ORIGINAL PAPER / Gynecology

Ginekologia Polska

2022, vol. 93, no. 6, 460–466

Copyright © 2022 PTGiP

ISSN 0017–0011, e-ISSN 2543–6767

DOI 10.5603/GP.a2021.0154

Analysis of incidence and overall survival of patients with vulvar cancer in Poland in 2008–2016 — implications for cancer registries

Waldemar Wierzba12Mateusz Jankowski3Krzysztof Placiszewski2Piotr Ciompa1Artur J. Jakimiuk45Anna Danska-Bidzinska6
1University of Humanities and Economics in Lodz, Poland
2Central Clinical Hospital of the Ministry of Internal Affairs and Administration, Warsaw, Poland
3School of Public Health, Centre of Postgraduate Medical Education, Warsaw, Poland
4Department of Obstetrics and Gynecology, Central Clinical Hospital of Interior Affairs and Administration, Warsaw, Poland
5Center of Reproductive Health, Institute of Mother and Child, Warsaw, Poland
6Chair and Department of Obstetrics, Gynaecology and Oncology, 2nd Faculty of Medicine, Medical University of Warsaw, Poland
ABSTRACT
Objectives: To analyze the incidence and overall survival rate of patients with vulvar cancer in Poland, based on the reporting data from the National Health Fund.
Material and methods: The incidence of vulvar cancer in Poland in 20082016 (9-year follow-up period) by voivodship and the number of patients undergoing combined hospital treatment were analyzed. For the group of patients treated systemically, overall survival (OS) probability was calculated using the Kaplan-Meier estimation method.
Results: In the period 20082016 in Poland, the diagnosis of malignant neoplasm of the vulva (C51% group) was made in 29,702 patients. The mean annual prevalence rate per 100,000 inhabitants was 8.3 ± 1.2 for Poland. The largest numbers of patients were reported in Mazowieckie and Slaskie voivodeships and the lowest in Opolskie and Podlaskie voivodeships. The median overall survival of patients treated with the combined method in 20082016 in Poland was 64.7 months (95% Cl: 58.070.0). One-year survival rate was observed in 77.6% of patients, 2-year in 64.4%, 3-year in 58%, over 5 years 54.22%.
Conclusions: In the years 20082016 in Poland, based on the data reported to the National Health Fund, the incidence of vulvar cancer was 4 times higher than the statistics of the National Cancer Registry, the WHO or the USA, which indicates either substantive or reporting errors. In Poland, 54% of patients treated with the combined therapy survive over 5 years which is a much lower result compared to highly developed countries.
Key word: vulvar cancer; overall survival; combined therapy; retrospective analysis; Poland
Ginekologia Polska 2022; 93, 6: 460466

Corresponding author:

Mateusz Jankowski

School of Public Health, Centre of Postgraduate Medical Education, Warsaw, Poland

e-mail: mateusz.jankowski@cmkp.edu.pl

Received: 21.05.2021 Accepted: 18.07.2021 Early publication date: 18.11.2021

This article is available in open access under Creative Common Attribution-Non-Commercial-No Derivatives 4.0 International (CC BY-NC-ND 4.0) license, allowing to download

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INTRODUCTION

Malignant neoplasms of the vulva occur most often after the age of 60 [1] and by some are classified as diseases of the menopausal age. Observations in recent years indicate an increase in the incidence amongst younger patients [2]. Malignant neoplasm of the vulva is a rare neoplasm, it accounts for only 25% of all malignant neoplasms of female genital organs [2]. However, in the last decade, an increase in new cases was observed from about 0.6% each year, which resulted in an increase in mortality due to this cancer by an average of about 1.2% in the period between 2005 and 2014 [4]. Malignant neoplasms of the vulva jointly with malignant neoplasms of the vagina, account for only one percent of all malignant neoplasms in women in Poland. Similarly, malignant neoplasms of the vulva and vagina are responsible for one percent of cancer deaths in women in Poland [3, 4]. According to the studies of the National Cancer Registry (NCR), in patients diagnosed with malignant neoplasm of the vulva and vagina (NCR studies those tumours jointly), the one-year survival rate in 20002002 was 71.2% and in 20032005 it was 69.4%. The five-year survival rates in the group of patients with vulvar and vaginal cancer in the years 20002002 accounted for 51.8% and in the years 20032005 for 48.6% of patients, respectively [4].

In the Polish literature, there are practically no in-depth data on the prevalence and overall survival rate of patients diagnosed with vulvar malignant neoplasm. Even the data of the Polish National Cancer Registry combine this information with the data on malignant tumours of vagina. Therefore, the aim of this study was to analyze the incidence and overall survival rate of patients with vulvar cancer in Poland, based on the reporting data from the National Health Fund.

