Since the announcement of the cancer control plan to increase the participation rate in cancer screening programs by the Japanese government [6], various promotion strategies including sending invitation letters and conducting awareness campaigns have been attempted [9, 19]. Although these strategies have been implemented nationwide, they had sadly not achieved the goal of increasing the participation rate to date. In the new WHO screening criteria, accessibility is defined as one of the basic requirements to maintain equity for the target population [11]. However, in Japan, there has been insufficient discussion regarding the resources for cancer screening programs at the introduction of new techniques except for endoscopic screening for gastric cancer [20]. In the U.S. and European countries, the capacity of colonoscopy has been investigated since the introduction of colorectal cancer screening using fecal blood occult testing and total colonoscopy [21–26]. The required numbers were estimated based on the model when the participation rate increased in colorectal cancer screening [25, 26]. From the national survey in Japan, the number of gynecologists and obstetricians has not increased sufficiently despite the increase in the number of all physicians. Also, there are huge disparities in terms of access to gynecologists and obstetricians between urban and rural areas. Two Japanese studies have reported consistent results regarding the association of human resources such as gynecologists and obstetricians with participation rates in cervical cancer screening [14, 15]. Taken together, to significantly improve the participation rate, it is crucial to reconsider how to secure human resources for cervical cancer screening from different perspectives other than promotion strategies alone.
Gynecologists are expected to take the primary role in making a diagnosis and planning the treatment during cervical cancer because of their special knowledge and techniques. Indeed, gynecologists have broad roles from screening to treatment. Unfortunately, their number has remained insufficient to fill each critical role. Cervical cancer screening methods are usually simple, and physicians can perform them regardless of their expertise. Taking Pap smears has been traditionally limited to gynecologists and obstetricians since the introduction of cervical cancer screening in Japan. In actuality, mobile clinics have been very useful in compensating for the insufficient opportunities for cervical cancer screening. However, even mobile clinics have become insufficient, particularly in rural areas. Besides, the number of certified gynecological oncologists has also remained insufficient, and their distribution has been biased [16]. As a result, the survival rates of patients with cervical cancer have been different between JSGO-accredited hospitals and JSGO-nonaccredited hospitals [17]. Based on the recent trend, a rapid increase in the number of gynecologists cannot be expected.
To increase the participation rate and improve treatment results, sharing various screening works with other health professionals, particularly taking Pap smears, should be considered in Japan. In several countries, medical systems that permit general physicians and midwives to take Pap smears for cervical cancer screening are now seeing the benefit [27–31]. These systems can help improve access to cancer screening programs, although they can also serve as a barrier to referring abnormal results to gynecologists. In Sweden, midwives have the responsibility of taking Pap smears during cervical cancer screening and of simultaneously conducting consultations on health problems [29]. In the U.S., most primary care physicians provide Pap tests to their patients following the specified guidelines [27]. However, although family and general physicians were more likely to follow the specified guidelines used by gynecologists [26], some nonexpert physicians feel that there are some barriers in accurately taking Pap smears, such as the lack of a training system [30]. Similar problems have been suggested in studies conducted in European countries [28, 29, 31]. On the other hand, even if general physicians have no constraint in taking Pap smears, they often hesitate to perform them because they believe that women are better served if Pap smears are taken by gynecologists [30, 31]. Although sharing the screening work with general physicians in rural areas might be one of the solutions to improve accessibility to cervical cancer screening in Japan, training programs and management guidelines are crucially needed.
Interestingly, recent studies have reported that self-sampling HPV testing is a useful approach to increasing the participation rate [32]. Also, the sensitivity and specificity of self-sampling HPV testing are nearly equal to those of a clinician performing the HPV testing [32–34]. Some countries have already introduced self-sampling HPV testing for non-attenders [35, 37]. It is also used in low-resource areas with poor access to screening services [38]. The introduction of self-sampling HPV testing can be a viable option for reducing the workload of gynecologists in taking Pap smears. Besides, self-sampling HPV testing can also be adopted in rural areas without gynecologists and obstetricians in Japan.
There are some limitations to this study. First, the literature search was limited to English and Japanese literature. Second, the information regarding human resources for cervical cancer screening is insufficient. We selected the articles only, and there is publication bias. This information might be included in the conference abstracts or other reports. Finally, the analysis of human resources based on the national survey was a descriptive study. To clarify the appropriate supply of cervical cancer screening, the demands in local areas should be investigated.