Consolidation radiation after complete remission in Hodgkin's disease following six cycles of doxorubicin, bleomycin, vinblastine, and dacarbazine chemotherapy: is there a need?

PURPOSE

Combined modality treatment using multidrug chemotherapy (CTh) and radiotherapy (RT) is currently considered the standard of care in early stage Hodgkin's disease. Its role in advanced stages, however, continues to be debated. This study was aimed at evaluating the role of consolidation radiation in patients achieving a complete remission after six cycles of doxorubicin, bleomycin, vinblastine, and dacarbazine (ABVD) chemotherapy using event-free survival (EFS) and overall survival (OS) as primary end points.

PATIENTS AND METHODS

Two hundred and fifty-one patients with Hodgkin's disease attending the lymphoma clinic at the Tata Memorial Hospital (Mumbai, India) from 1993 to 1996 received induction chemotherapy with six cycles of ABVD after initial staging evaluation. A total of 179 of 251 patients (71%) achieved a complete remission after six cycles of ABVD chemotherapy and constituted the randomized population. Patients were randomly assigned to receive either consolidation radiation or no further therapy.

RESULTS

With a median follow-up of 63 months, the 8-year EFS and OS in the CTh-alone arm were 76% and 89%, respectively, as compared with 88% and 100% in the CTh+RT arm (P =.01; P =.002). Addition of RT improved EFS and OS in patients with age < 15 years (P =.02; P =.04), B symptoms (P =.03; P =.006), advanced stage (P =.03; P =.006), and bulky disease (P =.04; P =.19).

CONCLUSION

Our study suggests that the addition of consolidation radiation helps improve the EFS and OS in patients achieving a complete remission after six cycles of ABVD chemotherapy, particularly in the younger age group and in patients with B symptoms and bulky and advanced disease.

Experience with telepathology at a tertiary cancer centre and a rural cancer hospital

BACKGROUND

Telepathology allows quick and timely access to an expert opinion, no matter where the patient is located. We analysed the experience with the use of telepathology between a tertiary cancer centre and a rural cancer hospital.

METHODS

Ninety-three cases were analysed in which static telepathology was used to obtain a consultation between Tata Memorial Centre and Nargis Dutt Memorial Cancer Hospital at Barshi, a rural area.

RESULTS

Successful teleconsultation was achieved in all cases. A diagnosis was offered in 92 cases (98.9%) and was deferred in 1 case (1.1%). Complete concordance, clinically unimportant minor discrepancy and hedged diagnosis were obtained in 83 cases (90.2%). Major discrepancies were encountered in 9 cases (9.7%). The number of images per case ranged from 3 to 27 (average: 7 images). Images were of diagnosable quality in 89.2% of cases. Most of the cases (77.4%) were reported within 3 days; 32.2% were reported within 8 hours (a single working day) and 45.1% within 1-3 days.

CONCLUSION

Telemedicine can be effectively used to bridge the gap between medically underprivileged, geographically distant rural areas and advanced centres using the static store and forward methodology.

Hypofractionated radiotherapy in carcinoma cervix IIIB: Tata Memorial Hospital experience

PURPOSE OF THE STUDY

To analyze the role of hypofractionated radiotherapy in advanced carcinoma of cervix.

BASIC PROCEDURE

Medical records of 62 women with advanced carcinoma cervix III3 treated during 1994-1996 were reviewed. Patients were treated with standard pelvic portals to a total dose of 39Gy in 13 fractions over 17 days followed by intracavitary brachytherapy. Forty-eight patients completed the planned treatment and were considered suitable for analysis of late reactions and survival.

MAIN FINDINGS

The 5-year disease free survival was 59% and the overall survival was 50% at the mean follow up of 40 months. Twenty-one (44%) patients developed acute gastrointestinal toxicity of which 5 patients had grade III and one patient had grade IV reaction. Ten patients (21%) developed acute genitourinary complications, 13 patients (27%) had late rectal reactions and 10 patients (20%) had late bladder complications. Three patients had grade I, five had grade II and five had grade III late rectal toxicity.

CONCLUSION

Survival in patients treated hypofractionated radiotherapy appears comparable to that of standard fractionation. The acute gastrointestinal and skin reactions were mainly grade I or grade II. Hypofractionated radiotherapy can certainly be considered in a select group of patients where the local disease is extensive and is unsuitable for conventional treatment.

