Impact of postoperative radiation therapy for deeply invasive oral cavity cancer upstaged to stage III

Tongue tumor and prognostic factors: Could a diagnostic procedure influence patient outcomes?

OBJECTIVES

Diagnosis of tongue tumors is often performed in primary care centers with an incisional biopsy using stitches in the lesion at the end of the procedure. We hypothesize that stitches placed in tumor tissue could potentially increase local inflammation and significantly affect the tumor microenvironment, influencing the cancer spread and local relapses.

MATERIALS AND METHODS

We conducted a retrospective study involving a consecutive series of 299 patients with Oral Tongue Squamous Cell Carcinoma (OTSCC). The study population was divided into two groups: Group 1 consisting of patients who did not receive stitches during the biopsy and, Group 2 composed by patients who had stitches placed in the tumor at the time of diagnosis. All data collected were statistically analyzed.

RESULTS

The use of stitches during biopsy was associated with a negative prognostic role in Disease Free Survival (DFS), Disease Specific Survival (DSS) and a worsening trend in cause specific overall survival (cs-OS) for early stages (I-II) OTSCC. This negative prognostic impact was confirmed in the cumulative multivariable analyses of the DFS and DSS curves for stages I-II. The negative prognostic impact was not observed for patients with advanced-stage carcinoma and for OS.

CONCLUSION

Our analysis suggested that the placement of stitches during biopsy in patients with early OTSCC may worsen outcomes in terms of DFS and DSS. We recommend evaluating whether stitches are truly necessary during biopsy or if they could be avoided altogether by using less invasive biopsy techniques.

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.

Indication to postoperative radiotherapy for oral cavity squamous cell carcinoma: what’s new in the Depth of Infiltration (DOI) era?

Objectives:

The last edition of the American Joint Committee on Cancer (AJCC eighth) has introduced the depth of infiltration (DOI) as a new prognostic parameter in oral cavity squamous cell carcinomas (OCSCCs). Aim of this study is to analyze the impact of stage migration on the indication to postoperative radiotherapy (PORT).

Methods:

OCSCCs treated at two Institutions between 2014 and 2019 were retrieved. Per the AJCC eighth, only pT3 primarily OCSCCs were considered; availability of the pathologic specimen was a further inclusion criterion. Risk factors considered for PORT were: pT3-pT4, nodal involvement, positive/close surgical margins, perineural and lymph vascular invasion.

Results:

One-hundred forty-nine patients staged as pT3 AJCC eighth were included. A four-fold increase in the number of patients staged as pT3 from the seventh to the eighth AJCC was found. Stage migration to pT3 was equally due to the downstaging from former pT4 (38%) and upstaging of former pT1-pT2 (35%). Considering the former pT1-pT2 53 patients, 13 (25%) had no risk factors for PORT other than DOI. Among 25 cases with former pT1-pT2 and negative lymph nodes no additional risk factors were found in 11 (44%).

Conclusion:

Ninety percent of patients had at least one risk factor besides DOI and would have received PORT also according to the AJCC seventh; notably, of former pT1-pT2N0, half of them have been upstaged to pT3 in the current TNM classification. The role of PORT in this cohort of patients has not been clarified yet.

Advances in knowledge:

Other-than-DOI risk factors leading to PORT indication are highly prevalent in OCSSC patients classified as pT3 per the latest AJCC TNM staging system and should therefore be considered for a comprehensive oncological assessment.

The Impact of Post-Operative Radiotherapy in Early Stage (pT1-pT2N0M0) Oral Tongue Squamous Cell Carcinoma in Era of DOI

Simple Summary

The aim of the present study was to clarify the role of depth of infiltration (DOI) as an independent prognosticator in early stage (T1-T2N0M0) oral cavity tumors. Moreover, whether patients upstaged to pT3 for DOI > 10 mm need postoperative radiotherapy (PORT) in the absence of other risk factors has not been established yet. The DOI alone was not sufficient to impact the prognosis and therefore other risk factors should be considered to indicate PORT indications in upstaged patients due to DOI > 10 mm.

