paywalled - Survival of ovarian cancer patients in Germany in the early 21st century: a period analysis by age, histology, laterality, and stage

European Journal of Cancer Prevention:

Abstract

Population-based studies on ovarian cancer providing survival estimates by age, histology, laterality, and stage have been sparse. We aimed to derive the most up-to-date and detailed survival estimates for ovarian cancer patients in Germany. We used a pooled German national dataset including data from 11 cancer registries covering 33 million populations. A total of 21 651 patients diagnosed with ovarian cancer in 1997-2006 were included. Period analysis was carried out to calculate the 5-year relative survival (RS) for the years 2002-2006. Trends in survival between 2002 and 2006 were examined using model-based period analysis. Age adjustment was performed using five age groups (15-44, 45-54, 55-64, 65-74, and 75+ years). Overall, the age-adjusted 5-year RS in 2002-2006 was 41%. A strong age gradient was observed, with a decrease in the 5-year RS from 67% in the age group 15-49 years to 28% in the age group 70+ years. Furthermore, the prognosis varied markedly by histology, laterality, and stage, with the age-adjusted 5-year RS ranging from 25% (for carcinoma not otherwise specified) to 81% (for stromal cell carcinoma), reaching 46% for unilateral and 32% for bilateral carcinoma and reaching 82% for Federation of Gynecology and Obstetrics (FIGO) stages I and II, 36% for FIGO stage III, and 18% for FIGO stage IV. No improvement in survival could be observed for any of the subgroups in the period between 2002 and 2006. Our analyses suggest that an improvement in the 5-year RS for ovarian cancer may have stagnated in the early 21st century and underline the need for a more effective translation of therapeutic innovation into clinical practice.

(re: statistics) Comparison of methods for calculating relative survival in population-based studies

Comparison of methods for calculating relative survival in population-based studies: Publication year: 2012

Source:Cancer Epidemiology, Volume 36, Issue 1


Background: 

It is vital that unbiased estimates of relative survival are estimated and reported by cancer registries. A single figure of relative survival is often required to make reporting simpler. This can be obtained by pooling all ages or, more commonly, by using age-standardisation. The various methods for providing a single figure estimate of relative survival can give very different estimates.

Methods:

The problem is illustrated through an example using Finnish thyroid cancer data. The differences are further explored through a simulation study that investigates the effect of age on the estimates of relative survival.

Results: 

The example highlights that in practice the all-age estimates from the various methods can be substantially different (up to 6 percentage units at 15 years of follow-up). The simulation study confirms the finding that differing estimates for the all-age estimates of relative survival are obtained. Performing age-standardisation makes the methods more comparable and results in better estimation of the true net survival.

Conclusions: 

The all-age estimates of relative survival rarely give an appropriate estimate of net survival. We feel that modelling or stratifying by age when calculating relative survival is vitally important as the lack of homogeneity in the cohort of patients leads to potentially biased estimates. We feel that the methods using modelling provide a greater flexibility than life-table based approaches. The flexible parametric approach does not require an arbitrary splitting of the time-scale, which makes it more computationally efficient. It also has the advantage of easily being extended to incorporate time-dependent effects.

abstract : Hazard ratios in cancer clinical trials - a primer : Nature Reviews Clinical Oncology

Perspectives

Nature Reviews Clinical Oncology 9, 178-183 (March 2012) | doi:10.1038/nrclinonc.2011.217

Hazard ratios in cancer clinical trials—a primer

Abstract

The increase and diversity of clinical trial data has resulted in a greater reliance on statistical analyses to discern value. Assessing differences between two similar survival curves can pose a challenge for those without formal training in statistical interpretation; therefore, there has been an increased reliance on hazard ratios often to the exclusion of more-traditional survival measures. 

However, because a hazard ratio lacks dimensions it can only inform the reader about the reliability and uniformity of the data. It does not provide practitioners with quantitative values they can use, nor does it provide information they can discuss with patients. 

Motivated by a non-scientific poll of oncologists in training and those with board certification that suggested only a limited understanding of the derivation of hazard ratios we undertook this presentation of hazard ratios: a measure of treatment efficacy that is increasingly used and often misused.

abstract: Has equity in relative survival improved over time in Finland - a methodological exercise.

Blogger's Note: full access to the text would be preferable to elicit exact differences; study = population based stats/regional differences

BACKGROUND:

Population-based relative survival is widely used as a method of monitoring the success of cancer control. This success may not be relevant only for an entire country but also regional developments over time are of interest. It would not only be important that the relative survival improved but also that the differences between regions decreased over time.

METHODS:

In this paper the authors show how relative survival methods can be used to study such differences. In addition to standard methods, some more recently introduced approaches are used, most notably a method for checking the goodness of fit of the relative survival model. This gives confidence in the obtained results and provides additional insight when assumptions are not met.

RESULTS:

An analysis of cancers of the colon and ovary by cancer control region in Finland in 1953-2003 shows an overall improvement in relative survival, accompanied in colon cancer also by a decrease of differences in relative survival between the regions. Thus, the desired course was observed in colon cancer but not in cancer of the ovary.

CONCLUSIONS:

These results, applied to further sites, should lead to investigation of differences in cancer control policies between regions.

the Oncologist: Relentless Progress: ASCO Responds

Blogger's Note: the 'timeline' section includes stats on ovarian cancer

Relentless Progress: ASCO Responds
ALLEN S. LICHTER
American Society of Clinical Oncology, Alexandria, Virginia, USA

Dr. Beatty’s thoughtful piece [1] brings up a number of important
points. Progress against cancer has been relentless. To
summarize these advances, the American Society of Clinical
Oncology (ASCO) has created a website:

CancerProgress.net.http://www.cancerprogress.net/
 




It’s a summary of important milestones in each cancer and
each treatment modality, concentrating on the 40 years since
the signing of the National Cancer Act in 1971......