Transperineal low-dose rate iridium-192 interstitial brachytherapy in cervical carcinoma stage IIB

PURPOSE

To assess local control, survival and complications in patients with cervical carcinoma Stage IIB treated radically with transperineal Iridium-192 low-dose rate interstitial brachytherapy following external beam radiotherapy.

PATIENTS AND METHODS

65 women (age 25-70 years, mean 47 years) with cervical carcinoma Stage IIB were initially treated with external beam radiotherapy on a telecobalt or 6 MV linear accelerator to a dose of 50 Gy delivered in 5-6 weeks. After 2-3 weeks of completing external radiation, patients received interstitial brachytherapy with Iridium-192 (activity 0.5-1 mCi/cm) using a Syed-Neblett perineal template. The median dose delivered to the implant volume was 24 Gy (range 20-32 Gy) delivered at an average dose rate of 0.70 Gy/h (range 0.40-1.20 Gy/h). A point defined at 1.5 cm lateral to the central uterine tandem at the level of os was taken as a representative for assessing the dose to the cervix. Mean doses delivered by interstitial brachytherapy to point A, cervix, point B and rectum were 38 Gy, 34 Gy, 16 Gy and 16 Gy, respectively.

RESULTS

At a median follow-up of 53 months, the actuarial disease free survival and overall survival for 65 patients at both 5 and 10 years was 64% and 44%, respectively. Response to radiotherapy was a strong predictor of local control with 82% of patients continuing to have pelvic control after initial complete response. Overall, nine (14%) patients had persistent disease, ten (15%) developed a central recurrence after initial control and three patients developed distant metastasis on follow-up. No patient had any immediate treatment-related complication. Late toxicity included grade I-II rectal reactions in five patients and grade IV bladder complication (vesico-vaginal fistula) in two patients. 5 years after treatment, one patient developed intestinal obstruction, which was relieved after conservative management. Two patients developed vaginal stenosis. The 5- and 10-year disease free survival was 48% in patients aged less than 45 years as compared to 80% in patients of more than 45 years (p = 0.009). Dose to the cervical point was a prognostic indicator with 5- and 10-year disease free survival of 47% in patients who received < 35 Gy in comparison to 80% in patients who had > 35 Gy (p = 0.03). There was no difference in local control and survival in patients with minimal and moderate parametrial involvement. Bulky disease (> 4 cm) at presentation and a longer gap between external radiation and brachytherapy showed a trend towards inferior local control.

CONCLUSIONS

Interstitial brachytherapy after external beam irradiation in patients with cervical carcinoma Stage IIB results in acceptable local control, survival and complication rates. Increased dose to the cervical disease results in improved local control and survival and should therefore be considered while optimizing brachytherapy treatment plans. Comparison of the results with those of standard intracavitary therapy remains to be proven in a randomized trial.

Primary extranodal mucosa associated lymphoid tissue (MALT) lymphoma of the prostate

Low-grade B-cell mucosa associated lymphoid tissue (MALT) lymphoma can rarely present primarily in extranodal sites other than stomach, which is the most common site for it. Until now only four cases of primary prostatic MALTomas have been described in the literature and we report the fifth. We describe a case of primary prostatic MALToma in a 67-year-old man and the diagnosis was made on the trans-urethral resection specimen of the prostate. As the disease was limited to prostate (stage IEA), the patient was treated with external beam radiation therapy to a total dose of 4400cGy in 22 fractions. The patient achieved completed remission and has remained free of disease in the following 36 months.

Radiation therapy in T1-T2 glottic carcinoma: influence of various treatment parameters on local control/complications

PURPOSE

To evaluate the influence of various treatment parameters on local control as well as complications in T1 and T2 glottic carcinomas.

METHODS AND MATERIALS

Between 1975 and 1989, 676 patients with early glottic carcinoma (460 T1 and 216 T2) received curative radiation with three different treatment regimens, as follows: Regimen 1-50 Gy/15 Fr/3 weeks (3.33 Gy/daily) for 192 patients; Regimen 2-60-62.5 Gy/24-25 Fr/5 weeks (2.5 Gy/daily) for 352 patients; and Regimen 3-55-60 Gy/25-30 Fr/5-6 weeks (2-2.25 Gy/daily) for 132 patients.

