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Excision of Head and Neck Basal Cell Carcinoma With a Rapid, Cross-sectional, Frozen-Section Technique
Stuart H. Bentkover, MD;
Donald M. Grande, MD;
Henry Soto, MD;
Beth A. Kozlicak, RN, RNC;
Donna Guillaume, RN;
Sheila Girouard, RN
Arch Facial Plast Surg. 2002;4:114-119.
ABSTRACT
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Objectives To compare a rapid, cross-sectional frozen-section technique with Mohs
micrographic surgery, using recurrence rate and cost of treatment for excision
of basal cell carcinoma as indicators to validate our indications for Mohs
surgery.
Design Retrospective study of 557 head and neck basal cell carcinomas excised
over 10 years.
Main Outcome Measures Recurrence rates; tumor comparisons by size, location, and subtype;
a life table, and a patient satisfaction survey.
Results Recurrence rate for the cross-sectional technique was 2.1% at 5 years.
Recurrent tumors had an average diameter of 1.56 cm (vs 1.04 cm for nonrecurrent
tumors). Recurrences were in the cheek (30%), nose (20%), temple (20%), forehead/brow
(10%), conchal bowl (10%), and postauricular crease (10%). Recurrences were
nodular cystic (40%), micronodular (20%), multifocal (10%), and infiltrating
(30%). A total of 86.6% of patients surveyed rated the aesthetic outcome of
their surgery favorably. The cost compared with the cost of Mohs excision
varied depending on the Current Procedural Terminology
coding technique.
Conclusions Cross-sectional frozen-section recurrence rates can compare favorably
with Mohs micrographic surgery. The cross-sectional frozen-section technique
generated a cost savings over Mohs surgery that may not hold true for all
practice settings. Margin size did not adversely affect aesthetic results.
Loupe magnification x2.5 is important in our technique. We also offer
a useful definition for recurrence.
INTRODUCTION
THE APPROPRIATE utilization of expensive resources is a pervasive goal
in health care throughout the United States. We believe that defining what
is "appropriate" in this environment is best done through objective examination
of treatment outcomes.
This is a study of basal cell carcinomas excised from patients of the
Fallon Clinic, a multispecialty group practice with about 250 physicians.
Through a capitated arrangement, it is the primary provider of health care
for the Fallon Community Health Plan, a federally qualified health maintenance
organization in Massachusetts with more than 200 000 members. The Fallon
Clinic does not have a full-time Mohs micrographic surgeon. Mohs surgery is
performed on a fee-for-service basis by a contracted Mohs surgeon either at
the Fallon Clinic's New England Center for Facial Plastic Surgery or in the
private office of the contracted surgeon. With limited access to Mohs services
and payment coming out of the Fallon Clinic capitation, it is imperative that
only cases that absolutely need Mohs micrographic surgery be referred for
this service. Between 1979 and 1985, one of us (S.H.B.) developed the following
set of in-house indications for Mohs micrographic surgery for basal cell carcinoma
(BCC) of the head and neck:
- Indistinct visual margins of the tumor examined under x2.5
loupe magnification
- Visual margins within 3 mm of the conjunctival margin of the eyelid
- Recurrence after an excision with any frozen-section–controlled
technique
- Recurrence of a tumor excised more than once without frozen-section
control or treated more than once with cryotherapy or electrodesiccation and
curettage (if a patient is referred with a first recurrence after having undergone
a non–margin-controlled technique, the tumor is excised with our cross-sectional
frozen-section technique, since no previous attempt was made to establish
clear margins)
- Biopsy-proven, multifocal, infiltrating, or morphea-type BCC
- Tumors of the conchal bowl, external auditory meatus, or ear canal
- Tumors larger than 2 cm in diameter
- Recurrence after radiation therapy
- Tumors that will require a major staged reconstruction such as
a paramedian forehead flap to the nose, a cross-lip flap or cross-eyelid flap
Important goals of this study were to determine our recurrence rate
for BCC excised using a rapid, cross-sectional, frozen-section technique and
to validate our indications for Mohs micrographic surgery. We calculated a
5-year recurrence rate for our technique from a life table and examined tumor
size, location, and BCC subtype. We compared our recurrence rate with published
recurrence rates for Mohs micrographic surgery. We also compared cost with
the cost of Mohs surgery and conducted a patient satisfaction survey.
PATIENTS AND METHODS
All tumors were evaluated in the office under loupe magnification x2.5.
