Measuring the burden of cancer is vital to understand its impact on the refugee populations as well as to design cost effective, affordable and equitable control and management strategies. Several factors make it difficult to measure the burden of cancer among the refugee population. Availability of the data is one of the biggest challenges as most refugees live in low to low-middle income settings  where national statistical systems are either absent, weak or do not include refugees in the publications of national statistical reports due to sensitive political reasons. And even if collected access to scuh data is a challenge. Residential instability, the incomplete identity of refugees, incomplete sharing of data among different stakeholders, the quality and completeness of data are other significant challenges. Hence, the available data most often focus on registered economic migrants in high-income countries [16,17,18]. At present more than 5 million (UNHCR 2021 n = 5,221,588) Syrian refugees are in Turkey, Lebanon, and Jordan  and making this one of largest displaced refugees population in the world. Studies from these countries have focused on the “classical” areas of refugees health. There is limited literature available about cancer and the true burden of cancer is still unmeasured. The most recent systematic review focusing on the impact of armed conflict on cancer among civilians in LMICs reflected the relative paucity of basic epidemiological data including changes to risk factor exposure, behavioral changes, delays to presentation, the availability of timely and affordable complex care, as well as the ability to access care .
Konya is the largest province of Turkey by size and currently hosts 121,064 Syrian refugees . The population movement is relatively stable in Konya, in contrast to other cities. Syrian refugees can get the health care only in cities where they are registered to live. Their treatment costs are covered if they are treated in the state or public university hospitals. The referrals from other cities’ government hospitals are permitted for specific pre-authorized cases. The number of refugees who reside in Konya has increased markedly in previous years, growing the cancer burden amongst this population. However, similar to other refugee studies, such as in Jordan, the difference expected and observed number of Syrian cancer patients across the years implies routine under-reporting .
One of the previous studies using Turkish Ministry of Health public hospital data for years 2012–2015 reported that the breast, colon, and lung were the most common cancer types observed among adults older than 19 years . Another single-center analysis of 134 adult Syrian cancer cases in the city of Şanlıurfa for years 2015–2017 also reported that breast cancer is the most frequent cancer . The findings of our study were in general in agreement to these studies. Moreover, the frequency of different types of cancers among the refuges was comparable to the host population. The Globocan (global cancer observatory) estimates suggest lung, breast, and colon were the most common cancer types among the host population in Turkey in the year 2020 . Our finding that 40.4% of Syrian refugee patients presented at an advanced stage of their disease was similar to the above mentioned study at Şanlıurfa where 44.8% of all cases presented at an advanced stage. The median age (49.0 years) of adult patients at presentation in the present study is also comparable to the study in Şanlıurfa (47.5 years) .
Smoking is one of the major risk factors for various types of cancer. The smoking rate in the present study (30.6%) is similar to Şanlıurfa study (32.8%) . Moreover, the Health Status Survey of Syrian Refugees in Turkey shows that 31.6% of the Syrian refugees smoke a tobacco product daily . The high smoking rate among male population in our study explains why tobacco related tumors are more common in males than females (lung and bronchus, bladder, larynx). The survey results also showed low physical activity, and a diet that does not meet the healthy recommendations is also prevalent among Syrian refugees . Additionally, changes in the socio-cultural, physical, and economic environment due to migration also causes changes in risk for different types of cancers. Considering the high prevalence of these risk factors, host countries must expand their preventive interventions through public health programs and public policy as well as routine cancer care.
To the best of our knowledge, this is the first study that has estimated the median interval between the first cancer symptom and the cancer diagnosis in Syrian refugees. The median diagnostic interval was 96.5 (IQR = 112) days for adult patients. This is a significant delay and reflects the complex and long pathways Syrian refugees need to take, as well as a host of other factors e.g. economic factors that contribute to diagnostic and treatment delays. Earlier research among lung cancer patients in the Eastern Black Sea region of Turkey found that the patients presented on average 30 days (range 2–365) after symptoms with a very wide range . Delay in diagnosis and treatment are independently increase mortality . Strategies addressing delays in diagnosis and treatment for refugees are crucial for downstaging and increasing the proportion of patients who present with curative disease. The cancer control department in Turkey is working closely with primary healthcare physicians to alleviate the situation with various screening guidelines and more rapid cancer care referral pathways. However, the health literacy of Syrians in Turkey is inadequate  and many patients ignore or self-managing critical symptoms. It is noteworthy that MoH has established mobile cancer screening units for Syrian refugees which also acts to constructively engage in increasing awareness of cancer symptoms By November 2020 more than 420,000 refugees had been screened through this service .