MATERIAL AND METHODS

From the reporting database of the National Health Fund, the only public payer in Poland, the data of patients were collected for analysis from 2008-2016, who were shown to the payer with the diagnosis from C51% group vulvar malignant neoplasm, according to ICD-10 [5]. The PESEL number (personal identification number) [6] was recognized as the unique identifier of the patient. Then, from those data, further information was extracted on patient hospital treatment. The analysis included data in which there was a simultaneous occurrence of the unique individual patient number (PESEL number) and diagnosis from the selected group. Then, a subset was created in the database in order to distinguish the data of patients undergoing combined treatment (chemotherapy, radio[chemo]therapy, surgery). Overall survival was analyzed in this group. The analysis covered the data of patients treated in the period from 1st January 2008 to 31st December 2016. The start date was the first date of the treatment given; the observation cut-off date was set on 31st December 2016. The number of neoplasms diagnosed according to the ICD-10 classification reported to the NHF was analyzed [5] in given types of services (health care subsegments) [7]. The number of diagnoses was analyzed by voivodship (reporting to NHF regional departments) in the nine-year period, separately for each year. In addition, for the group of patients undergoing combined therapy within hospital treatment (subsegment 03 — Hospital Treatment) 12, 24, 36 and 60-month survival rates were calculated using the Kaplan-Meier estimator. The median follow-up time was calculated based on the censored observation time (the median follow-up time value represents the time during which 50% of living patients were observed until the end of the analysis, i.e., until 31st December 2016). Data on the date of patient death was obtained based on the PESEL database from the Home Office. Overall survival analysis was performed with the Kaplan-Meier estimator and use of survival tables [8]. The results were developed in SAS Enterprise software Guide 7.1.

RESULTS

In Poland, there are 17 types of health services otherwise referred to as health care subsegments [7]. In the period 20082016 in Poland, the diagnosis of malignant neoplasm of vulva (C51% group) was made in 29,702 patients, on average annual approximately 3,300 patients per year. The percentage distribution of those patients among individual health care segments in Poland is presented in Table 1. The largest number of patients diagnosed in the analyzed group occurred in the Outpatient Specialist (Secondary) Care (ambulatory specialized services 45%); then in primary care (general practitioners 21%) and in hospital treatment care (17.3%).

Table 1. Distribution of patients with malignant neoplasm of vulva (C51% diagnosis) between types of health services in Poland (healthcare subsegments) in the years 20082016

Type of healthcare service according to the National Health Fund classification

Percentage of patients receiving the healthcare service

1. Primary care

21%

2. Ambulatory specialized services

45%

3. Hospital treatment

17.3%

4. Psychiatric care and treatment of addictions

0.0%

5. Medical rehabilitation

1.2%

6. Long-term care

5.9%

7. Dental treatment

0.0%

8. Sanatorium treatment

0.0%

9. Emergency assistance and sanitary transport

0.0%

10. Preventive health programs

6.4%

11. Separately contracted services

0.8%

12. Supplied of orthopedic equipment, auxiliaries and medical technical measures

0.0%

13. Drug price reimbursement

0.0%

14. Nursing and care services

1.0%

15. Palliative and hospice care

1.4%

16. Emergency Medical services

0.0%

17. Emergency assistance and sanitary transport from 2009

0.0%

The number of patients diagnosed with C51% in individual voivodeships directly correlates with the size of the voivodeship and frequency of highly specialized centres (Tab. 2). The largest numbers of patients were reported in the following voivodships: Mazowieckie (average annual about 500 people); Slaskie (approx. 490 people average annual) as well as in Wielkopolskie and Dolnoslaskie (approx. 280 people on average annual).

Table 2. The prevalence of patients diagnosed with malignant neoplasm of vulva (C51% diagnosis) in Poland in 20082016 in all types of services and by voivodship

Provincial Branch of the National Health Fund (Voivodeship)

