Robert Y. Kim

CONVENTIONAL FOUR-FIELD PELVIC RADIOTHERAPY TECHNIQUE WITHOUT COMPUTED TOMOGRAPHY-TREATMENT PLANNING IN CANCER OF THE CERVIX: POTENTIAL GEOGRAPHIC MISS AND ITS IMPACT ON PELVIC CONTROL

PURPOSEnTo evaluate the impact of inadequate margins on pelvic control using the conventional four-field pelvic portals without computed tomography (CT)-treatment planning.nnnMETHODS AND MATERIALSnBetween 1986 and 1991, 34 patients with invasive cancer of the cervix were eligible for outcome study of conventional four-field radiation therapy (10 Stage I, 16 Stage II, 8 Stage III). The eligibility for this study includes four-field pelvic technique, definitive radiation therapy, and diagnostic CT scan of the pelvis. For this study, an inadequate margin is arbitrarily defined as < or = 1.0 cm of normal tissue around the CT-defined tumor volume.nnnRESULTSnAll 34 patients had adequate margins for anterio-posterior/posterio-anterior portals. However, 19 patients had an inadequate margin at the posterior border (S2-S3 interspace) and/or custom-shaped rectal block for lateral pelvic portals. Two patients had inadequate margins at the anterior border (level of symphysis pubis) due to an enlarged uterus. With a median follow-up of 36 months, pelvic control for adequate margins and inadequate margins was 100% and 71% for Stage IB disease and 88% and 50% for Stage IIB disease, respectively. However, pelvic control for Stage IIIB disease was 50% for both groups. There was no difference in total dose to point A or point B between the two groups.nnnCONCLUSIONnOur preliminary data show higher local failure in patients with an inadequate margin. For four-field pelvic radiation therapy, we strongly recommend CT-treatment planning. Otherwise, anterio-posterior/posterio-anterior pelvic therapy is the most reliable treatment for cancer of the uterine cervix.

Treatment of recurrent head and neck cancer with 5-fluorouracil, hydroxyurea, and reirradiation

Head and neck cancer locally recurrent after previous irradiation and surgery presents a difficult management problem. Conventional treatment alternatives include chemotherapy, reirradiation with interstitial implant, and hyperthermia. Reirradiation with external beam is generally not considered because of previous high radiation dose and limited tissue tolerance. In this study, 21 patients with recurrent and previously irradiated head and neck cancer were treated in a Phase I-II fashion. Patients received 5 days of 5-fluorouracil, 300 mg/m2/day IV bolus, Hydroxyurea 1.5 or 2 g/day by mouth and external beam radiation therapy every 2 weeks for up to four courses. Of 20 evaluable patients, 9 have attained a complete response (CR) and 6 a partial response (PR). Fifteen patients completed all planned therapy, eight on time, seven patients with delays. With a median follow-up of 7 months, 13 patients are alive, 7 disease-free (3 after salvage surgery) and 6 with recurrence. Eight patients have died. The 1-year survival is 56%. Treatment toxicity was mainly neutropenia. No major early or late radiation related side effects have been observed at a median follow-up of 7 months. Neither previous radiation dose, time since first radiation, prior chemotherapy, or site of recurrence was predictive of response or treatment tolerance. Patients with a performance status of at least 80 had a significant higher CR rate, with 7/10 patients in this group, as compared to 2/10 patients in patients with a performance status less than 80, achieving a CR. Reirradiation with 5-fluorouracil and hydroxyurea is a well tolerated outpatient treatment program for patients with recurrent and previous irradiated head and neck cancer that produces a high response rate and can provide significant palliation of symptoms.

Conventional four-field pelvic radiotherapy technique without CT treatment planning in cancer of the cervix: potential geographic miss

The advantage of 4-field radiation to the pelvis is the use of lateral ports which spare the small bowel anteriorly and a portion of the rectum posteriorly from radiation. However, guidelines for the lateral pelvic ports are poorly defined. This is a comparative analysis to determine adequate margins by correlating conventional lateral pelvic treatment portals with CT defined tumor volume. The study included 52 patients treated definitively for carcinoma of the uterine cervix between 1986 and 1991. The most common site of inadequate margin (< or = 1.0 cm) was at the rectal block. The incidence of inadequate margin ranged from 39% to 50% and was independent of the stage of the disease except non-bulky stage IB disease. The next most common site was at the posterior border where frequency of inadequate margin for cervical tumor depended on stage with 8% of stage IB, 27% of stage IIB and 22% of stage IIIB/IVA disease. For the anterior border, an enlarged uterus was the only reason for inadequate margin rather than cervical tumor in 8% of stage IB, 18% of stage IIB, and 27% of stage IIIB/IVA disease. Without knowledge of precise tumor volume, the 4-field pelvic technique is potentially dangerous, risking underdosing of the tumor volume. For 4-field pelvic radiotherapy, we strongly recommend CT treatment planning.

Malignant epidural spinal cord compression associated with a paravertebral mass: its radiotherapeutic outcome on radiosensitivity.

