Effective spatially fractionated GRID radiation treatment planning for a passive grid block

OBJECTIVE

To commission a grid block for spatially fractionated grid radiation therapy (SFGRT) treatments and describe its clinical implementation and verification through the record and verify (R&V) system.

METHODS

SFGRT was developed as a treatment modality for bulky tumours that cannot be easily controlled with conventionally fractionated radiation. Treatment is delivered in the form of open-closed areas. Currently, SFGRT is performed by either using a commercially available grid block or a multileaf collimator (MLC) of a linear accelerator. In this work, 6-MV photon beam was used to study dosimetric characteristics of the grid block. We inserted the grid block into a commercially available treatment planning system (TPS), and the feasibility of delivering such treatment plans on a linear accelerator using a R&V system was verified. Dose measurements were performed using a miniature PinPoint(TM) ion chamber (PTW, Freiburg, Germany) in a water phantom and radiochromic film within solid water slabs. PinPoint ion chamber was used to measure the output factors, percentage depth dose (PDD) curves and beam profiles at two depths, depth of maximum dose (zmax) and 10 cm. Film sheets were used to measure dose profiles at zmax and 10-cm depth.

RESULTS

The largest observed percentage difference between output factors for the grid block technique calculated by the TPS and measured with the PinPoint ion chamber was 3.6% for the 5 × 5-cm(2) field size. Relatively significant discrepancies between measured and calculated PDD values appear only in the build-up region, which was found to amount to <4%, while a good agreement (differences <2%) at depths beyond zmax was observed. Dose verification comparisons performed between calculated and measured dose distributions were in clinically acceptable agreements. When comparing the MLC-based with the grid block technique, the advantage of treating large tumours with a single field reduces treatment time by at least 3-5 times, having significant impact on patient throughput.

CONCLUSION

The proposed method supports and helps to standardize the clinical implementation of the grid block in a safer and more accurate way.

ADVANCES IN KNOWLEDGE

This work describes the method to implement treatment planning for the grid block technique in radiotherapy departments.

Quorum-sensing autoinducers resuscitate dormant Vibrio cholerae in environmental water samples

Cholera epidemics have long been known to spread through water contaminated with human fecal material containing the toxigenic bacterium Vibrio cholerae. However, detection of V. cholerae in water is complicated by the existence of a dormant state in which the organism remains viable, but resists cultivation on routine bacteriological media. Growth in the mammalian intestine has been reported to trigger "resuscitation" of such dormant cells, and these studies have prompted the search for resuscitation factors. Although some positive reports have emerged from these investigations, the precise molecular signals that activate dormant V. cholerae have remained elusive. Quorum-sensing autoinducers are small molecules that ordinarily regulate bacterial gene expression in response to cell density or interspecies bacterial interactions. We have found that isolation of pathogenic clones of V. cholerae from surface waters in Bangladesh is dramatically improved by using enrichment media containing autoinducers either expressed from cloned synthase genes or prepared by chemical synthesis. These results may contribute to averting future disasters by providing a strategy for early detection of V. cholerae in surface waters that have been contaminated with the stools of cholera patients or asymptomatic infected human carriers.

Clinicopathological stages of carcinoma breast patient

Carcinoma of breast is the second most common cancer among women next to uterine cervical cancer in Bangladesh. It was well established that 5 years survival rates greatly vary among the different stages of carcinoma of breast disease. The study was carried out to see the stages of presentation of carcinoma of breast patient to a tertiary level hospital attended first time for medical help as well as to find out the factors responsible for the late (advanced) stage presentation. This descriptive type of cross sectional study was carried out in the department of surgery, Mymensingh Medical College and Hospital (MMCH) during the period of May 2010 to April 2011. A total of 110 cases admitted with carcinoma breast diagnosed by means of FNAC positive or suspicious findings were selected purposively during the study period. Patients were staged initially according to the TNM staging system by through clinical examination as well as final clinicopathological stages were done after histopathological examination of the resected specimen (breast with or without axillary lymphnode) in resectable cases. Among the advanced stage presentation, attempts were made to find out the factors responsible for advanced stage of the disease. The results showed that carcinoma of breast predominantly a disease of female and comparatively younger age group 40-49 years affected mostly in 40.9% cases with a mean age of 44.02 ± 10.32 years. Premenopausal lady mostly affected in 63.6% cases. Majority of patients presented in advanced stage of the disease in 62.8% cases. Multiple factors were observed responsible for the advanced stage of the disease - among them delay in hospital presentation, poor socioeconomic condition and illiteracy have found to be associated which were statistically significant (p<0.001). It was needed for mass awareness program against the breast cancer in our society. Necessary steps should be taken for the initiation of breast self examination (BSE) to patients and clinical breast examination (CBE) to health care providers.

