Meticulous Pathologic Evaluation to Ensure Negative Margins Facilitates a Low Risk of Local Recurrence of Dermatofibrosarcoma

Protuburans (DFSP)

Marilyn M. Bui, Jane L. Messina, Jeffrey M. Farma, Suroosh S. Marzban, Vernon K. Sondak, Douglas Letson and Jonathan S. Zager

Departments of Sarcoma and

Cutaneous Oncology

Introduction

• DFSP is a rare dermal tumor with limited metastatic potential but significant risk of local recurrence

• Controversy regarding margin width and the risk of local recurrence

• Debate also exists regarding the optimal method for margin evaluation

• We reviewed our DFSP experience to determine outcomes using 1-2 cm resection margins and total peripheral margin pathologic evaluation

Our Study

• IRB approved retrospective review of all DFSP patients treated with surgery at Moffitt Cancer Center between 1994 and 2008

• Clinicopathological characteristics examined:– Confirmation of diagnosis– Margin width– Number of excisions needed to achieve (-)

margins– Reconstruction techniques– Postoperative radiation – Local or distant recurrence

Standard Institutional Protocol

• Wide local excision with 1-2 cm margins– Staged closure performed if unable to primarily

close

• Meticulous pathologic analysis with en face sectioning for total peripheral margin analysis

• Re-excision of any positive margin• Follow-up

– Every 6 months for 5 years by physical exam only

– If transformed DFSP include imaging of the thorax

En Face Margin Technique

12

3

6

9 DFSP

Pathologic Evaluation of Margins

• DFSP resection specimens were submitted intraoperatively for gross examination

• Additional tissue was taken when margin was positive

• Frozen section was used judiciously• Tangential sections of the entire margin

were submitted for histological examination after proper tissue fixation

• CD34 immunostain used in difficult cases

2 mm tangential sections removed from entire peripheral margin; Sections embedded with outer margin “face up”

12 9

9 6 36

123

Pathologic Evaluation of Margins

12

3

6

9 DFSP

When positive, additional 1 cm re-excisions were performed in the same fashion to achieve negative margin

Result: Demographics

Characteristic N (%)

Total 82

M: F 33:49

Race

White

African-American

Other

59 (72%)

13 (16%)

10 (12%)

Median age (years, range) 40 (3-84)

DFSP

DFSP with sarcomatous changes

79 (96%)

3 (4%)

Recurrent disease on presentation to Moffitt

17 (21%)

Result: DFSP Location

Margins of Excision35 Patients27 (77%) had (–) margin after 1st excision8 (33%) required multiple excisions1 with a persistent (+) margin

Margins of Excision

Margins of Excision 6 Patients4 (67%) had (-) margins after 1st excision2 (33%) required multiple excisions

Margins of Excision

4 Patients4 (100%) had (-) margins after 1st excision

Result: Margins of Excision

• The median number of excision for negative margins was 1 (range 1-3) with 53% having a negative margin after 1 excision

• The median excision margin was 1.5 cm (range 0.5-3)

• 75% were closed primarily without skin grafts or flaps

Result: CD34 Immunostain• Used in 5 difficult cases• Proven useful where a sense dermal scar

or small microscopic focus of DFSP

Result: Recurrence35 Patients27 (77%) had (–) margin after 1st excision8 (23%) required multiple excisions1 with a persistent (+) marginNO RECURRENCES

37 Patients32 (86%) had (-) margin after 1st excision5 (14%) required multiple excisions1 with a persistent (+) margin2 RECURRENCES

6 Patients4 (67%) had (-) margins after 1st excision2 (33%) required multiple excisionsNO RECURRENCES

4 Patients4 (100%) had (-) margins after 1st excisionNO RECURRENCES

Result: Recurrence

• At a median follow-up of 44 months, 2 patients (2.4%) recurred locally– Both in the head and neck region

(2/13)– Both with local recurrence underwent

re-resection– Time to recurrence was 13 months

and 84 months

Conclusions

• Standard en face surgical excision in conjunction with meticulous pathologic evaluation of margins for all DFSP patients with repeat excision as necessary to achieve negative margins

• A very low recurrence rate (2.4%) was achieved with fairly narrow margins (medium 1.5 cm)

• This approach limits the number of patients who require wider resection margins, allowing primary closure in 75% of patients

Comments

• It is misconception that WLE needs to be > 3 cm

• A high local recurrence rate is most likely related to unrecognized persistence of tumor at the margins of resection

• Experienced pathologists play a vital role in the successful multidisciplinary management of DFSP

Departments of Sarcoma and

Cutaneous Oncology