PURPOSEnTo evaluate clinical characteristics and functional outcome of malignant epidural spinal cord compression associated with a paravertebral mass.nnnMETHODS AND MATERIALSnBetween 1987 and 1990, 136 patients with epidural spinal cord compression were treated with irradiation. Of these, 25 patients (18%) had epidural spinal cord compression associated with a paravertebral mass. This report is based on analysis of these 25 patients. Fourteen patients received 3000 cGy in 10 fractions. Seven received 4000 cGy in 16 fractions. Four received 2000 cGy in 5 fractions. Motor function was evaluated by five grades.nnnRESULTSnLung cancer accounted for the majority of epidural spinal cord compression with a paravertebral mass (60%) followed by lymphoma (8%) and kidney tumor (8%). This pattern of epidural spinal cord compression has a longer duration of pain before developing neurologic symptoms and has a high propensity of the upper thoracic spine involvement by an apical lung cancers. The functional outcome of radiation treatment reveals a significant difference between moderately radiosensitive tumors (lung, prostate, cervix, esophagus) and very radiosensitive tumor (lymphoma). None of the nonambulatory patients became ambulatory following radiotherapy except for the very radiosensitive tumors. Higher doses of radiation treatment (4000 cGy in 16 fractions) did not improve functional outcome.nnnCONCLUSIONnDue to the larger tumor burden, radiation treatment for epidural spinal cord compression associated with a paravertebral mass is not as effective as treatment of epidural spinal cord compression without a paravertebral mass except for the very radiosensitive tumor. Therefore, combined treatment modality might be beneficial for improving functional outcome.

The efficacy of cranial irradiation in ovarian cancer metastatic to the brain: Analysis of 32 cases

Objective To determine the role of irradiation in the management of brain metastases from epithelial ovarian cancer. Methods Tumor registries from five university cancer centers were searched to identify ovarian cancer patients with brain metastases. During a 30-year period (1965–1994), 4027 ovarian cancer patients were evaluated, 32 of whom were found to have cerebral metastases. Each received fractionated whole-brain irradiation (median dose 30 Gy, range 20–52.5). Five patients received concomitant chemotherapy with whole-brain irradiation. Results The median survival time for the whole population was 4 months. For the entire series, symptomatic response (complete response and partial response) was achieved in 23, 16 of whom were palliated until death. Patients with higher Karnofsky performance status (70 or above versus below 70) were more likely to derive a palliative response and attained a statistically significant survival advantage. No other factor predicted the likelihood of deriving a palliative response or a survival advantage after treatment. Conclusions In this large review of patients with cerebral metastases from ovarian cancer, we found that most of those treated with whole-brain irradiation achieved palliation until death. Nearly all women with high performance status derived durable palliation from cerebral irradiation. Wholebrain irradiation was an effective means of palliating ovarian cancer metastatic to the brain and provided a favorable alternative to other means of management.

Effects of Bladder Distension on Organs at Risk in 3D Image-Based Planning of Intracavitary Brachytherapy for Cervical Cancer

PURPOSEnTo investigate the effects of bladder distension on organs at risk (OARs) in the image-based planning of intracavitary brachytherapy for cervical cancer.nnnMETHODS AND MATERIALSnThirteen patients with cancer of the cervix were treated with high-dose radiation brachytherapy (800 cGy/fraction for 3 fractions). For the three-dimensional (3D) analysis, pelvic CT scans were obtained from patients with indwelling catheters in place (defined as empty bladder) and from patients who received 180-cc injections of sterile water in their bladders (defined as full bladder). To compare the International Commission on Radiation Units and Measurements (ICRU) point doses with 3D-volume doses, the volume dose was defined by using two different criteria, D(2cc) (the minimum dose value in a 2.0-cm(3) volume receiving the highest dose) and D(50%) (the dose received by 50% of the volume of the OAR) for OARs.nnnRESULTSnThe bladder D(2cc) was located more cranially in the bladder base and was distributed in multiple spots in 46% of patients. The rectal D(2cc) was located in the area of the ICRU point as a single hot spot. For patients with a full bladder, the mean bladder D(2cc) increased from 634 to 799 cGy (28.8%, p = 0.002). However, the bowel D(2cc) decreased from 475 to 261 cGy (45.0%, p < 0.001). There were no substantial differences in rectal and sigmoid D(2cc) values. However, the mean D(50%) values of both the bladder and the bowel decreased from 108 to 80 cGy (23.7%, p < 0.001) and from 282 to 221 cGy (19.7%, p = 0.004) with a full bladder, respectively.nnnCONCLUSIONSnAn increase in bladder volume resulted in a significant reduction in bowel D(2cc) values at the expense of an increase in bladder D(2cc) values. Treatment with a distended bladder is preferable to protect the bowel.

Metastatic carcinoma to the tongue. A report of two cases and a review of the literature

Metastatic tumors of the oral cavity are uncommon. Most of them are located in the mandible while only a small percentage are found within the soft tissues. Two cases of metastatic bronchogenic carcinoma to the tongue are described. Review of the literature showed that cancer of the lung was the most common primary lesion that metastasized to the soft tissues of the oral cavity. The base of the tongue was the most prevalent site of metastases to soft tissue within the oral cavity.

