Risk of needing completion thyroidectomy for low-risk papillary thyroid cancers treated by lobectomy

Background

Low-risk differentiated thyroid cancers may, according to the American Thyroid Association (ATA) 2015 guidelines, be managed initially with lobectomy. However, definitive risk categorization requires pathological assessment of the specimen, resulting in completion thyroidectomy being recommended when discordance between preoperative and postoperative staging occurs. This study sought to establish the expected rate of completion thyroidectomy in patients with papillary thyroid cancer (PTC) treated by lobectomy.

Methods

Patients with PTC treated over 5 years (2013-2017 inclusive) and meeting the ATA criteria for lobectomy were identified from the prospectively developed database of a high-volume, university department of endocrine surgery. Concordance between the ATA initial and final recommendation, and the putative rate of completion thyroidectomy were calculated. Multivariable analysis was used to assess preoperative factors as predictors of the need for total thyroidectomy.

Results

Of 275 patients with PTC who met ATA preoperative criteria for lobectomy there was concordance between this and the final recommendation in 158 (57·5 per cent) and discordance in 117 (43·5 per cent). Most common reasons for discordance were: angioinvasion (30·8 per cent), local invasion (23·9 per cent) or both (20·5 per cent). Four patients (1·5 per cent) had permanent hypoparathyroidism. On multivariable analysis, age, sex, tumour size and family history did not independently predict the final treatment required.

Conclusion

Although many patients may be treated adequately with lobectomy, just under half would require completion thyroidectomy. Further work is needed on preoperative risk stratification but, before this, total thyroidectomy remains the treatment of choice for low-risk 1-4-cm PTC in the hands of high-volume thyroid surgeons who can demonstrate low complication rates.

An initial melanoma diagnosis may increase the subsequent risk of prostate cancer: Results from the New South Wales Cancer Registry

Emerging evidence suggests that a diagnosis of cutaneous melanoma (CM) may be associated with prostate cancer (PC) incidence. We examined if the incidence of CM was associated with an increased subsequent risk of PC. We used data from the New South Wales Cancer Registry for all CM and PC cases diagnosed between January 1972 and December 2008. We calculated the age standardized incidence ratio (SIR) and 95% confidence intervals (95% CI) for PC incidence following a CM diagnosis, applying age- and calendar- specific rates to the appropriate person years at risk. We determined rate ratio (RR) and 95% CI of PC incidence according to specified socio-demographic categories and disease related characteristics, using a negative binomial model. There were 143,594 men diagnosed with PC or CM in the study period and of these 101,198 and 42,396 were diagnosed with PC and CM, respectively, as first primary cancers. Risk of PC incidence increased following CM diagnosis (n = 2,114; SIR = 1.25; 95% CI:1.20.8-1.31: p < 0.0001), with the increased risk apparent in men diagnosed with localised CM (n = 1,862;SIR = 1.26; 95% CI:1.20-1.32). CM diagnosis increased the subsequent risk of PC incidence. This raises the potential for future PC risk to be discussed with newly diagnosed males with CM.

An examination of prostate cancer trends in Australia, England, Canada and USA: Is the Australian death rate too high?

PURPOSE

To compare prostate cancer incidence and mortality rates in Australia, USA, Canada and England and quantify the gap between observed prostate cancer deaths in Australia and expected deaths, using US mortality rates.

METHODS

Analysis of age-standardised prostate cancer incidence and mortality rates, using routinely available data, in four similarly developed countries and joinpoint regression to quantify the changing rates (annual percentage change: APC) and test statistical significance. Expected prostate cancer deaths, using US mortality rates, were calculated and compared with observed deaths in Australia (1994-2010).

RESULTS

In all four countries, incidence rates initially peaked between 1992 and 1994, but a second, higher peak occurred in Australia in 2009 (188.9/100,000), rising at a rate of 5.8 % (1998-2008). Mortality rates in the USA (APC: -2.9 %; 2004-2010), Canada (APC: -2.9 %; 2006-2011) and England (APC: -2.6 %; 2003-2008) decreased at a faster rate compared with Australia (APC: -1.7 %; 1997-2011). In 2010, mortality rates were highest in England and Australia (23.8/100,000 in both countries). The mortality gap between Australia and USA grew from 1994 to 2010, with a total of 10,895 excess prostate cancer deaths in Australia compared with US rates over 17 preceding years.

CONCLUSIONS

Prostate cancer incidence rates are likely heavily influenced by prostate-specific antigen testing, but the fall in mortality occurred too soon to be solely a result of testing. Greater emphasis should be placed on addressing system-wide differences in the management of prostate cancer to reduce the number of men dying from this disease.