Primary gastrointestinal cancers in the Western Region of Saudi Arabia. Is the pattern changing?

OBJECTIVE: To determine the age, sex and relative frequencies of various gastrointestinal malignancies in patients registered with the National Cancer Registry from the Western Region of Saudi Arabia from January 1994 till December 1997, and compare this data with previous hospital based studies about the pattern of these malignancies in Saudi Arabia. METHODS: A National Cancer Registry was established in Saudi Arabia in 1992, and since 1st January 1994 all cancer cases in Saudi Arabia have been registered with the National Cancer Registry. All National Cancer Registry data on patients with primary gastrointestinal cancers from the Western Region of Saudi Arabia from January 1994 till December 1997 was retrieved and analyzed according to ethnic origin, site, age, sex and relative frequencies of various tumors. RESULTS: Out of a total of 1833 cases with primary gastrointestinal malignancies 1207 (66%) were Saudis, while the rest were Non-Saudis. Colorectal cancer was the the most common malignancy found in both population groups accounting for 28.5% of cases in Saudis and 36% in Non-Saudis. Malignancies of liver, stomach and esophagus followed in decreasing frequencies. The mean age of the Saudi population was 58+16 years (standard deviation) with male to female ratio of 1.67:1. About 80% of the patients were above 40 years of age and the peak of onset for most of the tumors was between 50 and 70 years of age. CONCLUSIONS: This study highlights that colorectal cancer is the most common gastrointestinal malignancy seen in the Western Region of Saudi Arabia followed by hepatocellular carcinoma. This is in sharp contrast to the previous hospital based studies from Saudi Arabia and national trends as seen in the cancer incidence report from the National Cancer Registry of Saudi Arabia. The factors for this changing pattern of gastrointestinal malignancy remain to the determined.

Pattern and surgery for oesophageal carcinoma in Saudi Arabia.

Forty-three patients with carcinoma of the oesophagus are presented, 30 of whom were male and 13 female, with ages ranging from 42 to 88 years. Mean duration of symptoms was 4.6 months. Of patients, 65.2% were in stage III and 30.2% in stage IIA. Stages I and IV were encountered in one patient each. Twenty-five were Saudis and 14 non-Saudis. Of the Saudi patients, 64.3% were from the Qaseem region. 48.8% had subtotal oesophagectomy with neck anastomosis and 51.2% had limited oesophagectomy with intrathoracic anastomosis. The mortality rate was 11.6% The 5-year survival rate was 33.3%. We found sex, histology, stage of disease and extent of oesophageal resection influence long-term survival.

Fluoxetine treatment comprises the antiemetic efficacy of ondansetron in cancer patients.

Fluoxetine (Prozac) is an effective and increasingly widely used antidepressant. It is a 5-hydroxytryptamine (5-HT) re-uptake inhibitor. It produces its pharmacological effects by preventing the elimination of the 5-HT produced at nerve synapses, thus increasing its concentration at that location. Ondansetron (Zofran), is a 5-HT3 antagonist, which produces its pharmacological effect by competing with 5-HT receptors at the synapse. When both fluoxetine and ondansetron are used together, there is the possibility that the accumulation of 5-HT resulting from the use of fluoxetine may compete with ondansetron at the receptors, potentially reducing the antiemetic effects of ondansetron. Clinically, this has been observed in three patients treated with both compounds at the same time, while they were receiving carboplatin combination chemotherapy. The possibility that concurrent administration of the 5-HT re-uptake inhibitors, fluoxetine, may reduce the antemetic effectiveness of ondansetron is relevant to the established role of antidepressants in the management of patients with malignant disease, in whom the prevention of emesis is also important. Further investigation of this possible interaction is recommended.

Profile of cancer in Riyadh Armed Forces Hospital.

The relative frequency of malignant disease varies with sex, age, race and geographic location. The frequency differs among the developed and developing countries. A review of the first 5000 histologically confirmed malignancies seen at the Riyadh Armed Forces Hospital Oncology Department confirmed differences from those encountered elsewhere. With the absence of a National Cancer Registry, only relative frequencies can be reported. In this series, gastrointestinal tract cancers were the most frequent, at nearly 18%, with high relative frequency of cancers of the liver and esophagus. Colorectal malignancies were less frequent than in the West. Lymphoma was the second most frequent malignancy at 13% with 2.5:1 ratio of non-Hodgkin lymphoma to Hodgkin disease. In both groups, poor prognostic histological varieties were more frequent than in the West. Breast cancer was the most frequent malignancy in females, accounting for 24% of all female cancers, in spite of the infrequency of the traditional risk factors of nulliparity, late age of first pregnancy, late age of menopause, and high dietary fat consumption. Two-thirds of patients with breast cancer were premenopausal. Other malignancies encountered at a higher frequency than in developed countries include hepatocellular carcinoma and nasopharyngeal cancer. This high relative frequency could be related to the high incidence of viral hepatitis and Epstein-Barr virus infections, respectively. The high relative frequency of oral cavity cancers is presumed to be due to chewing Qat and Shama. Thyroid cancer relative frequency was just over 5%, with a high predominance in females. No obvious etiological factors are identified. The relative frequency of bronchogenic cancer is low at 5%. This is likely to increase with the progressive rise in the habit of cigarette smoking. Skin cancer, on the other hand, is low, presumably due to the traditional dress covering the entire body and the head.

Diet and cancer.

Environrnental and lifestyle factors, including diet, pray be responsible for the recognised worldwide variation in tire incidence of specific types or cancer. Chemical carcinogenesis is a multistage process occurring over a relatively long period or time. The mechanisms are complex as different factors damage develops following exposure to carcinogenic agents. Progression to malignancy is, at this stage, not inevitable. Specific agents are needed to 'promote', and induce 'progression' or inhibit subsequent changes to develop invasive malignancy. Understanding the roles played by different agents and mechanisms in the overall carcinogenic process For cc specific cancer nary form the basis for risk assessment and eventual prevention. The multistep process of carcinogenesis including initiation, promotion, and progression, are all needed for clinically invasive cancer to develop. Efforts directed to any of these phases can prevent the development of cancer.A variety of carcinogenic and mutagenic substances ore present in our diet. Some are found naturally in the food ingredients, whereas others result from pesticide residues, environmental pollution, food additives, preparation and processing procedures, curd fungal contamination. The control of these factors may render some cancers potentially avoidable.The role of macro and micro-nutrients in the causation of cancer and eventually in its prevention is complicated by their combined distribution in food products. Intensive research into the nature of cancer prevention by nutrient components and their synthetic analogs is still in its infancy. As cancer induction, promotion and progression is a slow mechanism that could take many years, it is uncertain what time-period of dietary intake is most relevant. Currently, recommended prevention strategies include choose more/choose less approach, through emphasizing a shift away from high fat, low-fiber foods that may increase cancer risks, toward foods low in fat and rich in fiber and nutrients.

Dacarbazine (DTIC) in malignant melanoma: reduced toxicity with protection from light.

Dacarbazine (dimethyl triazeno imidazole carboxamide, DTIC, NSC-45388), is the most effective oncolytic agent in the treatment of advanced malignant melanoma, but its side effects are considerable. These side effects are thought to be due to its photodegradation, which occurs within a few minutes of exposure to light. Fifteen patients with metastatic malignant melanoma were treated with dacarbazine protected from light, without troublesome haematological or other side effects. There was complete disappearance of metastases in 27% of cases and partial response in 47%. All lesions in skin, lungs and liver responded, but only half of the lymph node metastases showed response. It is suggested that dacarbazine should be protected from light during preparation and administration so as to reduce toxicity without influencing response.