RESULTS

The local control at 10 years was 82% and 57% for T1 and T2 lesions respectively (p = 0.0). For the T1N0M0 group, field size had significant impact on local control with both univariate (p = 0.05) and multivariate (p = 0.03) analysis. For T2N0M0, group field size (p = 0.03) as well as registration year (p = 0.016) were significant in univariate analysis whereas only field size remained significant on multivariate analysis. Persistent radiation edema was noted in 146 (22%) patients and was significantly worse with larger field size (p = 0.000) but not related to different treatment regimens.

CONCLUSION

The shorter fractionation schedule had comparable local control, without increased complications in comparison to the protracted schedule and is best suited for a busy department.

Discrepancies in Epstein-Barr virus association at presentation and relapse of classical Hodgkin's disease: impact on pathogenesis

BACKGROUND

Though Epstein-Barr virus (EBV) has been linked to classical Hodgkin's disease (cHD), only a proportion of cHD cases show EBV-association. While there has been evidence to suggest a crucial role for EBV in the early phase of cHD evolution, we are unclear whether continued presence of EBV is essential for the maintenance of the neoplasm. We have addressed this issue by investigating the EBV-association in paired samples of cHD obtained at presentation and relapse.

MATERIALS AND METHODS

We have analysed lymph node biopsy samples from 23 cases of cHD at presentation and relapse. In situ hybridization with EBER-1 probe and immunostaining with anti latent membrane protein-1 (LMP-1) antibody was performed on the paraffin sections. PCR for EBNA 3C gene was performed for EBV subtype analysis on the DNA extracted from paraffin sections.

RESULTS

EBV-association was documented in both the presentation and relapse samples of 14 cases. One case showed loss of EBV-association at relapse. PCR analysable DNA was obtained from both presentation and relapse samples in four of the EBV-associated cases. The EBNA 3C amplimer corresponded to type A strain of EBV in all the samples.

CONCLUSION

Loss of EBV-association between presentation and relapse seen in one case implies a hit and run mechanism in EBV-induced lymphomagenesis. Though EBV may be essential early in the evolution of cHD, it may not be required for maintenance of the neoplastic clone. Our study also brings out a speculation that a proportion of EBV-negative cHD could represent loss of EBV in the tumour prior to clinical presentation. Alternatively, an unidentified lymphotropic virus other than EBV might play a pathogenetic role in EBV-negative cHD.

Primary carcinoma of the vagina: Tata Memorial Hospital experience

PURPOSE

Carcinoma of the vagina is a rare gynecological malignancy comprising approximately 2% of all the gynecological malignancies. We have analyzed the treatment outcome of the patients treated at the Tata Memorial Hospital from January 1984 to December 1993.

METHODS AND MATERIALS

In this 10-year period, 134 patients of primary vaginal cancers were registered at our hospital. Of these, 75 patients received complete treatment and are analyzed.

RESULTS

Disease-free survival (DFS) for the whole group is 50%, and overall survival (OAS) is 60%. Most locoregional recurrences and distant failures are noted in the 2 years following treatment. DFS at 5 years is as follows: Stage I (5 patients), Stage IIA (37 patients), Stage IIB (15 patients), Stage III (14 patients), and Stage IV (4 patients); are 40%, 55%, 60%, 50%, and 25%, respectively. The DFS for patients with complete response (42 patients) to external radiation at 5 years is 68%, with partial response (25 patients) is 35%, and with poor or no response (6 patients) is 18% (p = 0.0000). We observed that brachytherapy was an important part of the treatment, and patients who received brachytherapy (59 patients), either with a vaginal intracavitary applicator (30 patients) or interstitial implant (29 patients) had a DFS of 53% and 56%, respectively, while 15 patients who received external radiation alone had a DFS of 30%. Patients receiving brachytherapy within 4 weeks of external radiation had a DFS of 60% as compared to 30% when the interval was more than 4 weeks.

CONCLUSION

The factors indicating prognosis are: site and extent of involvement, presence of lymph nodes at presentation, technique of brachytherapy, and interval between external radiation and brachytherapy.

Epstein-Barr virus association in classical Hodgkin's disease provides survival advantage to patients and correlates with higher expression of proliferation markers in Reed-Sternberg cells

BACKGROUND

Most Epstein-Barr virus (EBV) associated lymphoproliferative disorders have high proliferation indices. However, classical Hodgkin's disease (cHD) is heterogeneous, with respect to proliferation index of the Reed-Sternberg cell (RS cell), and EBV association. Hence, we investigated whether cHD with and without EBV-association differ with respect to the proliferation index of the RS cells. Further we investigated whether this would have a bearing on patients survival.

