Malignant Neoplasms of Urinary Tract (C64-C68) in the Osijek-Baranja County (Croatia) in the Period 2001-2009

Research Article

Austin J Public Health Epidemiol. 2014;1(3): 1011.

Malignant Neoplasms of Urinary Tract (C64-C68) in the Osijek-Baranja County (Croatia) in the Period 2001-2009

Josip Milas1*, Senka Samardžic1 and Krunoslav Milas2

1Faculty of Medicine, Josip Juraj Strossmayer University Osijek, Croatia

2Ministry of Health, Croatia

*Corresponding author: Josip Milas, Faculty of Medicine, Josip Juraj Strossmayer University Osijek, Josipa Huttlera 4, 31000 Osijek, Croatia

Received: August 20, 2014; Accepted: September 15, 2014; Published: September 16, 2014

Abstract

Purpose: We investigated the trends of the malignant neoplasms of the urinary tract in the Osijek-Baranya County (Croatia) during the 2001-2009 period.

Methods: Mandatory county hospitals data reports, County bureaus of statistics and the County Register of Deaths of 872 cohort patients (260 females and 612 males) were used in this analysis.

Results: For the both genders, the overall age-adjusted incidence rate was 24.5/100,000 with a weak upward chronological tendency (R2=0.059); also, the overall age-standardized mortality rate of 12.2/100,000 experienced a moderate upward trend line (R2=0.350). The age-adjusted 5-year relative survival rate of all patients totalled 51.0% in 2001-2005 period. The survival rate in males (51.1%) resembled the overall survival rate and it was slightly higher than in females (50.6%). An average patient was admitted to hospital 2.7 times during the course of their illness with the average length of stay in hospital of 11.3 days. The number of hospitalizations in years 2001 to 2009 progressively grew, both from the viewpoint of the entire population of patients and seeing genders separately (R2=0.777).

Conclusion: Although the data on the incidence and mortality rate from this cancer group do not deviate much from the corresponding data on the European and Croatian level, the survival rate is far below the EU average and thus directly suggests that the health care of these cancer patients in the OBC should be substantially improved and put on a much higher level.

Keywords: Neoplasms of urinary tract; Mortality rate; Incidence rate; 5-year relative survival rate; Length of stay in hospital; Croatia

Abbreviations

ICD-10: International Statistical Classification of Diseases and Related Health Problems, 10th Revision; C64-C68: Malignant Neoplasms of the Urinary Tract; C64: Malignant Neoplasm of Kidney, Except Renal Pelvis; C65: Malignant Neoplasm of Renal Pelvis; C66: Malignant Neoplasm of Ureter; C67: Malignant Neoplasm of Bladder; C68: Malignant Neoplasm of Other and Unspecified Urinary Organs; OBC: Osijek-Baranja County; ONKO: Mandatory Statistical Reports on Every Hospitalized Cancer Patients in Croatia; BSL: Mandatory Statistical Report on Every Hospitalized Person, Regardless of the Causes of Hospitalization; CI: Confidence Interval; EU: European Union; MADG: Median Age at Diagnosis; MAD: Median Age at Death; R: Relationship; LOSH: Length of Stay in Hospital; NOAH: Number of Hospital Admissions; IPHO: The Institute of Public Health of the Osijek-Baranja County; USA: United States of America; UW: upward trendline; COD(S): coefficient of determination (strength); N: number of cases; ASR: age-standardized rate (EU); N/A: not available; BG: Both genders; F: Females; M: Males; AA: average admission in hospital per patient

