Simultaneous Measurement of In vivo and Transit Mid-Plane Doses with Ionization Chambers in Gynecological Malignancy Patients Undergoing Three-Dimensional Conformal Radiotherapy.

PURPOSE: The aim of this study is to estimate delivered radiation doses inside planning tumor volume (PTV) using the in vivo (mid-plane dose) measurement and transit measurement methods in gynecological malignancy patients undergoing three-dimensional conformal radiotherapy (3DCRT) using calibrated ionization chambers. MATERIALS AND METHODS: Six patients with histopathologically proven carcinoma of the cervix or endometrium were planned with four-field 3DCRT to the pelvic site. Isocenter was at the geometric mid-plane of PTV with a dose prescription of 50 Gy in 25 fractions. Clinical mid-plane dose (D iso, Transit) estimates were done in one method (transit) using the FC-65 positioned at electronic portal imaging device level. In another method, a repeat computerized tomography scan was performed (at the 11th fraction) using CC-13 having a protective cap in the vaginal cavity for in vivo measurements (D in vivo ). Simultaneous measurements were performed with the two chambers from the 11th fraction onward at least 3-4 times during the remaining course of treatment. RESULTS: The agreement of mean doses from these two described methods and treatment planning system reference doses was in the range of -4.4 ± 1.1% (minimum) to -0.3 ± 2.0% (maximum) and -4.0 ± 1.7% (minimum) to 1.9 ± 2.4% for D in vivo and D iso, Transit , respectively, which are an acceptable range of daily radiation dose delivery. CONCLUSION: The fundamental importance of this study lies in simultaneous validation of delivered dose in real time with two methods. A study in this small number of patients has given the confidence to apply transit measurements for quality assurance on a routine basis as an accepted clinical dosimetry for the selected patients.

Ocular oncology practice guidelines during COVID-19 pandemic-An expert consensus.

The outbreak of rapidly spreading COVID-19 pandemic in December 2019 has witnessed a major transformation in the health care system worldwide. This has led to the re-organization of the specialty services for the effective utilization of available resources and ensuring the safety of patients and healthcare workers. Suspension of oncology services will have major implications on cancer care due to delayed diagnosis and treatment leading to irreversible adverse consequences. Therefore various oncology organizations have called for a continuation of cancer care during this crisis with diligence. The COVID-19 pandemic has forced the clinicians to transform the components of care from screening to outpatient care and primary management. The purpose of this article is to establish guidelines and recommendations for ocular oncology in the management of ocular tumors set by a multidisciplinary team of experts including ocular, medical and radiation oncologists, and pathologists. As the pandemic is evolving fast, it will require constant updates and reformation of health strategies and guidelines for safe and quality health care.

Pediatric recurrent aggressive spinal fibromatosis with progressive kyphosis and neurological deficits.

Aggressive fibromatosis is a benign, locally invasive fibroblastic proliferation that can cause compressive effects on adjacent structures. The primary cure of this disease rests in wide excision of the tumor. Unfortunately even when surgical margins are clear of tumor, recurrence rates are high. Postoperative radiotherapy is indicated following surgical excision. We present a 13-year-old girl who had been operated for the intraspinal mass in upper thoracic spine and paraparesis with thoracic limited laminectomy and excision of the tumor mass elsewhere. The histopathological examination was reported to be aggressive fibromatosis. After 2 years, she presented again with 1-year duration of progressive deformity in the upper thoracic spine and weakness of both lower limbs. Focal kyphosis at T4-T5 was measuring 68°. Magnetic resonance imaging (MRI) showed recurrent tumor involvement of posterior elements of T2-T5 and paravertebral soft tissues with signal changes in the cord at T2-T5 vertebral levels with focal kyphosis and internal gibbus. She underwent posterior spinal revision decompression with internal gibbectomy and instrumented fusion. The histopathology showed features suggestive of aggressive fibromatosis. After wound healing at 2 weeks, she underwent 3-D conformal radiotherapy, based on the preoperative tumor extent on MRI (dose of 45 Gy in 25 fractions over 5 weeks). She had normal neurology at 2-year follow-up and was tumor free on MRI. Hence, aggressive fibromatosis can recur following successful surgical wide excision. Multilevel thoracic laminectomy in growing children can cause progressive spinal deformity and neurological deficits. Operative treatment of recurrent tumor involves en bloc excision with instrumented fusion followed by local radiotherapy. This is the first pediatric recurrent spinal fibromatosis reported with successful treatment as per author's knowledge.

In vivo dose estimations through transit signal measured with thimble chamber positioned along the central axis at electronic portal imaging device level in medical linear accelerator in carcinoma of the middle-third esophagus patients undergoing three-dimensional conformal radiotherapy.