PATIENTS AND METHODS

We investigated 110 cases of cHD for: a) EBV association by immunohistochemical demonstration of EBV-latent membrane protein-1 and EBV encoded nuclear RNA 1 by mRNA in situ hybridisation; b) Proliferating cell nuclear antigen (PCNA) expression in the RS cells.

RESULTS

EBV association was noted in 86 of 110 cases (78%). Higher PCNA expression (P = 0.004) and younger age (P = 0.001) correlated independently with EBV association. The 10 year relapse free survival (RFS) of EBV+ and EBV- patients were 60% and 44%, respectively (P = 0.03). The 10 year overall survival (OS) of EBV+ and EBV- patients were 85% and 64%, respectively (P = 0.03). EBV association maintained its significant impact on RFS and OS within Cox proportional hazard model.

CONCLUSIONS

Our study suggests that EBV is likely to confer a higher PCNA expression and also contribute towards maintaining the RS cells of cHD in cell cycle. Hence, RS cells in EBV associated cHD would be more responsive to chemotherapy and radiotherapy associated DNA damage. Thus, EBV-association provides survival advantage to cHD patients treated with standard chemotherapy and radiotherapy protocols.

The quality of swallowing for patients with operable esophageal carcinoma: a randomized trial comparing surgery with radiotherapy

BACKGROUND

Surgery is considered the standard treatment for operable esophageal carcinoma, although there is no compelling evidence that surgery can achieve better results than radiotherapy. There has previously been no direct randomized comparison of these two modalities with survival or disease specific outcome end points.

METHODS

Ninety-nine patients with operable squamous cell carcinoma of the esophagus were randomly allocated to surgery or radiotherapy after stratification for tumor length (< or = or >5 cm). Those randomized to surgery underwent transthoracic esophagectomy with limited lymphadenectomy, whereas those in the radiotherapy arm received 50 gray in 28 fractions followed by a 15-gray boost to the primary tumor. Disease specific outcome was assessed for 4 subgroups: 1) disease specific symptoms, 2) physical symptoms, 3) ability to work, and 4) social/family interaction and global perception of disease specific outcome. The questionnaire was given prior to treatment and posttreatment at 3-month intervals for 1 year. Death was a secondary end point.

RESULTS

There was an overall improvement in the quality of swallowing in both treatment arms after treatment and with the passage of time. The swallowing status was better in the surgery arm than in the radiotherapy arm at 6 months after treatment (P = 0.03, Fisher's exact test). Logistic regression analysis showed randomization arm (P = 0.035), time since treatment (P = 0.003), and pretreatment swallowing status to be significant determinants of posttreatment swallowing status. Surgery was twice as likely to result in improvement in swallowing than radiotherapy after correction for time and pretreatment swallowing status. Overall survival was better in the surgery arm than in the radiotherapy arm (P = 0.002, log rank test) (OR = 2.74 with 95% confidence intervals 1.51-4.98; P < 0.009, Cox proportional hazards model).

CONCLUSIONS

Both surgery and radiotherapy can improve the quality of swallowing significantly for patients with operable esophageal carcinoma. Surgery is marginally superior to radiotherapy in improving the quality of swallowing. In this trial, survival in the surgery arm was significantly better than in the radiotherapy arm, although the small number of patients is a limitation.

Survival analysis of 5595 head and neck cancers--results of conventional treatment in a high-risk population

This is a study of 5595 head and neck cancer patients treated during 1987-89 at TMH, Mumbai. The study included 1970 oral cancers (ICD 140-145), 1495 oropharyngeal cancers (ICD 1410, 1453, 146), 1255 hypopharyngeal cancers (ICD 148), 125 nasopharyngeal cancers (ICD 147) and 750 laryngeal cancers (ICD 161). The clinical extent of disease at presentation was based on TNM group staging (UICC 1978). For the majority of sites, patients attended the hospital during stage III and stage IV of the disease; the only exception was for cancers of the lower lip, anterior tongue and vocal cord when between 46.2% and 56.5% of patients with localized cancer (stage I and II) were seen. Generally, surgery either alone or with radiation has been administered for oral cancer patients whereas radiation either alone or in combination with chemotherapy was administered for other head and neck sites. The overall 5-year survival rate was in the range of 20-43% for oral cancer, 8-25% for pharyngeal cancers and 25-62% for laryngeal cancer. The 5-year relative survival rates were more or less in agreement with the results published by the Eurocare study for head and neck cancers. The importance of primary prevention in head and neck cancer is stressed.

