Non-invasive cancers of the breast include DCIS, Paget's Disease and LCIS. For LCIS appears to be a marker for increased risk of developing multicentric distributions and bilateral involvement. Most diagnosis is pre-menopausal at an average age of 45, and is often seen as an incidental finding after biopsy due to changes in a screenng mammogram. LCIS is considered more of a marker for subsequent development of invasive breast cancers in either the index breast or the contralateral breast. Most of these cancers will be invastive ductal cancers. LCIS has not been seen in men. LCIS is commonly managed conservatively with increased surveillance.
Paget's disease is manifest in crusting and eczematous skin changes of the breast nipple-areolar complex. Paget's disease is rare, and is associated with an underlying malignancy the vast majority of the time. There is thought that Paget's originates from underlying in situ or invasive malignancy. It appears in those aged 40-60, and does appear in males. Bilateral cases have also been reported. The clinical manifestations are:
Breast conserving sugery is becoming increasingly the norm in the treatment of Paget's Disease. Small series have looked at various treatment methodologies, including surgery alone, radiation alone, wide local excision ⇒ radiation. Conservative surgery has local recurrence rates of 25% —40%. Radiotherapy alone has been reported to achieve an 85% local control (which is about a 15% recurrence rate, better than surgery alone, but not widely adopted). Combined limited surgery and radiation is the most common approach in breast conserving treatment.
EORTC 10873 was a multi-institutional trial which reported a 5 year local recurrence rate of 5.2% with complete excision, negative margins and whole breast radiation therapy. Median followup was 6+ years and the majority had underlying DCIS without a palpable mass. A second study was a retrospective review of collaborative review of 36 patients. This study found final margins negative in 56%, positive in 6%, unknown in 39%. All received post-operative radiation therapy to the whole breast and most received a boost to the resection cavity. The actuarial local failure rate as only site of first recurrence was 9% at 5 years, 13% at both 10 and 15 years. Two patients recurred in the treated breast and with regional and distant metastases at 69 and 122 months. There were no factors that were significant predictors for the risk of local recurrences.
Current data suggests a combined-modality therapy with breast conservation is an appropriate intervention in well selected patients with a known underlying localized non-invasive or invasive cancer.