Multicenter Retrospective Study of Adjuvant Therapy for Patients with Pathologically Lymph Node-Positive Oral Squamous Cell Carcinoma: Analysis of Covariance Using Propensity Score.
BACKGROUND
The presence of pathologically positive lymph nodes (pN+) is a well-known prognostic factor in oral squamous cell carcinoma (OSCC). The aims of this retrospective multicenter study were to assess the prognosis of OSCC patients with pN+ disease; to compare the prognosis of patients with pN+ disease who underwent surgery plus radiotherapy (RT) or concurrent chemoradiotherapy (CCRT) with that of patients who underwent surgery only; and to account for biases associated with treatment selection of adjuvant RT or CCRT.


METHODS
The records of 313 OSCC patients with pN+ disease were retrospectively reviewed. The main outcome measures were 5-year disease-specific survival (DSS) and overall survival (OS) rates. To reduce selection biases associated with retrospective data, the treatment groups were evaluated by Cox proportional hazard analysis with propensity score as a covariate.


RESULTS
The 5-year OS and DSS survival rates for the entire patient cohort were 51.8 and 59.2 %, respectively. T3-4 stage, closed (<5 mm) margin distance, ≥4 involved nodes, and extracapsular spread were significant poor prognostic factors for OS and DSS. In the propensity score analysis, postoperative RT/CCRT significantly improved OS and DSS compared to surgery only. However, OS and DSS were not significantly different between patients who received postoperative RT and CCRT.


CONCLUSIONS
The addition of cytotoxic chemotherapy to RT does not provide additional survival benefit in OSCC patients with pN+ disease. Alternative strategies, such as molecular targeted therapies, are needed to further improve the survival of high-risk OSCC patients with pN+ disease.
Department of Clinical Oral Oncology, Unit of Translational Medicine, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Japan. syana@nagasaki-u.ac.jp.
Souichi
S
Yanamoto
Department of Oral and Maxillofacial Surgery, Division of Surgery, Tokai University School of Medicine, Isehara, Japan.
Mitsunobu
M
Otsuru
Department of Oral and Maxillofacial Surgery, Division of Surgery, Tokai University School of Medicine, Isehara, Japan.
Yoshihide
Y
Ota
First Department of Oral and Maxillofacial Surgery, Graduate School of Dentistry, Osaka University, Osaka, Japan.
Masaya
M
Okura
First Department of Oral and Maxillofacial Surgery, Graduate School of Dentistry, Osaka University, Osaka, Japan.
Tomonao
T
Aikawa
Department of Dentistry and Oral Surgery, Shinshu University School of Medicine, Matsumoto, Japan.
Hiroshi
H
Kurita
Department of Dentistry and Oral Surgery, Shinshu University School of Medicine, Matsumoto, Japan.
Takahiro
T
Kamata
Department of Oral and Maxillofacial Surgery, School of Medicine, Nara Medical University, Kashihara, Japan.
Tadaaki
T
Kirita
Department of Oral and Maxillofacial Surgery, School of Medicine, Nara Medical University, Kashihara, Japan.
Nobuhiro
N
Yamakawa
Department of Oral and Maxillofacial Surgery, Keiyukai Sapporo Hospital, Sapporo, Japan.
Michihiro
M
Ueda
Department of Oral and Maxillofacial Surgery, Keiyukai Sapporo Hospital, Sapporo, Japan.
Tetsuro
T
Yamashita
Department of Oral and Maxillofacial Surgery, Kobe University Graduate School of Medicine, Kobe, Japan.
Takahide
T
Komori
Department of Oral and Maxillofacial Surgery, Kobe University Graduate School of Medicine, Kobe, Japan.
Takashi
T
Shigeta
Department of Stomatology and Maxillofacial Surgery, Gunma University Graduate School of Medicine, Maebashi, Japan.
Satoshi
S
Yokoo
Department of Stomatology and Maxillofacial Surgery, Gunma University Graduate School of Medicine, Maebashi, Japan.
Masaru
M
Ogawa
Department of Clinical Oral Oncology, Unit of Translational Medicine, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Japan.
Masahiro
M
Umeda
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use; D002294:Carcinoma, Squamous Cell / Q000556:secondary* / Q000628:therapy; D059248:Chemoradiotherapy; D059186:Chemoradiotherapy, Adjuvant; D003131:Combined Modality Therapy; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008198:Lymph Nodes / Q000473:pathology*; D008207:Lymphatic Metastasis; D008297:Male; D008875:Middle Aged; D009062:Mouth Neoplasms / Q000473:pathology* / Q000628:therapy; D009361:Neoplasm Invasiveness; D009367:Neoplasm Staging; D011379:Prognosis; D057216:Propensity Score; D012189:Retrospective Studies; D015996:Survival Rate; D055815:Young Adult