A survey of soft tissue sarcomas at Kenyatta National Hospital over a six year period January 1991 to December 1996

Abstract

Soft tissue sarcomas are a heterogenous group of neoplasms accounting for 1% of all malignancies and 5% of childhood malignancies according to Western Series, while locally they account for about 3.8% of all malignancies. Eighteen (18) different histological types were recorded compared with over 30 types recognised world wide so far. This study presents a reVlew of 187 patients whose histological diagnosis of soft tissue sarcomas was made at Kenyatta National Hospital and subsequently treated between 1991 and 1996. The peak incidence of soft tissue sarcomas is in the first decade of life with more than half of these tumours occurring during the first three decades. Mean age of occurrence is 29.5 years and male female ratio is 1.2:1 in this study. About 31 new patients ,are seen annually with soft tissue sarcomas. There is no evidence of decrease nor increase in the incidence of these cases. The commonest presenting complaint is painless swelling (85%) and our patients present late with 71% presenting with tumours greater than 5 cm. Of the 178 patients whose site of tumours was recorded at the Cancer Registry, 52 (29.3%) were in the lower limbs, 39 (19.1%) were in the trunk, 39 (19.1%) head and neck, 20 (11.3%) upper limb visceral, 16 (8.9%) retroperitoneal, 14 (7.8%) genitourinary, 6 (3.4%) and intrathoracic 2 (1.1%). Extremities therefore took 40.6% which is inkeeping with Memorial Sloan Kettering Cancer Centre Series (40-50%) (1). Retroperitoneal tumours are slightly less than in other series 7.8% cf 15-17%, head and neck were more in our series 19.1% cf 5-8% in Western Series (2) The five commonest histological types in this series were: Rhabdomyosarcoma 15 (20.8%), fibrosarcoma 13 (18.1%), liposarcoma 12 (16.7%), dermatofibrosarcoma 6 (8.4%) and malignant fibrous histiocytoma 5 (6.9%) Rhabdomyosarcoma was the predominant tumour below 20 years of age 54%, followed by fibrosarcoma (14%) and then atypical tumours (9%). After the age of 40 years, malignant fibrous histiocytoma 23%, fibrosarcoma 15% and liposarcoma were the commonest in that order. Eighty five (8~) patients had their tumours graded with 24 (53%) having high grade tumours, 9 (20%) intermediate grade and 27% low grade sarcomas. Diagnostic methods used were fine needle aspiration cytology 20%, excisional biopsy 35%, incisional biopsy 45%, CT scan 5% abdominal ultrasound 7% The high incidence of incisional biopsy is explained by the late presentation of the patients and lack of core needle biopsy facilities, No conclusive diagnosis was provided by FNAC and other biopsies had to be taken. Surgery was the mainstay of treatment offered 12 out of 85 patient (14%) underwent enucleation/shelling out which is wrong treatment, 19 (22.3%) wide excision, 6 (7%) amputation, 10 (11.8%) radiotherapy alone, 15 (18%) surgery and radiotherapy, 2 (2.3%) surgery and chemotherapy and 3 (3.5%) a combination of the three modalities. Enucleation, chemotherapy alone, radiotherapy alone or radiotherapy and chemotherapy alone had poor results with 2 years recurrence rate of 50%, 98%, 70% and 50% respectively with 3,4,3,4 patients dead within 2 years from the disease respectively. Wide excision and amputation and when combined with adjuvant therapyhadabest results. Of 19 patient treated with wide excision alone, 7 had greater than 2 years recurrence free period (37%), 10 had less than 2 years recurrence free period (53%), while only 2 were dead from disease within 2 years (10%), while all the six who underwent amputation were all alive and free of disease by the end of 2 year~. Size of the tumour, grade and site were noted to be prognosis determinants. Visceral tumours had the worst prognosis with 5 of the 6 patients dead within 2 years (8%), while 1 had no change in disease progress (17%), while extremity sarcoma had the best prognosis with 6 out of 10 (60%) getting greater than 2 years recurrence free period, 2 (20%) got recurrence within 2 years and 2 (20%) died within 2 years.Seven out of 22 (32%) of those with high grade tumours had recurrence within 2 years, 6 (27%) had recurrence free period> 2 years, while 9 out of 12 (41%) were dead within 2 years from sarcoma as compared to those with low grade tumours where 3 out of 13 (23%) with recurrence within 2 years, 8(81%) recurrence period greater than 2 years and only 1 dead (7.6%) within the same time span of the patients with low grade tumours less than 5 cm, all (100%) had no recurrence by the end of 2 years while for the 9 with tumours greater than 5 cm, 3 out of 9 (33%) had recurrence within 2 years, 4 out of 9 (44.4%) had recurrence period greater than 2 years and 2 out of 9 (22%) were dead within 2 years. These differences were treated statistically and found to be significant for the grade butOinsignificant for size. The main recommendation from this series is to sensitize our people in the need to report early when they notice lumps in the body: To discourage any temptations to do enucleation of these tumours To emphasize to the pathologists to give grades of tumours at histology and to be more aggressive surgically even when dealing with retroperitoneal tumour Planned adjuvant therapy should always be instituted and need to have more studies especially prospective ones carried out in order to come up with set down protocols for the management of these neoplasms.