Table 1 The VARIATE project: a mixed methods multiple case study combining qualitative and quantitative research

All patients diagnosed with esophageal and gastric cancer in the Netherlands are registered in the Netherlands Cancer Registry (NCR). Previous multivariable multilevel analyses of potentially curable patients diagnosed in the period 2015–2017 have shown that the probability of receiving treatment with curative intent differed according to the hospital of diagnosis.¹ Hospitals were divided into three tertiles: low, middle or high probability of undergoing treatment with curative intent using the hospital’s odds ratios based on random intercepts. Patients diagnosed in a hospital with a high probability of receiving treatment with curative intent had a significant better long-term survival.¹ In order to obtain in-depth information and knowledge of the underlying mechanisms of hospital practice variation in proposing treatment with curative intent the VARIATE project (VariAtion in the cuRatIve treatment of esophAgeal and gasTric cancEr) was developed, which was financed by the Dutch Cancer Society

Received treatment with curative intent was defined as endoscopic or surgical resection, initiation of surgery (without resection), definitive chemoradiation (external beam radiotherapy and concurrent chemotherapy; including initiation of definitive chemoradiation). Palliative treatment was defined as: palliative systemic therapy, palliative radiotherapy and best supportive care

Design:

The VARIATE project is a mixed methods multiple case study, which combines qualitative and quantitative research. A purposive sample² of eight cases (i.e., hospitals) participated. These hospitals were a representative sample of Dutch hospitals regarding the probability of offering treatment with curative intent, hospital type, size, and geographical location

Quantitative methods: data collection and analyses

Data collection:

Additional quantitative data for potentially curable patients (cT1-4a or Tx, any cN, cM0) diagnosed in 2015 – 2017 was gathered in 67 hospitals in the Netherlands (i.e., data was gathered by the NCR regarding diagnostics, the MDTM treatment proposal and outpatient clinic visits) in order to gain insight in clinical pathways and alterations in MDTM treatment proposal

Analyses:

Quantitative data was analyzed according to the probability of receiving treatment with curative intent using SAS® version 9.4 (SAS Institute, Cary, North Carolina, USA). A p-value below 0.05 was considered statistically significant

Qualitative methods: data collection and analyses

Data collection:

Recruitment: Surgeons or medical oncologists from 11 different hospitals were invited by email. After interest was voiced, JL presented the study during the MDTM of the eight interested hospitals to assess the interest of the multidisciplinary team. All hospitals and team members who saw the presentation wished to participate in the project

The project used an iterative approach for qualitative data collection and analyses. Data collection consisted of:

1. Observations of (Upper-GI specific) MDTMs (2 – 4 MDTMs per hospital) and outpatient clinic visits (minimum of 2 outpatient clinic visits per hospital)

2. Semi-structured interviews (n = 30) with clinicians involved in the multidisciplinary care for esophageal and gastric cancer (i.e., surgeons (S, n = 8), medical oncologist (MO, n = 6), radiation oncologist (RO, n = 5), gastroenterologists (GE, n = 6) and case managers (CM, n = 5))

3. Focus groups with clinicians in order to validate and further enrich the results of their own hospital (n = 7)

4. Focus groups with patients diagnosed with potentially curable esophageal or gastric cancer were organized to explore factors related to their treatment choices (n = 3: low, middle and high probability hospital)

Based on the analysis of the first 3 hospitals the following decisions regarding the quantitative and qualitative data collection in the further hospitals were made:

1. Depending on the emerging topics from previous interviews the topic list was altered (more focus on: MDTMs, cases of doubt, shared decision making)

2. Clinicians in the other five hospitals were selected for interviewing through emergent sampling (i.e., gastroenterologists who did not treat early carcinomas were not invited for participation, recent new members in multidisciplinary teams were not invited for participation)

Analyses:

Qualitative analyses: Interviews were audio recorded, transcribed per verbatim and summarized (all by JL), and shared with the interviewed clinicians serving as member check. Next, the interviews were reviewed and coded, open coding as described by Strauss and Corbin’s grounded theory approach was used.³ The first 11 transcripts were independently coded by two researchers (JL, PV) and discussed until consensus was reached.⁴ The remaining 19 transcripts were coded by JL. Using thematic content analyses emerging themes were found.⁵ Thereafter, through a constant comparison across and within cases (axial coding), relations were searched for and themes were identied.⁶ The core study group (JL, PV, RV, GN) met weekly to discuss analyses, refine the codebook and identify emerging themes. The coding process was facilitated by Atlas ti 8 software

References

1. Luijten JCHBM, Vissers PAJ, Lingsma H, van Leeuwen N, Rozema T, Siersema PD, et al. Changes in hospital variation in the probability of receiving treatment with curative intent for esophageal and gastric cancer. Cancer Epidemiol. 2021;71(Pt A):101,897

2. Patton MQ. Qualitative evaluation and research methods. Thousasnd Oaks, CA: Sage. (1990)

3. Strauss AL, & Corbin, J. M.. Basics of qualitative research: Grounded theory procedures and techniques.. Thousand Oaks: Sage Publications. 1990

4. Korstjens I, Moser A. Series: Practical guidance to qualitative research. Part 4: Trustworthiness and publishing. Eur J Gen Pract. 2018;24(1):120–4

5. Green, J., Thorogood, N., Qualitative Methods for Health Research (3th edn.). London: Sage Publications.2013

6. Yin RK. Case study research: Design and methods. Thousand Oaks, CA: Sage. 1994