A. Sandhu

INTERSTITIAL IRIDIUM-192 IMPLANTATION COMBINED WITH EXTERNAL RADIOTHERAPY IN ANAL CANCER: TEN YEARS EXPERIENCE

PURPOSE To report our experience in the use of interstitial iridium-192 implantation combined with external radiotherapy in anal cancer. METHODS AND MATERIALS From 1984 to 1994, 79 patients with anal cancer were treated with radical intent using radiotherapy (plus chemotherapy) at Beatson Oncology Centre, Glasgow, Scotland. The mean and median age at presentation were 68 and 70 years, respectively (range 34-85) with a male-to-female ratio of 0.39. The histologic distribution was as follows: 48 squamous, 16 basaloid, 14 adenocarcinoma, and 1 basal cell carcinoma. The T stages were: 8 T1, 40 T2, 26 T3, and 5 T4 lesions. Twelve (15%) patients had nodal involvement at presentation. All patients underwent interstitial implantation using iridium-192 as part of the initial treatment. Seventy-six patients were treated with external radiotherapy followed by implant with a mean delay of 37 days after the end of radiotherapy. Twelve patients also received chemotherapy with 5-fluorouracil and mitomycin-C concurrently with external radiotherapy. Follow-up ranged from 6 to 123 months, with a median of 37 months. RESULTS Seventy-nine patients were analyzed to assess local control, survival, and complications. A complete response rate of 91% (72 of 79) was achieved after planned radiation treatment. At the end of external radiotherapy, 29% (22 of 76) had achieved complete response, 58% (7 of 12) with chemotherapy and 23% (15 of 64) without it. Local control was achieved in 62 of 79 (78%) patients and 8 of 17 (47%) local failures were salvaged by abdominoperineal resection. Five patients developed inguinal node failure; four of these were salvaged. Overall, 10% of all patients developed distant metastasis as the first site of failure and 25% failed at any site after salvage therapy. Time to unsalvageable relapse was significantly different on comparing T stage (p = 0.005) and histology (p = 0.029) of tumor. Major complications requiring surgical intervention were seen in six (7.5%) patients. Anal function preservation with local control was possible in 56 of 79 (71%) patients. CONCLUSION We report excellent results with radiotherapy in T1 and T2 lesions. The role of chemoradiotherapy as radical treatment of anal cancer should be defined in the context of locally advanced tumors.

Side-effects of local hyperthermia: Results of a prospectively randomized clinical study

In 1986, 25 patients with stage II and III carcinoma of the cervix were treated by a combination of radiation and local hyperthermia using an endotract intravaginal applicator. Another 25 patients were treated with radiation alone. Both groups were followed up for a minimum period of 18 months. The acute and long-term toxicity of local hyperthermia was closely monitored. Our study shows that whereas local hyperthermia adds significantly to the local control achieved with radiation alone, it is not in any way associated with any significant short- or long-term toxicity, and does not enhance the radiation reactions.

Low-Dose Radiosurgery for Benign Intracranial Lesions

This study assesses the efficacy and neurotoxicity of radiosurgical treatment of benign intracranial tumors using a linear accelerator, with relatively low dose and homogeneous dosimetry. Between June 1998 and July 2000, 27 patients were treated for benign lesions with radiosurgery using a 6-MV linear accelerator-based X-knife system and circular collimators. The lesions included schwannoma, meningioma, papillary cyst adenoma, and hemangioblastoma. Five patients had tissue diagnosis. The mean peripheral dose to the tumor margin was 12.8 Gy. The mean dose to the isocenter was 16.3 Gy. One to five isocenters were used to treat these lesions, with a mean of 10 arcs per isocenter and mean collimator size of 1.25 cm. Follow-up information was available on all patients, with a mean follow-up duration of 33 months. Six patients (22%) had improved symptoms and 21 (78%) had stable symptoms. Eight patients (30%) had regression of tumor and 19 had stable disease (70%). No patient had tumor progression, and Radiation Therapy Oncology Group (RTOG) grade III or IV toxicity did not occur in any patients. In 3 patients (11%), RTOG grade I or grade II neurotoxicity developed. Of these, one patient had worsening of a preexisting VIIth nerve deficit that required temporary oral methylprednisolone, and in two patients a mild trigeminal deficit developed that did not require any medical intervention. Low-dose homogeneous radiosurgery using a linear accelerator is an effective treatment for benign intracranial tumors. If lower, more homogeneous radiation doses produce responses as durable as higher doses, then toxicity might be further reduced.

