The present historical cohort study investigated work status and work participation within the first five years after diagnosis among cancer patients in eleven different cancer types compared to populations of matched cancer-free controls. The findings show that, across all cancer types, cancer patients had a lower chance of working and a lower work participation compared with cancer-free controls during and after the first year. By the third year, the prospects had improved for all, and after five years, there were minimal differences between cancer patients and controls. However, employment prospects varied between the different cancer types, and after five years, seven cancer types still had both a lower chance of working and a lower work participation compared to their cancer-free controls.

Previous studies have found an increased risk of unemployment, sickness absence, and disability pension among cancer patients [15, 32, 33]. However, no previous study has investigated all cancer diagnoses separately to the extent as our study. Our findings show that lung, colorectal, upper gastrointestinal, and blood cancer patients had the lowest chances of working at all years. In contrast, kidney and bladder, gynecological, male genital, and melanoma skin cancer patients seemed to have equal or higher chances of working compared with their matched controls after five years. While extensive research has been made on the impact of colorectal cancer on work, indicating an increased risk of experiencing adverse work outcomes [34, 35], less research has been conducted on the impact of upper gastrointestinal cancer. Our results show that cancer patients of this type had one of the lowest chances of working at all-time points. Despite the limited number of previous studies, a negative impact on unemployment and return to work has been found in some diagnoses of the gastrointestinal cancer type [36, 37]. Thus, our findings add to the evidence of gastrointestinal cancer, although more research is needed. Regarding lung cancer, a systematic review [38] found that lung cancer patients had an increased risk of unemployment and sick leave compared to persons with non-malignant chronic diseases, other cancer types, or cancer-free persons. According to our results, lung cancer patients had the lowest chance of working of all cancer types at all-time points. This is further supported by several studies, which found that lung cancer patients had the highest risk of unemployment and the longest time to return to work among several cancer diagnoses [32, 39]. Besides lung cancer, blood, colorectal, and gastrointestinal cancer patients have been found to have the highest risk of unemployment or sick leave [15, 40]. Hence, our results align with previous research in the understanding of which cancer types have the highest risk of adverse work outcomes, adding further value to the evaluation of employment status after cancer.

Several studies have indicated that factors such as age, income, educational level, and ethnicity are associated with employment status after cancer [32, 33, 41, 42]. When examining the baseline characteristics of the study population, it reveals an uneven distribution of these factors across the different cancer types. Lung, colorectal, and upper gastrointestinal cancer patients tended to be older, less educated, and had lower incomes compared to the overall cancer population (Table 1). Thus, these factors could partially account for the lower chances of working among patients with these cancer types. Conversely, we found that melanoma skin cancer patients had a higher chance of working compared with controls after three and five years, consistent with previous research [12]. Cancer patients with melanoma were generally younger, and higher educated than the overall cancer population, which, combined with the low mortality of the disease [43], likely contributes to the good work prognosis for this particular cancer type. On the other hand, blood cancer patients experienced a low chance of working at all years, despite being younger and having a similar educational level compared to the overall cancer population. Moreover, kidney and bladder cancer patients were older and less educated than the overall population but still had similar odds of working as their controls after five years. Thus, other factors are likely to have contributed to the causality of employment status. Other factors that have been identified in previous research as associated with work outcomes include treatment modalities, symptom burden, type of work, and physical and mental comorbidities [16, 27, 44, 45]. However, information on the majority of these factors were not available in our data.

