Cancer incidence in the middle region of Libya: Data from the cancer epidemiology study in Misurata

Abstract Background Cancer incidence and cancer registries are essential for local epidemiological information. In Libya, scarce evidence exists with regard to incidence rates and distribution. Aim To estimate cancer incidence in Libya and draw trends of cancer type distribution compared to regional and worldwide data. Such incidence data are needed to inform strategic decisions on cancer facilities, training, and research in the given geographical area of Misurata, the major city in the middle region and third largest in Libya. Methods This is an observational, multi‐centre, city‐wide study to account for all cancer cases. All radiology (computed tomography and magnetic resonance imaging) and pathology reports were examined across all public and private hospitals in and around Misurata. Results Four hundred and thirty cancer cases were identified to have been diagnosed during 12 months (July 2019–June 2020), yielding a cancer incidence of 71.7 per 100 000 population. Breast cancer (84, 19.5%), colorectal cancer (83, 19.3%), lung cancer (33, 7.7%), and prostate cancer (21, 4.9%) had the highest prevalence. Conclusion Cancer incidence established in this study stands at 71.1, much lower than the worldwide reported incidence of 201.0. Several limitations lead to missing cancer cases from the survey period, mostly related to poor documentation, non‐research friendly environment, and disorganised healthcare structure. Nevertheless, distribution by type represents a true contrast to the world cancer report. Finally, a national or regional inclusive cancer registry is essential to the flow of information that supports strategic planning and decision‐making in developing cancer care in the country.


| INTRODUCTION
Cancer is an important cause of morbidity and mortality worldwide. It is the first or second leading cause of premature death in 134 of 183 countries. 1 The predicted global cancer burden is expected to exceed 27 million new cancer cases per year by 2040. Such an increase will be most significant in underdeveloped countries. 1 According to the WHO world cancer report 2020, which estimated cancer incidence at 19.3 million new cases, the six most common cancer types worldwide are lung, breast, colorectal, prostate, stomach, and cervical cancer. 1 Libya has no reliable contribution to this representative data, as there is no comprehensive national or local cancer registry to reliably account for the numbers, types, morbidity, and mortality of cancer.
Cancer registry in Arab countries: countries reporting in IARC volume 9 of CI5 (cancer in 5 continents) series are Kuwait, Oman, Algeria, Bahrain, Egypt, and Tunisia. Regarding other Arab countries, cancer incidence data are found on the Globocan 2020 website. 2 In male population, lung cancer is the most frequent neoplasm in all the Arab world, except for Yemen, Saudi Arabia, and Mauritania, in which the most common cancers are oral, liver, and prostate, respectively. Breast cancer, almost without exception, is the most frequent tumour type in females. 3 Liver and bladder cancers are exceptionally predominant in Egypt. 4 In Libya, local hospital-based cancer registries declare total numbers diagnosed and treated without any geographical reference, making it impossible to arrive at a cancer incidence rate in relation to the population of the area covered by the hospital.
The literature has scattered articles about cancer epidemiology in Libya. In 2017, a report accounted for 1051 new cancers seen in Tripoli Medical Centre, but the study had no geographical limits as it is a regional centre. 5 Similarly, 1160 were registered in Benghazi Medical Centre in Libya in 2003 but still lacked external validity. 6 Both published registers did not attempt to account for all cancers, whether seen in the medical centre or otherwise, that is, cancers were included even if they were outside Benghazi or Tripoli.
Knowledge of cancer epidemiology contributes not only to the national census but also serves to guide strategic health planning, structuring, capacity building, staff recruitment, and even medical research, education, and training.
By default, setting up and maintaining a national cancer registry is a central duty of the ministry of health and a recommendation by the WHO and IARC. 1,7 However, no such setup exists, and no ongoing local registry produces data relevant to a specific geographical population.
The research team came together to take the initiative to gather diagnostic information to estimate the incidence of cancer in the geographical location of Misurata, which is the largest city in the middle region and third largest in Libya, as well as clarifying other epidemiological features such as age and type distribution compared with previous regional studies in Eastern Libya and the rest of the world.
F I G U R E 1 Cancers identified by the study only and those found in the NCI's registry and cancers that were both present in the study and NCI registry 2 | METHODS

| Study type
The project is an observational, prospective, multi-centre city-wide study (survey) to calculate the annual incidence of cancer in Misurata, Libya. The survey lasted for 12 months between July 7, 2019 and June 30, 2020.

