The eligibility of treating early cancer breast by US-guided radiofrequency ablation in Egyptian females

Document Type : Original Article

Authors

1 Department of Surgery, Alexandria University, Alexandria, Egypt.

2 Department of Pathology, Alexandria University, Alexandria, Egypt.

3 Department of Radio-diagnosis, Alexandria University, Alexandria, Egypt.

Abstract

Introduction: This study was designed to determine the safety and efficacy of using percutaneous ultrasound-guided radiofrequency ablation  of early breast  carcinoma  in Egyptian  females.
Patients: Thirteen patients were included in the study to be treated just before scheduled mastectomy or breast conserving surgery.
Method: All patients were contraindicated  or refused to do breast conservative surgery. A needle-shaped treatment electrode, with umbrella spreading end, was placed into the center of the lesions using ultrasound  guidance. A temperature of 85°C was maintained for 10 min. All resected specimens were processed & examined histopathologically using conventional methods searching for viable tumor cells.
Results:  In 11 patients (84.6%), a complete ablation of the tumor was achieved. No extensive para-tumoural necrosis was detected in any case.
Conclusion: Ultrasound-guided radiofrequency ablation of breast carcinoma is feasible and safe. The success rate depends  on accurate  preoperative diagnostic  imaging as well as the exact position of the needle electrode.

Keywords


 

The eligibility of treating early cancer  breast by US-guided radiofrequency ablation in Egyptian females

 

Galal M M Abou El-Nagah,a MD; Saba M El-Gendy,b MD;

Ahmed M El-Gendy,a MD; Mohamed El-8hafei,c MD

 

 

a) Department of Surgery, Alexandria University, Alexandria, Egypt.

b) Department of Pathology, Alexandria University, Alexandria, Egypt.

c) Department of Radio-diagnosis, Alexandria University, Alexandria, Egypt.

 

 

 

Abstract

Introduction: This study was designed to determine the safety and efficacy of using percutaneous ultrasound-guided radiofrequency ablation  of early breast  carcinoma  in Egyptian  females.

Patients: Thirteen patients were included in the study to be treated just before scheduled mastectomy or breast conserving surgery.

Method: All patients were contraindicated  or refused to do breast conservative surgery. A needle-shaped treatment electrode, with umbrella spreading end, was placed into the center of the lesions using ultrasound  guidance. A temperature of 85°C was maintained for 10 min. All resected specimens were processed & examined histopathologically using conventional methods searching for viable tumor cells.

Results:  In 11 patients (84.6%), a complete ablation of the tumor was achieved. No extensive para-tumoural necrosis was detected in any case.

Conclusion: Ultrasound-guided radiofrequency ablation of breast carcinoma is feasible and safe. The success rate depends  on accurate  preoperative diagnostic  imaging as well as the exact position of the needle electrode.

Key words: Radiofrequency ablation, pathological examination, cancer breast.

 

 

 

 

 

 

Introduction:

Breast  cancer  accounts  for 25% of all

cancers in women worldwide. The percentage reaches near one third of allcarcinoma affecting Egyptian females. Although, incidence has been rising steadily over the last decades,l-2 the mortality rate has remained virtually unchanged.3 Today  cancer   treatment is multidisciplinary  and there is an important general trend towards more  selective interventions to minimize toxicity and late side effects without compromising efficacy. For example; sentinel node biopsy technique has, in many cases, replaced axillary lymph node clearance. Breast-conserving  surgery in the form of wide local excision followed by breast irradiation is the appropriate therapy for early breast cancer, provided that the margins of resected  specimens  are  free  and that  the


excision can be performed with reasonable cosmetic result. Mastectomy is preferred in cases of extensive DCIS or large-sized cancer. Breast-conserving treatment has shown equivalent survival rates when compared to total mastectomy in large randomized studies.4-5

During the past years several new methods for treatment of cancer breast have  been investigated. These  include  cryosurgery, stereotactic excision, laser ablation, focused ultrasound  and radiofrequency ablation.6-7

The main concerns and the remaining unsettled issues of these less invasive modalities of the treatment are the uncertainty of the extent (margin) of the lesion treated effectively and the viability of the tumor cells left potentially in the residual tissue afterward.8

Radiofrequency ablation is considered to be the  most  promising  method  due to its

 

 

 

constantly high success and low complication rates.9  This is based on numerous feasibility studies showing complete ablation rates of 80-

