Treatment of Paget disease, a type of breast cancer, with breast conservation therapy is shown to achieve excellent long-term prognosis while preserving existing healthy breast tissue according to findings in a recent study published in the journal Cancer.

In the longest follow-up of any prior study, the authors demonstrated that 10 to 15 years after treatment of the Paget disease of the breast with local excision of the tumor and radiation therapy to the rest of the breast, patients had only small rates of cancer recurrence and excellent rates of survival.

The authors conclude that breast conservation therapy "is an appropriate alternative to mastectomy in women with Paget disease of the breast presenting without evidence of a palpable mass or mammographic density."

Paget disease of the breast is a rare form of breast cancer representing only 3% of breast cancers. While its cause is unknown, scientists hypothesize that 1) cancer cells called Paget cells disperse from a primary tumor in the milk ducts of the breast and seed the nipple; or 2) cells of the nipple become malignant Paget cells. Symptoms generally begin as rash near the nipple or with discharge from the nipple. Very often, Paget disease is associated with ductal carcinoma in situ (DCIS). A coexistent invasive cancer of the breast indicates a poor prognosis.

Traditionally, treatment for Paget disease of the breast and other breast cancers has been a mastectomy with or without chemotherapy. Mastectomy, however, is associated with significant morbidity and is not a 100% cure. With the success of breast conservation surgery (BCS) in other breast cancers, its application to Paget disease of the breast has also been explored.

Local excision alone has been evaluated and shown to have unacceptably high recurrence rates. However, BCS in conjunction with post-surgical radiotherapy (RT) has shown promise for curing patients with either Paget disease or DCIS but has not been sufficiently evaluated. The authors of this study previously reported excellent rates of local disease control and survival at five years. In this study the authors report the results after 10- and 15-years of follow-up.

Because Paget disease is rare, the authors reviewed data from seven institutions, which included 36 cases of Paget disease of the breast without the presence of a palpable or mammographically identified mass that were treated with BCS and RT. These patients were followed up to 257 months.

Survival was 90% or greater after 15 years. Rates for survival without disease were 97% at five, 10 and 15 years. Overall survival was 93% at five years and 90% at 10 and 15 years.

BCS and RT therapy also effectively prevented the local recurrence of cancer in most patients. The local control rate, measuring the lack of recurrence of disease, was 91% at five years and 87% at 10 and 15 years.

The authors conclude: "This study demonstrates excellent rates of local control, cause-specific survival, and overall survival at 10 and 15 years."

SOURCE:
Cancer, May 1, 2003