Limited adequacy of thyroid cancer patient follow-up at a Canadian tertiary care centre

Endocrinologist-Perceived Factors Affecting the Transition of Thyroid Cancer Patients from Specialist to Primary Care Postcancer Treatment in Ontario, Canada

Background: Thyroid cancer patient discharge patterns from specialists are heterogeneous, with some specialists following patients for a longer period of time than others. With no well-established transitional plan, such as in breast and colorectal cancer, primary care physicians play a variable role in long-term thyroid cancer care. The objective of this study was to examine endocrinologist-perceived factors affecting the transition of care for thyroid cancer patients through a qualitative and quantitative survey of practicing endocrinologists in Ontario, Canada. Methods: All eligible practicing endocrinologists in Ontario were invited to participate in the study, via an email with an embedded survey link. Consent was assumed if the physician completed the survey. The survey collected physician demographics and asked a series of Likert-scale and open-ended questions on their views regarding transitioning care of their thyroid cancer patients. Quantitative analysis was based on mode and variability. Qualitative analysis was completed using inductive thematic analysis. Results: Seventy physicians completed the survey, with a response rate of 35.5%. Based on the responses to the Likert-scale questions, there was a lack of consensus in terms of discharging criteria for patients who had low-risk papillary thyroid cancer, stable thyrotropin levels, multiple nonthyroid-related comorbidities, and hemithyroidectomy with no disease recurrence. The majority of endocrinologists responded that the main factors affecting discharge included whether the primary care physician was able to follow their recommendations, whether the primary care physician could appropriately adjust levothyroxine doses, and whether the patient was confident that their primary care physician could manage their thyroid cancer follow-up. Themes extracted from the open-ended question also indicated that the main factors affecting the transition of care were related to the primary care physician, the patient, the imaging interpretation, and the discharge guidelines. Conclusion: The lack of consensus among endocrinologists affects the transition of patient care, and there is a need to provide clear and accurate information to primary care physicians and thyroid cancer patients on postcancer treatment care. Efforts should be sought to standardize discharge and long-term care.

Primary versus Tertiary Care Follow-Up of Low-Risk Differentiated Thyroid Cancer: Real-World Comparison of Outcomes and Costs for Patients and Health Care Systems

BACKGROUND

An unprecedented rise in the prevalence of low-risk well-differentiated thyroid cancer (TC) has been reported in several countries, which is partly due to an increased utility of sensitive imaging techniques. The outcome of these cancers has generally remained excellent and the overall 5-year survival is almost 100%. However, the extended follow-up strategy for these patients remains unclear and while the initial management is done in specialist centres some experts opt to follow them on a long-term basis while others discharge them to primary care after the initial management. The effectiveness of one strategy versus the other has not been studied.

METHODS

We conducted a real-world comparison to assess the outcome of low-risk TC (AJCC stage I) with undetectable thyroglobulin (TG) 2 years after radio-iodine (I-131) therapy. The outcome from Halifax (NS, Canada) and London (ON, Canada), where all TC patients are routinely followed by the tertiary care team, was compared with that from Edmonton (AB, Canada), where patients are routinely discharged to primary care.

RESULTS

All patients were diagnosed between January 1, 2006, and December 31, 2011. The mean follow-up in primary care after discharge was 62.2 months and in tertiary care it was 64.6 months (p = 0.43). Rates of recurrence were similar in both groups, i.e., 1.1% in primary care and 1.3% in tertiary care (p = 0.69). Ultrasound surveillance was conducted in 56.5% of the patients in primary care and 52.6% of the tertiary care group (p = 0.26). The rate of annual unstimulated TG testing per patient was 0.58 (range 0-14) in primary care and 0.96 (range 0-6) in tertiary care (p = 0.06). More patients in primary care (86%) than in tertiary care (29.9%) consistently had thyroid-stimulating hormone levels within the target range (p < 0.001). The mean healthcare cost, based on a single follow-up visit with a blood test and ultrasound in the primary care group was CAD 118.01 and in the tertiary care group it was CAD 164.12.

CONCLUSION

Our study shows that extended follow-up of low-risk TC patients is perfectly feasible in primary care and provides significant economic benefit for the healthcare system.

Detection of Polyethylene Glycol Thyrotropin (TSH) Precipitable Percentage (Macro-TSH) in Patients with a History of Thyroid Cancer

BACKGROUND

Owing to its large molecular size, polyethylene glycol (PEG)-precipitable thyrotropin (TSH) can accumulate in the circulation, elevating TSH levels. PEG-precipitable TSH can be used to detect macro-TSH (mTSH) in serum. Our aim was to evaluate the prevalence of mTSH in patients who had undergone thyroidectomy for thyroid cancer.

METHODS

Seventy-three thyroid cancer patients and 24 control subjects on levothyroxine (LT4) TSH-suppressive or replacement therapy were evaluated. Screening for mTSH was performed by adding PEG to serum in order to precipitate γ-globulin. A percentage of PEG-precipitable TSH ≥80% was considered suggestive of mTSH.

RESULTS

No correlation between free-T4 (fT4) and TSH levels was found. PEG-precipitable TSH was 39.3%±1.9% in thyroid cancer patients and 44.1%±3.9% in controls. Macro-TSH was deemed to be present in one thyroid cancer patient and in two control subjects. Only in the thyroid cancer group was PEG-precipitable TSH found to be negatively correlated with fT4 concentration. No correlation was found between PEG-precipitable TSH and other clinical conditions in any patients.

CONCLUSION

The presence of mTSH seems to be a rare phenomenon in thyroid cancer. In some patients with low PEG-precipitable TSH, a reduction in LT4 dosage could be suggested. LT4 dosage adjusted to body weight is the main factor in maintaining TSH in a semi-suppressed or normal range. Evaluation of mTSH could be necessary in patients in whom a balance is required between adequate TSH suppression and the avoidance of unnecessary exogenous hyperthyroxinemia.