Development of collimator insert for linac based stereotactic irradiation.

The aim of this study is to develop collimator inserts of various sizes which are either not commercially available or are expensive to import. The dosimetry parameters such as tissue maximum ratio (TMR), off-axis ratio (OAR) and output factor of the developed collimator insert are compared with that of the commercial collimator insert (Radionics). In order to check the suitability of the collimator insert developed locally for clinical use and to standardize the method of development, a collimator insert of 15 mm identical to the one supplied by Radionics is developed with low-melting alloy (Cerrobend). Moreover for the clinical use of the developed collimator insert, certain acceptance tests are performed which include a collimator concentricity test, beam size check and radiation leakage test. The dose verification is carried out with a thermoluminescent dosimeter (7LiF rods) and an FBX chemical dosimeter in a human-head-shaped Perspex phantom filled with water. The variation between the calculated and measured dose is found to be within +2.4% for 7LiF rods and -2.0% for the FBX chemical dosimeter thus ensuring the suitability of the developed collimator insert for clinical use. This has encouraged us to standardize the method adapted to develop the collimator insert and to develop collimator inserts of different field sizes.

Concomitant cisplatin and radiationtherapy in advanced head and neck cancers:.

Single modality treatment is not suitable to the treatment of Head and Neck cancers and surgery is often mutilating. Concomitant chemotherapy and radiation produce good local control. In this study cisplating givenconcomitantly with radiation is compared with radiation alone in advanced head and neck cancers.

Basaloid squamous carcinoma of the nasal cavity - a case report.

Basaloid squamous carcinoma is a rare variant of squamous carcinoma and is known for its aggressive behavior. Its presentation in the nasal cavity is uncommon . A case of this tumor arising from the nostril and showing good response to concomitant radiotherapy and cisplatinum is presented.

Breast metastases from primary leiomyosarcoma.

Two cases of metastatic leiomyosarcoma of the breast are presented. The reasons why they are considered as secondary tumours and not primary tumours are also discussed.

Adenoid cystic carcinoma of the external auditory canal with pulmonary, renal and liver metastases.

We report a patient with adenoid cystic carcinoma of the external auditory canal with multiple pulmonary, liver and renal secondaries. She had a palpable left renal mass. The clinical course and treatment of this unusual neoplasm as reported in literature are briefly reviewed.

Metastases to the hand from carcinoma of the lower alveolus.

A case of carcinoma of the lower alveolus metastasizing to the phalanges of the hand is reported. The possible mechanism of such metastases, the clinical and radiological features and the role of fine needle aspiration cytology are discussed.

Cancer associated with leprosy.

Eighty-seven leprosy patients with cancer, seen between 1960 to 1984, were studied. Cancer in patients with leprosy occurred in a younger age group compared to the general population. The most common type of malignancy seen among males was squamous cell carcinoma of the lower extremity while in hospital patient population it was cancer of head and neck. Among the females, carcinoma cervix was the most common as in the hospital patients. The types of malignancy occurring among leprosy patients was similar to that of the hospital patient population with the exception of an increase in incidence of squamous cell carcinoma of extremities.

Correlation of serum prostate specific antigen levels and bone scintigraphy in carcinoma prostate.

Serum prostate specific antigen (PSA) has been suggested as an accurate means of monitoring prostate cancer. An analysis of PSA levels and bone scan findings was carried out in a heterogeneous group of patients with a view to determine whether PSA can accurately predict bone metastases in carcinoma prostate. Of the 48 patients studied, all 10 untreated cases had elevated PSA levels, eight having bone metastases. In 29 cases on follow-up after treatment of the primary, 10 out of 11 cases with normal PSA had a negative bone scan. In the nine who received hormonal therapy, the PSA levels were generally lower than others in the study group. Two out of four with normal PSA had bone metastases. In 26 cases with positive bone scans, 23 had elevated PSA levels (mean 109.9 ng ml-1). Among 22 patients who had normal bone scans, all 10 with high PSA were found to have soft tissue disease which could explain the elevated PSA. In those with normal PSA, 12 out of 15 patients had negative scans. PSA has fairly high sensitivity (86.5%) and negative predictive value (80%). But it suffers from low specificity (54.5%) and low positive predictive value (69.7%) for bone metastases. In an untreated patient with elevated PSA, a bone scan may be required to exclude bone metastases, whereas during follow-up after treatment, a normal PSA level may obviate a "routine" bone scan.

Primary small intestinal lymphoma.

Gastro-intestinal tract is the most common site of extranodal presentation in non-Hodgkin's lymphoma. Among the subsites the small intestine predominates. This paper presents a review of 21 cases of primary gastro-intestinal lymphoma seen at the Department of Radiation Oncology, Christian Medical College, Vellore, during the period 1979-1986. All patients had laparotomy, and biopsy from the primary site. Histopathological subtypes were done in the International Working Formulation. Stage groupings were done applying the Crowther and Blackledge staging system. Post-laparotomy treatment decision was made depending on the patient's general condition, completeness of surgery and histological subtype. The overall survival rate was 31.5% at 5 years. Early stage disease and high-grade lymphomas have a better prognosis if treated adequately.

Hyperfractionation in advanced carcinoma of the uterine cervix: a preliminary report.

Experience with twice-a-day radiation therapy program for carcinoma of the uterine cervix (FIGO Stages IIB, IIIA & IIIB) is presented. The program consists of delivering 120 cGy per fraction, two fractions a day with 6 hours between fractions. A total of 6000 cGy was delivered in 50 fractions over 5 weeks. A control group was given conventional fractionation 5000 cGy in 25 fractions, 200 cGy per fraction over 5 weeks. This feasibility study enrolled 30 patients, 15 in each group. Normal tissue reactions in skin, mucosa and bowel were recorded. The acute normal tissue reactions were enhanced in the hyperfractionation group. This was significant with regard to the bowel complications. The tumor control rate did not show any significant difference between the two groups. A short follow-up period has revealed complete healing of all acute normal tissue reactions. This study shows that further dose escalation is feasible and a study with large sample size and longer follow-up is required to reach definite conclusions.

Ovarian and testicular damage by cytotoxic drugs.

The use of cytotoxic drugs has improved the survival figures in malignancies. These drugs exert harmful effects on the tumour cell and normal cells as well. The detrimental effects on gonads were studied in 36 patients who had cytotoxic chemotherapy for various malignancies. In Group I (20 adults in clinical remission after chemotherapy), sterility was noted in 93.7% of men and hundred percent of women experienced irregularly mensus during treatment, 50% of them subsequently developing persistent amenorrhoea. In Group II, (16 adults undergoing chemotherapy) 100% of men had oligospermia, with 75% of them developing azoospermia after 2-3 cycles of treatment. Women also showed similar effect, but were less vulnerable than men.