Stereotactic irradiation: Potential new treatment method for brain metastases resulting from ovarian cancer

Stereotactic irradiation (radiosurgery) is a method of precisely focusing well-defined beams of radiation at small intracranial targets. The technique has been applied to the treatment of brain lesions that are benign (e.g., arteriovenous malformations, meningiomas, pituitary adenomas) and malignant (e.g., gliomas, metastases). This paper introduces preliminary data suggesting the possible value of radiosurgery in the management of ovarian cancer metastatic to the brain. Among 32 women with ovarian cancer metastatic to the brain treated with whole brain irradiation, nine (29%) experienced a complete radiographic response, compared with two of the five patients (40%) treated with radiosurgery. The 2-year survival rate was 60% among those treated with radiosurgery and 15% among those who received whole brain irradiation without radiosurgical boost. Stereotactic irradiation may be of clinical benefit to select patients with brain metastases resulting from ovarian cancer. A prospective randomized trial has been implemented by the Radiation Therapy Oncology Group (RTOG 95-08) to determine whether such observations are reproducible on a national scale.

Image-Based 3D Treatment Planning for Vaginal Cylinder Brachytherapy: Dosimetric Effects of Bladder Filling on Organs at Risk

PURPOSEnTo investigate the dosimetric effects of bladder filling on organs at risk (OARs) using three-dimensional image-based treatment planning for vaginal cylinder brachytherapy.nnnMETHODS AND MATERIALSnTwelve patients with endometrial or cervical cancer underwent postoperative high-dose rate vaginal cylinder brachytherapy. For three-dimensional planning, patients were simulated by computed tomography with an indwelling catheter in place (empty bladder) and with 180 mL of sterile water instilled into the bladder (full bladder). The bladder, rectum, sigmoid, and small bowel (OARs) were contoured, and a prescription dose was generated for 10 to 35 Gy in 2 to 5 fractions at the surface or at 5 mm depth. For each OAR, the volume dose was defined by use of two different criteria: the minimum dose value in a 2.0-cc volume receiving the highest dose (D(2cc)) and the dose received by 50% of the OAR volume (D(50%)). International Commission on Radiation Units & Measurements (ICRU) bladder and rectum point doses were calculated for comparison. The cylinder-to-bowel distance was measured using the shortest distance from the cylinder apex to the contoured sigmoid or small bowel. Statistical analyses were performed with paired t tests.nnnRESULTSnMean bladder and rectum D(2cc) values were lower than their respective ICRU doses. However, differences between D(2cc) and ICRU doses were small. Empty vs. full bladder did not significantly affect the mean cylinder-to-bowel distance (0.72 vs. 0.92 cm, p = 0.08). In contrast, bladder distention had appreciable effects on bladder and small bowel volume dosimetry. With a full bladder, the mean small bowel D(2cc) significantly decreased from 677 to 408 cGy (p = 0.004); the mean bladder D(2cc) did not increase significantly (1,179 cGy vs. 1,246 cGy, p = 0.11). Bladder distention decreased the mean D(50%) for both the bladder (441 vs. 279 cGy, p = 0.001) and the small bowel (168 vs. 132 cGy, p = 0.001). Rectum and sigmoid volume doses were not affected by bladder filling.nnnCONCLUSIONSnIn high-dose rate vaginal cylinder brachytherapy, treatment with a distended bladder preferentially reduces high dose to the small bowel around the vaginal cuff without a significant change in dose to the bladder, rectum, or sigmoid.

Dynamics of the vaginal wall dose in HDR interstitial brachytherapy for gynecological cancer: Systematic analysis of phantom vs patient case

This study aimed to investigate the dynamics of the vaginal wall dose for interstitial brachytherapy (ISBT). A patient undergoing ISBT was selected as the patient case. The phantom case was generated to simulate the patient case in all regards with the exception of parallel needle positions. The vaginal wall was contoured as a 0.5-cm expansion around the vaginal surface of the obturator. The prescribed ISBT dose was 20u2009Gy in 4 fractions. Six treatment plans were generated by modifying relative dwell times and needle positions (DTNP). The volume of the vaginal wall receiving > 150% of prescription dose (V> 150%) and D2cc of the vaginal wall were compared among plans. The V> 150% was much larger in the patient case (49.3%) due to unparallel needles compared with the phantom case (14.3%) without modification (plan 1). Among the 6 plans, reduced dwell time (plan 3) and no dwell time (plans 5 and 6) on the vaginal surface needles had the lowest vaginal wall doses with the use of a central obturator needle in both cases. In comparison of patient case plans 1, 3, 5, and 6, V150% was 49.2%, 19.0%, 21.3%, and 28.7%, respectively, and D2cc was 41.15u2009Gy, 33.10u2009Gy, 36.51u2009Gy, and 34.37u2009Gy, respectively, which was limited around each loaded needle. Modification of DTNP is able to reduce the vaginal wall volume exceeding 150% of the prescription dose in the patient case. Understanding these dynamics of the vaginal wall dose will improve dose optimization of ISBT and may reduce vaginal morbidities.