2.1. Study Design

The study used a longitudinal mixed-methods design.

This research was reviewed by the NHS research ethics committee (REC reference 21/PR/1486, IRAS ID 300947). Informed consent to participate was received from all participants.

2.2. Participants and Procedures

Participants for the cross-sectional survey were recruited using a multi-pronged sampling strategy incorporating convenience and snowball sampling. Information about the questionnaire was disseminated via The Peritoneal Malignancy Institute Basingstoke (PMI), HASAG (a national asbestos support group charity), mesothelioma patient support groups, Mesothelioma UK and the Mesothelioma UK Research Centre (MURC). The study was shared via social media to gain wider participation.

The longitudinal case study used a convenience sampling method. Patient participants were identified via the survey, which asked respondents to provide their email address if they were interested in participating in the case study. Asbestos support workers, and HCPs such as oncologists and clinical nurse specialists (CNS), were referred to as ‘professionals’. Family/informal carers/friends were referred to as ‘carers’.

Based on the existing literature and previous studies conducted by the research team [8–10], a sample size of seven case studies was considered sufficient to ensure data saturation [11]. Carers and professionals were identified by the patient. This method of identifying carers and professionals allowed recruitment to take place in a timely fashion [12] and for patients to self-select those people who they felt had most involvement in their care pathway. Purposive sampling was used to select a range of participant demographics and variation in experience such as age, time since diagnosis and gender with a focus on positive deviance. Patients were invited to participate and were provided with written and verbal information prior to consenting to the interview. Professionals and carers identified by the participant were invited to participate.

2.3. Stage 1: Data Collection: Cross-Sectional Survey

Survey content was informed by previous studies conducted by the Mesothelioma Outcomes Research and Experience (MORE) survey [13], Mesothelioma UK Research Centre Research Prioritisation Exercise [14] and a rapid evidence review [15].

The survey collected data on demographic characteristics: pathway of treatment and care (including details of diagnosis, referrals, number of specialties seen, time to diagnosis, onward referral or not) to NMDT, CNS involvement and treatments offered and received and experiences of care. Potential participants were asked to complete the survey via Google Forms or a hard paper copy, depending on participant preference. At the beginning of the online survey, there was a link to the Patient Information Sheet (PIS). By completing the survey, the participant implied consent. On request, hard paper copy PIS and surveys were posted.

Data analysis included the use of descriptive statistics and exploration of the relationship between patient variability of treatment and care using bivariate correlations when appropriate. SPSS Version 29 was used for the analysis.

2.4. Stage 2: Data Collection: Longitudinal Case Study Series

We recruited seven case studies comprising seven patient participants, eight carers and six professionals (Table 1). Patients were asked to take part in serial interviews (up to three) over a course of 12 months. Carers and professionals were interviewed once. Each interview took place online or over the phone, depending on patient preference, and lasted up to 1 hour. Patient and carer interviews were undertaken between February and December 2022. Professional interviews were conducted between August and October 2022.

The interview topics were generated through the exploration of existing literature and previous studies conducted by a research team [8,10]. The semi-structured interview schedule focussed on patients/carers’ experiences of living with PM (from before diagnosis to current), experiences of the care pathway, diagnosis, referral, treatment; barriers and facilitators to a consistent care pathway; and satisfaction with care. The interview schedule (Appendix 1) for professionals asked about perceived variability in the PM patient pathway and any implications of this. Interviews were recorded, transcribed verbatim and imported into Quirkos© software for analysis.

Given the lack of evidence in patient experience and mesothelioma, it was decided to organise the case studies according to a descriptive framework of the pathway [16,17]. Once the framework was developed, findings were plotted onto this framework. Four steps in data analysis were followed: (1) the patient and carer transcripts were re-read through for accuracy, and any patterns were noted; (2) the descriptive framework based on key experiences in the peritoneal pathway was developed. VS, CG, SEM and SW developed separate frameworks and then discussed them and developed an amalgamated framework. They each then coded one patient and one carer interview and amended the coding framework. Iterative revisions to the coding framework were made following further team discussions; (3) data for all patients, carers and professionals was coded and (4) the framework was then populated with data from patients, carers and professionals. Developed codes were then organised into potential themes, which were arranged in tables and revised. Rigour was supported by data immersion, iteration, team discussions, reflexive analysis and audit trail. To ensure that the themes were grounded in the data, they were supplemented by direct quotes from the participants. All participant names are pseudonyms.

