METHODS
A total of 40 patients treated with concurrent chemoradiation were included in this study. All of these
patients had surgery for laryngeal cancer and had received 66 Gy (2Gy/fr) of radiotherapy and concurrent
weekly cisplatin. Patients were stratified into two groups according to surgical margin status.
Members of group 1 had a positive surgery margin; group 2 patients had close surgical margins and were
studied for comparative analyses.
RESULTS
At the median follow-up of 40 months, nine patients (44.4%) experienced local/regional failures, six
of which were detected on the second follow-up. In patients with positive surgical margin, overall survival
(OS), disease-free survival (DFS), and loco-regional progression-free survival (LRPFS) were 59%,
44% and 81%, respectively. OS, DFS and LRPFS for those with close surgical margins were 57%, 46%
and 71%, respectively. There was no statistically significant difference between Group 1 and Group 2
(p=0.802, p=0.610 and p=0.383, respectively). On univariate Cox-regression analysis, the presence of
perineural invasion and lymphovascular invasion was statistically significant for OS and DFS (p=<0.05).
Being 65 years old or above was statistically significant for OS (p=<0.05).
CONCLUSION
Although limited by small sample size, our results revealed that there was no significant difference between
close and positive margins in terms of OS, DFS and LRFS. More detailed and comprehensive
studies on the close surgical margin (2 mm, 3 mm and 4 mm) are needed.
Keywords: Concurrent chemoradiotherapy; close surgical margin; laryngeal cancer; positive surgical margin
In this study, we examined whether a significant difference exists between patients with close surgical margins and patients" positive surgical margins who received adjuvant C-CRT We looked specifically at LRPRS, DFS and overall survival.
Treatment Planning and Treatment Delivery
Surgery
The surgical suitability of all patients was determined
in the multidisciplinary head and neck team. For determining
the type of surgeon, the team considered the
primary site, the prevalence of the disease and the cosmetic
results, and complete tumour resection was the
established goal.
RT Planning
Patients were immobilized in a supine position with a
thermoplastic mask. An enhanced computed tomography
scan was acquired with IV plus contrast media
through 3 mm slices from the skull base to the diaphragm
inferior border. A standardized protocol with
140 kV/80 mA was used. One radiation oncologist defined
the target volumes and contoured the clinical target
volume (CTV), planning target volume (PTV) and
organs at risk (OARs).
PTV was defined as CTV+5 mm in each direction,
allowing for microscopic extension and setup errors.
The treatment was planned in accordance with the
ICRU-83 guidelines.[
The three target volume was irradiated via the simultaneous
integrated boost technique with dynamic
intensity-modulated radiation therapy (IMRT). Patients
received RT regimens using 6 MV photon energy
linear accelerators. A dose of 66 Gy (200 Gy/fr, 5 days/
week) was administered to the operative area, which
was a region having either a positive or close surgical
margin. A dose of 60 Gy (200 Gy/fr, 5 days/week) was
administered to the involved lymph nodes region. A dose of 54 Gy (180 Gy/fr, 5 days/week) was administered
to the uninvolved lymph nodes region. Isodose
curves were not cooler than 95% or hotter than 107%.
Dose-volume histograms assessed each patient"s target
volume coverage and organ-at-risk doses. For normal
tissues, maximum dose limits were 45 Gy for the spinal
cord, 45 Gy for the oral cavity, 54 Gy for the brainstem,
and 26 Gy for the parotid glands. Dose levels beyond
these limits were considered as exclusion criteria.
Chemotherapy
Response Evaluation and Follow-up
Statistical Analysis
Patients received weekly cisplatin (40 mg/m2/week)
throughout the RT course as a radiosensitizer.
During C-CRT, patients were evaluated at least once
a week with a clinical examination, and all patients"
blood counts and biochemistries were required. The
treatment responses were assessed by endoscopic examination
for the first control and were performed
two weeks after the treatment. Subsequent controls
included physical examinations and endoscopic and
radiological imaging every three months. Follow-ups
were arranged every three months for the first two
years and every six months for years three through
five. During the follow-up period, a magnetic resonance
imaging (MRI) or 18F-fluoro-deoxy-D-glucose
positron emission tomography (FDG-PET) examination
was requested in patients with suspected local/
regional recurrence and metastasis. Loco-regional recurrences
and metastasis suspicions were verified with
biopsies. The decision to request biopsy and additional
imaging modality (FDG-PET) for these patients was
determined by local MDT (multidisciplinary team).
Then, a surgeon was selected for re-excision. Patients
who underwent re-excision and metastasized were referred
to the Department of Medical Oncology for systemic
therapy.
