Daniel G. Petereit

THE ADVERSE EFFECT OF TREATMENT PROLONGATION IN CERVICAL CARCINOMA

PURPOSE Proliferation of surviving tumor clonogens during a course of protracted radiation therapy may be a cause of local failure in cervical carcinoma. The effect of total treatment time was analyzed retrospectively in relation to pelvic control and overall survival for squamous cell carcinomas of the uterine cervix. METHODS AND MATERIALS Two hundred and nine patients (Stage IB-IIIB) treated with a combination of external beam and low dose rate intracavitary irradiation were evaluable for study. Multivariate analysis and Kaplan-Meier statistical methods were used to determine the effect of treatment time on pelvic control and survival at 5 years. RESULTS The median treatment duration was 55 days. For all stages combined, the 5-year survival and pelvic control rates were significantly different with treatment times < 55 days vs. > or = 55 days: 65 and 54% (p = 0.03), 87 and 72% (p = 0.006), respectively. By stage, a shorter treatment duration (i.e., < 55 days vs. > or = 55 days) was significant for 5-year overall survival and pelvic control for Stages IB/IIA and III, but not for Stage IIB: Stage IB/IIA (81 and 67%, 96 and 84%), Stage III disease (52 and 42%, 76 and 55%) and Stage IIB (43 and 50%, 74 and 80%, respectively). Survival decreased 0.6%/day and pelvic control decreased 0.7%/day for each additional day of treatment beyond 55 days for all stages of disease. Additionally, significant late complications were not influenced by treatment time. CONCLUSION These results suggest that prolongation of treatment time is associated with decreased local control and survival in patients with cervical carcinoma. This is consistent with emerging data from other institutions. Therapeutic implications include avoidance of unnecessary treatment breaks, the design of fractionation schemes that decrease treatment duration, and possibly the use of tumor cytostatic drugs during conventional radiation.

Literature analysis of high dose rate brachytherapy fractionation schedules in the treatment of cervical cancer: is there an optimal fractionation schedule?

PURPOSE A literature review and analysis was performed to determine whether or not efficacious high dose rate (HDR) brachytherapy fractionation schedules exist for the treatment of cervical cancer. METHODS AND MATERIALS English language publications from peer reviewed journals were assessed to calculate the total contribution of dose to Point A from both the external and intracavitary portions of radiation for each stage of cervical cancer. Using the linear quadratic formula, the biologically effective dose to the tumor, using an alpha/beta = 10, was calculated to Point A (Gy10) in order to determine a dose response relationship for local control and survival. Significant complications were assessed by calculating the dose to the late-responding tissues at Point A using an alpha/beta = 3 (Gy3) as a surrogate for normal tissue tolerance, since few publications list the actual bladder and rectal doses. RESULTS For all stages combined, the median external beam fractionation schedule to Point A was 40 Gy in 20 fractions, while the median HDR fractionation schedule was 28 Gy in 4 fractions. For stages IB, IIB, and IIIB the median biologically effective dose to Point A (Gy10) was 96, 96 and 100 Gy10s, respectively. No correlation was identified between Point A BED (Gy10s) to either survival or pelvic control. A dose response relationship could also not be identified when correlating Point A Gy3s to complications. CONCLUSION A dose response relationship could not be identified for either tumor control nor late tissue complications. These findings do not necessarily question the validity of the linear quadratic model, as much as they question the quality of the current HDR brachytherapy literature as it is currently presented and reported. Most of the HDR publications report inadequate details of the dose fractionation schedules. Only a minority of publications report significant complications using the actuarial method. In the future, all HDR publications for the treatment of cervical cancer should provide accurate fractionation details for each stage of disease, while reporting actuarial complication rates. The optimal fractionation schedule for treating cervical cancer using HDR brachytherapy is still unknown, and presently can be based only on single institutions with significant experience.

