Treatment planning facilitates clinical decision making for hyperthermia treatments

Background: Treatment quality is important in clinical hyperthermia. Guideline-based treatment protocols are used to determine system settings and treatment strategies to ensure effective tumor heating and prevent unwanted treatment-limiting normal tissue hot spots. Realizing both these goals can prove challenging using generic guideline-based and operator-dependent treatment strategies. Hyperthermia treatment planning (HTP) can be very useful to support treatment strategies. Although HTP is increasingly integrated into the standard clinical workflow, active clinical application is still limited to a small number of hyperthermia centers and should be further stimulated.Purpose: This paper aims to serve as a practical guide, demonstrating how HTP can be applied in clinical decision making for both superficial and locoregional hyperthermia treatments.HTP in clinical decision making: Seven problems that occur in daily clinical practice are described and we show how HTP can enhance insight to formulate an adequate treatment strategy. Examples use representative commercially available hyperthermia devices and cover all stages during the clinical workflow. Problems include selecting adequate phase settings, heating ability analysis, hot spot suppression, applicator selection, evaluation of target coverage and heating depth, and predicting possible thermal toxicity in case of an implant. Since we aim to promote a general use of HTP in daily practice, basic simulation strategies are used in these problems, avoiding a need for the application of dedicated advanced optimization routines that are not generally available.Conclusion: Even fairly basic HTP can facilitate clinical decision making, providing a meaningful and clinically relevant contribution to maintaining and improving treatment quality.

Quantification of thermal dose in moderate clinical hyperthermia with radiotherapy: a relook using temperature-time area under the curve (AUC)

BACKGROUND

Thermal dose in clinical hyperthermia reported as cumulative equivalent minutes (CEM) at 43 °C (CEM43) and its variants are based on direct thermal cytotoxicity assuming Arrhenius 'break' at 43 °C. An alternative method centered on the actual time-temperature plot during each hyperthermia session and its prognostic feasibility is explored.

METHODS AND MATERIALS

Patients with bladder cancer treated with weekly deep hyperthermia followed by radiotherapy were evaluated. From intravesical temperature (T) recordings obtained every 10 secs, the area under the curve (AUC) was computed for each session for T > 37 °C (AUC > 37 °C) and T ≥ 39 °C (AUC ≥ 39 °C). These along with CEM43, CEM43(>37 °C), CEM43(≥39 °C), T_mean, T_min and T_max were evaluated for bladder tumor control.

RESULTS

Seventy-four hyperthermia sessions were delivered in 18 patients (median: 4 sessions/patient). Two patients failed in the bladder. For both individual and summated hyperthermia sessions, the T_mean, CEM43, CEM43(>37 °C), CEM43(≥39 °C), AUC > 37 °C and AUC ≥ 39 °C were significantly lower in patients who had a local relapse. Individual AUC ≥ 39 °C for patients with/without local bladder failure were 105.9 ± 58.3 °C-min and 177.9 ± 58.0 °C-min, respectively (p = 0.01). Corresponding summated AUC ≥ 39 °C were 423.7 ± 27.8 °C-min vs. 734.1 ± 194.6 °C-min (p < 0.001), respectively. The median AUC ≥ 39 °C for each hyperthermia session in patients with bladder tumor control was 190 °C-min.

CONCLUSION

AUC ≥ 39 °C for each hyperthermia session represents the cumulative time-temperature distribution at clinically defined moderate hyperthermia in the range of 39 °C to 45 °C. It is a simple, mathematically computable parameter without any prior assumptions and appears to predict treatment outcome as evident from this study. However, its predictive ability as a thermal dose parameter merits further evaluation in a larger patient cohort.

The addition of deep hyperthermia to gemcitabine-based chemoradiation may achieve enhanced survival in unresectable locally advanced adenocarcinoma of the pancreas

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Intensification of chemoradiation with hyperthermia was feasible in nine patients with LAPC.