A total of 536 tumors were excised under loupe magnification x2.5 and
examined using our rapid, cross-sectional, frozen-section technique. The closest
visual margin at the time of excision was routinely 2 to 3 mm. Specimens were
sent immediately to a pathologist for frozen-section inspection of the margins
using a cross-sectional technique that examines 4 opposite points created
by cutting 2 strips across the entire specimen at 90° to each other (Figure 1A). Reconstruction began immediately
after sending the specimen to the pathologist. If a margin was positive, the
defect was reopened and an additional margin was taken along that entire edge
of the defect. The entire outer surface of this margin was examined horizontally
(Figure 1B). If necessary, additional
margins were examined in this manner until all margins were judged to be free
of tumor. Each frozen-section examination generally took 15 minutes or less;
most cases took less than 1 hour. Twenty-one tumors were excised with Mohs
micrographic surgery.
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Figure 1. A roughly elliptical excision
is represented with the tumor (gray area) in the center. Initial margins are
2 to 3 mm. The specimen is sectioned by removing 2 cross-sectional strips
at right angles to each other (black horizontal bars and white vertical bars),
the second strip (black horizontal bars) being therefore halved. A, Current Procedural Terminology (CPT) code 88331 represents
the frozen-section examination of the ends of the first strip (top and bottom
arrows); CPT code 88332 represents the frozen-section examination
of the ends of each half of the second strip (left and right arrows). B, If
a frozen-section margin is positive, an additional frozen section is taken
(CPT 88331 again) of the entire edge of the defect where the
tumor persists (arc-shaped enclosure with shaded area representing residual
tumor). This is sectioned horizontally and the entire outside edge (arrows)
is examined microscopically. The "bow tie" marks at the top of each diagram
represent the marking sutures placed to help the pathologist orient the specimen.
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The study period was January 1, 1985, through December 31, 1995. To
find all BCCs excised during this 10-year period, we searched office and hospital
operating room logs and patient records by diagnosis (International
Classification of Diseases, Ninth Revision) and procedure code (Current Procedural Terminology). We found 557 tumors in
318 patients. We reviewed consultations, progress notes, operative notes,
and pathology reports to determine the size, location, BCC subtype, and sucess
of surgery for all 557 tumors.
During this period, our pathologists did not routinely subclassify BCC.
Slides on 383 of the 536 tumors excised using the cross-sectional technique
were still available for review and were subsequently subclassified by our
chief pathologist (H.S.) as nodular cystic, micronodular, multifocal, infiltrating,
or morphea-type BCC.
We defined a recurrence as a subsequently diagnosed BCC within 5 mm
of the original resection margin (ie, 7-8 mm from the edge of the original
tumor) and recorded the number of recurrences. We attempted to examine all
318 patients from October 14, 1997, through February 12, 1998. During this
period, 174 patients with 260 operative sites returned for a special examination.
If patients were unable to be examined or declined examination during this
time, we used the latest progress note by the senior author (S.H.B.), our
nurse practitioner (B.A.K.), or the patient's dermatologist to check for recurrence.
Each practitioner routinely checked all previous operative sites when examining
the patient.
RESULTS
Of the 318 patients studied, 176 were male (335 tumors) and 142 were
female (222 tumors). The mean age of the subjects was 66.3 years (66.6 years
for the men, 66.0 years for the women).
Of the 557 tumors excised, 536 (96.2%) were excised using a cross-sectional
frozen-section technique, and 21 (3.8%) were excised with a Mohs micrographic
technique. However, only 19 tumors (3.4%) met our criteria for Mohs micrographic
surgery. The 2 additional tumors excised by our Mohs surgeon were done for
patient convenience at the time of another indicated Mohs micrographic excision.
We located 10 recurrences among the 536 tumors removed with the cross-sectional
frozen-section technique during the 10-year period studied (1.9% raw calculation,
2.1% at 5 years, with SE <1%). There were no recurrences in the Mohs group.
Initial tumor diameter was recorded preoperatively for 441 (82.3%) of the
536 tumors. Those tumors that recurred were larger than those that did not.
The average initial overall diameter was 1.05 cm (1.56 cm for the tumors that
recurred using the cross-sectional frozen-section technique, and 1.04 cm for
the tumors that did not recur using this technique). Recurrences were distributed
as follows: cheek, 3 tumors (30%); nose, 1 tip and 1 ala (20%); temple, 2
(20%); brow, 1 (10%); conchal bowl, 1 (10%); and postauricular crease, 1 (10%).
