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January 1998, Volume 48, Issue 1

Original Article

Frequency of Gastrointestinal Tumours at A Teaching Hospital in Karachi

Itrat Mehdi  ( PMRC Research Centre, Jinnah Postgraduate Medical Centre, Karachi. )

Abstract

Malignant gastrointestinal tumours are amongst the commonest tumours exhibiting an annual increase globally. There is a change in the morphological site of involvement observed over the years. In this study biopsy proven malignant gastrointestinal tumours seen at Jinnah Postgraduate Medical Centre, Karachi from 1961 - 1992 were analyzed with reference to age, sex, topography and histology. The study showed an increase in malignant gastrointestinal tumours over the years, from 9% in 1961 to 17% in 1992 with respect to all malignant tumours reported. The tumours affected a much younger age in our population, 74% occurring between 35-64 years of age. Carcinoma oesophagus accounted for 10% of all malignancies (48.7% male and 62.4% female gastrointestinal tumours), while gastnc carcinoma remained unchanged (14% male and 9% female GI tuniours). The colorectal carcinoma (25.4% of male and 20.1% of female CI tumours) and carcinoma pancreas (1.2% male and 1.5% female CI tumours) were less frequently seen. It was observed that malignant gastrointestinal tumours have increased significantly over the years in our local population as part of international trend and are occurring at a much younger age as compared to western population. Carcinoma oesophagus was seen more frequently than gastric carcinoma and colorec­tal carcinoma. A substantially higher number tend to be more anaplastic being seen at an advanced stage of disease at the time of diagnosis (JPMA 48: 14,1998).

Introduction

Gastrointestinal tumours are one of the commonest malipant neoplasms, that are increasing annually world over1-4. There appears tobe analteration in the trend regarding sites of predilection, involvement and histological variants, with a substantial mortality associated with them5. There is a great difference in incidence, behaviour, treatment options, and prognosis of malignant neoplasms within the component sites of gastrointestinal tract, as well as between various histologic variants within the same morphological sites1. The microscopic analysis of these tumours and determination of histologic types is thus helpful in predicting prognosis, deciding treatment options, conducting epidemiological studies and research6. Different histologic variants at the same anatomical site may have varied etiology, biological behaviour, incidence, clinical features or presentation, prognosis and treatment planning and its success. In addition, similar tumours may have different biological behaviour thus influencing clinical presentation, prognosis and treatment decisions1.

Materials and Methods

The study included all biopsy proven malignant gastrointestinal turnouts seen from 1961 to 1992 at Jinnah PostgraduateMedical Centre, Karachi. The medical records of hospital based cancer registry comprising of Department of Pathology, Basic Medical Sciences Institute, Department of Surgery, Gastroenterology Unit of PMIRC and Department of Radiotherapy - Jinnah Postgraduate Medical Centre, Karachi were used as the data source. These cases were coded using ICD-O7 with reference to topography (site) and morphology (histology) and were studied in terms of age, sex and histology. The clinical data, wherever avallable, was also analysed for
topography and stage of disease (extent or metastasis). The tumours which had metastasized to gastrointestinal tract from some other primary site were excluded and similarly those cases which had incomplete clinical or histological data were also excluded. The results were tabulated and analysed on computer using the software programme CANREG from IARC WHO (International Agency for Research on Cancer World Health Organization) Lyon.

Results

There were a total of 2969 malignant gastrointestinal tumours from 1961 to 1992, including 1771 male and 1198 female cases giving a M:F ratio of 1.5:1.

Table I shows the age distribution of tumours indifferent age groups.

Table II shows a five yearly distribution of these tumours. Gastrointestinal neoplasms increased proportionately every year, from 09% in 1961 to 17% in 1992, of all malignant tumours reported. Majority (28%) had malignancy in the 4th decade of life and over all 74% cases were between 35-64 years of age. Twenty-five cases which were less than 15 years of age were excluded, as paediatric tumours are different inhistology from adult population in many significant ways, GI tumours were the second commonest male tumours (17.2%) during 1961-1971,fiflh commonest (08.9%) during 1971-1981 and the most frequent (19.9%) during 1982-1992. Amongst females these were fourth commonest (11.5% and 12.5%) during 1961 - 1971 and 1971 - 1982 and second commonest (16.5%) during 1982 - 1992.


Table III and IV shows the distribution of tumours according to age, major histological types (morphology) and site of involvement (topography) in males and females.
Ocsophageal carcinoma comprised 10% of all malignant tumours, it was seen in 48.8% males and 62.6% females. Amongst the oesophageal carcinomas more than 92% and 98% were squamous cell in males and females respectively. The ratio of oesophageal carcinoma in general (62.6% in females and 48.8% in males) and squamous cell carcinoma in particular (61.5% in females and 45.3% in males) was higher in females. Carcinoma of distal/lower oesophagus (of cardioesophageal junction) was found to be increasing over the time, from 29.7% to 38.9%. Adenocarcinoma also increased from 1.6% to 2.4% in males over the years. The disease was localised in 25%, regionally spread in 55% and metastasised distantly in 20% cases at the time of initial diagnosis. Carcinoma stomach was found in 13% males and 8.3% females, with a male to female ratio of
1.5:1. Nearly all were adenocarcinomas and less than 1% were lymphomas. Twenty-eight percent had local, 33% regional and 39% metastatic disease at presentation. Proximal gastric involvement increased, from 2.3% to 6.1%. The reporting of lymphoma (from 0.3% to 1%) and leiomyosarcoma (from 0.1% to 0.4%) also increased over the years. Colorectal carcinoma was 26.4% in males and 20.5% in females. This was adenocarcinoma in over 97% cases. The male to female ratio was 1:0.5. Rectal tumour was more common (68.9%) amongst males and colonic (57.8%) in females. The tumours were local in 19%, locoregional in 41%and metastatic in4O%. Anal canal was the fourth frequent site of malignant involvement, involving 4.4% males and 1.8% females. Tumour was mostly squamous cell carcinoma and basal cell carcinoma/malignant melanoma. Adenocarcinoma was less frequent (0.2%). Lymphomas (Hodgkin’s, Non-Hodgkin’s and malignant unclassified), originating from GALT (gut associated lymphoid tissue). were 1.7% amongst males and 1.6% amongst females usually involving the stomach. Carcinoid tumour was 0.5% in males and 0.6% in females principally involving appendix and adjacent ileocecal region. Sarcomas were 0.9% in males and 0.4% in females, stomach being the most frequent site and affecting males more frequently.