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Only one grade three toxicity was reported and two tumours became resectable.

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The 24 months median OS and 100% 1 year OS are superior to historical series.

Introduction

Driven by the current unsatisfactory outcomes for patients with locally advanced pancreatic cancer (LAPC), a biologically intensified clinical protocol was developed to explore the feasibility and efficacy of FOLFORINOX chemotherapy followed by deep hyperthermia concomitant with chemoradiation and subsequent FOLFORINOX chemotherapy in patients with LAPC.

Methods

Nine patients with LAPC were treated according to the HEATPAC Phase II trial protocol which consists of 4 cycles of FOLFORINOX chemotherapy followed by gemcitabine-based chemoradiation to 56 Gy combined with weekly deep hyperthermia and then a further 8 cycles of FOLFORINOX chemotherapy.

Results

One grade three related toxicity was reported and two tumours became resectable. The median overall survival was 24 months and 1 year overall survival was 100%.

Conclusions

Intensification of chemoradiation with deep hyperthermia was feasible in nine consecutive patients with LAPC.

Strategies to Maximize Available Resources With Minimum Cost Escalation for Improving Radiation Therapy Accessibility in the Post-Coronavirus Disease 2019 Era: An Analysis for Asia

PURPOSE

There is widespread accord among economists that the corona virus disease 2019 (COVID-19) pandemic will have a severe negative effect on the global economy. Establishing new radiation therapy (RT) infrastructure may be significantly compromised in the post-COVID-19 era. Alternative strategies are needed to improve the existing RT accessibility without significant cost escalation. The outcomes of these approaches on RT availability have been examined for Asia.

METHODS AND MATERIALS

The details of RT infrastructures in 2020 for 51 countries in Asia were obtained from the Directory of Radiotherapy Centers of the International Atomic Energy Agency. Using the International Atomic Energy Agency guidelines, the percent of RT accessibility and the additional requirements of teletherapy (TRT) units were computed for these countries. To maximize the utilization of the existing RT facilities, 5 options were evaluated, namely, hypofractionation RT (HFRT) alone, with/without 25% or 50% additional working hours. The effect of these strategies on the percent of RT access and additional TRT unit requirements to achieve 100% RT access were estimated.

RESULTS

In 46 countries, 4617 TRT units are available. The mean percent of RT accessibility is 62.4% in 43 countries (TRT units = 4491) where the information on cancer incidence was also available, and these would need an additional 6474 TRT units for achieving 100% RT accessibility. By adopting HFRT alone, increasing the working hours by 25% alone, 25% with HFRT, 50% alone, and 50% with HFRT, the percent of RT access could improve to 74.9%, 78%, 90.5%, 93.7%, and 106.1%, respectively. Correspondingly, the need for additional TRT units would progressively decrease to 4646, 4284, 3073, 2820, and 1958 units.

CONCLUSIONS

The economic slowdown in the post-COVID-19 period could severely impend establishment of new RT facilities. Thus, maximal utilization of the available RT infrastructure with minimum additional costs could be possible by adopting HFRT with or without increased working hours to improve the RT coverage.

Integrating Loco-Regional Hyperthermia Into the Current Oncology Practice: SWOT and TOWS Analyses