Pattern of malignancy in clinically solitary thyroid nodule

Solitary thyroid nodule (STN) is a common thyroid disorder. Clinically recognized thyroid carcinoma constitutes less than 1% of human malignant tumours. The risk of malignancy in solitary thyroid nodule is greater than other thyroid swelling. The risk of malignancy in generalized thyroid swelling is about 3% and in solitary thyroid nodule it is about 15%. This study was carried out in Surgery and ENT Department, Mymensingh Medical college Hospital from November 2008 to October 2009 to see pattern of malignancy in clinically solitary thyroid nodule. Total 108 patients of STN was included in this study, majority of the patients were within 20-39 years age group with female predominance. In addition to thyroid swelling some patients presented with other symptoms like cervical lymphadenopathy in 6(5.56%), dysphagia 2(1.85%), hoarseness of voice 2(1.85%) and metastatic lesion in bone 1(0.92%) cases. Among 108 cases of solitary thyroid nodule only 19 cases were malignant. Patients with malignant lesion presented with shorter duration of symptoms. Out of 19 malignant cases 6(31.58%) cases presented with features of metastasis. Malignancy was more predominant in male (25.00%) than the female (14.47%) in STN. Out of 19 malignant cases, 12(63.16%) were papillary carcinoma, 5(26.31%) were follicular carcinoma and 2(10.53%) cases were medullary carcinoma. Study showed significant difference (p<0.01) between papillary & follicular carcinoma and significant difference (p<0.001) between papillary & medullary carcinoma. Papillary carcinoma was most common among all thyroid malignancies in patients with solitary thyroid nodule.

A young lady with secondary tuberculosis of breast

Tuberculosis of breast is an extremly rare form of extrapulmonary tuberculosis even in endemic area like Bangladesh and the incidence is 0.25-4.5% of all breast lesions. The diagnosis is difficult because of nonspecific clinical, radiological and histopathological findings. Very often biopsy specimens are inadequate and microscopy or culture is negative. It is usually suspected in a multiparous woman who may be immunocompromised. We report a case of breast tuberculosis in a 26 years old multiparous lady who previously present with two times attack of right sided breast lump and then diagnosed as a case of breast abscess and treated by incision and drainage with antibiotics in a nearby local hospital. During her third time attack she admitted into Mymensingh Medical College Hospital with right sided breast lump with multiple discharging sinuses for one month. Biopsy was taken from the lump and sinus tract and histopathological report confirmed the diagnosis as a case of tuberculosis of breast. Her X-ray chest showed tubercular lesion in lungs. So this is a case of secondary breast tuberculosis. This case highlights how difficult is the diagnosis of a case of breast tuberculosis for which the patient may require even mastectomy at very late case. So this case is reported.

Drug Response Indicator Test (DRIT) as a predictive test for treatment outcomes in advanced breast cancer patients (ABC)