Introduction

Malignant neoplasms of the urinary tract (according to the International Statistical Classification of Diseases and Related Health Problems, 10th Revision (ICD-10), group codes C64-C68) belongs to the sixth most common cancers in the OBC [1]. Comparing to the incidence rate of this cancer group in the OBC, higher rates are found in Europe and North America and lower ones are determined in Asia and South America [2]. Exposure to chemicals, cigarette smoke and family history may increase the risk of this cancer group, particular of bladder cancer (C67) [3]. The C64-C68 cancer group accounts for around 8.5% of all cancers in the USA [4]. These cancers affect more often males than females, with a males to females ratio of about 2:1 (11.3% in males and 5.6% in females) [4]. Regarding the USA population, the trends in the incidence of kidney cancer (C64) revealed a statistically significant increase among members of both genders during the 2003-2007 period whereas the trends in the occurrence of urinary bladder cancer demonstrated neither a statistically significant increase nor decrease in males, but it came to a major decrease in females. The trends in the corresponding death rates during the same period revealed a decrease in mortality from kidney cancer in both genders and in the mortality from bladder cancer within the female population. Having regard to the same population, the 5-year relative survival rate from bladder cancer amounted to 72% in males and 67% in females while the 5-year relative survival rate from kidney cancer was 56% in males and 58% in females [5]. Concerning the same cancers, the estimated incidence and mortality rate in the EU were 6.9% and 5.9%, respectively. In males, the incidence and mortality rate ware 10.5% and 7.4%, respectively. What is curious is that in females, either of the parameters did not even reach 1% [6]. Taking account of the whole corpus of patients, the 5-year relative survival rate from kidney cancer in Europe was 57% and if seeing genders separately, this rate was 57% in females and 54% in males. Patients from France, Italy, Austria and Germany are above the European average in terms of the survival from this cancer while patients from eastern European countries, England, Wales, Scotland and Denmark were not even close to the European average in this context. The European 5-year relative survival rate from bladder cancer was 71%. This rate was 70% in males and 67% in females. Bladder cancer is one of the very few cancers from which survival is better in males than in females, although the incidence rate of bladder cancer was higher among males than among females. This is a consequence of the fact females pay less attention to hematuria and other discharges than males do. Survival from both cancers (kidney and bladder) decreases with the age [7]. The median age at diagnosis of bladder cancer within the USA population was 72.9 years (74.1 years for females and 72.5 years for males) [8]. In Denmark, patients were diagnosed with kidney cancer at the average age of 68 years in the 1998-2009 period [9]. In Europe, the median age at diagnosis of kidney cancer was generally around 60 years and the male to female ratio was 3:1 [10]. In Croatia, the kidney cancer incidence rates in males and females were 4% and 3%, respectively, while the bladder cancer incidence rates were 6% and 2%, respectively [11]. In the 1994-1998 period, the 5-year relative survival rate from urinary bladder and kidney cancer in Croatia was 75% and 56%, respectively, in males and 76% and 65%, respectively, in females.

This paper focuses on the demographic (gender, age, median age) and statistical features of C64-C68 cancer patients (incidence and mortality rate, survival rate, length of stay in hospital) and is aimed at obtaining information on the status of this group of cancer in the OBC in relation to the corresponding status in Croatia and Europe in period 2001-2009.

Materials and Methods

Data source

Although the representativeness of their data might be challenged, mandatory county hospitals data reports, county bureaus of statistics and the County Register of Deaths still represent the only available source of information on the profile of cancer in the OBC. All data from the 2001-2009 periods originate from these institutions. The cohort studied in this article included all people with cancer who were registered as the patients in one of two hospitals in the OBC in the time period from 2001 to 2009 (follow up period from 1996 to 2010). Based on these sources, a database of people who were hospitalized in the area of the OBC for any reason whatsoever (including cancer) has been generated [12,13]. The data on each of the hospitalized patients have been supplemented with data obtained from the Register of Deaths.

Data on every person with cancer are accompanied with their chronological order of illness and hospitalization. The database involved all hospitalizations and all data on ONKO or BSL forms (mandatory statistical patterns for all hospitalized patients in Croatia). The ONKO form is a mandatory statistical report on every hospitalized cancer patients in Croatia. The BSL form is a mandatory statistical report on every hospitalized person, regardless of the causes of hospitalization. All cancer patients coming from this area are hospitalized in state-owned (public) hospitals since there are still the only hospitals here.

Statistical analysis

The cancers were classified according to the International Statistical Classification of Diseases and Related Health Problems (ICD-10), codes C64-C68. The cancer incidence and mortality estimates in the period from 2001 to 2009 were prepared for all cancers based on gender and for age groups 0-19, 20-44, 45-64, 65+ by the year at cancer diagnosis. Based on the 2001 census, the analysis covered a total population of 330.506 people in the OBC. The Croatian National Health Insurance is a universal health insurance that covers all or almost all costs (depending on a personal choice of the type of insurance) of treatment of Croatia citizens and provides them with of four age groups. The analyses were conducted using age-specific rates, the age-standardization-direct method and 95% confidence intervals (95% CI). The standardized incidence and mortality ratios as well as the 95% confidence intervals were computed for C64-C68 pursuant to the year at cancer diagnosis. Also, both ratios were stratified according to the year at cancer diagnosis, age and gender. The median age is the observation ranked in the middle; that is 50% of patients are diagnosed at an older age and 50% are diagnosed at a younger age compared to the median. The EU standard population was used in the analysis [14]. The length of stay was determined according to the date of admission and to the date of discharge with regard to the index admission. The SAS statistical package (version 9.1, SAS Institute INC, Cary, NC, USA) was used for the statistical analysis [15] and Microsoft® Office Excel® 2007.

Results

According to the census in 2001, the analysis covered a total population of 330.506 people in the OBC. From 2001 to 2009, a total of 872 people (260 females and 612 males) were registered with malignant neoplasms of the urinary tract (C64-C68) and treated at the two hospitals in the OBC. Malignant neoplasms of the urinary tract can be said to be cancers typical for males (70.2%) due to their appearance two times more frequent among males than among females (29.8%, Table 2). Out of all cancers in the OBC, C64-C68 cancers accounted for 6.2% of all registered cancer patients. This percentage was 3.7% in females and 8.6% in males.