BCC SUBTYPES, RECURRENCE RATES, AND FOLLOW-UP
The distribution of BCC subtypes for the 383 tumors subsequently subclassified
was 292 nodular cystic (76.2%); 2 micronodular (0.52%); 22 multifocal (5.7%);
57 infiltrating (14.9%); 9 morphea-type (2.3%); and 1 specimen too small to
subtype (0.26%). There were 4 nodular cystic recurrences (40%); 2 micronodular
(20%); 1 multifocal (10%); and 3 infiltrating (30%). The shortest and longest
follow-up duration were 0 days and 14.5 years, respectively. Mean follow-up
duration was 4.5 years; median, 3.8 years. The soonest a tumor recurred was
at 9.6 months, and the latest was 8.4 years. Mean time to recurrence was 4.3
years; median, 4.0 years.
Figure 2 is a life table that
demonstrates the percentage of tumor-free sites for the 536 cross-sectional
excisions yearly for each year of follow-up in this study. A total of 97.9%
of original tumor sites were tumor free up to 5 years after surgery (SE <1%
up to that time). In addition, Kaplan-Meier analyses were performed using
the Stata1 statistical package. The Kaplan-Meier–estimated
5-year recurrence rate was 2.1% (95% confidence interval, 1.0%-4.55%). Figure 3 depicts the recurrence rates by
year up to 5 years after surgery. Because the number of tumors observed after
5 years was not large enough to yield an SE less than 1%, we cannot make a
definitive statement about recurrence rates after 5 years.
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Figure 2. This life table demonstrates the
percentage of tumor-free sites for the 536 cross-sectional excisions yearly
for each year of follow-up in this study. The error bars indicate SE. A total
of 97.9% of original tumor sites were tumor free up to 5 years after surgery
(SE <1%).
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Figure 3. Recurrence rates by year up to
5 years after surgery (SE <1%). The number of tumors observed after 5 years
was not large enough to yield an SE of less than 1%.
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COSTS OF TREATMENT
Procedure Categories
For the following reasons, in our system, comparing the cost of an excision
with our rapid, cross-sectional, frozen-section technique with the cost of
Mohs micrographic surgery involved comparing only the combined professional
and institutional costs for our pathologist's services with the cost for the
Mohs micrographic excision:
- The type of frozen-tissue examination was not related
to where the surgery was performed. Frozen-section examinations by a pathologist
and Mohs micrographic surgeon were available in our office or in the hospital.
Generally, cases were done in the hospital only if the reconstruction required
more than local anesthesia or if our office schedule was booked so far in
advance that it was unreasonable to have the patient wait for an office appointment.
- Since most of our patients came from the same health
maintenance organization, all other costs were already capitated.
- Even had all other costs not been covered under
a global capitation, laboratory, operating room facility, and other ancillary
costs in our system still were not related to the type of tissue excision.
Also, since most of these cases were performed in the office under local anesthesia,
there were generally no other laboratory or ancillary fees. Operating room
facility costs were significantly lower in the office than in the hospital;
but again, where the surgery was performed did not depend on the choice of
frozen-tissue examination. Cases requiring an extensive preoperative physical
examination were only those that required intravenous sedation or general
anesthesia, again not related to the choice of type of frozen-tissue examination.
- The primary author (S.H.B.) was a salaried physician,
and he routinely performed all the reconstructions. Hence, in either scenario,
the cost for the reconstruction was constant and did not figure into any cost-comparison
calculations.
Even though pathological services in our system were capitated at less
than Medicare prevailing rates, comparing Medicare rates for the cross-sectional
technique and Mohs surgery is probably still the fairest way to establish
a useful comparison. The application of Current Procedural
Terminology codes for Mohs micrographic surgery (17304-17307) is clear
and seems to be universally accepted. However, when coding for a pathologist's
services (88305, 88331, 88332), exactly how many frozen-section examinations
are included in the cross-sectioning of a specimen seems open to interpretation.
For each frozen-section examination (88331, first tissue block with frozen
section[s]; or 88332, each additional tissue block with frozen section[s]),
there is also a permanent-section examination (88305). Our pathologists consider
the initial frozen-section cross-sectional examination of all 4 points at
the periphery of the specimen to be from 1 tissue block and code for 1 frozen-section
examination (88331 + 88305). Subsequent frozen-section examinations for positive
margins also are coded 88331 + 88305. However, according to the 2001 Current Procedural Terminology code book,2
the way we section the specimen could also be considered to generate 3 tissue
blocks and be coded 88331 + 88305, 88332 + 88305, and 88332 + 88305 (see Figure 1). Subsequent frozen-section examinations
for positive margins would also be coded 88331 + 88305. Hence, the comparison
of cost for our technique with the cost for a Mohs excision will differ depending
on how the pathologist codes.