Moderate hyperthermia at temperatures between 40 and 44°C is a multifaceted therapeutic modality. It is a potent radiosensitizer, interacts favorably with a host of chemotherapeutic agents, and, in combination with radiotherapy, enforces immunomodulation akin to “in situ tumor vaccination.” By sensitizing hypoxic tumor cells and inhibiting repair of radiotherapy-induced DNA damage, the properties of hyperthermia delivered together with photons might provide a tumor-selective therapeutic advantage analogous to high linear energy transfer (LET) neutrons, but with less normal tissue toxicity. Furthermore, the high LET attributes of hyperthermia thermoradiobiologically are likely to enhance low LET protons; thus, proton thermoradiotherapy would mimic ¹²C ion therapy. Hyperthermia with radiotherapy and/or chemotherapy substantially improves therapeutic outcomes without enhancing normal tissue morbidities, yielding level I evidence reported in several randomized clinical trials, systematic reviews, and meta-analyses for various tumor sites. Technological advancements in hyperthermia delivery, advancements in hyperthermia treatment planning, online invasive and non-invasive MR-guided thermometry, and adherence to quality assurance guidelines have ensured safe and effective delivery of hyperthermia to the target region. Novel biological modeling permits integration of hyperthermia and radiotherapy treatment plans. Further, hyperthermia along with immune checkpoint inhibitors and DNA damage repair inhibitors could further augment the therapeutic efficacy resulting in synthetic lethality. Additionally, hyperthermia induced by magnetic nanoparticles coupled to selective payloads, namely, tumor-specific radiotheranostics (for both tumor imaging and radionuclide therapy), chemotherapeutic drugs, immunotherapeutic agents, and gene silencing, could provide a comprehensive tumor-specific theranostic modality akin to “magic (nano)bullets.” To get a realistic overview of the strength (S), weakness (W), opportunities (O), and threats (T) of hyperthermia, a SWOT analysis has been undertaken. Additionally, a TOWS analysis categorizes future strategies to facilitate further integration of hyperthermia with the current treatment modalities. These could gainfully accomplish a safe, versatile, and cost-effective enhancement of the existing therapeutic armamentarium to improve outcomes in clinical oncology.

Hyperthermia with radiotherapy reduces tumour alpha/beta: Insights from trials of thermoradiotherapy vs radiotherapy alone

PURPOSE

Hyperthermia inhibits the repair of irradiation-induced DNA damage and thereby could alter the α/β values of tumours. This study estimates the clinical α/β_HTRT values from clinical trials of thermoradiotherapy (HTRT) vs radiotherapy (RT) in recurrent breast (RcBC), head and neck (III/IV) (LAHNC) and cervix cancers (IIB-IVA) (LACC).

METHODS

Three recently published meta-analyses for HTRT vs RT in RcBC, LAHNC and LACC were evaluated for complete response (CR). Studies with specified RT dose (D), dose/fraction (d) and corresponding CRs were selected. Tumour biological effective dose (BED) for each study with RT (BED_RT) was computed assuming an α/β_RT of 10 Gy. As outcomes were favourable with HTRT, thermoradiobiological BED (BED_HTRT) was calculated as a product of BED_RT and %CR_HTRT/%CR_RT. The α/β_HTRT was estimated as Dd/(BED_HTRT - D).

RESULTS

12 trials with 864 patients were shortlisted - RcBC (3 studies, n = 259), LAHNC (5 studies, n = 338) and LACC (4 studies, n = 267). Overall risk difference of 0.28 favoured HTRT (p < 0.001). Mean BED_RT and BED_HTRT were 64.7 Gy (SD: ±15.5) and 109.5 Gy (SD: ±32.1) respectively and global α/β_HTRT was 2.25 Gy (SD: ±0.79). Mean α/β_HTRT for RcBC, LAHNC and LACC were 2.05 Gy, 1.74 Gy and 3.03 Gy respectively. On meta-regression, α/β_HTRT was the sole predictor for the corresponding risk differences of the studies (coefficient = -0.096; p = 0.03).

CONCLUSION

Thermoradiobiological effects on the repair of RT induced DNA damage results in reduction in α/β values of tumours. This should be considered to effectively optimize HTRT dose-fractionation schedules in the clinic.

