Borys Mychalczak

Deep inspiration breath-hold technique for lung tumors: the potential value of target immobilization and reduced lung density in dose escalation

PURPOSE/OBJECTIVE This study evaluates the dosimetric benefits and feasibility of a deep inspiration breath-hold (DIBH) technique in the treatment of lung tumors. The technique has two distinct features--deep inspiration, which reduces lung density, and breath-hold, which immobilizes lung tumors, thereby allowing for reduced margins. Both of these properties can potentially reduce the amount of normal lung tissue in the high-dose region, thus reducing morbidity and improving the possibility of dose escalation. METHODS AND MATERIALS Five patients treated for non-small cell lung carcinoma (Stage IIA-IIIB) received computed tomography (CT) scans under 4 respiration conditions: free-breathing, DIBH, shallow inspiration breath-hold, and shallow expiration breath-hold. The free-breathing and DIBH scans were used to generate 3-dimensional conformal treatment plans for comparison, while the shallow inspiration and expiration scans determined the extent of tumor motion under free-breathing conditions. To acquire the breath-hold scans, the patients are brought to reproducible respiration levels using spirometry, and for DIBH, modified slow vital capacity maneuvers. Planning target volumes (PTVs) for free-breathing plans included a margin for setup error (0.75 cm) plus a margin equal to the extent of tumor motion due to respiration (1-2 cm). Planning target volumes for DIBH plans included the same margin for setup error, with a reduced margin for residual uncertainty in tumor position (0.2-0.5 cm) as determined from repeat fluoroscopic movies. To simulate the effects of respiration-gated treatments and estimate the role of target immobilization alone (i.e., without the benefit of reduced lung density), a third plan is generated from the free-breathing scan using a PTV with the same margins as for DIBH plans. RESULTS The treatment plan comparison suggests that, on average, the DIBH technique can reduce the volume of lung receiving more than 25 Gy by 30% compared to free-breathing plans, while respiration gating can reduce the volume by 18%. The DIBH maneuver was found to be highly reproducible, with intra breath-hold reproducibility of 1.0 (+/- 0.9) mm and inter breath-hold reproducibility of 2.5 (+/- 1.6) mm, as determined from diaphragm position. Patients were able to perform 10-13 breath-holds in one session, with a comfortable breath-hold duration of 12-16 s. CONCLUSION Patients tolerate DIBH maneuvers well and can perform them in a highly reproducible fashion. Compared to conventional free-breathing treatment, the DIBH technique benefits from reduced margins, as a result of the suppressed target motion, as well as a decreased lung density; both contribute to moving normal lung tissue out of the high-dose region. Because less normal lung tissue is irradiated to high dose, the possibility for dose escalation is significantly improved.

The deep inspiration breath-hold technique in the treatment of inoperable non–small-cell lung cancer☆

PURPOSE Conventional radiotherapeutic techniques are associated with lung toxicity that limits the treatment dose. Motion of the tumor during treatment requires the use of large safety margins that affect the feasibility of treatment. To address the control of tumor motion and decrease the volume of normal lung irradiated, we investigated the use of three-dimensional conformal radiation therapy (3D-CRT) in conjunction with the deep inspiration breath-hold (DIBH) technique. METHODS AND MATERIALS In the DIBH technique, the patient is initially maintained at quiet tidal breathing, followed by a deep inspiration, a deep expiration, a second deep inspiration, and breath-hold. At this point the patient is at approximately 100% vital capacity, and simulation, verification, and treatment take place during this phase of breath-holding. RESULTS Seven patients have received a total of 164 treatment sessions and have tolerated the technique well. The estimated normal tissue complication probabilities decreased in all patients at their prescribed dose when compared to free breathing. The dose to which patients could be treated with DIBH increased on average from 69.4 Gy to 87.9 Gy, without increasing the risk of toxicity. CONCLUSIONS The DIBH technique provides an advantage to conventional free-breathing treatment by decreasing lung density, reducing normal safety margins, and enabling more accurate treatment. These improvements contribute to the effective exclusion of normal lung tissue from the high-dose region and permit the use of higher treatment doses without increased risks of toxicity.

