Cure indicators and prevalence by stage at diagnosis for breast and colorectal cancer patients: A population-based study in Italy

People alive many years after breast (BC) or colorectal cancer (CRC) diagnoses are increasing. This paper aimed to estimate the indicators of cancer cure and complete prevalence for Italian patients with BC and CRC by stage and age. A total of 31 Italian Cancer Registries (47% of the population) data until 2017 were included. Mixture cure models allowed estimation of net survival (NS); cure fraction (CF); time to cure (TTC, 5-year conditional NS >95%); cure prevalence (who will not die of cancer); and already cured (prevalent patients living longer than TTC). 2.6% of all Italian women (806,410) were alive in 2018 after BC and 88% will not die of BC. For those diagnosed in 2010, CF was 73%, 99% when diagnosed at stage I, 81% at stage II, and 36% at stages III-IV. For all stages combined, TTC was >10 years under 45 and over 65 years and for women with advanced stages, but ≤1 year for all BC patients at stage I. The proportion of already cured prevalent BC women was 75% (94% at stage I). Prevalent CRC cases were 422,407 (0.7% of the Italian population), 90% will not die of CRC. For CRC patients, CF was 56%, 92% at stage I, 71% at stage II, and 35% at stages III-IV. TTC was ≤10 years for all age groups and stages. Already cured were 59% of all prevalent CRC patients (93% at stage I). Cancer cure indicators by stage may contribute to appropriate follow-up in the years after diagnosis, thus avoiding patients' discrimination.

Complete prevalence and indicators of cancer cure: enhanced methods and validation in Italian population-based cancer registries

Objectives

To describe the procedures to derive complete prevalence and several indicators of cancer cure from population-based cancer registries.

Materials and methods

Cancer registry data (47% of the Italian population) were used to calculate limited duration prevalence for 62 cancer types by sex and registry. The incidence and survival models, needed to calculate the completeness index (R) and complete prevalence, were evaluated by likelihood ratio tests and by visual comparison. A sensitivity analysis was conducted to explore the effect on the complete prevalence of using different R indexes. Mixture cure models were used to estimate net survival (NS); life expectancy of fatal (LEF) cases; cure fraction (CF); time to cure (TTC); cure prevalence, prevalent patients who were not at risk of dying as a result of cancer; and already cured patients, those living longer than TTC at a specific point in time. CF was also compared with long-term NS since, for patients diagnosed after a certain age, CF (representing asymptotical values of NS) is reached far beyond the patient's life expectancy.

Results

For the most frequent cancer types, the Weibull survival model stratified by sex and age showed a very good fit with observed survival. For men diagnosed with any cancer type at age 65-74 years, CF was 41%, while the NS was 49% until age 100 and 50% until age 90. In women, similar differences emerged for patients with any cancer type or with breast cancer. Among patients alive in 2018 with colorectal cancer at age 55-64 years, 48% were already cured (had reached their specific TTC), while the cure prevalence (lifelong probability to be cured from cancer) was 89%. Cure prevalence became 97.5% (2.5% will die because of their neoplasm) for patients alive >5 years after diagnosis.

Conclusions

This study represents an addition to the current knowledge on the topic providing a detailed description of available indicators of prevalence and cancer cure, highlighting the links among them, and illustrating their interpretation. Indicators may be relevant for patients and clinical practice; they are unambiguously defined, measurable, and reproducible in different countries where population-based cancer registries are active.

Patient presentation, skin biopsy utilization and cutaneous malignant melanoma incidence and mortality in northern Italy: Trends and correlations

BACKGROUND

The global increase in incidence of cutaneous malignant melanoma (CMM) occurring in the past decades has been partly attributed to increased diagnostic scrutiny of early lesions, with a potential phenomenon of overdiagnosis. The reported positive linear relation between skin biopsy rate and incidence of early CMM is compatible with this hypothesis.

OBJECTIVES

We explored the ecological association between the trends in annual dermatologic office visit rates, skin biopsy rates, incidence rates of in situ and invasive CMM by tumour thickness category, and CMM mortality rates in the Emilia-Romagna Region (northern Italy).

METHODS

Four cancer registries covering a population of 2,696,000 provided CMM incidence data for the years 2003-2017. Dermatologic office visit rates and skin biopsy rates were calculated using the Regional outpatient care database. All rates were age-standardized. Trends were described with the estimated average annual per cent change (EAAPC). Correlations were tested with the Spearman correlation coefficient.

