Intraoperative radiotherapy (IORT) for breast cancer and diagnostic management: a case report

Clinical History

A 62-year-old woman presented to our institution to perform her annual screening mammography (Fig.1). BI-RADS R0 result, due to dense pattern, required further examination.

Imaging Findings

US showed a nodular finding (55mm) in the right breast supero-intern quadrant (E4). We performed a US-guided cytological sampling and a MR to exclude multifocality. Cytological diagnosis of invasive ductal carcinoma oriented iter towards surgery. MR showed a c.e. nodular finding in right breast supero-intern quadrant consistent with the previous finding (Fig.2-3). Furthermore an area of c.e. at the confluence of left breast upper quadrants (Fig.3), undetectable at US, was seen: we planned a MR evolutive control after 6 months. The surgeon chose a tumorectomy in the right breast, dissection of axillary lymphnodes, intra-operatory radiotherapy (IORT) followed by external radiotherapy. Histology revealed an invasive ductal carcinoma. 6 months later the patient underwent follow-up MR: an area of c.e. (20mm) on place of previous surgery was detected (Fig.4): “second look” US showed a nodular finding (Fig.5) of which histologic diagnosis must be performed. Histology revealed absence of neoplastic lesions (Fig.6).

Discussion

During the last years, remarkable progress in breast cancer therapy has been made. A careful sensitisation of women together with the diffusion of screening campaigns allowed an increasingly early diagnosis and the detection of smaller lesions. These facts led to the introduction of more conservative surgical approaches, integrated with post-operative radiotherapy. Nowadays, association of conservative surgery and radiotherapy represents the standard treatment option in early breast cancer. Preoperative MR is essential to exclude tumour multicentricity or multifocality. Standard irradiation usually takes several weeks and requires numerous accesses: this extensive radiotherapeutic involvement led to several attempts to reduce treatment timetables, preserving parallel results in terms of disease control and cosmesis. Different techniques have been developed, such as IORT: it consists in the association of radiotherapy and surgery, by administration of a radiation dose directly to the tumour (in order to eliminate the visualised tissue which is not surgically removable) or, after surgical excision, directly on the tumour bed (in order to reduce the risk of microscopic infiltration) [1-4].
IORT may be performed as exclusive therapy and constitute the only irradiation modality after conservative surgery: this technique is reserved to patients with radically excised tumours and patients with histological features confirming a low risk of whole-breast involvement; it allows the administration of a dose equivalent to the entire standard treatment in only one session, during surgery. Another option consists in intra-operatory delivering of a smaller dose, as a “boost”, after tumour removal, followed by external radiotherapy on the whole breast. The second part of the radiant treatment takes place when the surgical wound has recovered and it requires a few weeks. IORT showed several advantages: easy identification of tumour bed and prompt irradiation of well-irrorated tissues; shield of adjacent normal tissues; abatement of waiting time between surgery and radiotherapy; elimination of external radiotherapy; reduction of the number of patient’s accesses to the centre. At disadvantage of IORT there are the middle-long term effects on radiological images reading, in particular the localised alterations such as liponecrosis, seromas, haematomas and parenchymal alterations [5, 6].
After subsequent radiotherapy, oedema and skin thickening may occur. All these lesions can be detected in the follow-up program patients undergo after surgery: mammography after 6-12 months can be performed and complementary US may be necessary [7, 8]. These alterations deserve appropriate monitoring and represent a challenge for the radiologist, who has to differentiate a disease relapse from a post-radiotherapy finding.

Differential Diagnosis List

Final Diagnosis

Post-radiotherapy fibrosclerosis

URL:	https://www.eurorad.org/case/9871
DOI:	10.1594/EURORAD/CASE.9871
ISSN:	1563-4086