Partial Breast Re-irradiation for Breast Cancer

Breast cancer is the most common malignancy in women. Breast-conserving surgery (BCS) with adjuvant whole-breast irradiation (WBI) is currently the standard of care in the oncological treatment of primary breast cancer and offers an equivalent alternative to mastectomy. The primary aim of adjuvant radiotherapy (RT) is to improve local control and thus improve overall survival and breast cancer-specific mortality. However, nodal-negative women have a 10-year risk for local recurrences after RT in up to 15.6%. The management of ipsilateral breast cancer recurrence depends on the extent of tumor disease and staging results at the time of recurrence and mastectomy is currently the standard of care for previously irradiated patients. The application of particle therapy using proton beam therapy (PBT) represents an innovative radiotherapeutic technique for breast cancer patients. This trial will be conducted as a prospective single-arm phase II study in 20 patients with histologically proven invasive breast cancer recurrences with negative margins after repeat BCS and with an indication for local re-irradiation. Required time interval will be 1 year after previous RT to the ipsilateral breast. Patients will receive partial breast re-RT with proton beam therapy in 15 once daily fractions up to a total dose of 40.05 GyRBE. The primary endpoint is defined as the cumulative overall occurrence of acute / subacute skin toxicity grade ≥3 within 6 months after the start of re-RT.

Sex

Female

Minimum age

18 Years

Inclusion Criteria:

* histologically confirmed recurrent (or new primary) ipsilateral invasive breast cancer or DCIS after prior RT of the ipsilateral breast
* indication for re-irradiation after repeat breast conserving surgery (e.g. lumpectomy, wide excision, …)
* tumor size \< 3 cm
* clinically node-negative (cN0)
* negative resection margin (R0)
* time interval: start of re-RT to prior RT ≥ 12 months
* ECOG Performance status ≤ 2
* ability of subject to understand character and individual consequences of the clinical trial
* written informed consent
* ≥18 years of age

Exclusion Criteria:

* distant metastases

  * concomitant chemotherapy (concomitant endocrine hormonal therapy is allowed; sequential chemotherapy is allowed)
  * patients who have not recovered from acute toxicities of prior therapies
  * known carcinoma \< 5 years ago (excluding Carcinoma in situ of the cervix, basal cell carcinoma, squamous cell carcinoma of the skin) requiring immediate treatment interfering with study therapy
  * pregnant or lactating women
  * participation in another competing clinical study or observation period of competing trials
  * history of active connective tissue disorder (i.e. systemic lupus erythematosus, scleroderma, dermatomyositis, xeroderma pigmentosum, …)
  * medical implants, which are at the time of reirradiation not eligible for particle therapy at Heidelberg Ion Beam Therapy Center