Discussion

This data is fmm a hospital based registry, catering to about 10% of national population whtch represent almost all ethnic and cementic groups of the country. The data thus can be taken as a representative sample of country’s population. This study has highlighted many aspects of gastrointestinal malignancies and has also shown certain inferences in line withpreviouslyreporteddata.Themalignantneoplasmsofthe gastrointestinal tract are occurring at a much younger age in our population as compared to the western opulation/white race as evidenced by age adjusted rates1,8,9. . Approximately 3/4 of the tumours occurred in the age group 35-64 years. The tumours occurring at a younger age tend to be more anaplastic1. This may be the reason for more undifferentiated and anaplastic tumours being reported locally. How occurrence of malignancy at a younger age influences the anaplastic grade, needs to be explored? In this study an increase in GI malignancies was observed, from 9% in 1961 to 17% in 1992. This phenomenon of an annual increase in malignant GI neoplasms is also reported from elsewhcreh1-4. This annual increment is more than expected with the advances in the diagnostic and screening pmgranimes. Gastrointestinal neoplasms now acquire the top position on frequency table of male malignancies and is the second frequent femaletumour in the period 1982-1992.
Carcinoma oesophagus accounted for 10% of all malignancies. This frequency is much higher than USA and Western countries where it is reported to be 1.5% of all malignancies and 7% of gastrointestinal malignancies10. Oesophageal carcinoma is showing high geographic variation in the world in terms of incidence, highest being in China and lowest being in Austria10, Squamous cell carcinoma oesophagus especially and malignancy of oesophagus generally is reported to be higher locally, being a little more frequent amongst females in contrast to American white population where it is predominantly a disease of males8,10. These incidence are close to those of black population in the world10. Carcinoma of lower oesophagus, especially. adenocarcinoma of cardioesophageal junction is increasing locally, like the trend observed worldover11. Carcinoma oesophagus, being asymptomatic is diagnosed late in our population. The disease is localised in 1/4 cases, regional in 1/2 and metastasised distantly in 1/5 of cases. Adenocarcinoma seems to be on the rise in recent years, especially amongst males, parallel to a trend found elsewhere in the world8,11. Gastric cancer has shown a remarkable decline over the years in USA12,13 a trend not so evident locally. The dietary practices, dmg intake (acid suppressing agents), tobacco use, alcoholic beverages and chemical exposure are probably the reasons ma significant difference of incidence in the Western and local population12. In our study, carcinoma stomach appears to be more frequent in males, nearly all being adenocarcinomas and lymphomas account for only 1%. Somehow, the presentation of gastric malignancy is earlier in our population, 61%being locoregional. The ratio of locoregional disease is lower, usually less than 50% at presentation in the western population1. Gastric malignancies are detected earlier in our population because being symptomatic they cause outlet obstmction, or metastasise early and become evident. This phenomenon, is yet to be evaluated for its possible logical analysis and reasoning.
Colorectal carcinoma is infrequent (23%) locally in contrast to the West where it is 15% of all malignant tumours2,9,14,16. It is even lower than the black American population1. It is regarded as a highly curable disease in the west, due to early detection16. The peak age of involvement was lower in our study, which was similar to other malignancies9. The male to female ratio is found to be 1.9:1. Rectal involvement was higher in males and colonic in females. A change in relative frequency and pattern of involvement is reported14,15, which is yet to be established in our local population. The overall survival rate have improved significantly overthe years16. The geographic trend difference is diminishing over the years in this particular cancer, a trend of progressively proximal colonic disease is becoming more evident16. The disease is found to be locoregional in 60% and metastatic in 40% cases at diagnosis. The mucinous carcinoma is metastatic mostly from the outset. The anal canal tumours are more than double in males. Carcinoma of anal canal is found to be more frequent amongst males and at a relatively younger age locally contrasting to the reports  It is reported to be more common amongst blacks and homosexuals in the West1,18. Adenocarcinoma of pancreas was found to be 1-2% in our gastrointestinal series, while it is reported much higher (2.5% of all malignant neoplasms) from elsewhere in the World17. It is a disease of older age group and less than 74% is confirmed histologically17. A much laige scale international/regional studies are required setting up the guidelines and should target to uncoveryet unidentified etiologic factors by appreciating the peculiarities in different tumour distributions, to quantify the exposure and dose associated risks, to increase the present understanding of carcinogenesis, to suggest new prevention methods and to assess the efficacy of already practised preventive measuits19. The international variations between different tumour incidence are due to environmental factors, differences in diagnostic and reporting practices, genetic factors, migrating population, certain time trends of different malignancies, ethnic variations, socioeconomic patterns, survival trends and age patterns19.

Acknowledgements

Acknowledgements are due to Cancer registiy Jinnah Postgraduate Medical Centre, Karachi (being organised and managed by ProfessorN.A. Jafarey, Professor S.H.M. Zaidi and Professor Mahmood Alam), Civil Hospital Karachi and Armed Forces Institute of Pathology, Rawalpindi, without whose efforts and support this work could not have been accomplished successfully.

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