High-dose-rate versus low-dose-rate brachytherapy in the treatment of cervical cancer : Analysis of tumor recurrence-the University of Wisconsin experience

PURPOSE To retrospectively compare the clinical outcome for cervical cancer patients treated with high-dose-rate (HDR) vs. low-dose-rate (LDR) brachytherapy. METHODS AND MATERIALS One hundred ninety-one LDR patients were treated from 1977 to 1988 and compared to 173 HDR patients treated from 1989 to 1996. Patients of similar stage and tumor volumes were treated with identical external beam fractionation schedules. Brachytherapy was given in either 1 or 2 LDR implants for the earlier patient cohort, and 5 HDR implants for the latter cohort. For both patient groups, Point A received a minimum total dose of 80 Gy. The linear-quadratic formula was used to calculate the LDR dose-equivalent contribution to Point A for the HDR treatments. The primary endpoints assessed were survival, pelvic control, relapse-free survival, and distant metastases. Endpoints were estimated using the Kaplan-Meier method. Comparisons between treatment groups were performed using the log-rank test and Cox proportional hazards models. RESULTS The median follow-up was 65 months (2 to 208 months) in the LDR group and 22 months (1 to 85 months) in the HDR group. For all stages combined there was no difference in survival, pelvic control, relapse-free survival, or distant metastases between LDR and HDR patients. For Stage IB and II HDR patients, the pelvic control rates were 85% and 80% with survival rates of 86% and 65% at 3 years, respectively. In the LDR group, Stage IB and II patients had 91% and 78% pelvic control rates, with 82% and 58% survival rates at 3 years, respectively. No difference was seen in survival or pelvic control for bulky Stage I and II patients combined (>5 cm). Pelvic control at 3 years was 44% (HDR) versus 75% (LDR) for Stage IIIB patients (p = 0.002). This difference in pelvic control was associated with a lower survival rate in the Stage IIIB HDR versus LDR population (33% versus 58%, p = 0.004). The only major difference, with regard to patient characteristics, between the Stage IIIB patients was the incidence of hydronephrosis in the HDR vs. LDR group--28% vs. 12%, respectively (p = 0.05). For Stage IIIB patients treated with HDR, our analysis suggested that pelvic control rates improved when the first brachytherapy insertion was performed after the majority of external beam radiotherapy had been delivered. CONCLUSION Similar outcome was observed for Stage IB and II patients treated with either HDR or LDR brachytherapy-regardless of tumor volume. However, poorer survival and pelvic control rates were observed for Stage IIIB patients treated with HDR brachytherapy. If HDR is used for Stage IIIB patients, our results suggest the majority of external beam radiotherapy should be delivered prior to initiating the brachytherapy to allow for adequate tumor regression. HDR brachytherapy is more convenient for patients, decreases the radiation exposure for health care workers, and should be considered a standard therapy for women with Stage I or II cervical cancer.

The role of postoperative radiation therapy for endometrial cancer: Executive summary of an American society for radiation oncology evidence-based guideline

PURPOSE To present evidence-based guidelines for adjuvant radiation in the treatment of endometrial cancer. METHODS AND MATERIALS Key clinical questions to be addressed in this evidence-based guideline on endometrial cancer were identified. A comprehensive literature review was performed to identify studies that included no adjuvant therapy, or pelvic radiation or vaginal brachytherapy with or without systemic chemotherapy. Outcomes included local control, survival rates, and overall assessment of quality of life. RESULTS Patients with grade 1 or 2 cancers with either no invasion or <50% myometrial invasion (MI), especially when no other high risk features are present, can be safely observed after hysterectomy. Vaginal cuff brachytherapy is as effective as pelvic radiation therapy at preventing vaginal recurrence for patients with grade 1 or 2 cancers with ≥50% MI or grade 3 tumors with <50% MI. Patients with grade 3 cancer with ≥50% MI or cervical stroma invasion may benefit from pelvic radiation to reduce the risk of pelvic recurrence. There is limited evidence for a benefit to vaginal cuff brachytherapy following pelvic radiation. Multimodality treatment is recommended for patients with positive nodes or involved uterine serosa, ovaries or fallopian tubes, vagina, bladder, or rectum. CONCLUSIONS External beam and vaginal brachytherapy remain integral aspects of adjuvant therapy for endometrial cancer.