Dosimetry of intracavitary applications in carcinoma of the cervix: rectal dose analysis

The International Commission on Radiation Units and Measurements (ICRU), in its Report-38, has given certain recommendations regarding the specifications of bladder and rectal reference points in the intracavitary treatment of carcinoma of the cervix. Conforming to this report, 182 intracavitary applications performed in stage I and II cervix cases were analyzed. In 113 applications, the maximum rectal dose was found to be in a point on the anteroposterior line drawn through the centre of colpostat sources. However, for our type of applications, the point on the anteroposterior line drawn through the lower end of the uterine tube seldom gets maximum dose. In addition, it was observed that there are other dose points than the ICRU reference point receiving doses close to maximum dose. It was concluded that doses to multiple rectal reference points should be recorded, in addition to the ICRU-defined rectal reference point.

Design and comparison of wedge shaped midline block with rectangular block used in early stage cervical cancers

PURPOSE

Design of an universal wedge shaped midline block for early stage cervical cancers to get uniform dose distribution around the target volume.

MATERIAL AND METHODS

The method of fabrication of wedge shaped midline block is discussed for treatment of early stage cervical cancers based on the configuration of 137Cs pellets used in intracavitary applications and along with external photon beams obtained by using 60Co teletherapy machine and 6 and 10 MV linear accelerators.

RESULTS

The dosimetric measurements are carried out to confirm the adequacy of thickness and shape of the block using radiation field analyzer for all the 3 energies.

DISCUSSION

The dose distribution comparison has been made with wedge shaped midline block and conventional rectangular shields to show its superiority in getting homogeneous dose distribution around target volume. The shift in 184 intracavitary applications is analyzed in actual clinical applications with respect to central axis of external beams and its comparison is made with both types of blocks. With the shift of 1 cm towards lateral from midline an overdose can occur upto 12 Gy at certain points with rectangular block compared to wedge shaped midline block.

CONCLUSION

Since the preparation of individual wedge shaped midline block for every application will be a difficult process for busy centers, the single wedge shaped midline block for each energy is more convenient to handle for busy centers instead of individualized compensating blocks for every intracavitary application.

Geometrical considerations in dose volume analysis in intracavitary treatment

PURPOSE

The present work was aimed at to study the relationship between the volume enclosed by reference isodose surface and various geometrical parameters of the intracavitary applicator in treatment of carcinoma of cervix.

MATERIAL AND METHODS

Pearshape volume of the reference isodose derived from the Total Reference Air Kerma (TRAK) and the product of its dimensions, height H, width W and thickness T which is dependent on the applicator geometry, were estimated for 100 intracavitary applications treated by Selectron LDR machine. Orthogonal radiographs taken for each patient were used for measurement of actual geometric dimensions of the applicator and carrying out the dosimetry on TP-11 treatment planning system. The dimensions H, W and T of reference isodose surface (60 Gy) were also noted.

RESULTS

Ratio of the product HWT and the pearshape volume was found mainly to be a function of colpostat separation and not of other geometrical parameters like maximum vertical and anterio-posterior dimension of the applicator. The ratio remained almost constant for a particular combination of uterine tandem and colpostat. Variation in the ratios were attributed to the non-standard geometry.

CONCLUSION

The ratio of the volume of reference isodose surface to the product of its dimensions in the applicator depends upon the colpostat separation.

Hodgkin's disease relapse presenting as Pancoast's syndrome

Among the various infrequent causes of Pancoast's syndrome, Hodgkin's disease is one. A 26 year old man was diagnosed as Hodgkin's disease. Five years later the disease relapsed producing Pancoast's syndrome. The importance of precise aetiological diagnosis before treatment of such cases with similar presentation is emphasized.

Treatment results of Hodgkin's disease in Indian children

This is a retrospective study of Hodgkin's disease in children less than 15 years of age who were registered at Tata Memorial Hospital in India from January 1985 through December 1990. Clinicopathologic characteristics and response were evaluated in 147 patients and survival was calculated in 187. There were 126 boys and 21 girls (6:1). All patients were treated with combination chemotherapy and involved field radiotherapy. The COPP schedule was given to 108 patients. COPP/ABVD to 33, and ABVD to 6. Ninety-three patients (63%) had stage I or II disease and 54 (37%) had stage III or IV disease. B symptoms were observed in 65 patients (56%) and bulky disease in 40 (27%). Histologically, the most common subtype was mixed cellularity, seen in 95 patients (65%). Complete response was observed in 136 (89%), partial response in 6 (4%), and there were 4 treatment-related deaths. Relapse has been observed in 11%. Seven-year actuarial survival was 73% and event-free survival was 64%. Median survival has not yet been reached, with a median follow-up of 36 months.

