Partial Breast Re-irradiation for Breast Cancer

The therapeutic challenge in re-irradiation involves finding a balance between tumor control and the risk of severe toxicity from cumulative radiation doses in previously irradiated organs. Re-RT options include the use of brachytherapy (BT) ], intraoperative radiotherapy (IORT) or external beam RT with photons or electrons. Depending on the time interval since previous RT and applied technique, high-grade (≥3) toxicity rates for re-RT range from about 9% acute skin to 12 % - 17 % late fibrosis and 1% - 10 % G4 toxicity for BT, late grade 3 fibrosis of 21% for IORT and grade 3 toxicity (skin, esophagitis, wound dehiscence) of 7 - 24% - 35% for EBRT including late breast volume asymmetry in 12%, acute and late grade 4 ulceration (1-2%) and even grade 5 (treatment related deaths) in 1.2%.

The dosimetric profile of PBT with the Bragg Peak offers advantageous physical properties and has proven to be superior to photon-based techniques in respect of dose reduction to adjacent organs-at-risk (OAR) and effective target volume coverage with lower integral doses to the patient's whole body. In addition, this technique could potentially offer higher radiobiological effects and tumor responses [28], which is particularly advantageous in potentially more therapeutically resistant disease biology in breast cancer recurrences. Overall, prospective experience related to re-RT of the ipsilateral breast after recurrences is limited and most commonly involves the technique of invasive multicatheter brachytherapy.

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