Medical Mistrust and Less Satisfaction With Health Care Among Native Americans Presenting for Cancer Treatment

Purpose. To assess barriers to cancer care among Native Americans, whose health outcomes compare unfavorably with those of the general U.S. population. Methods and patients. We undertook a comparative community-based participatory research project in which newly-diagnosed cancer patients were prospectively surveyed using novel scales for medical mistrust and satisfaction with health care. Socio-demographic information was obtained. Mean scale scores for mistrust and satisfaction were analyzed by race. Multivariable models were used to adjust for income, education level, and distance lived from cancer care institute. Results. Participation refusal rate was 38%. Of 165 eligible patients, 52 were Native American and 113 where non-Hispanic White. Native Americans expressed significantly higher levels of mistrust (p =.0001) and lower levels of satisfaction (p = .0001) with health care than Whites. In multivariable analyses, race was the only factor found to be significantly predictive of higher mistrust and lower satisfaction scores. Conclusion. Native Americans exhibit higher medical mistrust and lower satisfaction with health care.

A comparison of the efficacy and complication rates of low dose-rate versus high dose-rate brachytherapy in the treatment of uterine cervical carcinoma

PURPOSE To compare the outcome and complication rates for treatment of uterine cervical carcinoma with low dose-rate (LDR) vs. high dose-rate (HDR) brachytherapy at the University of Wisconsin Comprehensive Cancer Center (UWCCC). METHODS AND MATERIALS One-hundred ninety-eight evaluable patients with cervical carcinoma, Stages IB to IIIB, treated with curative intent with a combination of megavoltage teletherapy and LDR brachytherapy from 1977 to 1988 were the subject of an initial review. In 1989, a HDR treatment program was initiated where all patients with cervical carcinoma were subsequently treated with a combination of HDR brachytherapy and teletherapy. Using the linear-quadratic model (LQ), the dose and schedule of HDR brachytherapy and teletherapy were designed to give similar tumor control and late effects as LDR therapy. Technically, the HDR schedule required meticulous attention to treatment geometry to limit severe late effects. Forty patients treated with the HDR program with 2-4 year follow-up were reviewed and compared to the previous LDR patient group. The LDR and HDR treatment groups were comparable with regards to age, weight, stage distribution, bulk of disease, and histology. RESULTS No significant difference in survival was found between the LDR and HDR groups with 3-year actuarial overall survival being 66% and 77%, respectively. Three-year actuarial pelvic control rates were similar at 80% and 77% for the LDR and HDR groups, respectively. No significant difference in late treatment complications requiring hospitalization or surgery was found between the two treatment groups with a complication rate of 10% (20/198) for the LDR patients and 2.5% (1/40) for the HDR patients. CONCLUSION As predicted by our LQ calculations, treatment results for LDR and HDR brachytherapy were similar with respect to survival, pelvic control and late complications in the treatment of cervical carcinoma. The HDR brachytherapy program at the UWCCC appears to be a safe and effective alternative to LDR therapy in the treatment of cervical carcinoma.

Establishing a patient navigator program to reduce cancer disparities in the American Indian communities of Western South Dakota: initial observations and results.

BACKGROUND American Indians (AIs) in the Northern Plains region suffer disproportionately high cancer mortality rates compared with the general US population and with AIs from other regions in the United States. METHODS The National Cancer Institute developed the Cancer Disparity Research Partnership to address these inequities. This initiative in Rapid City, South Dakota, attempts to lower cancer mortality rates for AIs by access to innovative clinical trials, behavioral research, and a genetic study. Patient navigation is a critical part of the program. Two navigation strategies are described: navigators at the cancer center and navigators on each reservation. A retrospective analysis was performed to determine if navigated patients (n = 42) undergoing potentially curative radiotherapy had fewer treatment interruptions compared with nonnavigated patients (n = 74). RESULTS A total of 213 AIs with cancer have undergone patient navigation. For those undergoing cancer treatment, the median number of patient navigation interactions was 15 (range 1 to 95), whereas for those seen in follow-up after their cancer treatment, the median number of contacts was 4 (range 1 to 26). AIs who received navigation services during curative radiation treatment had on average 3 fewer days of treatment interruptions compared to AIs who did not receive navigation services during curative radiation treatment (P = .002, N = 116). CONCLUSIONS Early findings suggest that patient navigation is a critical component in addressing cancer disparities in this population. The program has established trust with individual cancer patients, with the tribal councils, and with the general population on each of the three reservations of western South Dakota.

