Response to Letter to the Editor Regarding “Translation,Cross-Cultural Adaptation,and Validation of the Kannada Version of the Exercise Adherence Rating Scale (EARS-Kn) Among Head and Neck Cancer (HNC) Survivors in a Tertiary Care Setup in India” in Integrative Cancer Therapies

Dear Editor,

We the authors of the manuscript “Translation, Cross-Cultural Adaptation, and Validation of the Kannada Version of the Exercise Adherence Rating Scale (EARS-Kn) Among Head and Neck Cancer (HNC) Survivors in a Tertiary Care Setup in India” ¹ appreciate the constructive feedback regarding our study provided in the Letter to the Editor. We would like to acknowledge the opportunity to provide a response to the important points raised by the author.

In India, Head and Neck Cancer (HNC) accounts for a significant public health burden, primarily due to widespread tobacco chewing habits and alcohol consumption. ² Considering the diverse sociocultural backgrounds of Indian HNC survivors, that is, linguistic diversity, varying literacy levels and cultural beliefs regarding cancer as a disease and its associated treatments, it is essential that patient reported outcome measures (PROMs) undergo meticulous cultural adaptations to ascertain their applicability and validity in the concerned population. Thus, our study aimed to provide a culturally and linguistically robust version of the Exercise Adherence Rating Scale (EARS) for the Kannada speaking population.

The absence of cognitive debriefing interviews in the target population was one of the primary concerns raised by the author. We would like to clarify that cognitive interviewing was conducted in the development of the original English version of the EARS. ³ Given that the cognitive validity of the tool has been previously established by the developers, it remains unclear if there is a necessity to repeat this process for all linguistic and cultural adaptations. Studies that have cross culturally adapted the EARS have not necessarily repeated the process instead resorted to other methods to ensure robustness of the validation process. ⁴ While we recognize the importance of the cognitive debriefing process, we utilized the Visual Analogue Scale (VAS) to determine participants’ comprehension and relevance to the adapted items, a method used in prior adaptation studies.

We also appreciate the concern raised regarding the sampling method and a need to include a wider range of participant characteristics. Our study included HNC survivors from diverse socio-economic, and educational backgrounds as well as presented with different stages of the disease. We do acknowledge that stratification based on the aforementioned points by the author, could potentially enhance the generalizability of our findings.

Future studies should consider stratifying the population based on age, gender, stage of the disease, and habits to increase the understanding of adherence behaviors of the population under consideration.

We acknowledge the discussion regarding the sample size determination. The number of participants to be included in a non – experimental study still remains a debate, we do agree that the rule of thumb varies from 4 to 10 subjects per item however, the recruitment feasibility in our tertiary care set up necessitated a sample size of 34 survivors. Previous studies have demonstrated meaningful psychometric results with smaller sample sizes given that appropriate statistical methods were used. Our study provides preliminary insights into the validity and reliability of the EARS Kannada version, future research with a larger sample size and a diverse cohort of patients would further strengthen the psychometric properties of the tool.

Another crucial point raised was restricting the study population to HNC stages III, IVa, and IVb. While several studies have reiterated that benefits of exercise extends to all stages of cancer, ⁵ our rationale for focusing on advanced stages were to maintain a consistency in the clinical characteristics of our population, particularly due to the increased functional impairments and rehabilitation needs of this population. Moreover, the majority of HNC survivors in our tertiary care set up present with advanced stages of the disease, likely due to lack of awareness regarding the disease as well as lower literacy levels. However, we agree that inclusion of survivors across all stages of cancer treatment could further benefit the validity of the scale, and we encourage future studies to explore its applicability among a broader cohort of survivors.

We appreciate the opportunity to engage in a collegial and constructive discussion to further refine our methodologies for future research. The suggestions and insights provided in the letter to the editor underscores the importance of continued improvements in research involving cultural adaptations. We look forward to future collaborations to enhance the applicability and reach of these essential PROMs in cancer rehabilitation research thus enhancing survivorship outcomes.

Hritika D. Pai, MPT K Vijaya Kumar, PhD Prasanna Mithra, MD, DNB Kasturba Medical College Mangalore, Manipal Academy of Higher Education, Karnataka, India Stephen Rajan Samuel, PhD Mount Vernon Nazarene University, Ohio, USA Mariappan Senthiappan Athiyamaan, MD, DNB Kasturba Medical College Mangalore, Manipal Academy of Higher Education, Karnataka, India Emma Louise Godfrey, PhD King’s College London, UK Institute of Psychiatry, Psychology and Neurosciences, King’s College London, UK