Calculating Costs
Our average rate of frozen sections per tumor was 1.1. Table 1 and Table 2
compare the costs of our technique with those of Mohs micrographic surgery
using the 2002 local Medicare rates in our region3
for specimen processing and interpretation. Table 1 summarizes the costs as billed by our pathologists. Table 2 summarizes a more expensive but
still correct way of billing for pathological services. The cost of the initial
frozen section and all subsequent frozen sections as actually billed was $286.98
less than it would have been under the 3-block billing method, and the cost
per 1.1 frozen sections as actually billed was $315.67 less than it would
have been billed as 3 blocks.
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Table 1. Cost Comparison as Actually Billed for Rapid, Cross-sectional,
Frozen-Section Technique With Mohs Surgery
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Table 2. Cost Comparison Using 3-Block Billing Method of Rapid, Cross-sectional,
Frozen-Section Technique With Mohs Surgery
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Assuming a reasonable scenario of the same average number of Mohs stages
per tumor (1.1), our technique costs $470.50 less per tumor than Mohs micrographic
surgery ("non-facility" fee) as billed by our pathologists and $154.83 less
if billed to the maximum. If all 557 of the tumors had been removed with a
Mohs micrographic technique at 1.1 stages per tumor, the total cost would
have been $384 140.62. Adhering to our criteria for Mohs surgery, there
would have been only 19 tumors done by the Mohs surgeon, at a cost of $13 103.54.
The cost for the other 538 tumors, as billed by our pathologists would be
$117 908.08. It would be $287 738.54 if billed to the maximum. Therefore,
the total cost for all 557 tumors following our criteria for Mohs surgery
would be $131 011.62 as billed by our pathologists and Mohs surgeon or
$300 842.08 if billed to the maximum. Compared with Mohs surgery only,
this represents a savings of $253 129.00 as actually billed by our pathologists
or $83 298.54 if billed to the maximum, a gain of $454.45 per tumor or
at least $149.55 per tumor.
Of the 174 patients who agreed to participate in a satisfaction survey
between October 14, 1997, and January 12, 1998, 86.6% rated the aesthetic
outcome of their surgery favorably. A total of 81.5% rated their overall treatment
experience (preoperative, intraoperative, and postoperative care) favorably.
COMMENT
Outcome is arguably the most important element to consider when establishing
or verifying a standard of care. However, in a predominantly capitated, managed
care system, we must also be aware of the cost of maintaining a given standard.
We have had an active working relationship with a Mohs surgeon for over 15
years; but he is a contracted nongroup physician paid from the group capitation
on a fee-for-service basis. In 1985, with the group's capitated population
growing rapidly, the dilemma we faced was to determine whether we were sending
an appropriate number of patients for Mohs surgery. Because of its associated
low recurrence rate and tissue-sparing effect, Mohs micrographic surgery is
considered by many surgeons the standard of care for excision of BCC of the
head and neck. The primary objectives of this study were to compare the recurrence
rate and cost of a rapid, cross-sectional, frozen-section technique with the
recurrence rate and cost of Mohs micrographic surgery and to validate our
indications for Mohs surgery.
To evaluate our recurrence rate, we first had to define recurrence. Many Mohs surgeons report 5-year recurrence rates for excision
of primary BCCs ranging from 0.7% to 1.8%.4-8
Our Mohs surgeon (D.M.G.) reports a personal recurrence rate of about 1.5%.
But what exactly is a recurrence? At the time of a Mohs excision, if the tumor
is found growing directly in a scar microscopically, it is safe to assume
that the lesion is a recurrence. However, we found no reports in the literature
that defined an acceptable distance from the scar of a previous excision past
which a tumor could be considered a new primary tumor and not a recurrence.
Our initial resection margin was generally 2 to 3 mm from the visual edge
of the tumor under magnification x2.5. By defining a recurrence as any
tumor growing within 5 mm of the original scar, we are saying that any tumor
growing within 8 mm of the original tumor edge could be a recurrence. One
could argue that this is a very wide radius, but as a starting point for a
definition it seemed reasonable.