| Study setting
Sixteen centres in and around Misurata were identified; these include the National Cancer Institute (NCI), a dedicated national cancer centre, Misurata Medical Centre (MMC), a tertiary regional centre, and 14 private hospitals.

| Inclusion and exclusion criteria
• All public and private healthcare facilities were included in the study.
• All patients who have had cross-sectional imaging, that is, computed tomography (CT) or magnetic resonance imaging (MRI), or pathological sample, were included in the survey.
• Reports with a malignant histopathology diagnosis were included.
• Non-malignant histopathology reports were excluded.
• Imaging reports highly suggestive of malignancy were included but after considerations by a senior member of the team.
• Imaging with non-malignant reports was excluded.

| Data collection procedure
Pathology and imaging reports were collected directly from the clinical team, regularly (weekly to monthly depending on work size) by the research team, filtered to exclude non-malignant reports. The research team only examined the reports rather than the images or samples.
Patients/relatives were contacted to confirm or refute the diagnosis. when and where a cancer diagnosis has been confirmed or excluded.
Missing information was discussed within the research team, and a decision is made to include or exclude it as a cancer case. Cancers were represented according to the WHO world cancer report, 1 and Globocan 2020 report, 7 that is, data on lung cancer were not represented in its subtypes, but only as lung cancer. There have been several meetings and workshops to train the newly graduated doctors in the research team on examining and filtering reports. Finally, coding and classification followed the WHO world cancer report and Globocan 2020 report. 8 To ensure no overestimation of cancer, cases were dismissed if the city was not confirmed, or cancer was not confirmed new for the study period, or CT/MRI reported a possibility, but no histopathological confirmation was found.
In addition to the above data collection procedure being carried out at the NCI, other cases were collected from the institute's own registry, provided the address of Misurata was documented.
All cancer cases were recorded on a data spreadsheet. Further processing, including filtration, sorting, matching, and final analysis, was conducted using the same spreadsheet.

| RESULTS
Sixteen centres had all their radiology and pathology surveyed and filtered for a diagnosis of cancer. Initial readings survey resulted in 874 rows on the collection sheet, marrying names (e.g., CT and pathology report of the same person) and dismissing reports of no cancer and reports with no specific city address resulted in a final number of 430 cases of cancer over 12 months in Misurata.
Of the 430 cancer cases, 208 (48.4%) were identified by the current study but were not found in the NCI's cancer registry; 157 (36.5%) appeared only in the NCI's cancer registry but were F I G U R E 3 Study and worldwide distribution by type of cancer missed by the study. Only 65 (15.1%) were covered by both the current study and NCI's cancer register (Figure 1).
There were 192 (44.7%) males with cancer and 238 (55.3%) females with cancer, giving a ratio of 1:1.24. Figure 2 shows the age distribution of cancer cases demonstrates the sixth decade having the highest number of cancers at 88 (20.5%), followed by the fifth decade at 84 (19.5%), as in Figure 2. Otherwise, the study ranked ovary, thyroid, kidney, non-Hodgkin's lymphoma, endometrial, and head/neck in the top 10, respectively. The world cancer report ranked stomach, liver, oesophagus, cervix uteri, thyroid, and bladder among the top 10, respectively.
The variabilities and differences in cancer incidence in the study are related to cultural, environmental, genetic, nutritional, and occupational factors, the analysis of which is outside the scope of the study.
However, healthcare-related factors also influence cancer incidence rates as well as distribution. These include ( Furthermore, this survey faced significant hurdles when collecting data, mainly related to the many data collection sites (16 sites) and differing attitudes to epidemiological research amongst healthcare workers (doctors, nurses, and support staff), yielding a non-research friendly environment. Accordingly, it was not possible to collect data on non-cancer cases to allow for analysis of excluded cases to account for any bias relating to site, speciality, or private versus public. Future work tackling such extensive but essential horizons should take into account the many burdensome, exhausting, and in some instances, non-remediable barriers.

| CONCLUSION
In Misurata, cancer incidence stands at 71.7 per 100 000 population with 430 cases during the 12 month survey period (July 2019-June 2020). This incidence rate is at least an underestimate, with differences in distribution by type to the world populations.
Furthermore, a single centre cancer registry is an unreliable alternative to a national or regional cancer registry that collects information from all healthcare facilities in the region. All the above should support strategic planning and decision-making in developing cancer care in the country. 7 therefore, exempt from requiring explicit consent. Funding, despite several attempts at the city and national levels, no funding was secured to complete the study.

DATA AVAILABILITY STATEMENT
The data that support the findings of this study are available from the corresponding author upon reasonable request.