The descriptive statistics included the mean, standard
deviation, median, minimum, maximum, frequency,
and ratio values of the data. Survival analysis was
performed using the Kaplan-Meier method. A multivariate-
univariate analysis (Cox regression analysis)
was used to evaluate the independent risk factors that
affected survival. Effect size or hazard ratio (HR) and
95% CI were used to report the magnitude of difference.
All analyses were performed using statistical software
IBM SPSS ver. 22.0 (IBM Co., Chicago, USA). P<
0.05 was considered significant.
At a median follow-up of 40 months (range: 16- 72). 14 of 40 patients (35 %) were dead. Nine patients (22.5%) developed field recurrences, six of which were positive margins group, and three of which were close margins group. While most of the recurrence in the operation field, only two of them were observed in neck lymph nodal field. Distant relapses without local failures were encountered in 11 (27.5%) patients and all of them were positive surgical margins. Distant failure site included the lung.
The OS rate were 57% (n=14) at patient with group:
1 and 59% (n=26) at patients with group: 2. There was
no statistically significant difference between concerning
OS rate (p=0.802, Fig.
The DFS rate was 44% in patients with close surgical
margins and 46% in patients with positive surgical
margins. There was no statistically significant difference
between concerning DFS rate (p=0.610, Fig.
LRFS ratio was 71% in the patients" close margin group, and 81% in the patient"s positive margin group. There was no statistical difference between the two groups (p=0.383). Cox-regression could not be performed because a significant variable could not be obtained in univariate analysis.
1. Free surgical margin: absence of tumour around 5
mm border
2. Close to surgical margin: tumour present in the region
containing 5 mm of borderline (1-5 mm); but
there is no tumour at border.
3. Positive surgical margin: border tumour present or
<1mm
Close margin or the appropriate margin clearance from tumor remains as a controversial debate in the literature.
A microscopically positive and close margin is associated
with a higher risk for local recurrence and
poor clinical outcome. Sutton et al. reported that local
recurrence rates found as 55% in oral squamous cell
carcinomas with positive surgical margin and 33%
in the close surgical margin.[
Two prospective, randomized clinical trials that
used in the decision making about adjuvant RT and
CRT for squamous cell cancer of the head and neck
included margin status as their selection criteria. The
Radiation Therapy Oncology Group (RTOG) 9501
study only included patients with positive margins,
whereas the European Organization for Research and
Treatment of Cancer Trial (EORTC) 22931 study also
included patients with a close margin, defined as less
than 5.0 mm.[
In EORTC-22931, OS was 53% in C-CRT group and
DFS was 47% in C-CRT group. In our study, OS was
59% in the positive margin group and 57% in the close
margin group. In addition, DFS was 44% in the positive
margin group and 46% in a close margin group. Our
results were found to be similar to literature. There was
no significant difference.
We compared the local control rates found higher
in both groups (group 1: 81% vs. group 2:71%). There
was no difference between 2-3mm and positive margin
at the LRPFS. Zanoni et al. reported that a surgical
margin of 2.2 mm was optimal to predict for loco-regional
recurrence-free survival.[
Limitations
In all the above mentioned clinical study, the reason
why few percent (around 10-15%) of patients presented
local relapse is unknown and could have nothing to do
with an inadequate resection margin, but rather with
unfavorable tumour biology.
Abbreviations
RT: Radiotherapy
C-CRT: Concurrent chemoradiotherapy
IMRT: Intensity- modulated radiotherapy
FDG-PET: 18F-fluoro-deoxy-D-glucose positron emission
tomography
MRI: Magnetic resonance imaging
CT: Computerized tomography
PTV: The planning target volume
CTV: The clinical target volume
OARs: Organ at risk
MV: Million volts
LVI: Lymphovascular invasion
PNI: Perineural invasion
MDT: Multidisciplinary Team
Peer-review: Externally peer-reviewed.
Conflict of Interest: The authors declare that they have no conflict of interest.
Ethics Committee Approval: This study was approved by the local ethics committee of the University of Health Science, Istanbul Education and Research Hospital, Turkey, Human Research Ethics Committee (approval number: H-2018-1431).
Financial Support: Not applicable.
Authorship contributions: Concept - B.İ.; Design - B.İ.; Supervision - B.İ.; Funding - None; Materials - B.İ., S.B., M.Ç.; Data collection and/or processing - B.İ.; Data analysis and/or interpretation - S.B., M.Ç., Ö.Y.; Literature search - K.İ.; Writing - B.İ.; Critical review - Ö.Y.