In our setting, the only real difference in cost between our rapid,
cross-sectional, frozen-section technique and Mohs micrographic surgery was
the difference in third-party reimbursement for pathology services and Mohs
surgery. With our frozen-section sampling rate of 1.1 examinations per specimen,
the cost of this service at current prevailing Medicare rates2
in 2002 would be $219.16 per tumor as billed by our pathologists or $534.83
if billed to the maximum. The cost for Mohs surgery in an office setting with
1.1 stages per tumor would be $689.66 per tumor. To remove all the tumors
in our study with Mohs surgery, the total cost at 2002 reimbursement rates
would be $384 140.62. Following our indications for Mohs surgery, the
cost for all tumors studied (19 Mohs; 538 cross-sectional frozen sections)
would be $131 011.62 as billed by our pathologists and Mohs surgeon,
or $300 842.08 if billed to maximum.
We had 10 recurrences of the 536 tumors excised with the cross-sectional
technique. (Only 19 tumors met criteria for Mohs surgery, but 2 additional
Mohs procedures were performed for patient convenience.) Had we used Mohs
micrographic surgery for all the tumors, we reasonably could have expected
our recurrence rate to have decreased from 2.1% at 5 years to a theoretical
1.5% or so. Thus, using Mohs micrographic surgery exclusively to eliminate
perhaps 2 or 3 more recurrences of 557 excisions could have cost an additional
$253 129.00 compared with actual cross-sectional billing by our pathologists
or $83 298.54 compared with maximum Medicare allowable billing for cross-sectional
pathological services. Also, with a patient satisfaction score of 86.6% for
the aesthetic results, we think we can probably also assume most patients
were reasonably satisfied.
In our opinion, our recurrence rate is close enough to published Mohs
recurrence rates to validate our current indications for Mohs micrographic
surgery for a practice situation like ours where there is limited access to
a Mohs surgeon. Over the 10 years of cases studied, we have demonstrated considerable
potential cost savings over exclusive use of Mohs surgery. The magnitude of
the savings, however, is related not only to our technique but also to how
pathologists interpret the coding rules for frozen sections laid out by the
Centers for Medicare & Medicaid Services (formerly the Health Care Financing
Administration). Furthermore, all fee calculations are subject to the yearly
changes in Centers for Medicare & Medicaid Services financing.
Our current volume of BCC excised yearly is much higher than during
the period of this study. A legitimate question, therefore, is whether we
should employ a full-time Mohs surgeon. This question can only be answered
by looking at the total expense of salary, benefits, equipment, and support
staff for a high-quality, highly experienced Mohs surgeon. Also, since our
actual pathology costs are really capitated below Medicare prevailing rates,
the calculation becomes even more complex. These calculations are worth considering
in a future budgetary process but are beyond the intent and scope of this
study.
We believe our patient satisfaction score indicates that the 2- to 3-mm
width of our margin is not a disadvantage of our technique. We also believe
we have established a reasonable definition of recurrence that can be used
in future publications and the importance of x2.5 loupe magnification
in examining and removing BCC without Mohs micrographic surgery.
AUTHOR INFORMATION
Accepted for publication December 14, 2000.
We wish to express our appreciation to Patricia O'Mara, RN, for her
assistance with the statistical evaluations in this article.
Preliminary data evaluation presented at the Seventh International Congress
of Facial Plastic Surgery, Orlando, Fla, June 20, 1998.
Corresponding author and reprints: Stuart H. Bentkover, MD, Bentkover
Facial Plastic Surgery & Laser Center, 10 Winthrop St, Worcester, MA 01604
(e-mail: bentkov{at}quixnet.net).
From the Fallon Clinic (Dr Bentkover and Mss Kozlicak, Guillaume, and
Girouard); Donald M. Grande & Associates (Dr Grande); and the Department
of Pathology, Saint Vincent Hospital (Dr Soto), Worcester, Mass. Dr Bentkover
is now with the Bentkover Facial Plastic Surgery & Laser Center, Worcester.
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3. Centers for Medicare & Medicaid Services. Participation Enrollment and Fee Disclosure. Baltimore, Md: Centers for Medicare & Medicaid Services; November
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5. Lim JK, Stewart MM, Pennington DG. Microscopically controlled excision of skin cancer. Med J Aust. 1992;156:486-488.
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RELATED LETTERS
Modified Mohs Technique for Basal Cell Carcinomas of the Head and Neck
Joshua E. Lane, Christopher M. Peterson, and John L. Ratz
Arch Facial Plast Surg. 2003;5(1):116.
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