Discussion
When the suspicion of cancer is raised, it is a time of stress and
anxiety for patients and their families (3). The cancer waiting times
targets have been introduced to support diagnosis and treatment delivery
in Scotland (1). Although 10 major cancers are included in these times,
currently thyroid cancer is not (1). This is despite the fact that the
lifetime risk in women is similar to liver and oral cancers, both of
which are included (1, 4). In addition, global incidence of DTC is
increasing (5).
In contrast to most malignancies, patients diagnosed with DTC generally
have an excellent prognosis, with survival exceeding 90% at 10 years
(6). Despite the favourable disease biology, the level of psychological
distress suffered by patients diagnosed with DTC is similar to that of
malignancies with much worse prognoses (3).
Few groups have looked at waiting times in DTC cohorts. To date, no
effect of treatment delay on mortality has been established. Although
diagnostic status of the cohort prior to thyroidectomy in most studies
is unclear, they show variation in the time to treatment following DTC
diagnosis from 15.3 days (7) to 114 days (8). This is likely due to
discrepancies in resource availability and differences in departmental
approaches.
One centre in England, where thyroid cancer is subject to
‘two-week-wait’ outpatient review targets, recorded 100% attainment
(10). Interestingly, only 7% of these two-week-wait referrals resulted
in a thyroid cancer diagnosis. When combining this pattern of diagnostic
yield with excellent oncological outcomes, it may be the case that the
application of waiting time targets in Scotland has negative
repercussions for the broader cancer population while offering little
benefit for the DTC cohort.
Classical cancer pathways include: a symptomatic presentation;
pre-diagnostic testing; a point of diagnosis and staging; treatment
planning; treatment and follow up. Our results confirm the fact that DTC
is often found incidentally (22%). In these cases, the suspicion of
cancer is only raised after the initial surgery performed for a benign
indication. Clearly, in this situation, cancer target times are
inappropriate.
Of the 62 patients in our study who were referred with a mass which
ultimately proved to be a DTC (non-incidental) only 24 were referred on
the cancer pathway (39%). A similar percentage of patients were
referred from primary care as ‘routine’ (27%), ‘urgent’ (34%) and
‘urgent - suspicion of cancer’ (39%). This suggests uncertainty within
primary care regarding how to refer such cases, although there was a no
effect of the referral priority on time to diagnosis and treatment. It
is also likely that more prominent clinical signs are associated with
more advanced disease. In particular, 56% of our cohort who had a
pre-operative biopsy suggestive or diagnostic of malignancy had N1
disease. Such patients are likely to be triaged to treatment with more
urgency given the stage of disease.
In our unit, a significant number of the non-incidental patients did not
have a diagnosis or suspicious FNA at the point of first treatment
(44%). For these patients, the time from diagnosis to treatment is
actually negative. Again, the cancer waiting time model is not well
suited to this group.
Our results highlight the impact that a pre-operative cytological
diagnosis has on a patient’s pathway, with surgeons clearly prioritising
such cases. This observation confirms the importance of accurate
radiological and cytological assessment in overall treatment planning.
This study is limited by low numbers and the inability to identify all
patients referred with a suspected thyroid mass. This prevented us from
calculating the percentage of referrals which result in a cancer
diagnosis.
Our study suggests that the overall cancer time model is not well suited
to DTC. 64% of patients referred from primary care were either
identified incidentally or following a diagnostic procedure which
actually amounted to initial therapy.
Although the biology of DTC is such that the time to treatment does not
appear to impact on oncological outcomes, the psychological impact is
less clear. Long waiting times from referral to diagnosis introduce
uncertainty, nervousness and worry for patients and their families (3).
This is true both for patients who ultimately are diagnosed with
malignancy but also for those who are investigated and have confirmation
of benign disease. This potential distress may reduce after surgery (3).
Given the difficulty in differentiating patients with DTC from those
with either benign disease, or in the setting of nodal disease, from
other malignancies, it seems reasonable to recommend that those patients
with rapidly enlarging thyroid nodules, metastatic nodes, those at
elevated risk of malignancy (prior radiation or family history) or those
with additional risk factors should be offered rapid review in secondary
care. Not only does this offer the potential to make a swift diagnosis,
but allows the patient access to a healthcare professional with
experience in management of this condition with whom the prognosis can
be discussed. The importance of appropriate referral from primary care
and accurate pre-operative cytology is clear, as both factors
significantly impact the time to diagnosis and treatment.