≤2.5 cm, negative resection margins, negative post-biopsy mammogram). The purpose of this study is to report long term outcome of conservative surgery and radiation for mammographically detected DCIS with emphasis on the results in patients (pts.) considered candidates for excision alone. Materials and Methods: From 1983 to 1992, 110 women with mammographically detected DCIS (calcifications 72%, mass ± calcifications 27%) and no prior history of breast cancer underwent needle localization biopsy followed by radiation. The median age of the patient population was 56 yrs. (range 37-81). The median followup was 5.3 yrs. (range .5-12). Re-excision was performed in 55%. Final margins of resection were negative in 62%, positive 7%, close 11%, and unknown 20%. Axillary dissection was performed in 31 pts. and all had negative nodes. 31% had a positive family history of breast cancer (1 affected relative-25 pts., two-7 pts., three-2 pts.). The most common predominant histologic subtype was comedo (54%) followed by cribriform (22%). The median pathologic tumor size was 8 mm (range 2 mm to 5 cm). A post-biopsy mammogram prior to radiation was performed in 46% of the patients. Radiation consisted of treatment to the entire breast (median 5000 cGy) with a boost to the primary site (97%) of an additional 1000 cGy. The median total dose to the primary site was 6040 cGy (range 5000 to 6660). Results: Three patients developed a recurrence in the treated breast at 52, 106, and 107 months. All 3 recurrences were invasive ductal cancers and all were treated with mastectomy. The location of the recurrence was in the same quadrant as the primary in 1 pt. and in a separate quadrant in 2 pts. The 5 and 10 yr. actuarial rates of breast recurrence were 1% and 15% respectively. The 5 and 10 yr. overall survival were 96% and 94%. The cause-specific survival was 100% at 5 and 10 yrs. Two patients subsequently developed a contralateral invasive breast cancer. There was no significant correlation between the risk of a breast recurrence and race, the location of the primary, patient age, mammographic finding, the histologic subtype, pathologic tumor size, or a positive family history. One of 34 pts. (3%) with a positive family history (single affected relative) developed an invasive recurrence in a separate quadrant compared to (2(72)) (3%) pts. with a negative family history (one separate quadrant, one same quadrant). Patients with a positive margin had a higher risk of breast recurrence (12%) when compared to those with negative margins (1.5%). 29 pts. had negative resection margins and a negative post-biopsy mammogram (52% comedo histologic subtype). None of these patients has developed a breast recurrence. There were only 16 pts. who met all of the criteria for surveillance (path size ≤2.5 cm, negative resection margins, negative post-biopsy mammogram) and none of these has recurred (44% comedo). Considering all patients with negative margins, 1 of 68 developed an ipsilateral invasive cancer at 8.8 yrs. 6% of the patients who did not have a post-biopsy mammogram prior to radiation experienced a breast recurrence. Conclusion: Conservative surgery and radiation for mammographically detected DCIS results in a low risk of recurrence in the treated breast and a 100% cause-specific survival at 5 and 10 yrs. A positive family history of breast cancer was not associated with an increased risk of breast recurrence. In the subgroup of patients considered candidates for surveillance, there have been no breast recurrences. Negative margins of resection and a negative post-biopsy mammogram are important to decrease the risk of a breast recurrence. Long term follow-up is essential as late failures tend to predominate in patients with adequate surgical resection followed by radiation