Elective nodal irradiation in the treatment of non–small-cell lung cancer with three-dimensional conformal radiation therapy

PURPOSE Dose escalation using three-dimensional conformal radiation therapy (3D-CRT) has been investigated as a means to improve local control. However, with higher doses, the risk of toxicity increases. Early in our experience, we ceased treating elective nodal areas (lymph node stations without evidence of tumor involvement) in an effort to decrease toxicity while treating the gross tumor to higher doses. This report measures the rate of regional failure without elective radiation therapy to uninvolved lymph nodes. METHODS AND MATERIALS A total of 171 patients with non-small-cell lung cancer treated with 3D-CRT at Memorial Sloan-Kettering Cancer Center between 1991 and 1998 were reviewed. Only lymph node regions initially involved with tumor either by biopsy (55%) or radiographic criteria (node > or =15 mm in the short axis on CT) were included in the clinical target volume. Elective nodal failure was defined as a recurrence in an initially uninvolved lymph node in the absence of local failure. RESULTS Only 11 patients (6.4%) with elective nodal failure were identified. With a median follow-up of 21 months in survivors, the 2-year actuarial rates of elective nodal control and primary tumor control were 91% and 38%, respectively. In patients who were locally controlled, the 2-year rate of elective nodal control was 85%. The median time to elective nodal failure was 4 months (range, 1-19 months). Most patients failed in multiple lymph node regions simultaneously. CONCLUSION Local control remains one of the biggest challenges in the treatment of non-small-cell lung cancer. Most patients in our series developed local failure within 2 years of radiation therapy. The omission of elective nodal treatment did not cause a significant amount of failure in lymph node regions not included in the clinical target volume. Therefore, we will continue our policy of treating mediastinal lymph node regions only if they are clinically involved with tumor.

Advances in 4D Medical Imaging and 4D Radiation Therapy

This paper reviews recent advances in 4D medical imaging (4DMI) and 4D radiation therapy (4DRT), which study, characterize, and minimize patient motion during the processes of imaging and radiotherapy. Patient motion is inevitably present in these processes, producing artifacts and uncertainties in target (lesion) identification, delineation, and localization. 4DMI includes time-resolved volumetric CT, MRI, PET, PET/CT, SPECT, and US imaging. To enhance the performance of these volumetric imaging techniques, parallel multi-detector array has been employed for acquiring image projections and the volumetric image reconstruction has been advanced from the 2D to the 3D tomography paradigm. The time information required for motion characterization in 4D imaging can be obtained either prospectively or retrospectively using respiratory gating or motion tracking techniques. The former acquires snapshot projections for reconstructing a motion-free image. The latter acquires image projections continuously with an associated timestamp indicating respiratory phases using external surrogates and sorts these projections into bins that represent different respiratory phases prior to reconstructing the cyclical series of 3D images. These methodologies generally work for all imaging modalities with variations in detailed implementation. In 4D CT imaging, both multi-slice CT (MSCT) and cone-beam CT (CBCT) are applicable in 4D imaging. In 4D MR imaging, parallel imaging with multi-coil-detectors has made 4D volumetric MRI possible. In 4D PET and SPECT, rigid and non-rigid motions can be corrected with aid of rigid and deformable registration, respectively, without suffering from low statistics due to signal binning. In 4D PET/CT and SPECT/CT, a single set of 4D images can be utilized for motion-free image creation, intrinsic registration, and attenuation correction. In 4D US, volumetric ultrasonography can be employed to monitor fetal heart beating with relatively high temporal resolution. 4DRT aims to track and compensate for target motion during radiation treatment, minimizing normal tissue injury, especially critical structures adjacent to the target, and/or maximizing radiation dose to the target. 4DRT requires 4DMI, 4D radiation treatment planning (4D RTP), and 4D radiation treatment delivery (4D RTD). Many concepts in 4DRT are borrowed, adapted and extended from existing image-guided radiation therapy (IGRT) and adaptive radiation therapy (ART). The advantage of 4DRT is its promise of sparing additional normal tissue by synchronizing the radiation beam with the moving target in real-time. 4DRT can be implemented differently depending upon how the time information is incorporated and utilized. In an ideal situation, the motion adaptive approach guided by 4D imaging should be applied to both RTP and RTD. However, until new automatic planning and motion feedback tools are developed for 4DRT, clinical implementation of ideal 4DRT will meet with limited success. However, simplified forms of 4DRT have been implemented with minor modifications of existing planning and delivery systems. The most common approach is the use of gating techniques in both imaging and treatment, so that the planned and treated target localizations are identical. In 4D planning, the use of a single planning CT image, which is representative of the statistical respiratory mean, seems preferable. In 4D delivery, on-site CBCT imaging or 3D US localization imaging for patient setup and internal fiducial markersfor target motion tracking can significantly reduce the uncertainty in treatment delivery, providing improved normal tissue sparing. Most of the work on 4DRT can be regarded as a proof-of-principle and 4DRT is still in its early stage of development.

