Cancer patients faced a myriad of challenges during the initial months of the Covid-19 pandemic. Many cancer treatments, such as chemotherapy and radiation therapy, were postponed or altered to minimize the risk of exposure to the virus [18]. Elective surgeries, including certain cancer-related procedures, were delayed, affecting treatment timelines [19].

We found that the number of outpatient visits for cancer patients decreased immediately after the onset of Covid-19, which was consistent with findings made for different patients in other countries in other countries during the Covid-19 pandemic [20]. Furthermore, the findings revealed that the various waves occurring after the onset of the Covid-19 pandemic in Iran resulted in a decrease in both referrals and outpatient visits patients with cancer. The most noteworthy reason that can justify this decrease was the patients’ fear of contracting Covid-19 [21, 22].

Fear of contracting Covid-19 at hospitals and healthcare facilities led some cancer patients to avoid seeking necessary medical care [23]. Support services, such as counseling, support groups, and in-person interactions, were limited, affecting the mental health and emotional well-being of cancer patients [24]. Different studies showed that cancer patients had experienced a higher level of stress, anxiety and depression to receive health services when compared to non-cancer patients with the onset of Covid-19 [25, 26].

After the spread of Covid-19 in Iran, severe restrictions were adopted by the government to control this disease. Many cancer patients, especially those on immunosuppressive treatments, were concerned about the increased risk of contracting Covid-19 in healthcare settings. Studies have shown that patients avoided receiving services in the early stages of Covid-19 [27, 28]. The same fear of exposure to the virus has caused some patients to delay or avoid scheduled appointments [29]. Measures such as social distancing and traffic restrictions, which were applied to control the spread of Covid-19, are also effective factors in reducing the outpatient visits of cancer patients [26].

Studies from other countries indicated a decrease in cancer patient visits due to control policies such as social distancing and quarantine [30, 31]. These studies showed that with the reduction of these policies, the number of patients’ referrals to service centers increased.

Cancer patients were reluctant to travel, especially to medical centers, due to concerns about exposing themselves and their companions to the virus. As a vulnerable population, these patients may be especially cautious about attending healthcare appointments during periods of strict social distancing and traffic restrictions [32].

On the other hand, increasing cases of Covid-19 strained healthcare systems around the world. Hospitals and clinics faced challenges in managing the influx of Covid-19 patients, which led to disruptions in routine medical services [33]. Resources were diverted to address the immediate crisis, affecting the capacity to provide regular care, such as services to cancer patients [34].

Other studies showed that providing health care with a relatively low priority or postponement for non-Covid-19 patients was on the agenda of health centers at the beginning of the pandemic [35,36,37].

To manage the demand for healthcare resources and reduce the risk of transmission of the virus, many hospitals and healthcare facilities have canceled or postponed non-urgent medical procedures, including cancer screenings, surgeries and follow-up appointments [34].

The increase in Covid-19 cases, especially severe cases requiring hospitalization in the first months, strained the healthcare system and resources, including staff and facilities, to manage the influx of Covid-19 patients, which potentially led to a reduction in available resources for routine outpatient visits [19].

Our findings showed that after the start of Covid-19 vaccination in Iran and its priority for cancer patients, they saw an increase in the number of patients for their visits.Cancer patients are generally more vulnerable to infections. With the start of vaccination and its availability, patients’ fear of contracting Covid-19 will decrease and they felt more secure. Studies showed that vaccination and reducing the fear of patients increased visits and receiving services, and on the other hand, service providers were more willing to provide services to non-Covid-19 patients [38, 39].

Studies have shown that people with cancer and other people with weakened immune systems are at high risk of severe complications from Covid-19, and getting the Covid-19 vaccine reduces the risk of hospitalization and death from Covid-19 [40,41,42].

Knowing that they are a priority for vaccination will increase their confidence to seek health care services. Additionally, vaccination campaigns and emphasis on uptake for vulnerable populations, such as cancer patients, can encourage them to prioritize routine medical visits, including cancer-related appointments [43]. Initiating a Covid-19 vaccination program may imply a commitment to greater healthcare and patient safety and instill confidence in the healthcare system. This confidence can lead to an increase in cancer patients’ willingness to interact with the healthcare system [26, 44].

By implementing control and prevention policies and programs, the government has succeeded in reducing the burden of the Covid-19 disease in the society [32]. With the start of vaccination, this reduction intensified, leading to a decrease in the risk of contracting the virus during hospital or clinic visits, which in turn increased cancer patients’ willingness to seek medical care [34].

Also, with the start of the Covid-19 vaccination in Iran, there was a reduction in travel restrictions and quarantine measures. Patients who were worried about traveling a distance for their visits were able to make their visits more regularly. It seems that positive vaccination experiences in the cancer patient community or among peers may create a ripple effect and encourage more people to seek medical visits after vaccination. It is important to note that specific factors influencing patient behavior can vary based on local conditions, public health measures, and the success of the vaccination campaign. Additionally, the interplay of psychological, social, and healthcare system factors can contribute to changes in patient referral and healthcare-seeking behavior.

While our study provides valuable insights into the impact of the Covid-19 pandemic on cancer patients and the subsequent changes in healthcare-seeking behavior post-vaccination, it is essential to acknowledge several limitations inherent in our study design. Firstly, the retrospective nature of our study may introduce biases related to data availability and accuracy. The reliance on medical records and patient self-reports might not capture the full spectrum of factors that influence healthcare-seeking behavior during the pandemic. Future studies employing a prospective design and incorporating qualitative methodologies could offer a more nuanced understanding of patient experiences. Secondly, our study primarily focused on quantitative measures, such as the number of outpatient visits, and referrals. While these metrics provide important insights, they may not fully capture the qualitative aspects of patient experiences, such as the emotional and psychological factors influencing healthcare decisions. A more comprehensive approach, including patient interviews or surveys, could enhance our understanding of the nuanced challenges faced by cancer patients. Furthermore, the study’s generalizability may be limited due to its specific focus on the Iranian context. Cultural, socioeconomic, and healthcare system differences may influence the applicability of our findings to other regions. Comparative studies across diverse populations can provide a more comprehensive understanding of the global impact of the pandemic on cancer care. The study design also did not explicitly explore variations in the quality of healthcare services received by cancer patients. Understanding whether disruptions in routine care translated into adverse outcomes or disease progression would have added valuable clinical context. Future research should aim to assess the long-term consequences of healthcare interruptions on cancer patient outcomes. Additionally, the ITSA method makes several assumptions, most notably that the method cannot distinguish the effect of the intervention/change under investigation (namely ‘start of Covid-19’) and other changes that may have occurred around the same time. In other words, it is assumed that the modeled pre-interruption trend would have continued in the absence of the event that occurred at the time of the interruption in the time series. While it seems plausible that the observed effects on healthcare utilization can be attributed mainly to the start of Covid-19, it is important to briefly discuss the importance of these methodological assumptions.