Abstracts / The Breast 22 S3 (2013) S19–S63 S37

Clinical Issues: Radiation Oncology

PR51

PATTERNS OF FAILURE IN BREAST CANCER PATIENTS TREATED WITH MASTECTOMY WITHOUT RADIOTHERAPY

Tahir Mehmood, Muhammad Ali, Uzma Masood, Mazhar Ali Shah,

Shahid Hameed, Arif Jamshed

Shaukat Khanum Memorial Cancer Hospital and Research Centre, Lahore,

Pakistan

Introduction: Pakistan has the highest rate of breast cancer for any

South Asian population and majority of the patients present with locally

advanced or metastatic disease. We report on patterns of failure and

survival in breast cancer patients treated with mastectomy and adjuvant

chemotherapy/hormonal therapy and without post mastectomy

radiotherapy (PMRT).

Materials and Methods: Between 1995 to 2009, the hospital information

system identified 428 women with pathologically confirmed breast

cancer. All patients were treated with mastectomy (including level

I-II axillary dissection) without PMRT. 71% of the patients received

doxorubicin based chemotherapy either in neo-adjuvant or adjuvant

setting. 56% of the patients with positive ER/PR receptors also received

hormonal manipulation. Median age was 50 years (range 22-88 years).

Axillary nodes were clinically palpable in 32% of the patients at

presentation. Median number of dissected lymph nodes were 15 (range

1-33). Distribution of pathologic tumor size was up to 2 cm, 2.1 to 5 cm,

and more than 5 cm in 27%, 64%, and 9% of the patients respectively.

Distribution of pathologically positive number of lymph nodes (LN) was

zero, one to three, four to nine, and more than 10 in 71%, 17%, 5.5%, and

6.5% of the patients respectively. Patterns of failure and disease free

survival (DFS) were determined.

Results: Median follow-up duration was 5.4 years. Patterns of failure;

isolated local (LF) 4.5%, isolated regional (RF) 1.5%, loco-regional (LRF)

1%, distant (DF) 21%, and LRF alongwith DF were seen in 1.5% of the

patients respectively. Cumulative incidences for LF, RF and LRF with or

without DF for patients with zero, one to three, four to nine, and more

than 10 positive LN were 13%, 8.5%, 3% and 4.5% respectively (p = 0.000).

For patients with a tumor size of up to 2 cm, 2.1 to 5 cm, and more than

5 cm, these incidences were 6.5%, 17.5%, and 5% respectively (p = 0.000).

The 10 years DFS for the whole group was 62%. The 10 years DFS for

patients with zero, one to three, four to nine, and more than 10 positive

LN was 74%, 46%, 28% and 17% respectively (p = 0.000).

Conclusions: The role of PMRT may have some value in patients with

tumor size up to 5 cm and with up to three positive lymph nodes. This

merits further evaluation in large scale randomized trials.

PO52

ARE POSTCHEMOTHERAPY TARGET VOLUME ADEQUATE AS BOOST VOLUME FOR CONSERVED BREAST IN LOCALLY ADVANCED BREAST CANCER?

Sushma Agrawal, Mohammed Waseem Raza, Punita Lal, K.J.Maria Das,

Shaleen Kumar

Sanjay Gandhi postgraduate Institute of Medical Sciences, Lucknow, India

Introduction: There is no consensus on boost target volume delineation in

conserved breast in locally advanced breast cancer (LABC) after neoadjuvant

chemotherapy (NACT). Inclusion of prechemotherapy target volume has

the disadvantage of large volumes which will have a detrimental effect on

cosmesis. Inclusion of postchemotherapy target volume has the advantage

of smaller target volume but there could be a higher risk of recurrence.

We therefore did a retrospective analysis of LABC patients who underwent

breast conservation (BCS) after NACT to assess whether post NACT target

volumes are adequate for achieving local control.

Materials and Methods: Patients of LABC who underwent BCS and

radiotherapy after NACT, registered between 2007-2011 were the

subject of our analysis. After BCS, patients received whole breast

and supraclavicular radiotherapy (50 Gy/25 fractions/5 wk or 42.4

Gy/16#/3 wk) which was followed by boost (10-16 Gy/5-8#/1-1.5 wk).

After evaluating patterns of recurrence in these patients, the information

on lumpectomy specimen size, method of estimating tumour boost field

size (whether based on visible scar, cavity on CT scan, prechemotherapy

tumour size or postchemotherapy tumour size) was sought to gain an

insight on whether these had an impact on the local recurrence.

Results: 43 patients were the subject of this analysis. The median age

was 47 years, 42% were premenopausal and 58% were postmenopausal.

Histopathological subtypes were luminal A (23%), luminal B (23%), Her- 2

type (14%) and basal type (40%). (47.7%) patients had stage II disease and 12

(27.2%) had IIIA and 10 (22.7%) had IIIB disease at presentation. After NACT

33.3% patients acheived CR (complete response), 54.8% PR (partial response)

and 11.8% had SD (stable disease). The surgical margins around tumour in

lumpectomy specimens were based on pre-chemotherapy tumour size

in all patients. Radiotherapy planning scan revealed tumour cavity in 33

patients and clips in 19 patients. Boost target delineation was based on

visible scar: 4, tumour cavity: 5, prechemotherapy target volume: 5 and

post chemotherapy target volume: 27 patients. 2 patients did not receive

a boost. At a median followup of 27.2 months (4-71 months), no patient

had ipsilateral breast tumour recurrence (IBTR), one patient had ipsilateral

axillary node recurrence and four patients had distant metastases.

Conclusions: Postchemotherapy target volume seems to be safe as

boost volume delineation for radiotherapy in patients with LABC who

undergo BCS after NACT.

PO53

CLINICAL TARGET VOLUME IN CONSERVED BREAST IN LOCALLY ADVANCED BREAST CANCER

Sushma Agrawal, Punita Lal, K.J.Maria Das, Shaleen Kumar

Sanjay Gandhi Postgraduate Institute of Medical Sciences, Lucknow, India

Purpose: It is important to characteristise the postoperative cavity in

conserved breast after neoadjuvant chemotherapy in locally advanced

breast cancer for accurate targeting during boost phase of intact breast

radiotherapy.This has not been described earlier. So the aim of this work

is to describe and measure the postoperative complexes (POC) and their

relationship to the chest wall and skin.

Materials and Methods: Patients of LABC who underwent BCS and

radiotherapy after NACT, registered between 2007-2012 were the subject

of our analysis. Appearances and measurements of CT postoperative

cavities were analyzed in a cohort of 56 patients who underwent a

radiation treatment planning CT scan before 3D conformal radiotherapy

to the intact breast.

Results: 56 patients were the subject of this analysis. The median time

interval from surgery to radiation was 3 months. In the radiotherapy

planning scan, POC could be identified in 85% patients, clips were found

in 56% patients. POC was situated in medial region (28%), central (30%)

and mediolateral (35%) region. The cavity visualization score was 5

(4%), 4 (33%), 3 (30%), 2 (28%) and 1 (5%).The POC shape was irregular

in 50%, oval in 40% and irregular ellipsoid in 10%. The POC texture was

homogenous in 28%, heterogenous in 72%.The POC was in direct contact

with the chestwall in 93% patients and with skin in 75% patients. The

mean shrinkage in POC from the time of surgery was 68%.

Conclusions: Postsurgical cavities in the conserved breast after

neoadjuvant chemotherapy are usually heterogeneous, irregular, and

are in contact with chest wall and skin in majority of cases. These results

have implications for treatment planning.