High dose rate intraoperative radiation therapy (HDR-IORT) as part of the management strategy for locally advanced primary and recurrent rectal cancer

PURPOSE Primary unresectable and locally advanced recurrent rectal cancer presents a significant clinical challenge. Local failure rates are high in both situations. Under such circumstances, there is a significant need to safely deliver tumoricidal doses of radiation in an attempt to improve local control. For this reason, we have incorporated a new approach utilizing high dose rate intraoperative radiation therapy (HDR-IORT). METHODS AND MATERIALS Between 11/92-12/96, a total of 112 patients were explored, of which 68 patients were treated with HDR-IORT, and 66 are evaluable. The majority of the 44 patients were excluded for unresectable disease or for distant metastases which eluded preoperative imaging. There were 22 patients with primary unresectable disease, and 46 patients who presented with recurrent disease. The histology was adenocarcinoma in 64 patients, and squamous cell carcinoma in four patients. In general, the patients with primary unresectable disease received preoperative chemotherapy with 5-fluorouracil (5-FU) and leucovorin, and external beam irradiation to 4500-5040 cGy, followed by surgical resection and HDR-IORT (1000-2000 cGy). In general, the patients with recurrent disease were treated with surgical resection and HDR-IORT (1000-2000 cGy) alone. All surgical procedures were done in a dedicated operating room in the brachytherapy suite, so that HDR-IORT could be delivered using the Harrison-Anderson-Mick (HAM) applicator. The median follow-up is 17.5 months (1-48 mo). RESULTS In primary cases, the actuarial 2-year local control is 81%. For patients with negative margins, the local control was 92% vs. 38% for those with positive margins (p = 0.002). The 2-year actuarial disease-free survival was 69%; 77% for patients with negative margins vs. 38% for patients with positive margins (p = 0.03). For patients with recurrent disease, the 2-year actuarial local control rate was 63%. For patients with negative margins, it was 82%, while it was 19% for those with positive margins (p = 0.02). The disease-free survival was 47% (71% for negative margins and 0% for positive margins) (p = 0.04). Prospective data gathering indicated that significant complications occurred in approximately 38% of patients and were multifactorial in nature, and manageable to complete recovery. CONCLUSION HDR-IORT using our technique is versatile, safe, and effective. The local control rates for primary disease compare quite well with other published series, especially for patients with negative margins. For patients with recurrent disease, locoregional control and survival are especially encouraging in patients with negative resection margins. Further follow-up is needed to see whether these encouraging data will continue.

