Optimized decision support for selection of transoral robotic surgery or (chemo)radiation therapy based on posttreatment swallowing toxicity

Abstract

Background: A primary goal in transoral robotic surgery (TORS) for oropharyngeal squamous cell cancer (OPSCC) survivors is to optimize swallowing function. However, the uncertainty in the outcomes of TORS including postoperative residual positive margin (PM) and extranodal extension (ENE), may necessitate adjuvant therapy, which may cause significant swallowing toxicity to survivors.

Methods: A secondary analysis was performed on a prospective registry data with low- to intermediate-risk human papillomavirus-related OPSCC possibly resectable by TORS. Decision trees were developed to model the uncertainties in TORS compared with definitive radiation therapy (RT) and chemoradiation therapy (CRT). Swallowing toxicities were measured by Dynamic Imaging Grade of Swallowing Toxicity (DIGEST), MD Anderson Dysphagia Inventory (MDADI), and the MD Anderson Symptom Inventory-Head and Neck (MDASI-HN) instruments. The likelihoods of PM/ENE were varied to determine the thresholds within which each therapy remains optimal.

Results: Compared with RT, TORS resulted in inferior swallowing function for moderate likelihoods of PM/ENE (>60% in short term for all instruments, >75% in long term for DIGEST and MDASI) leaving RT as the optimal treatment. Compared with CRT, TORS remained the optimal therapy based on MDADI and MDASI but showed inferior swallowing outcomes based on DIGEST for moderate-to-high likelihoods of PM/ENE (>75% for short-term and >40% for long-term outcomes).

Conclusion: In the absence of reliable estimation of postoperative PM/ENE concurrent with significant postoperative PM, the overall toxicity level in OPSCC patients undergoing TORS with adjuvant therapy may become more severe compared with patients receiving nonsurgical treatments thus advocating definitive (C)RT protocols.

Keywords: decision analysis; definitive (chemo)radiation therapy; head-and-neck cancer; oropharyngeal squamous cell cancer; posttreatment toxicity; transoral robotic surgery.

FIGURE 1

(Top) The underlying process for determining the eligibility of the patient for TORS and its probabilistic outcomes; (Bottom) General decision Tree for TORS decision‐making; scenario 1: definitive RT versus TORS; scenario 2: CRT versus TORS; $p_M^{+}\left(p_M^{-}\right):$ probability of having (not having) positive margins after surgery; $p_N^{+}\left(p_N^{-}\right):$ probability of having (not having) extranodal extension after surgery; $p_{\mathit{TM}}^{+}\left(p_{\mathit{TM}}^{-}\right):$ probability of having tumor resection margin of more (less) than 2 mm after surgery; CRT, chemoradiation therapy; RT, radiation therapy; TORS, transoral robotic surgery

FIGURE 2

Expected deterioration in swallowing function for the first scenario based on (A) short‐term measures and (B) long‐term measures. ${\mathrm{c}}_{\mathrm{S}}$, cut‐off value for TORS; ${\mathrm{D}}^{\text{DIGEST}}$, DIGEST‐based absolute short‐term deterioration in swallowing function; ${\mathrm{R}}^{\text{DIGEST}}$, DIGEST‐based absolute long‐term deterioration in swallowing function; ${\mathrm{\Delta }}_L^{\text{MDADI}}$, MDADI‐based absolute long‐term deterioration; ${\mathrm{\Delta }}_L^{\text{MDASI}}$, MDASI‐based absolute long‐term deterioration; ${\mathrm{\Delta }}_{\mathrm{S}}^{\text{MDADI}}$, MDADI‐based absolute short‐term deterioration; ${\mathrm{\Delta }}_S^{\text{MDASI}}$, MDASI‐based absolute short‐term deterioration; $\mathrm{r},$ risk associated with TORS; RT, radiation therapy; TORS, transoral robotic surgery

FIGURE 3

Expected deterioration in swallowing function for the second scenario based on (A) short‐term measures and (B) long‐term measures. ${\mathrm{c}}_{\mathrm{S}}$, cut‐off value for TORS; ${\mathrm{D}}^{\text{DIGEST}}$, DIGEST‐based absolute short‐term deterioration in swallowing function; ${\mathrm{R}}^{\text{DIGEST}}$, DIGEST‐based absolute long‐term deterioration in swallowing function; ${\mathrm{\Delta }}_L^{\text{MDADI}}$, MDADI‐based absolute long‐term deterioration; ${\mathrm{\Delta }}_L^{\text{MDASI}}$, MDASI‐based absolute long‐term deterioration; ${\mathrm{\Delta }}_S^{\text{MDADI}}$, MDADI‐based absolute short‐term deterioration; ${\mathrm{\Delta }}_S^{\text{MDASI}}$, MDASI‐based absolute short‐term deterioration; CRT, chemoradiation therapy; $\mathrm{r},$ risk associated with TORS; TORS, transoral robotic surgery