Besides the influence on employment, it is well-established knowledge that socioeconomic status impacts the incidence and mortality of cancer [46]. For many, particularly tobacco- and lifestyle-associated cancers, the incidence and mortality is higher among people who have low education, low income, and are living alone. We excluded all who died, emigrated, and received disability or age-related pension during follow-up, as we wanted to investigate the patients who survived their cancer and were available for employment. This resulted in considerable reductions in the study population over time, and we therefore explored potential differences in population characteristics between baseline and follow-up. This was presented in two post hoc descriptive tables, showing the characteristics along with the reasons for exclusions after the third and fifth years (Supplementary Table 1 and 2). Most exclusions during follow-up were due to death or disability pension of which the highest numbers were seen in lung, colorectal upper gastrointestinal, and CNS cancer. For all cancer types, the population available at both years three and five had a higher proportion of females, were younger and higher educated, had higher income, had no comorbidities, and had no sick leave before diagnosis, compared with the population at baseline. This suggests that cancer patients, who were more socioeconomically advantaged at baseline, had higher chances of remaining available for employment after cancer. Notably, the previously discussed variations in baseline characteristics between the different cancer types showed a similar pattern. The cancer types consisting of a higher proportion of patients with low socioeconomic status, such as lung, colorectal, and upper gastrointestinal cancer, were also the cancer types with the lowest chances of working. Taken together, these observations indicate a possible association between low socioeconomic status and poor employment prospects. However, we cannot conclude whether the differences between the baseline population and the follow-up samples are merely a result of higher mortality among those with lowest socioeconomic status. Neither can we conclude whether the distribution of these characteristics between working and not working cancer patients follows the same tendency. Despite this, our results showed that certain cancer types had poorer employment prospects than others, and it is likely that the observed differences in employment status between the eleven cancer types are not solely attributable to the specific cancer type but rather are a result of complex interactions between several socioeconomic, demographic, and diagnosis-specific factors. Thus, it is important to consider all these factors in the organization and implementation of vocational rehabilitation for cancer patients.

Only few interventions, directly aimed at vocational aspects of rehabilitation for cancer patients, have been evaluated, and the evaluations of such interventions have shown ambiguous effects [47, 48]. Furthermore, a population-based study found that socioeconomically disadvantaged cancer patients reported a higher need for rehabilitation but were to a lesser extent participating in rehabilitation services [49]. This supports our theory of social inequity in employment prospects after cancer. Therefore, more research on the subject is needed in order to identify cancer patients who potentially could benefit from vocational rehabilitation and to enhance their participation in such interventions.

Another aspect to consider when evaluating employment status after cancer is the time perspective. Our results showed that all cancer types had lower chances of working after the first year compared with cancer-free controls. However, for most cancer types, odds of working were similar as for controls after five years. Most previous studies found comparable time perspectives, despite some variations. One study found the highest rate of sick leave during the first year [33]. Another study found that 90% of all cancer patients who returned to work did so within the first two years [50], and further two studies found the highest risk of unemployment between two and four years after diagnosis [15, 51]. The differences in peaking risk might be the result of varying outcome definitions. Irrespective, the overall evidence suggest that the risk of experiencing adverse work outcomes is highest during the first years post-diagnosis, after which the risk decreases and stabilizes at a level either equal to or higher than that of cancer-free controls. The negative impact of cancer treatment on the ability to work [44] could possibly explain this. Although treatment duration varies with type and extent of the cancer, some cancer patients are likely to still receive treatment or be in the recovery phase one year after diagnosis [52]. In order to achieve the greatest effect of vocational rehabilitation, interventions should therefore be initiated early in the disease trajectory to support patients in resuming work once they have finished treatment.

A strength of the present study is the high validity of data and complete follow-up using several well-documented Danish registers and the ability to cross-link them with the unique personal identification number given to all Danish citizens. Another strength of the study is the large study population of all Danish cancer patients, and the inclusion of a matched control group, which, together with the minimal amount of missing information, decreased the risk of selection and information bias. However, given the large sample size, minor differences in odds of working between cancer patients and controls were likely to result in statistically significant estimates, which must be considered in the interpretation of the clinical importance of the results.

We adjusted for several important factors in the matching process and during analyses. However, we were unable to adjust for disease-specific factors like stage of the cancer disease or type of treatment [42]. Furthermore, we lacked information on a number of psychosocial and work-related factors like cohabitation, mental illness, and type of work [16, 19, 41]. Collectively, the inability to adjust for these important factors could therefore have confounded the results.

We only included persons who were still alive and available for employment at each year of follow-up. Thus, all persons who had died or received disability pension or age-related pension in between each follow-up were excluded from the subsequent analyses. This has possibly led to an underestimation of the overall impact of cancer on employment status due to healthy worker bias. However, we wished to investigate employment status among cancer patients who could potentially benefit from vocational rehabilitation initiatives in order to investigate the need for such.