Subclinical thyroid disease after radiation therapy detected by radionuclide scanning

Results: Seven patients (21.6%) had abnormal scans, and the percentage was higher among children (25%) and females (25%) compared to adults (16.7%) and males (16.7%), respectively. Two of 34 patients (5.9%) were discovered to have a thyroid cancer; histopathologies were papillary and follicular carcinoma. Conclusion: In this population of clinically normal cancer survivors who had been irradiated to the cervical region, subclinical thyroid disease, of potential clinical significance, was detected by 99m Tc TcO4 2 in about 20%. Children may be more commonly affected. Although the cost effectiveness of screening will require a larger sample number, we propose a surveillance schema for this patient population.

Carcinoma of the maxillary antrum — A 10 year experience

A retrospective analysis was performed of 250 cases of carcinoma of the maxillary antrum seen over a 10 years period (1975–1984). 98.24% patients were seen in T3 and T4 stages (UICC 1985). 40.7% patients presented with clinically palpable nodes. 42.9% patients were treated by radical radiation and 18.6% by a combination of preoperative radiation followed by surgery. Rest 38.5% patients were treated with palliative intention. Three year disease free survival was 39.58% with radiation alone and 51.91% with combined modality treatment which includes patients salvaged by surgery. Failures were mainly at the local site, 75.86% with radiation alone and 60% with combined modality treatment. Combined modality treatment, preferably preoperative radiation followed by radical surgery, gives the best results in the management of carcinoma of the maxillary antrum.

Late Effects of Radiation Therapy

Tissue complications of radiation therapy depend on the interplay of therapy, patient and tumor factors. Acute local effects result from parenchymal cell hypoplasia. Chronic damage is caused by both injury to parenchymal cells and to the underlying vasculature. No body tissue or system is immune to damage from radiation therapy, but many effects are dose-dependent. Many of the toxicities can currently be avoided by the optimal use of this important cancer therapy.

Subclinical thyroid disease after aadiation therapy (RT) detected by radionuclide scanning

PURPOSE The actuarial risk for developing benign or malignant thyroid disease following radiation therapy (RT) is controversial, but may be as high as 50% at 20 years. An effective screening modality should be specific but not overly sensitive, a limitation of ultrasound. We questioned whether Technetium-99 m pertechnetate ((99m)Tc TcO(4)(-)) scanning could detect clinically significant disease in ostensibly disease-free cancer survivors. METHODS AND MATERIALS Eligibility criteria included an interval of at least 5 years after RT to the cervical region, a thyroid gland that was normal to palpation, euthyroid status determined by clinical examination, free T4 and TSH. The 34 patients scanned included 16 children (<18 years old) and 18 adults at the time of RT, 16 females and 18 males. The mean age at RT was 20 years (range, 2.1-50.3 years), and the mean age at (99m)Tc TcO(4)-scanning was 33 years (range, 13.6-58 years), providing a mean interval of 13 years (range, 5.3-26.6 years). The mean RT dose to the thyroid was 36.4 Gy (range, 19.5-52.5). Thyroid scanning was performed with a 5 mCi dose of (99m)Tc TcO(4)(-) obtaining flow, immediate and delayed static, and pinhole collimator images. RESULTS Seven patients (21.6%) had abnormal scans, and the percentage was higher among children (25%) and females (25%) compared to adults (16.7%) and males (16.7%), respectively. Two of 34 patients (5.9%) were discovered to have a thyroid cancer; histopathologies were papillary and follicular carcinoma. CONCLUSION In this population of clinically normal cancer survivors who had been irradiated to the cervical region, subclinical thyroid disease, of potential clinical significance, was detected by (99m)Tc TcO(4)(-) in about 20%. Children may be more commonly affected. Although the cost effectiveness of screening will require a larger sample number, we propose a surveillance schema for this patient population.