1)Pre operative diagnosis of breast cancer

Needle biopsies have become an increasingly important tool in the management of breast cancers. A preoperative diagnosis of malignancy allows the surgeon to offer the patient the appropriate surgical procedure and to aim for a single definitive surgery.

Once a malignant result has been established, a complete pre operative imaging workup can be done so that the extent of disease is assessed -

• Is the lesion small enough for lumpectomy or does it require mastectomy? Are there additional lesions that require evaluation prior to surgery?
• Is there invasive disease requiring axillary clearance or
• Is it carcinoma in situ?

2) Types of needle biopsy – who performs the biopsy?

Freehand needle biopsies

This is done by the surgeon in outpatient clinic under local anesthesia when the patient first presents with a lump. In a “freehand” biopsy the surgeon is guided by his clinical examinaion.

One possible situation with “freehand” needle biopsy is that malignant lesions are often very much smaller than the palpable lump. This is because many breast malignancies incite a scirrhous reaction around the main tumour. A freehand biopsy may therefore only obtain the fibrous component and miss the tumour.

In many cases, image guided needle biopsy is preferred. This is usually performed by radiologists. The advantages of an image guided procedure are that the center of the lesion can be targeted, hardcopy evidence of the needle traversing the lesion is obtained, non palpable lesions can be biopsied, and if necessary, a clip can be left at the biopsy site to mark it should future intervention be necessary.

Image guided biopsies

These procedures take place in the Radiology Department on an outpatient basis under local anesthesia.

i) Ultrasound guided biopsies

The main indication is usually for a solid or complex cystic mass. The patient lies supine, the lesion is localized by ultrasound and a small amount of local anesthetic is infiltrated. Using a biopsy gun, a 14G needle is fired through the lesion. Usually 4-6 samples are obtained which are sent for histological examination. The patient is allowed home after a short period of observation. The whole procedure often can be completed in 1/2 an hour.

FIG 1a Ultrasound guided biopsy of a suspicious mass – the needle is placed just proximal to the nodule

FIG 1b The needle is fired through the nodule

ii) Mammographic guided biopsies

These are usually performed for calcifications that are not seen by ultrasound. Biopsy attachments in many hospitals in Singapore are upright similar to a regular mammography unit. At NCC, our unit is attached to a prone table. The patient lies facing downwards and the breast is placed through a hole in the table.

FIG 2

FIG 3 After targeting the calcifications, the biopsy needle is inserted through a small skin nick and digital images are obtained to check the position before sampling.

FIG 4 Following completion, a metallic clip (arrow) is inserted as the calcifications are often excised completely.

FIG 5 A specimen radiograph confirms the presence of calcifications in the samples obtained.

Mammgraphic guided biopsies take slightly longer than ultrasound guided biopsies due to the time in positioning and priming the equipment. The entire procedure usually takes approximately 1-2hours though the sampling time is about 5-10 minutes.

3) Excision biopsies

Excision biopsies refer to open or surgical biopsies where the surgeons are the operators. These take place in an operating theatre and are usually performed under general anesthesia. If the lesion is non palpable, the surgeon will require image guided localization where a hookwire is inserted into the lesion before surgery.

The indications for performing excision biopsy following needle biopsy would include a diagnosis of atypical histology where the pathologist requires a larger volume of tissue to exclude malignancy. For biopsy proven malignancy where the lesion is non palpable and the patient chooses breast conservation rather than mastectomy, surgical excision is preceded by hookwire localization by the radiologist. In both cases (mammographic or ultrasound) specimen radiographs will be taken to confirm that the target lesion has been removed at surgery.

i) Ultrasound guided hookwire localization

If the original lesion was a nodule that is not palpable, then the radiologist will insert a hookwire through the lesion under ultrasound guidance prior to surgical excision.

ii) Mammographic hookwire localization

Patients who undergo needle biopsy for calcifications with atypical histology require surgical excision. A proportion of these patients will be “upstaged” to cancer – usually ductal carcinoma in situ. These patients will either have residual calcifications after the needle biopsy or if there are no residual calcifications, a clip will have been inserted at the time of needle biopsy.

FIG 6 Mammographic hookwire localisation showing the hook is adjacent to the clip.

FIG 7 A specimen radiograph confirms the clip has been successfully removed.

In summary, image guided needle biopsies are simple and minimally invasive procedures. In using a multidisciplinary approach between radiologists, pathologists and surgeons, we aim to optimize the type of oncologic surgery for each patient. If a needle biopsy result is benign, open excision biopsy can be avoided. If a malignant result is obtained, the surgeon can assess whether the patient is a suitable candidate for conservation surgery and whether axillary clearance is necessary.

 

Jill Wong
Oncologic Imaging
Senior Consultant
National Cancer Centre