Adjuvant radiotherapy after curative surgery for oral cavity squamous cell carcinoma and treatment effect of timing and duration on outcome—A Taiwan Cancer Registry national database analysis

Abstract

Conduct an accurate risk assessment of resected oral cavity squamous cell carcinoma (OSCC) patients by accessing a nationwide systemic investigation is pivotal to improve treatment outcomes. In this article, we tried to determine the impact of different prognostic factors for OSCC patients who received adjuvant radiotherapy (RT) after curative surgery, using Taiwan's national cancer registry database (TCR). A nationwide, large population‐based study was conducted using TCR with patients identified from 2007 to 2015. The study variables included age, gender, cancer subsites, stage, histology grade, margin and extra‐nodal extension (ENE) status, treatment type, surgery to RT interval (ORI), total RT treatment time (RTT), and RT dose. Univariate and multivariate analysis were performed to identify predictors of the variables associated with overall survival (OS), cause‐specific survival (CSS), local‐regional relapse‐free survival (LRFS), and distant metastasis‐free survival (DMFS). 8986 OSCC patients treated with surgery and adjuvant RT were analyzed. In multivariate analysis, worse outcomes were associated with males, older age, subsite in the oral tongue, advanced stage, higher histologic grade, involved margin, and positive ENE. ORI only showed an adverse trend in LRFS, when exceeding 7 weeks (P = .06). RTT >8 weeks was a significant poor predictor in OS, CSS and LRFS (P < .001). Extreme RT dose (>70 Gy or ≤50 Gy) also demonstrated an adverse impact on the outcomes. Prolonged RT treatment time and extreme RT doses were identified as significantly poor prognostic predictors in OSCC patients who received adjuvant RT after curative surgery.

Characteristics and prognosis of primary treatment-naïve oral cavity squamous cell carcinoma in Norway, a descriptive retrospective study

“…This is according to current recommendations [35], and was a positive finding, as these patients were treated nine to 14 years ago when MDT meetings were less established than today. Cancer in the oral cavity is normally managed by surgical removal of the primary tumor, sometimes combined with neck dissection and/or RT, while chemotherapy is seldom used [28][29][30][31][32][33][34]. The same standard of treatment was also found in our cohort.…”

“…Primary surgery is the preferred treatment for oral cavity squamous cell carcinoma (OCSCC) in most institutions when the tumor is regarded resectable, with or without reconstruction and neck dissection. Postoperative adjuvant radiation therapy (RT) is often necessary, whereas chemotherapy is seldom used, except sometimes for advanced stages [28][29][30][31][32][33][34]. The treatment should be decided by a multidisciplinary team (MDT) [35].…”

Not So Fast: Deintensification Therapy for Locally Advanced Oral Cavity Cancer

“…It was observed that males over the age of 70 years with tongue cancer who received the standard of care (surgery þ adjuvant radiation therapy) had poorer locoregional recurrence-free survival, overall survival, and response to adjuvant radiation compared with younger patients. 2 In conclusion, the findings from Lin et al identify a subgroup of patients with locoregionally advanced oral cavity SCC who may be optimally treated by surgery alone with good local control and very good disease-specific and overall survival. In light of the well-known caveats of retrospective studies, we cannot recommend deintensification of this cohort as the standard of care at this time.…”

Missed radiation therapy sessions in first three weeks predict distant metastasis and less favorable outcomes in surgically treated patients with oral cavity squamous cell carcinoma

“…Adherence to the initially prescribed RT regimen is paramount to ensure optimal treatment outcomes, and deviations from the initial schedule may have adverse prognostic implications. In this context, published studies have shown that several variables related to the RT scheduleincluding length of radiation time, premature discontinuation of RT, and time to initiation of postoperative RTpredict prognosis in patients with head and neck malignancies [7][8][9][10][11][12].…”