2.5. Stage 3: Case Note Review

For the case note review, data were collected from hospital medical records, using a standard proforma, which collected information on the date first presenting to an HCP, presenting symptoms, any alternative diagnoses documented, hospital specialist/s referred to, date diagnosis received, who gave diagnosis, number of hospital admissions, treating speciality oncologist and did the patient have a named CNS allocated to them. The case notes of seven patients were those of the seven interviewed patients, and the data obtained from the case notes were entered onto a pseudonymised case report form and given a unique study number.

3.1. Demographics of Study Participants

Forty-seven patients (30 women and 17 men) responded to the survey between February 2022 and December 2022 (Table 1). Overall, most patients had epithelioid mesothelioma (46%); 6% had sarcomatoid, 4% had a well-differentiated papillary mesothelial tumour, 23% had multicystic mesothelioma and 21% did not know which type of mesothelioma they had. All patients had primary PM and did not have pleural mesothelioma upon diagnosis. Half (51%) of the respondents had a spouse as a carer. Twenty-five percent of the respondents had a high level of education (postgraduate).

3.2. Pathway to Diagnosis

The survey and interview data revealed considerable variation in the symptoms that patients experienced prior to receiving their diagnosis. The most reported presenting symptoms were abdominal pain, tiredness, change of bowel habit, shortness of breath, sweating and weight loss. Interviews with patients reported that the nature of the PM symptoms had led to some delaying going to their GP as they had not recognised them as serious or requiring urgent attention.

The survey revealed a median of 183 days to receive a diagnosis of PM (Table 2), and 45% of surveyed patients perceived avoidable delays in their diagnosis. Survey results and case note review data indicated that extended diagnostic pathways were partly explained by the broad range and multiple specialities patients were referred to (Figure 1) and show that multiple alternative diagnoses were given (Table 3). Interviews and case note review data reflected the complex routes to receiving a diagnosis of this rare cancer.

Eighteen surveyed patients and four case note patients were informed of an alternative diagnosis before PM diagnosis (Tables 2 and 3): ovarian cancer (n = 5), endometriosis (n = 3), cancer of unknown primary (n = 3), pseudomyxoma peritonei (PMP) (n = 3), no cancer found (n = 2), irritable bowel syndrome, appendicitis, sarcoma, paraganglioma, peritonitis, mullerian tumour and pancreatic cancer (n = 1). Forty patients were given a PM diagnosis by a consultant. Seventy percent said the diagnosis was understandable, 19% said the diagnosis was not understandable and 62% said it was given in a sensitive way.

3.3. Management

Survey results demonstrate variation in oncology speciality for ongoing management and treatment for PM patients (Table 2). Sixteen patients were referred to the NMDT and/or a peritoneal malignancy surgeon. Six patients sought a second opinion from the NMDT for diagnosis confirmation and surgical opinion for CRS and HIPEC. Two patients had a second opinion with a mesothelioma oncology expert, and two patients sought a second opinion overseas. Case note data showed that one patient asked their GP to refer them to another oncologist to explore the option of an immunotherapy clinical trial. Professionals interviewed demonstrated a recognition that much of their (HCP) experience came from pleural mesothelioma as this formed the largest part of their clinical caseload.

However, there was evidence that this may not be a consistent practice across England as some oncologists may not be aware of the NMDT; others were more likely to refer only if surgery was felt to be a treatment option. Factors influencing referral to the NMDT were awareness of the NMDT, the local MDT decision to refer, for example, deciding not to refer due to the delays in waiting for NMDT meeting outcomes (NDMT being monthly), and individual perspectives of the local team on benefits of surgery versus SACT in PM.

3.4. Treatment

Of the surveyed patients, 87% were satisfied with their treatment. Seeing a gynaecological oncologist was associated with being less satisfied with treatment (Pearson statistic −0.395, p = 0.006, p ≤ 0.01 n = 47), though these numbers are small. Patients were asked if they were offered various treatments, such as chemotherapy, immunotherapy and clinical trials (Table 2). No patients received radiotherapy. Most patients referred to the NMDT were recommended SACT. Sixteen patients received CRS and HIPEC at the PMI surgical centre. Review of case note data revealed one patient, and their family enquired with the oncology clinic registrar about CRS and HIPEC offered at the NMDT, but the professional explained there was significant peritoneal involvement and therefore first-line treatment would be chemotherapy. The case notes continued, with the doctor explaining that if there was a suitable response to chemotherapy, referral to the NMDT would be appropriate.

3.5. Factors Influencing Variability

Survey data showed vast variability of the pathway but no correlations. There was no significant correlation between satisfaction (in investigation or treatment) and time to referral or time to diagnosis (Table 4). There was no significant correlation between avoidable delays (Pearson 0.269, p = 0.11, n = 47). There were no relationships between presenting symptoms and the first specialist the patient was referred to (Table 5). There was no significant correlation between avoidable delays and patients’ perception of how delays affected their quality of life (Pearson 0.269, p = 0.11, n = 47), with patients who had experienced delays more likely to have an effect on the quality of life. Lack of correlation is likely due to the small sample size or because indeed the PM pathway is hugely varied between patients.