Year of observation

Annual average
in the province
2008–20016

Morbidity rate per
100 000 inhabitants
in voivodeship

2008

2009

2010

2011

2012

2013

2014

2015

2016

Dolnoslaskie

228

274

247

262

280

310

292

300

288

275.67

9.46

Kujawsko-Pomorskie

145

167

169

160

166

196

196

191

191

175.67

8.34

Lubelskie

153

157

153

157

167

178

179

186

194

169.33

7.71

Lubuskie

75

85

70

83

100

87

87

86

80

83.67

8.27

Lodzkie

150

189

191

193

209

221

199

204

197

194.78

7.71

Malopolskie

205

242

236

236

276

240

255

263

259

245.78

7.31

Mazowieckie

469

496

510

550

531

486

496

543

511

510.22

9.66

Opolskie

81

63

63

62

62

57

75

72

80

68.33

6.59

Podkarpackie

109

122

120

124

126

144

117

136

127

125.00

5.89

Podlaskie

78

78

91

88

78

95

93

109

98

89.78

7.44

Pomorskie

190

184

184

219

205

201

196

210

182

196.78

8.74

Slaskie

492

506

538

469

465

479

484

462

500

488.33

10.55

Swietokrzyskie

94

114

125

127

138

132

117

127

121

121.67

9.60

Warminsko-Mazurskie

122

118

107

110

106

120

99

109

126

113.00

7.74

Wielkopolskie

235

277

263

286

323

286

264

290

288

279.11

8.07

Zachodnio-pomorskie

158

189

165

159

148

155

144

168

182

163.11

9.41

Poland in total

2984

3261

3232

3285

3380

3387

3293

3456

3424

Total: 29702
Annual average: 3300.22

Average in Voivodeship
X+/
SD*

186.5
+/–125.6

203.8
+/–132.84

202.0
+/–139.21

205.3
+/–135.88

211.3
+/–34.71

211.7
+/–126.47

205.8
+/–129.29

216.0
+/–131.92

214.0
+/–131.55

206.26 +/–131.17

8.28 +/–1.23

*Average value +/–Standard deviation

The lowest number of patients was reported in the following voivodships: Opolskie (about 70 people on average annual) and Podlaskie (approx. 90 people on average annual) as well as Swietokrzyskie and Podkarpackie (approx. 120 people on average annual). Mean annual prevalence rate per 100,000 inhabitants was 8.28 ± 1.23 for Poland.

The mean age of the patient with malignant neoplasm of vulva (C51% diagnosis) at the time of providing with healthcare services increased with the year of observation (Tab. 3)

Table 3. The mean age of the patient with malignant neoplasm of vulva (C51% diagnosis) at the time of providing with healthcare services in years 20082016 in Poland

Year of observation

Average age, Average value +/–standard deviation

2008

65.61+/–13.04

2009

66.17+/–13.48

2010

66.58+/–13.28

2011

67.29+/–13.20

2012

67.60+/–12.90

2013

68.58+/–12.54

2014

68.24+/–12.53

2015

68.78+/–12.66

2016

69.08+/–12.64

On average, 24% of patients from a cohort of patients diagnosed with malignant neoplasm of vulva (C51% dia­gnosis) received treatment as part of inpatient therapy. The number of these patients by voivodship is presented in Table 4.

Table 4. Number of patients diagnosed with malignant neoplasm of vulva (C51% diagnosis) treated with the combined method in hospital care in individual years 20082016

Provincial Branch of the National Health Fund (Voivodeship)

Year of observation

Annual average
in the province
2008–2016

Morbidity rate per
100 000 inhabitants
in voivodeship

2008

2009

2010

2011

2012

2013

2014

2015

2016

Dolnoslaskie

72

57

49

80

80

96

82

102

99

79.67

2.66

Kujawsko-Pomorskie

33

45

43

33

54

53

52

60

56

47.67

2.24

Lubelskie

38

33

46

46

49

48

41

54

50

45.00

2.06

Lubuskie

25

10

3

11

17

11

19

20

22

15.33

1.43

Lodzkie

45

55

60

60

60

68

58

65

54

58.33

2.33

Malopolskie

63

82

81

81

83

73

94

90

76

80.33

2.42

Mazowieckie

128

99

120

147

118

120

133

140

148

128.11

2.38

Opolskie

9

17

16

17

12

14

15

21

26

16.33

1.49

Podkarpackie

32

32

32

42

38

41

37

38

40

36.89

1.72

Podlaskie

25

27

30

23

30

21

24

32

30

26.89

2.22

Pomorskie

43

43

42

54

44

58

56

56

50

49.56

2.18

Slaskie

104

118

145

99

106

118

119

113

141

118.11

2.50

Swietokrzyskie

28

25

28

31

27

37

31

45

34

31.78

2.48

Warminsko-Mazurskie

23

17

17

23

16

27

24

22

30

22.11

1.47

Wielkopolskie

83

69

70

82

81

77

70

99

71

78.00

2.29

Zachodniopomorskie

41

28

34

42

38

40

38

48

60

41.00

2.26

Poland in total

792

757

816

871

853

902

893

1005

987

Total: 7876
Annual average: 875.11

Average in Voivodeship
X+/–SD*

49.5
+/–32.4

47.31
+/–31.06

51.0
+/–37.79

54.43
+/–35.92

53.31
+/–32.24

56.37
+/–33.85

55.81
+/–35.46

62.81
+/–36.10

61.69
+/–38.20

54.69 +/–33.96

2.13 +/–0.39

*Average value +/–Standard deviation

The highest percentage of people receiving hospital treatment was observed in the following voivodships: Mazowieckie (56.2%), Slaskie (51.8%), Malopolskie (35.2%); the lowest percentage is in the following voivodeships: Lubuskie (6.87%), Opolskie (7.2%), Warminsko-Mazurskie (9.7%).