Post-operative high dose rate brachytherapy in patients with low to intermediate risk endometrial cancer

BACKGROUND AND PURPOSE This paper investigates the outcome using different dose/fractionation schedules in high dose rate (HDR) post-operative vaginal vault radiotherapy in patients with low to intermediate risk endometrial cancer. MATERIALS AND METHODS The world literature was reviewed and thirteen series were analyzed representing 1800 cases. RESULTS A total of 12 vaginal vault recurrences were identified representing an overall vaginal control rate of 99.3%. A wide range of dose fractionation schedules and techniques have been reported. In order to analyze a dose response relationship for tumor control and complications, the biologically effective doses to the tumor and late responding tissues were calculated using the linear quadratic model. A threshold was identified for complications, but not vaginal control. While dose fractionation schedules that delivered a biologically effective dose to the late responding tissues in excess of 100 Gy(3) (LQED=60 Gy) predicted for late complications, dose fractionation schedules that delivered a modest dose to the vaginal surface (50 Gy(10) or LQED=30 Gy) appeared tumoricidal with vaginal control rates of at least 98%. CONCLUSIONS By using convenient, modest dose fractionation schedules, HDR vaginal vault - brachytherapy yields very high local control and extremely low morbidity rates.

Inguinofemoral radiation of N0,N1 vulvar cancer may be equivalent to lymphadenectomy if proper radiation technique is used

PURPOSE To update a previous retrospective study that compared inguinofemoral irradiation (N = 23) to lymphadenectomy (N = 25) for N0,N1 vulvar carcinoma with more patients and longer follow-up. These results, unlike the recent randomized Gynecologic Oncology Group (GOG study), suggest that radiation is a viable alternative to groin dissection, and the differences may be explained on the basis of irradiation technique. METHODS AND MATERIALS Based on a growing body of data supporting control of subclinical nodal disease with irradiation in vulvar cancer, the decision was made to offer patients with squamous cell carcinoma of the vulva and clinically negative groins (N0,N1), either lymphadenectomy or inguinofemoral irradiation based on clinical factors. Because of the acute skin reaction and possible underdosing of deep femoral nodes with electrons as used in the GOG study, opposed photon fields to 50 Gy were used. From 1983 to 1991, 48 patients underwent a radical vulvectomy followed by either lymphadenectomy (Group I, n = 25) or inguinofemoral irradiation (Group II, n = 23). RESULTS The actuarial nodal control was 100% in Group I and 91% in Group II (p = 0.14). In addition, there was no difference in cause specific survival at 3 years (96% and 90%, respectively, p = 0.47). The morbidity of lymphadenectomy (Group I) included: 16% lymphedema, 16% seromas, 44% infection, and 68% wound separation. In the irradiated patients (Group II), 16% developed lymphedema and only 9% had a significant skin reaction. CONCLUSION Based on this analysis of local control and survival with longer follow-up and more patients, irradiation of the N0, N1 inguinofemoral nodes may be a viable alternative to lymphadenectomy for squamous cell carcinoma of the vulva if proper radiation technique and dose are used. In addition, the acute and delayed morbidity of lymphadenectomy exceeds that of irradiation.

Hypofractionation for prostate cancer.

Hypofractionation for prostate cancer was originally carried out in the pursuit of efficiency and convenience but has now attracted greatly renewed interest based upon a hypothesis that prostate cancers have a higher sensitivity to fraction size, reflected in a low &agr;/&bgr; ratio, than do late responding organs at risk such as the rectum or bladder. Tumor control and acceptable toxicity outcomes from several hypofractionation or brachytherapy analyses do in fact support an &agr;/&bgr; ratio for prostate cancer that is low, perhaps even lower that that for the normal organs that ordinarily constrain the delivery of radiation therapy. However, many of these studies lack sufficient patient numbers and follow-up, are clouded by dose inhomogeneity issues in the case of brachytherapy, or delivered effective doses that were too low by contemporary standards. Thus, the clinical efficacy of the approach has yet to be fully validated. However, a number of newer prospective trials, some randomized, are underway or have reached accrual but await sufficient follow-up for analysis. These studies, which cover a wide range of doses per fraction, should ultimately be capable of validating the utility of prostate hypofractionation and the models that predict its effects. With hypofractionations significant potential for therapeutic gain, cost savings, and improved patient convenience, the future management of localized prostate cancer could be profoundly altered in the process.