100%.10-17 Furthermore an intrinsic property

of  this  technique results in  a preferential destruction of tumor  cells  with  sparing  of adjacent mammary tissue.18  Considerable experience with this technique has already been  acquired since it was previously demonstrated to effectively treat unresectable liver metastasis.21 Furthermore, it has been shown in studies on small patient series that RFA can be performed in an outpatient setting under   local  anesthesia or  blockade.20-21

Because of  utilization of  the intensive screening mammography, women's awareness of  the  disease, and  our  cosmesis-minded females, finding the small early breast cancer has become more of a reality than ever before. Therefore, these less  invasive ablative procedures may have a chance to become a "standard procedure" for the local therapy of the  early  breast cancer if the  oncological efficacy and safety is well established. Although radiofrequency ablation is an attractive approach as a local control method for small breast  cancer,  the problems of histological effectiveness and safety management remain.

The purpose of this study was to determine the  efficacy and safety of percutaneous ultrasound-guided radiofrequency ablation (PRFA) of  unifocal breast  cancers with  a radiological diameter of  up  to  30 mm.

 

Patients:

Thirteen patients aged between 37 and 69 years with tumor sizes of 16-30 mm where selected to  receive PRFA treatment immediately before undergoing modified radical mastectomy or  breast conserving surgery.

The current study was done  between November 2010 to May 2011.  The main inclusion criteria were presence of a unifocal tumor clearly distinguishable under US with a diameter  of less than 30mm. None of the patients underwent preoperative chemo-or radiotherapy.

This  study  was  approved by the  Ethics Committee of Alexandria Faculty of Medicine, Egypt.  If the patient  fulfilled the inclusion


criteria and  was  scheduled for  radical mastectomy or  breast  conserving surgery, detailed information about the study was given and in case the patient agreed to participate a written informed consent was  obtained.

A histopathological analysis of the tumor

by core tissue biopsy was performed prior to surgery  since  the expected outcome  of the study procedure was a destruction of the entire tumor. Histopathological examintion included: tumor type, grade, estrogen receptor, progesterone receptor and Her2.

 

Method:

Ultrasound was used  to identify tumor, needle introduction and to monitor treatment. The US instrument  used was a Philips iU22 with a L5-17 linear broadband transducer (17-

5 MHz  frequency range). The  specially

designed RF-generator incorporated insulated cardiac-floating and low-impedance output subsystems. The electrodes used were of two different sizes. For  the  temperature measurement an integrated thermocouple, a specially designed low-pass filter and low level amplifier were used. The ablation procedures were  performed by single experienced radiologists. In all cases, general  anesthesia was induced and chest electrodes were attached to the back of the patient.  The lesions were identified with ultrasound. Depending on the size of the tumor, a suitable needle electrode was selected  and introduced into the lesion through  a small  incision under  ultrasound guidance Figure(l). With the goal to place the electrode inthe center of the lesion, US images were taken in  different projections. Thermoablation was then initiated by passing a successively  regulated current between the needle electrode and  the dispersive pad electrode. Tissue temperature was maintained at 70-85°C for 10 min. Electrical impedance was  monitored to improve thermal lesion control.

In order to protect  the patient  from burn

effects to skin and underlying muscle special measures were taken. Inten cases several boli oflocal anesthesia (mepivacaine) with a nearly isotonic conductivity were injected to increase the distance between the tumor and the skin or pectoral muscle respectively to at least 1 em.

 

 

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Table (1): Demographics and diagnostic findings prior to treatment (n 13).

 

Patient Age (years)

Menstrual status

Location of tumor

Age

53.2±7.8

Premenopausal

2

(16%)

Left breast

5

(32%)

Range

36-69

Perimenopausal

1

(7%)

Right breast

8

(68%)

 

 

Postmenopausal

10

(77%)

 

 

 

 

Table (2): Comparison of assessed tumor sizes using mammography and US.

 

Mammo. tumor size [mm]

US tumor size [mm]

Size

22±2.1

Size

24±1.6

Range

17-30

Range

16-30

 

Table (3): Patholgicalfindings of the tumors.

 

Histology

Grade

Ductal

11

(86%)

I

3

(20%)

Lobular

1

(7%)

II

8

(67%)

Tubular

1

(7%)

III

2

(13%)

 

Table (4): Clinical data of  patients and their management

 

No.