1119

Background: There are limited options for selecting an optimal treatment regimen for ABC patients (pts). DRIT is a platform technology that provides a profile of a patient's tumor's sensitivity or resistance to commonly used chemotherapeutic, hormonal, or biological agents as a basis for individualized anticancer treatment approach. DRIT may allow physicians to choose more effective drug treatments before initiation of therapy and improve the efficacy and toxicity profile of cancer therapies. Methods: DRIT analysis is based on fluorescent dye-labeled monoclonal antibody staining followed by computer-assisted microscopy to quantitatively measure expression levels in tumor sections. The interpretation of DRI expression levels results in classification of tumors as sensitive or resistant to treatment with a mechanistically related drug. This study utilized the following drug/DRI combinations: hormonal therapy/estrogen receptor; capecitabine/thymidylate synthase; docetaxel, paclitaxel, abraxane/β-tubulin isoform III; trastuzumab/HER-2; gemcitabine/ribonucleotide reductase. DRIT was performed on the tumor tissue of consented study participants with ABC who were then deemed to be sensitive or resistant to a given agent/agents. We then analyzed retrospectively clinical treatment outcomes (clinically sensitive to therapy defined as-stable disease+partial response+complete response or resistant to therapy-no response to therapy) for 91 treatment interventions in 71 pts with the DRIT tissue data. Results: We found that the DRIT sensitivity was 0.99, with specificity of 0.59, positive predictive value of 0.88, negative predictive value of 0.93 and overall predictive value of 88% for treatment outcomes for this cohort of ABC pts. Conclusions: This study suggests that DRIT can provide more accurate prediction of treatment outcomes for ABC pts than the standard of care approach and therefore has a potential to avoid unnecessary ineffective drug treatment exposure. Prospective study in ABC pts is currently conducted at the UMGCC.

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Comparative analysis of the post-lumpectomy target volume versus the use of pre-lumpectomy tumor volume for early stage breast cancer: implications for the future

Abstract #5134

Purpose: Accelerated partial breast irradiation (APBI) is increasingly being utilized for the treatment of early stage breast cancer. Planning target volume (PTV) generation with this approach is based on the post-lumpectomy cavity volume (post-LPC) and is often associated with treatment of large amounts of normal breast tissue which can result in patient ineligibility for external beam APBI (EB-APBI). In malignancies such as soft tissue sarcomas, neoadjuvant radiation therapy (RT) has been shown to be associated with smaller volumes of tissue irradiated compared to adjuvant RT. However, neoadjuvant RT has not been attempted in the setting of APBI. We hypothesized that a PTV generation based on an expansion of the pre-lumpectomy (pre-LP) intact tumor volume would result in a significant reduction in the volume of irradiated normal breast tissue compared to the current approach of using the post-LPC. We further hypothesize that the use of EB-APBI utilizing the pre-LP tumor will result in greater patient eligibility for APBI.&#x2028; Materials and Methods: 40 patients with 41 early stage breast cancers previously treated with breast conserving lumpectomy and RT were analyzed. Pre-operative imaging and pathology reports were used to determine a pre-LP tumor volume. A sphere, the diameter of which was the largest determined radiographic dimension, representing the pre-LP tumor volume was placed in the center of the previously contoured and treated lumpectomy cavity. PTVs were developed for the pre-LP tumor volume and the post-LPC volume as per the NSABP-B39 protocol guidelines. The pre-LP and post-LPC PTV volumes were compared. Suitability for APBI was analyzed using criteria set forth by NSABP-B39 guidelines.&#x2028; Results: For all patients, the pre-LP PTV was smaller than the post-LPC PTV. The median volume for the pre and post-LPC PTVs were 93 cc (range 24 – 570 cc) and 250 cc (range 45 – 879 cc), respectively. Paired t-test analysis demonstrated the pre-LP PTV to be significantly smaller than the post-LPC PTV, p &lt; 0.001. The average difference between pre-LP and post-LPC PTVs represented 173 cc (range 21 – 482 cc) or 18% (range 3 - 42%) of the whole breast volume. Based on our analysis, only 3 of 41 cases were ineligible for EB-APBI when using the pre-LP tumor volume, (2 based on pathologic criteria and 1 based on dose/volume constraints) while 13 of 41 cases were ineligible when using the post-LPC PTV (2 based on pathologic criteria and 11 based on dose/volume constraints).&#x2028; Conclusion: PTVs based on the pre-LP tumor expansion are likely to be associated with a significantly reduced amount of normal breast tissue irradiated compared to post-LPC PTVs potentially leading to improved breast cosmesis, decreased dose to critical structures and decreased toxicities. Additionally, eligibility for EB-APBI would potentially increase if administered in the pre-lumpectomy setting. The findings from this study support future investigation as to the implications and feasibility of neoadjuvant APBI.

Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 5134.

