1. Meticulous Pathologic Evaluation to Ensure Negative Margins Facilitates a Low Risk of Local Recurrence of Dermatofibrosarcoma Protuburans (DFSP)
Departments of Sarcoma and Cutaneous Oncology
Marilyn M. Bui, Jane L. Messina, Jeffrey M. Farma, Suroosh S. Marzban,
Vernon K. Sondak, Douglas Letson and Jonathan S. Zager 1

2. 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 2

3. 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
Explain inclusion criteria – were all DFSP patients included or only “surgically” treated patients? What about transformed cases? I believe we only included fibrosarcomatous transformation – transformation to leiomyosarcoma, rhabdomyosarcoma etc were probably not included – and even then only those fibrosarcomatous transformed patients who were still resectable. I know of one case of mine with DFSP-FS that was unresectable, and I assume was excluded. Remember that with our excellent outcome results, people will be looking to poke holes in our results if we’re not clear about exactly what we did! And saying “evaluation included” seems to suggest that is what the pathologic evaluation included. I think we need a better term than that. Maybe “Factors examined”? Keep in mind that the factors you say you examined should be the same ones that are described in the results, and they aren’t quite. 3

4. 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 4

5. En Face Margin Technique12
DFSP 3 9 6 5

6. 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

7. Pathologic Evaluation of Margins12 3 6 9
DFSP 12 3 12 9 9 6 3 6
2 mm tangential sections removed from entire peripheral margin; Sections embedded with outer margin “face up” 7

8. When positive, additional 1 cm re-excisions were performed in the same fashion to achieve negative margin 8

9. 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%)
Start with TOTAL number of patients, 83, again emphasizing the high level of ‘inclusiveness’ of our data and indicate the size relative to other modern series. What does initial resection at outside hospital mean?? Who cares where the resection was. What is ‘persistent disease’? What is ‘recurrent disease on presentation’? These are non-standard terms for what should be very straightforward concepts. Did we include any patients who weren’t treated at Moffitt – ie, really had their resection at an outside hospital and we just blessed the margins? I wouldn’t think those are cases we would want to be including. 9

10. Result: DFSP Location
The n = 83 doesn’t need to be here if you adequately explained this on the first slide. I must say this doesn’t really look that good as a bar chart. Do you want to try it as a pie chart and see if that looks better? 10

11. Margins of Excision 35 Patients
27 (77%) had (–) margin after 1st excision
8 (33%) required multiple excisions
1 with a persistent (+) margin 11

12. Margins of Excision 12

13. Margins of Excision 6 Patients
4 (67%) had (-) margins after 1st excision
2 (33%) required multiple excisions 13

14. Margins of Excision 4 Patients
4 (100%) had (-) margins after 1st excision 14

15. 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

16. Result: CD34 Immunostain
Used in 5 difficult cases
Proven useful where a sense dermal scar or small microscopic focus of DFSP

17. Result: Recurrence 35 Patients 4 Patients
27 (77%) had (–) margin after 1st excision
8 (23%) required multiple excisions
1 with a persistent (+) margin
NO RECURRENCES
4 Patients
4 (100%) had (-) margins after 1st excision
NO RECURRENCES
6 Patients
4 (67%) had (-) margins after 1st excision
2 (33%) required multiple excisions
NO RECURRENCES
37 Patients
32 (86%) had (-) margin after 1st excision
5 (14%) required multiple excisions
1 with a persistent (+) margin
2 RECURRENCES 17

18. 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
2 patients recurred locally – any distant mets? What was the time from resection to recurrence in those two patients? Obviously a mean or median time is meaningless with n of 2 but if both recurred after 100+ months it would serve as a warning not to get too overexcited about 44 month median follow-up! This is a key slide and needs to be very tight and well integrated with what you actually say. We also need to provide the recurrence rate for subsets: All patients (DFSP and DFSP-FS) who presented with their original occurrence of disease and were resected to negative margins, all nontransformed DSFP patients who were resected to negative margins regardless of initial/recurrent disease status, all patients who received RT, all transformed patients. 18

19. 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
A final warning about the relatively short follow-up time is warranted – we should say it so other people don’t have to! It’s probably also worth saying whether we feel that transformed cases and/or recurrent tumors are at “higher risk” and require any different therapy. 19

20. 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

21. Departments of Sarcoma and Cutaneous Oncology