RESULTS

Incidence increased significantly. The increase was steeper for in situ CMM (EAAPC: men, 10.2; women, 6.9) followed by CMM <0.8 mm thick (9.1; 5.2), but the rates grew significantly for most subgroups of CMMs ≥0.8 mm thick. Mortality decreased significantly among women (-2.3) and non-significantly among men. For dermatologic office visit rate and skin biopsy rate the EAAPC were, respectively, 1.7 and 1.8 for men and 1.2 and 0.9 for women. Annual dermatologic office visit rate correlated with skin biopsy rate in both sexes. However, the proportion of skin biopsies out of dermatologic office visits was constant across the years (range: men, 0.182-0.216; women, 0.157-0.191).

CONCLUSIONS

In Italy, the increasing CMM incidence trend is, at least in part, genuine. Overdiagnosis-if any-is due to an increased patient presentation at dermatologic offices and not to a lower dermatologic threshold to perform biopsy.

The relative contribution of the decreasing trend in tumour thickness to the 2010s increase in net survival from cutaneous malignant melanoma in Italy: a population-based investigation

BACKGROUND

The long-term increase in survival from cutaneous malignant melanoma (CMM) is generally attributed to the decreasing trend in tumour thickness, the single most important prognostic factor.

OBJECTIVES

To determine the relative contribution of decreased tumour thickness to the favourable trend in survival from CMM in Italy.

METHODS

Eleven local cancer registries covering a population of 8 056 608 (13.4% of the Italian population in 2010) provided records for people with primary CMM registered between 2003 and 2017. Age-standardized 5-year net survival was calculated. Multivariate analysis of 5-year net survival was undertaken by calculating the relative excess risk (RER) of death. The relative contribution of the decrease in tumour thickness to the RER of death was evaluated using a forward stepwise flexible parametric survival model including the available prognostic factors.

RESULTS

Over the study period, tumour thickness was inversely associated with 5-year net survival and multivariate RER in both sexes. The median thickness was 0.90 mm in 2003-2007, 0.85 mm in 2008-2012 and 0.75 mm in 2013-2017 among male patients, and 0.78 mm, 0.77 mm and 0.68 mm among female patients, respectively. The 5-year net survival was 86.8%, 89.2% and 93.2% in male patients, and 91.4%, 92.0% and 93.4% in female patients, respectively. In 2013-2017, male patients exhibited the same survival as female patients despite having thicker lesions. For them, the increasing survival trend was more pronounced with increasing thickness, and the inclusion of thickness in the forward stepwise model made the RER in 2013-2017 vs. 2003-2007 increase from 0.64 [95% confidence interval (CI) 0.51-0.80] to 0.70 (95% CI 0.57-0.86). This indicates that the thickness trend accounted for less than 20% of the survival increase. For female patients, the results were not significant but, with multiple imputation of missing thickness values, the RER rose from 0.74 (95% CI 0.58-0.93) to 0.82 (95% CI 0.66-1.02) in 2013-2017.

CONCLUSIONS

For male patients in particular, decrease in tumour thickness accounted for a small part of the improvement in survival observed in 2013-2017. The introduction of targeted therapies and immune checkpoint inhibitors in 2013 is most likely to account for the remaining improvement.

A comprehensive assessment of the impact of a colorectal cancer screening program in a northern Italian area

BACKGROUND

The impact of a faecal immunochemical test-based colorectal cancer (CRC) screening program in terms of patient prognosis could be affected by lead-time bias, which artificially increases the survival of screen-detected patients due to the early diagnosis.

AIMS

To provide a description of the impact of the CRC screening program in the Trentino Region (Italy), including the Cure Fraction (CF), a prognostic indicator not affected by lead-time bias.

METHODS

The program started in 2008, inviting the resident population aged 50-69 years. In this retrospective cohort study, 1,697 CRC diagnosed between 2003 and 2014 in patients aged 50-69 years were classified as pre-screening (PS), screen-detected (SD), interval cancers (IC) and not-screen-detected (NSD). We compared groups by stage at diagnosis and CF. Trends in CRC mortality were reported.

RESULTS

The proportion of stage I among SD cases was 51%, higher than PS (19%; OR 4.66, 95%CI 3.50-6.20), NSD (20.6%; OR 3.96, 95%CI 2.95-5.32) and IC (33.3%; OR 2.11, 95%CI 1.10-4.04). The CF of PS, NSD and SD cases was respectively 57% (95%CI 54-60%), 60% (95%CI 58-63%) and 93% (95%CI 89-96%). CRC mortality dropped from 40.7 to 25.6\100,000.

CONCLUSION

The program significantly improved the prognosis of patients, decreasing CRC mortality and incidence of advanced CRCs.