Results of intraarterial cisplatin and hyperfractionated radiotherapy in locally advanced cancer of the oropharynx and oral cavity

5563

Background: Intraarterial cisplatin and hyperfractionated radiation (HYPERADPLAT) is an accepted therapy for Stage III and IV head and neck cancer. We present long-term follow-up of patients with OP and OC cancer treated with HYPERADPLAT at a single institution. Methods: 44 patients with Stage III-IV squamous cell carcinomas of the OP or OC were treated with the HYPERRADPLAT regimen consisting of external beam radiotherapy (76.8–81.6 Gy) delivered in 1.2 Gy BID fractions with intraarterial cisplatin (150 mg/m2) administered when patients had reached 60 Gy. Tumor response, disease free survival (DFS), overall survival (OS), and toxicity were assessed for all patients according to NCI CCT criteria. Results: Of 44 patients, 21 had tumors of the base of tongue, 14-tonsil, 4-floor of mouth, and 5-other. Eighty eight percent of patients had T4 tumors and 7% had T3 tumors. Complete tumor response was observed in 86% of patients and 14% had a partial response. Lymph node metastases were present in 84% of patients with 78% of node positive patients having a complete nodal response and 19% with a partial response to treatment. Three-year DFS was 55% and OS was 45%. Locoregional recurrence was noted in 30% of patients and 16% had distant failure. Overall recurrence was noted in 47% of patients with a median time to recurrence of 8 months (range 4–55 months). Median weight loss during treatment was 9% of initial body weight and 28 patients required a feeding tube within 6 months of starting treatment. Grade 3 mucositis was noted in 68% of patients and 3 patients developed Grade 4 toxicity (2 mucosal, 1 hematologic). Conclusions: HYPERRADPLAT results in excellent tumor control that is well tolerated with minimal Grade 4 toxicity in patients with advanced poor prognosis cancers of the OP and OC. These results compare favorably with historically reported control rates and response for patients with a significantly high percentage of T4 tumors of the oropharynx and oral cavity.

No significant financial relationships to disclose.

Clair WH, Brill Y, Given C, Regine WF, Arnold SM. Results of reduction of treatment intensity based on response to a novel induction therapy in stage III and IV head and neck cancer

5561

Background: Concurrent cisplatinum based chemotherapy and qd radiotherapy (RT) to 70 Gy is standard therapy for stage III-IV head and neck (H/N) SCCA. Presented is a prospective IRB approved study tailoring the definitive therapy based on response to induction therapy. Methods: 25 patients with Stage III-IV H/N SCCA were treated with 2 cycles of induction therapy every 21 days comprised of carboplatin (AUC 6 day 1), paclitaxel (75 mg/m2 days 1, 8, and 15), and low dose RT (0.5 Gy BID days 1, 2, 8, and 15) for chemosensitization. The response rates of this mode of induction therapy have been presented previously (ASCO 2005 #3184). Patients with complete response (CR) to induction were treated with reduced dose RT at the primary site (reduced from 70 to 60–66 Gy) and 2 cycles of IV cisplatin (100 mg/m2) instead of 3. Those with partial response (PR) or stable disease (SD) were treated with surgery and adjuvant therapy or with altered fractionation regimens. The impact of dose reduction on survival (OS and DFS), failure patterns, compliance and toxicity (according to NCI CTCAE) were used as end points for the study. Results: Patients included 9 with tonsil, 5-L, 3-HP, 3-OC, and 5-BOT. There were 4-T1,9-T2,9-T3,and 3-T4 tumors. The nodal involvement was N0–5, N1–3, N2–13, N3–4. Patients presented with Stage III (28%), IVA (52%), and IVB (20%). Sixty percent had a CR, 32% had a PR, and 8% had SD after induction therapy. Two patients with CR were non-compliant after induction therapy and not further evaluated. With a median FU of 20.5 months (range 11–36 mo) the OS and DFS is 100% (13/13) in the dose reduced group (CR) and 60% (6/10) in the PR/SD treated with more aggressive regimens. The incidence of distant failure is 40% (4/10) in the PR vs 0% (0/13) in the CR. No patients in the dose reduced group required feeding tubes; however 30% (3/10) were required in patients with PR. Compliance with chemotherapy was 79% (10/13) in the CR vs 80% (8/10) in the PR. Conclusions: Our early results show that the patients showing a CR to induction chemotherapy are a favorable group of patients and they may be treated with reduced treatment intensity. This report provides strong evidence that RT dose deescalation for head and neck cancers may be feasible following assessment after induction therapy.