OBJECTIVE: This study presents a method to estimate midplane dose (Diso, transit) in vivo from transit signal (St) measured with thimble ionization chamber in cancer of the middle-third esophagus patients treated with three-dimensional radiotherapy (RT). This detector is positioned at the level of electronic portal imaging device in the gantry of a medical linear accelerator. MATERIALS AND METHODS: Efficacy of inhomogeneity corrections of three dose calculation algorithms available in XiO treatment planning system (TPS) for planned dose (for open fields) (Diso, TPS) was studied with three heterogeneous phantoms. Diso, transit represents measured signal at transit point (St) far away correlating to dose at isocenter. A locally fabricated thorax phantom was used to measure the in vivo midplane dose (Diso, mid) which was also estimated through St. Thirteen patients with carcinoma of the middle-third esophagus treated with three-dimensional conformal RT were studied. St was recorded (three times, with a gap of 5-6 fractions during the treatment) to estimate Diso, transit, which was compared with the doses calculated by TPS. RESULTS: The dose predictions by superposition algorithm were superior compared to the other algorithms. Percentage deviation of Diso, transit, Diso, mid with Diso, TPS combined all fields was 2.7 and -2.6%, respectively, with the thorax phantom. The mean percentage deviation with standard deviation of estimated Diso, transit with Diso, TPS observed in patients was within standard deviation -0.73% ±2.09% (n = 39). CONCLUSIONS: Midplane dose estimates in vivo using this method provide accurate determination of delivered dose in the middle-third esophagus RT treatments. This method could be useful in similar clinical circumstances for dose confirmation and documentation.

On-line estimations of delivered radiation doses in three-dimensional conformal radiotherapy treatments of carcinoma uterine cervix patients in linear accelerator.

Transmission of radiation fluence through patient's body has a correlation to the planned target dose. A method to estimate the delivered dose to target volumes was standardized using a beam level 0.6 cc ionization chamber (IC) positioned at electronic portal imaging device (EPID) plane from the measured transit signal (St) in patients with cancer of uterine cervix treated with three-dimensional conformal radiotherapy (3DCRT). The IC with buildup cap was mounted on linear accelerator EPID frame with fixed source to chamber distance of 146.3 cm, using a locally fabricated mount. Sts were obtained for different water phantom thicknesses and radiation field sizes which were then used to generate a calibration table against calculated midplane doses at isocenter (Diso,TPS), derived from the treatment planning system. A code was developed using MATLAB software which was used to estimate the in vivo dose at isocenter (Diso,Transit) from the measured Sts. A locally fabricated pelvic phantom validated the estimations of Diso,Transit before implementing this method on actual patients. On-line dose estimations were made (3 times during treatment for each patient) in 24 patients. The Diso,Transit agreement with Diso,TPS in phantom was within 1.7% and the mean percentage deviation with standard deviation is -1.37% ±2.03% (n = 72) observed in patients. Estimated in vivo dose at isocenter with this method provides a good agreement with planned ones which can be implemented as part of quality assurance in pelvic sites treated with simple techniques, for example, 3DCRT where there is a need for documentation of planned dose delivery.

Non-Hodgkin's lymphoma: is India ready to incorporate recent advances in day to day practice?

BACKGROUND: Non Hodgkin's Lymphoma (NHL) cure rates are increasing and morbidities are decreasing, with more active pharmacological agents and technological advancements. In spite of this, India is still battling with the prejudices of an economically and educationally impoverished patient base. METHODS AND RESULTS: We analyzed NHL cases from 2000 to 2006 using data from case sheets. Of 303 cases, only 100 patients had complete workup and received some form of treatment. For 203 patients, reasons for non-compliance were: financial constraint (119), distance from center (38), inability of physician to provide guarantees of cure (13), poor prognosis/fear of recurrence (28)), preferences for alternate medicine (5). Most common investigations that could not be afforded for staging were whole body CT scans and bone marrow aspiration and biopsy. Thirteen patients were in stage III and 53 in Stage IV. The most common regimen was CHOP (Cyclophosphamide, Adriamycin, Vincristine, Prednisolone). Forty-five patients did not complete six courses of CHOP and 35 patients had significant delay. Reasons for delay were intermittent availability of cash (35), intolerable toxicities (30), absence of supportive care (21), given-up attitudes (17). Eighty-three patients suffered Grade III/IV debilitating toxicities. Overall survival at five years was 50%. CONCLUSIONS: NHL in India is no different from the developed world. However, there are disparities in survivorship and outcomes, due to un-affordability and attitudes of the patients. Therefore, we suggest the development of Community Health Insurance Schemes (CHIs), with the hospital as the nodal center to address the above mentioned issues.

An overview on applications of optical spectroscopy in cervical cancers.