3.6. Overall Experience of the Diagnostic and Treatment Pathway

4.1. National Health Service (NHS) and the Management of Peritoneal Malignancy in the United Kingdom

The NHS was established in 1948 to provide free health services in the United Kingdom to everyone in the country based on need, not ability to pay. The NHS is funded by national taxation and is led by NHS England. The government sets the framework for the NHS and is accountable to Parliament for its operation. However, most decisions are made by the local NHS and by patients with their clinicians.

There are a limited number of centres in the United Kingdom providing peritoneal malignancy services (PMS). NHS England commissioned a service for the assessment and management of patients with peritoneal malignancy, and as such, PMP and colorectal peritoneal metastases have highly specialised commissioning at PMI Basingstoke Hospital and the Christie Hospital in Manchester. As part of this commissioning arrangement, the service must evaluate the assessment and management of this disease type and report on its effectiveness. An interim commissioning policy for PM has been superseded by NHS England’s decision not to routinely commission CRS and HIPEC for PM. Requests to date have been unsuccessful, and PMI Basingstoke currently offers this service at local tariff rates and continues to host the NMDT.

Surgical, gynaecological and colorectal specialities are likely to have the knowledge of PMS available in the United Kingdom; however, nonsurgical specialities could be less aware. The authors believe that specialities unaware of PMS could negatively impact the care pathway and suggest that PMS positivity impacts the patient care pathway and experiences through cohorting a rare cancer within centres of excellence and expert HCPs.

4.2. Multidisciplinary Team Working

While our findings show that referral to the NMDT for PM patients does not appear to be a routine practice in England, the wider literature shows that there may be benefits to MDT referral for mesothelioma patients. MDTs have been integrated in routine cancer care in the United Kingdom since 2000. Specifically, the NHS Cancer Plan recommends that all cancer patients should be discussed in cancer-specific MDT meetings [19]. To facilitate this, the UK Department of Health Mesothelioma Service Framework [20] recommends mesothelioma cases be discussed at a specialist mesothelioma MDT meeting to provide opportunity for discussion among experts. This is also the recommendation in the British Thoracic Society guidance [21]. The National Mesothelioma Audit [4] and the European Society for Medical Oncology pleural mesothelioma clinical guidelines recommend that treatment strategies should be discussed at an MDT with experience in mesothelioma management [22]. The benefits of a specialist mesothelioma MDT are enhanced patient satisfaction, staging, diagnostic accuracy, classification of subtype, treatment and increased recruitment in clinical trials [3,7,19,23,24]. Brandl et al. [1] suggest that centralising expert surgical opinion is effective at selecting patients appropriate for CRS and HIPEC and this expertise makes important contributions to the management of patients with PM.

4.3. Communicating a Diagnosis

Interviewed patients commented on the need for better communication and discussion around diagnostic tests and treatment options including CRS and HIPEC. They also reported the need for more information about what to expect from having PM and regular HCP–patient check-ins. Patients wished to understand different treatment options available as they could make more informed decisions. Well-coordinated, timely, thorough and compassionately delivered diagnoses were valued, but often HCPs lacked the depth of knowledge about PM.

When communicating a PM diagnosis, HCPs are faced with balancing the provision of accurate information while maintaining hope [25]. Taylor, Warnock and Tod [18] studied the challenges associated with communicating a mesothelioma diagnosis, which included the lack of time allocated to patients and carers at diagnosis, the lack of access to ongoing training for HCPs delivering diagnoses and the lack of suitable clinical environments in which to deliver information. Furthermore, Wittmann et al.’s [26] study of oesophagogastric cancer found that some patients wanted a great deal of information regarding their illness compared to the HCP’s perception. By identifying how much information a patient wishes to receive and the best way to deliver this information, patient experience can be positively impacted.

Patient participants also expressed they wanted their HCP to acknowledge the prognosis differences between pleural and PM. Most published studies including pleural and PM do not differentiate between the two, and many studies only include pleural patients [27]. There is a scarcity of information available for people living with PM and those that care for them in both personal and professional capacities.

7.1. Footnote

Since completing this study, the first-line SACT has been changed from chemotherapy using a platinum-based agent and pemetrexed to immunotherapy using ipilimumab and nivolumab. The Checkmate 743 clinical trial [27] included pleural mesothelioma only, and it is important to note that immunotherapy research is limited in PM. PM patients can receive first-line ipilimumab and nivolumab.