Clinical evaluation of Lugol’s iodine staining in the treatment of stage I–II squamous cell carcinoma of the tongue

Abstract

Oral squamous cell carcinoma (OSCC) is often surrounded by epithelial dysplasia; leaving it unresected can result in local recurrence. Staining with Lugol’s iodine solution detects epithelial dysplasia in oral mucosa, but whether it decreases local recurrence after OSCC surgery is unknown. This study investigated local recurrence rates in patients with early tongue cancer who underwent surgery using Lugol’s staining. 93 patients with T1-2N0 tongue SCC underwent partial glossectomy using Lugol’s staining during surgery. Resection was performed at least 5 mm from the margin of the unstained area. Patients were investigated retrospectively for local recurrence status. Postoperative histology revealed negative surgical margins for SCC or epithelial dysplasia in 81 patients, close margins for SCC in 5, positive margins for mild epithelial dysplasia in 6, and a positive margin for SCC in one. Those with a positive or a close margin for SCC underwent additional resection 2–4 weeks after surgery; one was proved histologically to have residual SCC. No patients developed local recurrence, but 2 died of neck metastasis and 2 of distant metastasis. The 5-year disease specific survival rate was 93.8%. Lugol’s staining during surgery can reduce local recurrence and improve survival in patients with early tongue SCC.

Squamous cell carcinoma (SCC) of the tongue is often surrounded by epithelial dysplasia, and leaving it unresected can result in local recurrence or secondary primary cancers . The authors previously reported that patients with oral SCC (OSCC) developing local recurrence more than 3 years after the initial treatment often showed epithelial dysplasia of the adjacent mucosa, in contrast to those developing local recurrence within 3 years, but the region of epithelial dysplasia cannot be easily distinguished macroscopically from the normal epithelium during surgery.

Several studies have shown that viral staining with an iodine solution was useful for detecting the extent of epithelial dysplasia surrounding oral or esophageal carcinoma . K urita and K urashina reported that vital staining with an iodine solution had great potential in determining the precise borders of the dysplastic epithelium and that a margin of 5 mm from the iodine unstained area was adequate for the complete removal of the dysplastic epithelium. Some investigators described the usefulness of iodine staining in the diagnosis of epithelial dysplasia , but it has not been well documented whether the use of staining decreased local recurrence after OSCC surgery. In this study, the local recurrence rate in patients with early tongue cancer who underwent surgery using iodine staining during surgery was investigated.

Materials and methods

The subjects were 93 patients with T1-2N0 SCC of the tongue who underwent surgery between 2000 and 2008. The tongue lesion was dried with gauze, 10% Lugol’s solution was applied to it and was washed off immediately. The lesion was observed macroscopically 1 min after the application. Resection was performed 10 mm away from the induration of the cancer and 5 mm away from the margin of the Lugol’s unstained area ( Fig. 1 ). The histological features of the surgical margin and clinical courses of the patients were examined with special reference to the local control status.

Fig. 1
Surgery for early tongue cancer: (a) before surgery, (b) unstained area with Lugol’s staining, (c) incision line almost 5 mm away from the Lugol’s unstained area, and (d) operation wound after partial glossectomy.

Results

The distribution of patients with early tongue cancer by sex, age, stage, treatment method is summarized in Table 1 . 51 patients were male and 42 female, they were 29–91 years old (average 61.4 years). 54 patients were in stage I and 39 were in stage II. All 93 patients underwent surgical resection of the tumour under general anaesthesia. 79 patients underwent partial glossectomy alone; 14 underwent partial glossectomy accompanied by reconstructive surgery including a free forearm flap (FAF) in 10 patients, a free rectus abdominis myocutaneous flap (RAM) in 2, a pedicled pectoralis major myocutaneous flap (PMMC) in 1, and a pedicled platysma myocutaneous flap in 1.

Table 1
Patient distribution.
Sex
Male 51
Female 42
Age 29–91 (mean; 61.4 years old)
Stage
Stage I 54
Stage II 39
Treatment method
Glossectomy alone 79
Glossectomy + platysma flap 1
Glossectomy + FND + FAF 10
Glossectomy + FND + RAM 2
Glossectomy + PMMC 1
Total 93
FND: functional neck dissection; FAF: free forearm flap; RAM: rectus abdominal myocutaneous flap; PMMC: pectralis major myocutaneous flap.

Postoperative histological examination revealed a negative surgical margin for SCC or epithelial dysplasia in 81 patients, a close margin for SCC (<1 mm) in 5, a positive margin for mild epithelial dysplasia in 6, and a positive margin for SCC in 1 ( Table 2 ). Five patients diagnosed with a close margin for SCC underwent additional resection 2–4 weeks after surgery, none of the 5 showed any residual cancer. 6 patients with a positive margin for mild dysplasia were followed without secondary resection. One patient who showed a positive margin for SCC underwent additional resection 2 weeks after the initial surgery, and was proved histologically to have residual SCC. None of the 93 patients developed any local recurrence for a postoperative period of 6–100 months (average 46 months).

Table 2
Histological surgical margin findings.
Surgical margin Patients Additional therapy Local recurrence
Free from SCC or dysplasia 81 None None
Positive for mild dysplasia 6 None None
Positive for SCC (superficial margin) 1 Immediate resection → histologically proven residual cancer None
Close for SCC (deep margin) 5 Immediate resection → histologically no residual cancer None

Functional neck dissection was performed as initial surgery in 13 patients who underwent reconstructive surgery using a FAF, RAM or PMMC. Amongst them, 2 had histologically proven neck metastasis, but all 13 patients were loco-regionally cured. Of 80 patients without neck dissection as the initial therapy, 16 developed secondary neck metastasis. Of these 16, 2 resulted in neck failure and 2 others developed distant metastasis despite loco-regional control.

The final outcome was as follows: 87 alive without disease, 2 died of neck metastasis, 2 died of distant metastasis, and 2 died of other causes (esophageal cancer and Idiopathic Thrombocytopenic Purpura (ITP)). No patients developed local failure. The 5-year disease-specific survival rate was 93.8%.

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Feb 7, 2018 | Posted by in Oral and Maxillofacial Surgery | Comments Off on Clinical evaluation of Lugol’s iodine staining in the treatment of stage I–II squamous cell carcinoma of the tongue
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