Hemithoracic radiation after extrapleural pneumonectomy for malignant pleural mesothelioma

PURPOSE The treatment of malignant pleural mesothelioma remains a therapeutic challenge, with median survival rates of about 12 months and local failure rates of up to 80%. Our institution recently published results showing that extrapleural pneumonectomy (EPP) followed by hemithoracic radiation yielded excellent local control. This paper reports our technique for high-dose hemithoracic radiation after EPP. METHODS Between 1990 and 2001, 35 patients with malignant pleural mesothelioma were treated with EPP followed by hemithoracic radiation therapy (median dose: 54 Gy, range: 45-54 Gy) at Memorial Sloan-Kettering Cancer Center. EPP was defined as en bloc resection of the entire pleura, lung, and diaphragm with or without resection of the pericardium. The radiation therapy target volume was the entire hemithorax, including the pleural folds and the thoracotomy and chest tube incision sites. Patients were treated with a total dose of 5400 cGy delivered in 30 fractions of 180 cGy. Radiation therapy was well tolerated, and toxicity data are described. RESULTS Of the 35 patients analyzed, 29 patients were male, and 18 had right-sided tumors. Twenty-six had epithelioid histologies. UICC stage was I in 4, II in 11, III in 19, and IV in 1 patient. As shown by axial and sagittal isodose distributions, we were able to deliver adequate doses to the target volume while limiting dose to critical structures such as heart, spinal cord, liver, and stomach. The most common toxicities were RTOG Grades 1 and 2 nausea and vomiting, as well as lung, esophageal, and skin toxicities. CONCLUSION Extrapleural pneumonectomy followed by high-dose hemithoracic radiation therapy is a feasible treatment regimen that is well tolerated for patients with malignant mesothelioma. We have demonstrated adequate dose distributions, using a combined photon and electron technique with blocking of critical normal structures.

PRONE BREAST RADIOTHERAPY IN EARLY-STAGE BREAST CANCER: A PRELIMINARY ANALYSIS

PURPOSE Women with large breasts have marked dose inhomogeneity and often an inferior cosmetic outcome when treated with breast conservation compared to smaller-sized patients. We designed a prone breast board, which both minimizes breast separation and irradiated lung or heart volume. We report feasibility, cosmesis, and preliminary local control and survival for selected women with Stage 0-II breast cancer. MATERIALS AND METHODS Fifty-six patients with clinical Stage 0-II breast cancer were treated with lumpectomy and breast irradiation utilizing a prototype prone breast board. A total of 59 breasts were treated. Indications for treatment in the prone position were large or pendulous breast size (n = 57), or a history of cardiopulmonary disease (n = 2). The median bra size was 41D (range, 34D-44EE). Cosmesis was evaluated on a 1-10 (worst-to-best) scale. RESULTS Acute toxicity included skin erythema (80% of patients experienced Grade I or Grade II erythema), breast edema (72% of patients experienced mild edema), pruritus (20% of patients), and fatigue (20% of patients reported mild fatigue). One patient required a treatment break. The only late toxicity was related to long-term cosmesis. The mean overall cosmesis score for 53 patients was 9.37 (range, 8-10). Actuarial 3- and 5-year local control rates are 98%. Actuarial overall survival at 3 and 5 years are 98% and 94%. CONCLUSION Our data indicate that treating selected women with prone breast radiotherapy is feasible and tolerated. The approach results in excellent cosmesis, and short-term outcome is comparable to traditional treatment techniques. This technique offers an innovative alternative to women who might not otherwise be considered candidates for breast conservation.

