Why did you develop the Salivary Gland Cancer Model?
Salivary gland malignancies are relatively rare with extensive taxonomy and morphological diversity making them challenging to study with prospective randomized trials. To date there are no randomized data to support the use of postoperative radiotherapy (PORT) for major salivary gland malignancies, though retrospective analyses have demonstrated that PORT for locally advanced and high-risk major salivary gland cancers offers an overall survival benefit compared to no adjuvant therapy. Our primary objective was to develop and internally validate a prediction model to estimate overall survival with and without PORT for resected major salivary gland cancers.
What pearls, pitfalls and/or tips do you have for users of the Salivary Gland Cancer Model?
The model was developed and internally validated using the National Cancer Database (NCDB) and is subject to the inherent limitations of the data source including but not limited to coding errors, incomplete data, selection bias, and lack of locoregional recurrence. However, only subjects with completely coded demographic and pathologic data in the prognostic factors of interest were included in the creation and validation of this nomogram. This nomogram is strengthened by a large number of patients treated in a contemporary era when intensity modulated radiation therapy (IMRT) was widely available. It is also strengthened by mature median follow-up of 4.9 years for the entire population. Additionally, stringent radiotherapy thresholds were utilized to minimize underestimating the true benefit of PORT by excluding subjects who received an insufficient dose or had an excessively long radiotherapy treatment duration.
What recommendations do you have for practitioners who utilize this Salivary Gland Cancer Model?
I would caution practitioners to not use these results to justify omitting adjuvant therapy if there is no predicted overall survival benefit with versus without PORT. In the appropriate population, such as those with adverse features specified in NCCN guidelines, PORT may meaningfully reduce the risk of locoregional recurrence.
How do you use the Salivary Gland Cancer Model in your own clinical practice?
The predicted score with the 95% confidence interval helps me more accurately counsel patients regarding their individual prognosis when they specifically request this information.
