Incidence of second primary tumors in patients with
carcinoma of the oral cavity: A clinical review
Yuriko Toeda1, Morihiro Higo 2, Atsushi Kasamatsu2, Yosuke Endo-Sakamoto2, Katsunori Ogawara2,
Masashi Shiiba3, Katsuhiro Uzawa1,2, and Hideki Tanzawa1,2*
1
Department of Oral Science, Graduate School of Medicine, Chiba University, Chiba, Japan
Department of Dentistry and Oral-Maxillofacial Surgery, Chiba University Hospital, Chiba, Japan
3
Department of Clinical Oncology, Graduate School of Medicine, Chiba University, Japan
2
*Address correspondence to: Hideki Tanzawa, Department of Oral Science, Graduate School of Medicine, Chiba University, 1-8-1 Inohana, Chuo-ku,
260-8670, Chiba, Japan
E-mail: tanzawap@faculty.chiba-u.jp ; telephone: +81-43-226-2300; fax: +81-43-226-2151
Abstract. A high incidence of second primary tumors in patients with carcinoma of the oral cavity has been reported, and their
frequency is increasing. The aim of current study was to review the patients with second primary cancer and evaluate the screening
modalities for detecting second malignancies. In a retrospective study of 416 patients with oral cancer, 61 (14.7 %) had second
primary tumors. Upper gastrointestinal endoscopy revealed second primary tumors in 22 (5.3%) of 416 patients with carcinoma of
the oral cavity. The incidence of rectal cancer in a preoperative patient was found by FDG-PET. Postoperative FDG-PET detected
second primary tumors including bile duct (n=2), rectal (n=2), and breast cancer (n=1). This study showed the value of upper
gastrointestinal endoscopy and FDG-PET as screening methods for detecting second malignancies.
Key words: oral cancer, second primary cancer, screening method
retrospective study. The patients underwent some screening
modalities including CT, MRI, GF and FDG-PET.
The second primary tumors found within 12 months after
the diagnosis of oral cancer were defined as synchronous
lesions.
1. Introduction
The incidence of second primary tumors involving the oral
cavity is showing an increasing trend worldwide. Oral cancer is
very often accompanied by synchronous malignant disease
[1,2]. The most frequently accompanying lesion is a second
primary cancer in the oropharynx, followed by cancer of the
esophagus and lungs [2].
Endoscopic examination as a preoperative screening
method is valuable for detecting the synchronous esophageal
and gastric cancers [3]. In recent years, positron emission
tomography (PET) with the radio pharmaceutical fluorine-18
fluorodeoxyglucose (18F-FDG) has been shown to be
complementary to CT and MRI, and to demonstrate a greater
accuracy than anatomical imaging methods [4]. The advantage
of whole body FDG-PET is its high sensitivity in detecting
second primary tumors in any part of the body in a single
diagnostic modality [5].
In the present study, we investigated the frequency of the
second primary tumors in patients with oral cancer and
evaluated the usefulness of upper gastrointestinal endoscopy
and FDG-PET as screening methods for detecting second
malignancies.
3. Results
416 patients with oral cancer included 250 men and 166
women. Of the 416 patients, 338 (81.3 %) had single oral
cancer and 61 (14.7 %) had second primary tumors (Fig. 1).
Multiple primary cancer of the oral cavity was found in 17
(4.0%) patients. The patients included 45 men and 16 women.
Figure 1. Incidence of second primary cancer
2. Materials and methods
Four hundred sixteen patients who were diagnosed with
carcinoma of the oral cavity at the Department of Dentistry and
Oral-Maxillofacial Surgery in Chiba University Hospital
between April 2002 and June 2013 were entered into this
Figure 2. The distribution of patients with oral cancer
and second primary cancer according to age and sex
1
The percentage of male was higher in patients with second
primary cancer. The distribution of age is shown in Figure 2.
The mean age of patients with a primary oral cancer only and
second primary cancer was 70.3 years and 62.5 years
respectively.
The number of combined second primary cancers in each
site of first primary cancer of the oral cavity is shown in Table 1.
Of the 61 cases, 31 had first primary cancer of the oral cavity.
endoscopy still plays a decisive role in management of oral
cancer.
FDG-PET has been shown to be able to detect second
primary tumors in patients with carcinoma of the oral cavity
with a high sensitivity and specificity [9]. In the current study,
the incidence of rectal cancer in a preoperative patient was
found by FDG-PET. Postoperative FDG-PET detected second
primary tumors including bile duct (n=2), rectal (n=2), and
breast cancer (n=1). FDG-PET might be considered as a first
diagnostic modality for detecting second primary tumors in
patients with oral primary cancer.
This study showed the value of upper gastrointestinal
endoscopy and FDG-PET as screening methods for detecting
second malignancies. We conclude that these modalities should
be included in the routine examination in patients with oral
cancer for the early detection of second primary tumors.
Table 1. The number of second primary cancers in
patients with first primary cancer of the oral cavity
Competing interests
The authors declare that they have no competing interests.
Acknowledgement
The tongue, gingiva, and buccal mucosa represented the most
commonly involved site of first primary cancer of the oral
cavity, making up 9 of the 31 patients respectively. The
distribution of second primary cancer according to site of
involvement was as follows: stomach in 12 cases (39%);
esophagus in 8 (26%); large intestine in 4 (13%); larynx in 3
(10%); bile duct in 2 (6%); breast in 2 (6%).
Synchronous lesions were found in 26 (42.6%) of 61 cases.
Of these, 20 were detected as first primary cancer of the oral
cavity accompanied by second primary cancer, using
preoperative screening modalities.
The screening modalities, identifying the second primary
cancer in patients with first primary cancer of the oral cavity,
are upper gastrointestinal endoscopy (n=22), FDG-PET (n=6)
and CT (n=3). FDG-PET detected preoperative second primary
cancer in a case and postoperative second primary cancer in 5
cases
We thank Lynda C. Charters for editing the manuscript.
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4. Discussion
The high incidence of second primary tumors in patients
with oral cancer has been well established worldwide, although
the exact incidence varies from 9 [6] to 21 % [7] depending
upon the report. Our results showed that the incidence of second
primary tumors was 14.7 %, showing same trend in previous
reports.
The presence of second primary tumors in patients with
carcinoma of the oral cavity is an important factor determining
therapeutical approach. Preoperative screening methods are
essential for detecting second primary tumors. Screening for
second primary tumors has changed during the past years. In
1979, endoscopy was postulated as the method of choice [8].
Recently, FDG-PET has received more focus.
In the present study, stomach was the most common site
of second primary tumors. Upper gastrointestinal endoscopy
revealed second primary tumors in 22 (5.3%) of 416 patients
with carcinoma of the oral cavity. This screening method
provided the opportunity to identify second malignancies,
including gastric and esophageal carcinoma. Although new
imaging techniques have been available, upper gastrointestinal
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