Patterns of failure and clinical outcomes of post-operative buccal mucosa cancers treated with adjuvant ipsilateral radiotherapy

Clinical outcomes and failure patterns after postoperative radiotherapy for oral cavity squamous cell carcinoma

PURPOSE

This study aimed to assess recurrence patterns and identify the optimal dose and target volumes of postoperative radiotherapy (PORT) in patients with oral cavity squamous cell carcinoma (OSCC).

METHODS

Data of 111 patients who received PORT for OSCC between January 2010 and April 2020 were retrospectively reviewed. The median age was 68 years (range 19-88). PORT was administered as initial treatment to 63 patients and as salvage treatment for recurrent tumors to 48 patients. The median prescribed dose was 60 Gy (range 50-66) administered in 30 fractions (range 25-33).

RESULTS

Median follow-up time was 73 months (range 24-147). Overall survival (OS), progression-free survival (PFS), local control (LC), and locoregional control (LRC) at 3 years were 55.6%, 45.6%, 74.6%, and 63.1%, respectively. There were no significant differences in OS, PFS, LC, and LRC between the initially diagnosed and postoperative recurrent cases. Of 22 patients (20%) who developed regional nodal recurrences, 17 (15%) and 11 (10%) had in-field and out-of-field recurrences, respectively. Of 105 patients who received irradiation to the primary tumor bed, 24 (23%) developed recurrence at the primary site. The PFS and LC rates were significantly worse in patients receiving ≤ 56 Gy to the primary site than those receiving > 56 Gy (p = 0.016 and p = 0.032, respectively).

CONCLUSION

PORT was effective for postoperative recurrences as well as for initially diagnosed oral cavity cancer. Doses greater than 56 Gy to the primary site may be required in PORT for OSCC.

Pattern of locoregional failure in postoperative cases of locally advanced carcinoma of buccal mucosa treated with unilateral versus bilateral neck radiation: lesson learned from a basic practice setup

Background

Carcinoma of buccal mucosa forms a sizeable percentage of the diagnosed oral cavity cancers in India. There is limited data on elective treatment of the contralateral neck for well-lateralized carcinoma with no involved nodes in the contralateral neck. We conducted this study to compare locoregional control in patients treated with unilateral vs. bilateral neck irradiation.

Materials and methods

48 patients with carcinoma of buccal mucosa were selected. Patients were divided into unilateral and bilateral arms based on radiation treatment of the ipsilateral or bilateral neck. All patients received adjuvant radiation with Cobalt 60 unit. Patient-specific and follow-up data were collected from records and dosimetric data from treatment planning system (TPS). Chi-square and unpaired t-test was used to compare data between arms and Kaplan Meier plot; Cox regression was used for survival analysis.

Results

After a median follow-up of 23 months, 15 (31.3%) patients had developed disease recurrence, 8 and 7 in the unilateral and bilateral arms, respectively (p = 0.591). There was no contralateral neck failure during the follow-up period. The 2-year disease-free survival was 68.2% and 72.2% in the unilateral and bilateral arms, respectively. Among risk factors for disease recurrence, depth of invasion (DOI), delay in starting radiation and planning target volume (PTV) coverage were significant contributing factors. Cox multivariate regression suggested DOI and delay in starting radiation to be significant prognostic factors for disease-free survival (DFS).

Conclusion

Bilateral neck radiation does not provide any advantage over ipsilateral neck radiation for properly selected well lateralized buccal mucosal squamous cell carcinoma. Ipsilateral neck radiation facilitates better sparing of organs at risk.

Adjuvant contralateral neck irradiation for oral cavity cancer - A systematic review and meta-analysis

INTRODUCTION

Whether contralateral neck irradiation should be administered for oral cavity cancer is a critical question because patients receiving bilateral neck irradiation experience more adverse effects. Patients not receiving contralateral neck irradiation are at risk of contralateral neck recurrence of oral cavity cancer MATERIALS AND METHODS: Meta-analysis and subgroup analysis were performed for the rates of contralateral neck recurrence of oral cavity cancer in patients receiving no contralateral neck radiation. We aimed to identify the patient group suitable for contralateral neck radiotherapy omission. The PRISMA guideline was used for this study. We extracted data including the first author, country, sample size, numbers of patients receiving ipsilateral neck radiotherapy and experiencing contralateral neck recurrence, participant characteristics, and details of cancer types RESULTS: The rate of contralateral neck recurrence is extremely low, 3.4% (95% confidence interval: 2.2%-5.4%). Isolated contralateral neck recurrence occurred in 18 of 524 patients receiving radiotherapy to the primary tumor site with or without ipsilateral irradiation. The subgroup analysis was conducted to investigate pathological lymph node stage and subsite. Subgroup analysis showed that the N2-3 group was more likely to exhibit recurrence in contralateral neck than the N0-1 group was (14.4% versus 1.5%, p = 0.0008). In addition, the contralateral neck recurrence rate was 6.3% (95% CI = 2.3%-13.1%) and 2.8% (95% CI = 1.5%-4.8%), in the tongue cancer patient group and the non-tongue cancer patient group, respectively. Meta-regression showed that the rate of contralateral recurrence was not different between both groups (p = 0.08). Only 2 exhibited isolated contralateral neck recurrence (5.1%) in pN0-1 tongue cancer patient. Most of them (>90%) are lateralized.

CONCLUSION

In conclusion, the omission of contralateral irradiation is reasonable in pN0-1, well lateralized oral cavity cancer.