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Clair WH, Kudrimoti MR. The effect of induction therapy with carboplatin-paclitaxel and low dose radiotherapy followed by hyperfractionated radiotherapy and intraarterial chemotherapy on advanced cancers of the head and neck

15517

Background: The purpose of this study is to evaluate the potential benefits of induction therapy followed by intraarterial cisplatin and hyperfractionated radiation (HYPERRADPLAT) on patients with advanced head and neck tumors. Methods: 20 patients with Stage III-IV squamous cell carcinoma of the head and neck were treated with induction therapy consisting of 2 cycles of carboplatin (AUC 6) and paclitaxel (225 mg/m2) and 0.8 Gy BID on the day of and the day following chemotherapy. Induction therapy was given over 2 cycles separated by 3 weeks (previously described in ASCO 2002 abstract # 921 and 2004 abstract # 5593). Patients were then treated with the HYPERRADPLAT regimen consisting of external beam radiotherapy (74.4–81.6 Gy) delivered in 1.2 Gy BID fractions with intraarterial cisplatin (150 mg/m2) administered when patients had reached 60 Gy. Tumor response, disease free survival, overall survival, and toxicity were assessed for all patients according to NCI CTCAE criteria. Results: Of 20 patients, 9 had tumors of the oropharynx, 9-supralaryngeal, and 2-hypopharyngeal. Fifty percent of patients had T4 tumors and 35% had T3 tumors. Complete tumor response was observed in 80% of patients and 20% had a partial response. Three-year disease free survival was 75% and overall survival was 75%. Locoregional recurrence was noted in 25% of patients and 15% had distant failure. Overall recurrence was noted in 40% of patients with a median time to recurrence of 12 months (range 6–55 months). Median weight loss during treatment was 10% of initial body weight and 13 patients required a feeding tube within 6 months of starting treatment. Grade 3 mucositis was noted in 65% of patients and no patients developed Grade 4 toxicity. Conclusions: Two cycles of carboplatin-paclitaxel induction therapy followed by intraarterial cisplatin and hyperfractionated radiotherapy produces excellent tumor response and reduces distant failure. These results compare favorably with historical controls and produce tolerable toxicity profiles.

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Aggressive fibromatosis--impact of prognostic variables on management

OBJECTIVE

To determine the impact of prognostic variables on local control in patients with aggressive fibromatosis treated with or without radiation.

MATERIALS AND METHODS

Forty-two patients presenting to the combined sarcoma clinic at Johannesburg Hospital with aggressive fibromatosis from 1990 to 2003 were analysed retrospectively. There were 14 males and 28 females. The lesions involved the head and neck in 6 cases (14%), the thorax in 6 (14%), the extremities in 19 (45%) and the abdomen in 11 (26%). Thirty-seven patients (88%) presented to the clinic for the first time, whereas 5 (12%) had recurrent disease at presentation. Fifteen patients (36%) underwent excision only, 15 (36%) had excision followed by postoperative radiation, 8 (19%) had biopsy only, and 4 (9%) had radiation only. The median dose of radiation was 60 Gy (range 9 - 70 Gy).

RESULTS

One patient had local failure following excision and postoperative radiation therapy. The local control was 100% for surgery alone and 86% for surgery followed by postoperative radiation at > or = 24 months. On univariate analysis, age, sex, positive margins, primary or recurrent presentation, site of involvement and initial treatment did not affect local control significantly. Eight of 19 patients (42%) receiving radiation developed severe moist desquamation following treatment, and all these patients had doses of 60 Gy or more.

CONCLUSION

Surgery with or without radiation therapy gave excellent local control. The addition of radiation therapy to surgery as well as other known prognostic parameters did not impact on local control. The morbidity of radiation treatment is considerable, as noted in this series, and adjuvant radiation therapy should therefore be considered only in situations where the risk of recurrence and the morbidity of re-excision are high.