Age

Axillary Lymph nodes

T. size Clin. [mm]

T.size us [mm]

RF Time [min]

Degree of ablation

Comments

1

36

No

10

8.5

10

yes

 

2

52

No

9

9

9

yes

 

3

69

No

10

7

10

yes

 

4

46

No

n/a

10

7

yes

Treatment halted prematurely

because of proximity to muscle

5

57

No

12

14

10

yes

 

6

54

No

10

13

11

yes

Intraoperative detection and

treatment of tumor extension

7

59

yes

12

8

10

no

Tumor extent larger than radiologically diagnosedbifocal

with an extra lesion of 11 mm

8

56

No

10

10

7

no

Treatment halted prematurely

because of significant swelling

9

57

yes

10

14

7

yes

Treatment time reduced due to

location of the tumor

10

61

No

15

15

7

yes

Treatment time reduced due to

location of the tumor

11

67

No

15

15

11

yes

 

12

54

No

14

14

10

yes

 

13

58

No

13

13

10

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additional effects other than the difference in tissue  parameters  might be   involved.

During the last decade, several studies have been performed using different study designs9-16 combining  immediate, delayed or excluding surgery as well as applying different treatment electrodes and patient inclusion criteria Success rates  were  generally high with  only minor complications and  excellent cosmetics. Incomplete tumor ablation was often explained by improper insertion of the needle electrode, too short  distance  to skin/pectoralis and an underestimation of tumor extent preoperatively.

It has been stated that to correctly  assess the effects ofradiofrequency ablation, NADH­ diaphorase is more suited, since H&E often underestimates the lesion  size. Judging  that measurement of radicality and lesion size were of  primary  importance to the  study  which demands immediate fixation and  inking excluding enzymatic stain as well as following hospital protocols we decided to use classical morphology with H&E staining. Due to the short time interval between PRFA and surgery, the zone of ablation in this study is probably underestimated as there was no time for the injured tissue  to  develop the  spectrum of degenerative changes  seen  in longer  time intervals. The therapy response was therefore graded in either necrotic or non-necrotic. The observed borderline between viable and regressive areas furthermore had a magnitude of millimeters  and there is no adverse effect for the study with regards for this possible underestimation of the size of the ablation. The SEM findings indicate an even more abrupt transitional zone.

Lobular cancer was  not  an exclusion criterium in  this  study. Two  cases  were accepted due to the fact that one important circumstance  in this study situation was that all primary cancers were to be subsequently removed by surgical excision. In agreement with other authors, we find that lobular cancers have properties that are unfavorable for PRFA treatment.

Our study confirmed the need for a safety distance  between  the tumor  and the skin by using active cooling or by infusion of a bolus volume such as mepivacaine to increase  the distance and   maintain similar electric


impedance. However, there are limitations of the possibility to manipulate tumor location in this way. We observed that injected liquid volumes diffuse into the surrounding fat tissue. This could be visualized as the procedure was followed by US. In addition, we used traction sutures to manually increase the  distance between lesion and thoracic wall and skin respectively.

This study also confirmed that one drawback for this method is the difficulty to deploy the needle in a suitable position in the center of the tumor. A possible way to tackle this is to use 3D ultrasound to determine  the position of the needle electrode as was previously shown to be effective for hepatic malignancies.25 A further idea to facilitate the insertion especially when dealing with hard tumors, is to add a mechanical vibration. A longitudinal sinusoidal movement of the needle would significantly reduce  friction  and thus decrease insertion force.

The other main drawback of this method is the  inability to  validate ablation margins without surgical resection as  well  as  the pretreatment detection of extensive intraductal components. This problem could be reduced by including MR.I into the treatment protocol.

 

Conclusion:

The outcome  of our  study  confirms the potential of PRFA for the treatment of small breast cancer in Egyptian females. It offers a high  success rate, a low  rate  of minor complications as well  as good  cosmetics. Compared to current treatment protocols, this method is far less traumatic, making it possible to provide local tumor control for previously untreatable patients in  weak  and  unstable condition. Several publications report PRFA treatments performed in an outpatient setting under local anesthesia. By treating breast cancer in  an  outpatient setting, the  need  for  an operating room  setup  is  avoided, thereby possibly creating economic advantages. Another aspect of this technique is the potential as an adjuvant measure to invasive surgery. PRFA treatment could be performed immediately following pretreatment diagnosis, thus  halting  further tumor  progression. Of course,  local  hospital protocols have  to be

 

 

 

taken into consideration.Inconclusion, PRFA promises  to be a safe, feasible  and patient­ friendly  method  of treating small  unifocal breast  adenocarcinoma. If  our  results are conflrmed by larger clinical trials in future, then PRFA would eliminate open surgery and decrease the  morbidity associated with lumpectomy and radiation.

 

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