Abstract

Background: This study investigated the role of depth of infiltration (DOI) as an independent prognosticator in early stage (T1-T2N0M0) oral cavity tumors and to evaluate the need of postoperative radiotherapy in the case of patients upstaged to pT3 for DOI > 10 mm in the absence of other risk factors. Methods: We performed a retrospective analysis on patients treated with surgery and re-staged according to the 8th edition of malignant tumors classification (TNM). The role of DOI as well as other clinical/pathological features was investigated at both univariable and multivariable analyses on overall survival (OS), disease free survival (DFS), relapse free survival (RFS), and local RFS. Results: Among the 94 included patients, 23 would have been upstaged to pT3 based on DOI. Multivariable analysis showed that DOI was not an independent prognostic factor for any of the considered outcomes. The presence of perineural invasion was associated with a significant worse RFS (p = 0.02) and LRFS (p = 0.04). PORT was found to be significantly associated with DFS (p = 0.04) and RFS (p = 0.06). Conclusions: The increasing DOI alone was not sufficient to impact the prognosis, and therefore, should not be sufficient to dictate PORT indications in early-stage patients upstaged on the sole basis of DOI.

TNM 8 staging is a better prognosticator than TNM 7 for patients with locally advanced oral cavity squamous cell carcinoma treated with surgery and post-operative radiotherapy

PURPOSE

To assess TNM 8 staging in discriminating overall survival (OS) amongst patients with locally advanced oral cavity squamous cell carcinoma (OCSCC) treated with surgery and post-operative radiotherapy (PORT), compared to TNM 7.

MATERIAL AND METHODS

Data from OCSCC patients treated with surgery and PORT between January 2010 and December 2018 were reviewed. Demographics, tumour characteristics and treatment response data were collected, and patients staged according to both TNM 7 and TNM 8. OS and disease free survival (DFS) were estimated using the Kaplan Meier method. Univariate and multivariable analyses were conducted for factors affecting OS, DFS and early disease recurrence within 12 months.

RESULTS

Overall 172 patients were analyzed. Median follow up was 32 months for all patients and 48 months for surviving patients. TNM 8 staging demonstrated significant stratification of OS and DFS amongst the entire cohort, whereas TNM 7 staging did not. On multivariable analysis, TNM 8 stage, performance status (PS) and a positive surgical margin were prognostic for OS. Looking at disease recurrence within 12 months, TNM 8 stage IVB, presence of lymphovascular invasion (LVSI), younger age and lesser smoking history were predictive factors on multivariable analysis.

CONCLUSION

TNM 8 is a good development of its predecessor in terms of predicting survival for patients with locally advanced OCSCC. We have also identified younger age (<60 years) and a smoking history of <10 pack years as risk factors for early disease recurrence, potentially representing a separate biological cohort within OCSCC patients.

Immortal Time Bias in National Cancer Database Studies

PURPOSE

In studies evaluating the benefit of adjuvant therapies, immortal time bias (ITB) can affect the results by incorrectly reporting a survival advantage. It does so by including all deceased patients who may have been planned to receive adjuvant therapy within the observation cohort. Given the increase in National Cancer Database (NCDB) analyses evaluating postoperative radiation therapy (PORT) as an adjuvant therapy, we sought to examine how often such studies accounted and adjusted for ITB.

METHODS AND MATERIALS

A systematic review was undertaken to search MEDLINE and EMBASE from January 2014 until May 2019 for NCDB studies evaluating PORT. After appropriate exclusion criteria were applied, 60 peer-reviewed manuscripts in which PORT was compared with postoperative observation or maintenance therapy were reviewed. The manuscripts were reviewed to evaluate whether ITB was accounted for, the method with which it was adjusted for, impact factor, year of publication, and whether PORT was beneficial.

RESULTS

Of the 60 publications reviewed, 23 studies (38.3%) did not include an adjustment for ITB. Most studies that did adjust for ITB employed a single landmark (LM) time (n = 31), 4 used a sequential landmark analyses, and 2 used a time-dependent Cox model. In 23 of 31 studies (74.2%) that did adjust for ITB via a single LM time, the rationale behind why the specified LM time was chosen was not clearly explained. There was no relationship between adjusting for ITB and year of publication (P = .074) or whether the study was published in a high-impact journal (P = .55).

CONCLUSIONS

Studies assessing adjuvant radiation therapy by analyzing the NCDB are susceptible to ITB, which overestimates the effect size of adjuvant therapies and can provide misleading results. Adjusting for this bias is essential for accurate data representation and to better quantify the impact of adjuvant therapies such as PORT.