Clinical trials and evidence-based guidelines have demonstrated that curative-intent therapy for early-stage nsclc
includes surgical resection of the primary tumour and consideration of cisplatin-based act4
. Beyond the evidence and treatment guidelines, a multitude of complex patient-, disease-, and system-related factors determine the care of patients with cancer.
In this large population-based study, we explored the factors associated with two steps in the care pathway after surgical resection: namely, referral to medical oncology and administration of act. Several important findings emerged. First, 22% of incident patients undergo surgical resection. After surgery, only 55% of those surgical patients see a medical oncologist and only 31% receive act. Those observations mean that, in Ontario, only 7% of all incident cases of nsclc received curative-intent surgery and adjuvant chemotherapy. Furthermore, among surgical patients not treated with act, 65% never saw a medical oncologist in consultation. Age, stage of disease, comorbidity, and extent of surgery are associated with each step of care, but age, comorbidity, and postoperative length of stay appear to have more influence over the decision at the medical oncology and patient levels to use act than over the decision by surgeons to refer to oncology. Finally, large regional differences in practice, evident at both steps in the care pathway, are not explained by differences in patient demographics or comorbidity. Our data suggest that the regional differences are driven to a greater extent by upstream differences in referral rates to medical oncology than by treatment decisions at the consultant–patient level. It is possible that the discordant referral patterns and treatment rates across geographic regions reflect the fact that physicians and centres may interpret the evidence and magnitude of benefit associated with act quite differently.
The literature exploring factors associated with referral to medical oncology and use of act
among patients with resected nsclc
is limited. A study by Winget et al.28
that included 561 patients with stage ib
and ii nsclc
diagnosed in Alberta during 2004–2006 found that advanced age and rural residence were inversely associated with the likelihood of attendance at a consultation with a medical oncologist. Among the 226 patients who saw a medical oncologist, act
was not recommended in 25% of cases, and it was refused by patients in 13% of cases 15
. Kassam et al.29
described patterns of referral and use of act
at the University Health Network or Princess Margaret Hospital in Toronto during 2003–2005. Among the 204 patients with resected early-stage nsclc
, referral to oncology increased to 63% in 2004–2005 after presentation of the jbr
.10 and Cancer and Leukemia Group B results at the 2004 annual meeting of the American Society of Clinical Oncology. Among patients seen by medical oncology after presentation of those results, 54% were treated with act
—a proportion that is remarkably similar to the result of 55% in the present study. A third Canadian study led by Younis 30
reported referral rates and use of act
among patients with resected nsclc
in Nova Scotia during 2005. Of the 108 patients with resected early-stage disease, 44% were referred to medical oncology (73% of patients with stage ii
disease), and act
was delivered to 62% of those referred (73% of patients with stage ii
disease. Consistent with the results from Winget et al.
and from the present study, age, stage, and centre or regional variation were found to have an effect on referral patterns and treatment practices. Data from a single-centre report in Paris are consistent with the Canadian studies: among 219 patients with resected nsclc
in 2004–2005, act
was delivered to 40% 31
. Age, stage, and comorbidity were found to influence patterns of treatment.
Consistent across the present and the foregoing studies is the observation that older age is associated with lower rates of referral to medical oncology and lower rates of act
use. Although part of the differential might relate to greater comorbidity and patient preference, it is also possible that surgeons and medical oncologists might believe the survival benefit to be less and the toxicities greater in elderly patients treated with act
. However, recent data from clinical trials and population-based studies suggest that act
is well tolerated and associated with a survival benefit in elderly patients 32–34
. However, patients who meet the eligibility criteria for clinical trials might not be representative of the overall lung cancer population.
Our study is the largest reported to date to evaluate factors influencing referral to medical oncology and use of act in a contemporary population, but several methodologic limitations merit comment. Although the data sources used describe the general aspects of disease, treatment, and outcome for all patients in Ontario, detailed information related to chemotherapy administration, treatment toxicity, performance status, and stage of disease is not available for all patients. That lack of detail limits our ability to evaluate the appropriateness of case selection for act. Furthermore, our data do not allow us to understand which patients may have refused referral or act after referral, and why those patients elected not to pursue aggressive cancer care despite the potential for an increased cure rate. Furthermore, because medical oncologists are not explicitly identified in the current health administrative databases used in our study, we had to use surrogate measures to identify those physicians, which might have led to some misclassification error. However, the data suggest that our approach has good face validity, because 98% of cases receiving act were classified as having seen medical oncology.
The lack of information about pathologic stage makes it difficult to understand the degree to which low referral rates and underutilization of act
is a problem in Ontario. The published literature contains very few population-based studies that describe stage distribution among unselected patients with nsclc
who undergo surgical resection. In one of the only such studies, Strand et al.35
used a population-based national cancer registry to describe stage distribution for 2411 nsclc
patients who underwent surgical resection in Norway during 1993–1999. Stage ib
, and iiia
disease was identified in 38%, 25%, and 6% of patients respectively. Extending those estimates to the Ontario nsclc
surgical population in 2004–2006 would yield approximately 2314 patients with stage ib
, or iiia
disease, all of whom would potentially be considered eligible for act
. Yet our study demonstrates that only 1830 patients were referred to medical oncology and only 1032 received act
, suggesting that a substantial proportion of patients potentially eligible for act
based on stage were not being referred or treated. Although it is likely that the distribution of disease stage among resected patients in Norway during 1993–1999 is different from the distribution in Ontario during 2004–2006, the projected figures provide a starting point for estimating the unknown denominator of potential act
-eligible cases in the province. Stage of disease is now routinely captured in Ontario for all cases of nsclc
). Accordingly, future work will be able to identify the number of stage ib
, and iiia
cases more accurately in Ontario and will generate benchmark estimated utilization figures for the province.
Not all patients who undergo potentially curative surgical resection will be eligible for act
. No survival benefit has been demonstrated for small stage i
, and so it may be totally appropriate for surgeons to make a decision not to refer that subgroup of patients. Similarly, given that nsclc
is a disease of the elderly, not all patients might be able to tolerate act
because of greater comorbidity. However, it is worth noting that pooled data from clinical trials 34
and a population-based study 32
have both demonstrated improved outcomes in elderly patients treated with act
. In the present population-based study, age and comorbidity index both had a significant influence on referral and treatment patterns. But what cannot be gleaned from our study is whether the decision not to refer to oncology and not to offer act
to the entire eligible elderly population or to those with comorbidities was indeed the correct one. Only a more intensive chart review would be able to determine whether patients who are fit enough for treatment are truly being denied act
by lack of referral. Similarly, our population-based study could not identify the subset of patients who were offered referral and act
, but who declined treatment.
In addition to its very large sample size and resulting statistical power, a major strength of the current study is the fact that, by virtue of the ocr
, our study population included all cases of nsclc
within Ontario. Being unselected, it therefore represents the largest such study of act
in the contemporary era. By including the entire population of interest, it is possible to minimize the referral and selection biases that plague traditional institution-based observational studies 36