Brachytherapy Catheter Insertion for Breast Cancer

DEFINITION

Breast conservation therapy (BCT) requires postlumpectomy radiation.
Radiation can be given to the entire breast as whole breast irradiation (WBI) or to the area at the highest risk of recurrence—the breast tissue surrounding the lumpectomy cavity—by accelerated partial breast irradiation (APBI).
APBI can be delivered from an external source (3-D conformal) or an internal source (brachytherapy).

DIFFERENTIAL DIAGNOSIS

Brachytherapy can be delivered via multiple inserted catheters (interstitial multicatheter; FIG 1) or via a single insertion/multiple catheter device (FIGS 2, 3, 4) (see videos 1 and 2 in the accompanying eBook).

FIG 1 • Multiple catheter interstitial brachytherapy.

FIG 2 • Strut-adjusted volume implant (SAVI)—single insertion multicatheter strut-based device. ©Cianna Medical, Inc.

FIG 3 • MammoSite ML—single insertion multicatheter balloon device.

FIG 4 • Contura—single insertion multicatheter balloon device.
Radiation oncologists usually perform the multiple catheter insertions and surgeons insert the single insertion/multiple catheter devices (which is the focus of this chapter).

PATIENT HISTORY AND PHYSICAL FINDINGS

Patient selection for APBI is critically important (not everyone is a candidate).
The American Society of Breast Surgeons¹ and the American Brachytherapy Society² have published guidelines for patient selection (Table 1).
The American Society of Radiation Oncology (ASTRO) has published a consensus statement on patient selection for APBI (Table 2).³

IMAGING AND OTHER DIAGNOSTIC STUDIES

Controversy exists whether all patients undergoing APBI should get preoperative advanced breast imaging (magnetic resonance imaging [MRI] or positron emission mammography); however, most surgeons only do so selectively.
Ultrasound skills by the surgeon are helpful for insertion but are not mandatory.

Table 1: Patient Selection Guidelines for Accelerated Partial Breast Irradiation

Criteria	American Brachytherapy Society	American Society of Breast Surgeons
Age	≥50	≥45
Histology	IDC	IDC, DCIS
Tumor size	≤3 cm	≤3 cm
Node status	N0	N0
Margins	Negative	Negative
IDC, invasive ductal carcinoma; DCIS, ductal carcinoma in situ.

SURGICAL MANAGEMENT

Brachytherapy devices are routinely placed in the surgeon’s office.
Cavity evaluation devices (CEDs) (FIG 5) can be inserted at the time of the lumpectomy as a “space holder” until exchanged in the office for the brachytherapy device.

Preoperative Planning

Preoperative consultation with the radiation oncologist will be helpful in facilitating postoperative treatment scheduling.
Postlumpectomy placement in the office begins with the preoperative plan for the lumpectomy including
- Location of incisions (do not perform sentinel lymph node biopsy through the lumpectomy incision)
- Use of oncoplastic techniques (minimal flap rearrangement is okay but major flap movement with obliteration of the lumpectomy cavity negates the use of APBI)
- Thicker wound closure if possible (more tissue between skin and cavity may require skin resection and multilayer closure)

Table 2: American Society of Radiation Oncology Consensus Statement on Patient Selection for Accelerated Partial Breast Irradiation

	“Suitable”	“Cautionary”	“Unsuitable”
Definition	Off clinical trial	Limited clinical data	Only on trial
Age	≥60 y	50-59 y	<50 y
T size	≤2 cm	2-3 cm	>3 cm
Nodes	Neg	—	Pos
Histology	IDC	ILC or DCIS	—
Margins	Neg (>2 mm)	Close (<2 mm)	Pos
Path features	No EIC or LVI	EIC or focal LVI	>3 cm EIC/DCIS
Grade	Any	—	—
Multicentricity	Unifocal	—	—
ER status	Pos	Neg	—
IDC, invasive ductal carcinoma; ILC, invasive lobular carcinoma; DCIS, ductal carcinoma in situ; EIC, extensive intraductal component; LVI, lymphovascular invasion; ER, estrogen receptor.

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