Despite advances in the treatment modalities, cervical cancers are one of the leading causes of cancer death among women. Pap smear and colposcopy are the existing screening methods and histopathology is the gold standard for diagnosis. However, these methods have been shown to be prone to reporting errors, which could be due to their subjective interpretation. Radiotherapy is the mainstay of treatment for the locally advanced stages of cervical cancers. The typical treatment regimen spans over 4 months, from the first fraction of radiation to clinical assessment of tumor response to radiotherapy. It is often noticed that due to intrinsic properties of tumors, patients with the same clinical stage and histological type respond differently to radiotherapy. Hence, there exists a need for the development of new methods for early diagnosis as well as for early prediction of tumor radioresponse. Optical spectroscopic methods have been shown to be potential alternatives for use in cancer diagnosis. In this review, we provide a brief background on the anatomy and histology of the uterine cervix and the etiology of cervical cancers; we briefly discuss the optical spectroscopic approach to cervical cancer diagnosis. A very brief discussion on radiation therapy and radiation resistance is also provided. We also share our experiences with the Raman spectroscopic methodologies in cervical cancer diagnosis as well as in the prediction of tumor radioresponse.

Prediction of radiotherapy response in cervix cancer by Raman spectroscopy: a pilot study.

Radiotherapy is the choice of treatment for locally advanced stages of the cervical cancers, one of the leading female cancers. Because of intrinsic factors, tumors of same clinical stage and histological type often exhibit differential radioresponse. Radiotherapy regimen, from first fraction of treatment to clinical evaluation of response, spans more than 4 months. Clinical assessment by degree of tumor shrinkage is the only routinely practiced method to evaluate the tumor response. Hence, a need is created for development new methodologies that can predict the tumor response to radiotherapy at an early stage of the treatment which can lead to tailor-made protocols. To explore the feasibility of prediction of tumor radioresponse, Raman spectra of cervix cancer tissues that were collected before (malignant) and 24 h after patient was treated with 2nd fraction of radiotherapy (RT) were recorded. Data were analyzed by Principal Components Analysis (PCA) and results were correlated with clinical evaluation of radioresponse. Mean Raman spectra of RT tissues corresponding to different levels of tumor response, complete, partial, and no response, showed minute but significant variations. The unsupervised PCA of malignant tissues failed to provide any classification whereas RT spectra gave clear classification between responding (complete and partial response) and nonresponding conditions as well as a tendency of separation among responding conditions. These results were corroborated by supervised classification, by means of discrimination parameters: Mahalanobis distance and spectral residuals. Thus, findings of the study suggest the feasibility of Raman spectroscopic prediction of tumor radioresponse in cervical cancers.

Vibrational spectroscopy studies of formalin-fixed cervix tissues.

Optical histopathology is fast emerging as a potential tool in cancer diagnosis. Fresh tissues in saline are ideal samples for optical histopathology. However, evaluation of suitability of ex vivo handled tissues is necessitated because of severe constraints in sample procurement, handling, and other associated problems with fresh tissues. Among these methods, formalin-fixed samples are shown to be suitable for optical histopathology. However, it is necessary to further evaluate this method from the point of view discriminating tissues with minute biochemical variations. A pilot Raman and Fourier transform infrared (FTIR) microspectroscopic studies of formalin-fixed tissues normal, malignant, and after-2-fractions of radiotherapy from the same malignant cervix subjects were carried out, with an aim to explore the feasibility of discriminating these tissues, especially the tissues after-2-fractions of radiotherapy from other two groups. Raman and FTIR spectra exhibit large differences for normal and malignant tissues and subtle differences are seen between malignant and after-2-fractions of radiotherapy tissues. Spectral data were analyzed by principal component analysis (PCA) and it provided good discrimination of normal and malignant tissues. PCA of data of three tissues, normal, malignant, and 2-fractions after radiotherapy, gave two clusters corresponding to normal and malignant + after-2-fractions of radiotherapy tissues. A second step of PCA was required to achieve discrimination between malignant and after-2-fractions of radiotherapy tissues. Hence, this study not only further supports the use of formalin-fixed tissues in optical histopathology, especially from Raman spectroscopy point of view, it also indicates feasibility of discriminating tissues with minute biochemical differences such as malignant and after-2-fractions of radiotherapy.

Primary papillary carcinoma of the thyroglossal duct cyst--a case report.

Thyroglossal duct cyst is the most common developmental anomaly of the thyroid gland, presenting as a mid line neck swelling. Malignancy arising in them is a rare event, with papillary thyroid carcinoma being the commonest. Thyroglossal duct cyst carcinomas are usually asymptomatic and are not suspected preoperatively in most instances, hence the need for surgical excision and careful pathological examination of these cysts. We present a case of a 57 year old lady who underwent a Sistrunk procedure for the removal of thyroglossal duct cyst, which was responsible for a progressive mid line neck swelling of 2 months duration. The thyroid gland was normal. Histological examination of the excised cyst showed a papillary thyroid carcinoma arising in the thyroglossal duct cyst. Long term survival of patients with thyroglossal duct cyst carcinoma is excellent.