Overall survival was based on a cohort of patients undergoing combination therapy as part of hospital treatment (Fig. 1). The median overall survival in the analyzed cohort of patients (4319 people) in the years 20082016 (9 years) was 64.7 months (95% Cl: 58.070.0). 1783 were full observations and 2536 (58.72%) were censored. one-year (12 months) survival occurred in 77.6% of patients, two-year (24 months) in 64.4%, three-year (36 months) in 58.43 (months), over five years (60 months) 54.22%.

207702.png
Figure 1. Kaplan-Meier estimation of overall survival in patients with malignant neoplasm of vulva (C51% diagnosis)

DISCUSSION

Cancer of vulva makes 25% of all malignant neoplasms of the female genital organs and one percent of all malignancies in women. The incidence rate ranges from 0.12.6 per 100,000 in various populations and regions of the world. The world average is 1.2 [1–4].

In Poland, vulvar cancer ranks fourth in terms of the incidence of malignant neoplasms of the reproductive organs: after cervical, ovarian and endometrial cancer. There are approximately 350 new cases of this cancer diagnosed in Poland every year. Every year 200 women die from vulvar cancer in Poland (National Cancer Registry data). The average (raw) incidence rate in our country is 1.4 per 100,000 [4]. According to the data reported to the National Health Fund, this ratio is 8.3 per 100,000, which may indicate over-diagnosing or errors in reporting. The mean age at diagnosis is 69 years. In the group of patients diagnosed with vulvar cancer, only one in four (24%) was qualified for systemic treatment. There is a significant difference in the number of patients undergoing combined inpatient treatment between the voivodships: Mazowieckie 56%, Slaskie 51% vs. Lubuskie 6.8%, Warmińsko-Mazurskie 9.7%. These data indicate organizational problems (distance from reference medical centres), insufficient specialist knowledge amongst medical personnel, difficulties with access to highly specialized services, but also probably low patient health awareness in the age group over 60 and their health condition related to multiple co-morbidities disqualifying them from combined therapy. The consequence of the above-mentioned problems is the result of only 54% of five-year survival in the group of patients treated with combined therapy.

For comparison, according to data from the United States, 0.3% of the female population is at risk of being diagnosed with vulvar cancer. Every year, there are 6,070 new cases (2.2 per 100,000) and 1,280 deaths (0.5 per 100,000), 71.1% will survive five years these data have remained unchanged for 40 years. Cancer of vulva is diagnosed in locally advanced stage in 59% of patients, in 29% in regionally advanced stage and in six percent in the stage of dissemination beyond the regionally advanced stage. The mean age of patients diagnosed with vulvar cancer is 69 years and death 78 years [9, 10]. These values are comparable with the data of the International Federation of Gynaecology and Obstetrics [11] and the data from Australia [12].

The above differences between Polish and American data indicate that despite the same age of patients at the time of diagnosis with vulvar cancer, it occurs four times more often in the population of Polish women and five-year survival rates are recorded only in 54% of Polish women [13–15] (only group treated with combined therapy) versus 71% of American women (the whole group). The comparison of the data suggests that vulvar neoplasms are diagnosed in more advanced clinical stages in Poland. Another explanation may be less effective treatment in this group of patients. Organizational problems mainly related to pathomorphological diagnostics may be an indirect cause of suboptimal therapies. The above presented data require further detailed analysis within the framework of the national statistics (Statistics Poland, Social Insurance Institution, National Health Fund, National Cancer Registry).

This study has several limitations. Firstly, our study is based on the data collected from the registry of the National Health Fund and the quality of reported data may influence the obtained results. Secondly, our analysis is limited to nine-year period and further analysis are needed to assess the epidemiology of vulvar cancer in Poland. However, our study also has practical implications. The incidence of vulvar cancer presented in this study and differences between data from the registry of the National Health Fund and other public institutions collecting data on cancer (including vulvar cancer) indicate an urgent need to verify the existing caner registers and introduce methods to improve the quality of collected data and ensure their comparability between institutions. In addition, data on the prevalence of vulvar cancer can be used to plan health policy programs at both the national and regional levels.

CONCLUSIONS

1. In the years 20082016 in Poland, based on the data reported to the National Health Fund, the incidence of vulvar cancer was four times higher than in the statistics of the National Cancer Registry, data from the WHO or the USA, which indicates either substantive or reporting errors.
2. Systemic treatment covered a greater percentage of patients in voivodships where oncology reference centres were located.
3. In Poland, 54% of patients treated with combined method survive over five years. Compared to highly developed countries, this result is unsatisfactory, in the USA this percentage is as high as 71%.
4. Joint data from Statistics Poland, Social Insurance Institution, National Health Fund, National Cancer Registry and oncology registries are essential to develop standards of care and improved treatment outcomes for vulvar cancer patients.
Conflict of interest

All authors declare no conflict of interest.

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