Modified MACOP-B chemotherapy for intermediate and high grade non Hodgkins lymphomas

Combination chemotherapy consisting of methotrexate with leucovorin rescue, doxorubicin, cyclophosphamide, vincristine, prednisolone and bleomycin (MACOP-B) has been extensively used for the treatment of Non Hodgkins Lymphoma. However, different results have been reported. The aim of this study was to assess the feasibility of administration of this regimen on an out patient basis and to confirm the efficacy of MACOP-B. 51 patients with intermediate--and high--grade lymphoma were treated with this regimen in a single institute study. Numerous clinical features predictive of response and disease free survival were analysed. The Median age was 48 years (range 14-77). Diffuse large cell lymphoma was seen in 65%, diffuse small cleaved in 10% and diffuse mixed in 15%. Eight patients (15%) had Stage I disease, 18 (35%) Stage II, 12 (23%) Stage III and 13 (25%) Stage IV. Complete remission was achieved in 65% of the patients. With a median follow up of 18 months, 40% of the patients are alive at 40 months. Sixty percent of the complete responders are disease free at 40 months. Response rates did not differ significantly for age, sex, stage, histology, bone marrow involvement and extranodal disease. However patients with absence of B' symptoms, non bulky disease at presentation and diffuse large cell histology had a higher percentage of complete remission. Hematological toxicity occurred in 90% and was grade IV in 14% patients. Three patients died of sepsis. Severe mucositis occurred in 40% of the patients. In conclusion, while it is possible to give aggressive chemotherapy at the out patient basis in India we failed to confirm the high response rates as originally reported.

Dilation of esophageal strictures induced by radiation therapy for cancer of the esophagus

During a 2-year period, 103 consecutive patients undergoing dilation of esophageal strictures induced by radiation therapy for cancer of the esophagus were prospectively studied. The length of the strictures ranged from 0.5 to 13.5 cm (median, 5 cm) and the luminal diameter from 1 to 11 mm (median, 6 mm). Patients were referred for dilation from 2 weeks to 5 years (median, 2 months) after completion of radiation therapy. The guide wire was placed using fluoroscopy in 21 patients, endoscopy in 61, and a combination of endoscopy and fluoroscopy in 21. At least one dilator larger than the stricture could be passed in 101 (98%) patients. Five strictures were dilated to 16 mm, 29 to 15 mm, 28 to 14 mm, 16 to 12.8 mm, and 23 to 12 mm or less during the initial procedure. Development of complications and severe resistance were the limiting factors for optimal dilation. Relief of dysphagia was adequate in 66% of patients. The duration of dysphagia relief was 3 to 84 weeks (median, 16 weeks). Complications included persistent pain in 7 patients, unexplained fever in 2, perforation in 2, and delayed tracheo-esophageal fistula in 1. Two patients died of treatment-related complications. Repeated dilation was required in 32 of the 75 patients on long-term follow-up. We conclude that adequate palliation of dysphagia can be achieved by dilation in two-thirds of patients with radiation therapy-induced strictures of the esophagus. Dilation of these strictures is relatively simple and safe if performed with care.

Treatment volume from total reference air kerma (TRAK) in intracavitory applications and its comparison with ICRU reference volume

PURPOSE

A systematic dosimetry study conforming to International Commission on Radiation Units and Measurements Report Number 38, was carried out for, cancer of Cervix Stage I and II cases at Tata Memorial Hospital.

METHODS AND MATERIALS

The reference Volume dimension were noted for each applicator. Also 3-D dosimetry was performed for selected cases, and actual geometric volume enclosed by various isodose surfaces were obtained. A relation was derived, which gave the volume enclosed by any isodose surface as a function of total reference air kerma of the sources in the applicator. The volume enclosed by reference isodose surface was compared with the product of its dimensions height, width, and thickness.

RESULTS

The volume enclosed by any isodose surface of an intracavitary application can be easily derived from total reference air kerma of the sources within the applicator.

CONCLUSION

Ratio of the volume enclosed by reference isodose surface with the product of its dimensions (HWT) could be a predictive parameter for clinical outcome, besides the reference volume specified by the report.