Soft-tissue sarcoma of the vagina and vulva : a clinicopathologic study

Objective To review the clinicopathologic characteristics of vulvovaginal soft-tissue sarcomas, and to correlate these variables with response to treatment. Methods We performed a retrospective review of the records of 24 women treated at Memorial Hospital for sarcoma of either the vulva or vagina over 20 years (1974–1993). Archival pathology specimens were reviewed to confirm the diagnosis, histology, and grade of the tumor. Results Fifteen patients had sarcomas arising from the vagina and nine had primary vulvar tumors. Leiomyosarcoma was the most common histology (n = 13). Twentythree of 24 women underwent surgical excision as their primary therapy. Twenty-three were available for follow-up, and 16 of them (70%) are free of disease at a median follow-up time of 47 months (range 12–156, mean 59). Five women died of progressive disease and two are currently alive with persistent or recurrent disease. Grade was the most important predictor of outcome; all seven women with low-grade tumors are alive without evidence of disease. Conclusion Soft-tissue sarcomas are rare tumors of the lower genital tract. The primary therapy is surgical; adjuvant radiation therapy is indicated for high-grade tumors and locally recurrent low-grade sarcomas.

The importance of brachytherapy technique in the management of primary carcinoma of the vagina.

This retrospective analysis of 49 cases of primary carcinoma of the vagina treated with radiation therapy alone from 1970-1988 examines the results of treatment with an emphasis on the importance of brachytherapy technique. Thirty-six patients were treated with combined external beam radiation and brachytherapy, 11 patients were treated with external beam alone, and two patients were treated with brachytherapy alone. Brachytherapy techniques used included intracavitary implants, temporary Ir-192 interstitial implants, and permanent I-125 interstitial implants. Intracavitary therapy included the use of a fractionated high dose rate intravaginal cylinder, tandem and ovoids, and a low dose rate intravaginal cylinder. The 5-year actuarial survival was 44% for Stage I (six patients), 48% for Stage II (27 patients), 40% for Stage III (10 patients), and 0% for Stage IVa and IVb (six patients). There was a significant increase in the 5-year actuarial survival for those patients who had brachytherapy as part of their treatment compared to those patients treated with external beam alone (50% vs. 9%) (p < .001). For Stages II and III, there was a trend toward improved actuarial and crude disease free survival with the use of a temporary Ir-192 interstitial implant as part of the treatment compared to the use of intracavitary brachytherapy as part of the treatment (80% vs. 45%) (p = 0.25) and (75% vs. 44%) (p = 0.08), respectively. Brachytherapy plays an important role in the management of primary vaginal cancer. A temporary interstitial implant should be used over an intracavitary form of therapy for more invasive disease.

Management of endometrial adenocarcinoma with cervical involvement

Seventy-seven patients with endometrial cancer with cervical involvement were treated at Memorial Sloan-Kettering Cancer Center from 1968 to 1982. Fractional curettage specimens showed that 25 patients (32%) had involvement of cervical stroma and 52 (68%) had only detached fragments of carcinoma present in endocervical curettings. Six patients treated for palliation only are excluded from analysis of treatment and survival. Our preferred treatment during the time interval studied consisted of preoperative whole pelvic radiotherapy followed by modified radical hysterectomy and bilateral salpingo-oophorectomy with post-operative intravaginal brachytherapy. This regimen was well tolerated by the 37 patients so treated. The remaining patients were treated with a variety of regimens, most commonly radiotherapy and simple hysterectomy (25 patients). With a mean follow-up among survivors of 97 months, disease-free survival is 72%. Mean time to relapse was 19 months, with 90% of relapses occurring within 40 months. Initial sites of relapse included abdomen, 9 (12.6%); lungs, 8 (11.3%); brain, 2 (2.8%); lateral pelvis, 2 (2.8%); and bone, 1 (1.4%). Clinicopathologic variables significantly related to risk of relapse included presence of extrauterine disease at surgery (P = 0.0001), extent of cervical involvement as determined prior to hysterectomy (P = 0.001), depth of myometrial invasion (P = 0.005), and papillary serous histology (P = 0.0002). Treatment of endometrial cancer with cervical involvement with combinations of radiotherapy and surgery is well tolerated and results in an excellent long-term disease-free survival and a low rate of pelvic relapse.