Multimodal combination therapy is a cornerstone of cancer treatment . Our study showed that refugee cancer patients in Turkey have access to all types of modern cancer treatment modalities and they are not, per se, a clinically underserved population. Interruption of ongoing treatment, however, is an important issue in cancer care. There are few cases of treatment abandonment in our population. However, due to the retrospective nature of the study and limited availability of such data in the hospital record the result need to be interpreted with caution as it is not very clear whether the patients truely abdonded their treatments or moved to a different location and were effectively lost to follow up but still being treated.
The overall 5-year survival rate of 37.5% for adult Syrian cancer patients was lower than the host population  mostly reflecting delays in presentation and diagnosis.
Two previous studies reported on childhood cancer among Syrian refugees. Kebudi et al. , evaluated retrospective data of 212 refugee cancer children from 17 centers in 2015, where leukemia, lymphoma, and brain cancers were the most common cancer types. Yağcı et al. , evaluated single-center data of 105 Syrian cancer children in the Adana province where CNS tumors, leukemia, and lymphoma were the most frequent site specific childhood cancers. Though the number of childhood cancer patients in the present is small the frequency of different types of cancer was similar to other studies. The delayed presentation, treatment abondement is an important concern for refugees’ children with cancers. Yağcı et al. , found that refugee children had a high frequency of advanced/metastatic disease, and lower treatment compliance compared to host children. We found overall survival for children with cancer at two years as 78%, although due to the small number of cases the interpretation is difficult. However, a previous study reported that overall survival was 55.7% in Syrian cancer children and this rate was significantly lower than host children receiving oncologic treatment .
The cost of the cancer care for Syrian refugees is not completely known but the raw estimates based on crude incidence suggest an expenditure of €33·68 million (Turkey €25·18 million; Lebanon €6·40 million; Jordan €2·09 million) . Nevertheless, the financial costs of cancer care are high for both patients and the health system. Syrian refugees in Turkey are in a much better position than many other places as most of the healthcare services are available at freely without discrimination . Moreover, as observed in the current study, to benefit from the health system cancer patient from Syria migrate temporarily to Turkey, obtain refugee status, undergoing cancer treatment, and go back and live in Syria. It is also important to note that the conflict environment has resulted in the disruption of cancer care in Syria and only 23% of functional public hospitals in Syria provide cancer treatments . Thus incidence of cancer may have been over-reported in Syrian refugees living in host countries . This speaks the need to build up capacity, capability and maintain proper computerized patient records in host country systems for externally displayed and also internally displayed refugees back in Syria.
In summary, Cancer is not a neglected disease for the Syrian refugees living in Turkey. This study found that Syrian patients can access cancer care in public and university hospitals. Moreover, the diagnostic and treatment costs for non-communicable diseases including cancer are covered by the government . Nevertheless, delayed diagnosis is an important issue. We found that the median time between the onset of symptoms and diagnosis of cancer is three months for adult patients. As to the retrospective nature of the study, we are unable to identify the reason for the delay. It could be related with migration process itself and other additional factors including financial barriers, the difficulties on access to care due to registration requirement, health literacy, other socio-cultural reasons. Treatment abandonment is also an important factor that limits the survival of cancer. We found that near 10% of adult cancer patients abandoned the cancer treatment. Previous studies highlighted the issue of displacement and interruption of cancer treatment among Syrian refugees [5, 33]. We found a high proportion of lung, larynx, and bladder cancer among men. This could be explained by the high prevalence of smoking among men as compared to women. We also found that the metastatic disease and treatment abandonment were slightly higher in men. However, the limited number of cases makes the comparison difficult. Females also have better survival rates than in males in this study. Based on our study we recommend that the management of cancer should not be ignored at the time of humanitarian crises. Investment on the health system capacity is essential. Having the crisis plan ready for such humanitarian emergencies and developing the new funding models are required. The states of the world must also focus on how to prevent and protect people of the world from the harm of conflict and forced displacement. Research and data collections are also among the major obligations to better understand and proper management the such major crisis.
The results of this study are subject to some limitations. The retrospective nature of the study design is the major limitation. Additionally, the data for this study come from the hospital database, which was not collected primarily for research purposes therefore analysis was limited to the available variables only. Furthermore, due to a large number of missing values for some variables of interest such as smoking and the presence of chronic disease, the conclusion regarding these variables should be interpreted with caution. The absolute incidence or prevalence of cancer cannot be deduced from this data, because the patients diagnosed and/or treated at Konya might come from another city through the referral process, thus it is not possible to determine the precise reference population for this study. The relatively low number of pediatric patients also limits the interpretation of results. Future prospective studies with large sample sizes and better study designs are required to confirm.