Efficacy and Safety Evaluation of the Various Therapeutic Options in Locally Advanced Cervix Cancer: A Systematic Review and Network Meta-Analysis of Randomized Clinical Trials

Treatment options in locally advanced cervix cancer (LACC) have evolved around radiation therapy (RT) and/or chemotherapy (CT), hypoxic cell sensitizers, immunomodulators (Imm), and locoregional moderate hyperthermia (HT). A systematic review and network meta-analysis was conducted to synthesize the evidence for efficacy and safety in terms of long-term locoregional control (LRC), overall survival (OS), and grade ≥3 acute morbidity (AM) and late morbidity (LM). Five databases were searched, and 6285 articles (1974-2018) were screened per the Preferred Reporting Items for Systematic Reviews and Meta-analysis guidelines. Fifty-nine randomized trials in untreated LACC without surgical intervention were shortlisted. These used 13 different interventions: RT alone and/or neoadjuvant CT (NACT), adjuvant CT (ACT), concurrent chemoradiation therapy (CTRT) (weekly cisplatin [CDDP]/3-weekly CDDP/combination CT with CDDP/non-CDDP-based CT), hypoxic cell sensitizers, Imm, or HT. Odds ratios (ORs) using random effects network meta-analysis were estimated. Interventions for each endpoint were ranked according to their corresponding surface under cumulative ranking curve values. Of the 9894 patients evaluated, the total events reported for LRC, OS, AM, and LM were 5431 of 8197, 4482 of 7958, 1710 of 7183, and 441 of 6333, respectively. ORs and 95% credible intervals (CrIs) for the 2 best strategies were HT + RT versus CTRT + ACT (OR, 1.23; 95% CrI, 0.49-3.19) for LRC, CTRT (3-weekly CDDP) versus HTCTRT (OR, 1.14; 95% CrI, 0.35-3.65) for OS, RT + ACT versus RT (OR, 0.01; 95% CrI, 0.00-1.04) for AM, and NACT + RT + ACT versus RT + Imm (OR, 0.42; 95% CrI, 0.02-7.39) for LM. The 3 interventions with the highest cumulative surface under cumulative ranking curve values for all 4 endpoints were HTRT, HTCTRT, and CTRT (3-weekly CDDP). Articles with low risk of bias and those published during 2004 to 2018 also retained these interventions as the best. Two-step cluster analysis grouped these 3 modalities in a single distinctive cluster. HTRT, HTCTRT, and CTRT with 3-weekly CDDP were identified as therapeutic modalities with the best comprehensive impact on key clinical endpoints in LACC. This warrants a phase 3 randomized trial among these strategies for a head-to-head comparison and additional validation.

Clinical estimation of α/β values for prostate cancer from isoeffective phase III randomized trials with moderately hypofractionated radiotherapy

BACKGROUND

The α/β values for prostate cancer (PCa) are usually assumed to be low (1.0-1.8 Gy). This study estimated the α/β values of PCa from phase III randomized trials of conventional (CRT) versus hypofractionated (HRT) external beam radiotherapy (RT), reported as isoeffective in terms of their 5-year biochemical (BF) or biochemical and/or clinical failure (BCF) rates.

MATERIAL AND METHODS

The α/β for each trial was estimated from the equivalent biological effective doses using the linear-quadratic model for each of their HRT and CRT schedules. The cumulative outcomes of these trials were evaluated by meta-analysis for odds ratio (OR), risk ratio (RR) and risk difference (RD).

RESULTS

Eight trials from seven studies, randomized 6993 patients between CRT (n = 2941) and HRT (n = 4052). RT treatment varied between the two treatment groups in terms of dose/fraction, total dose, overall treatment time and %patients on androgen deprivation therapy (ADT). Differences in OR, RR, and RD for both BF and BCF were nonsignificant. The computed α/β ranged from 1.3 to 11.1 Gy (4.9 ± 3.9 Gy; 95% CI: 1.6-8.2). On multivariate regression, %ADT was the sole determinant of computed α/β (model R²: 0.98, p < .001).

CONCLUSIONS

Clinically estimated α/β for PCa from isoeffective randomized trials using known variables in the linear-quadratic expression ranged between 1.3 and 11.1 Gy. The estimated α/β values were inversely related to %ADT usage, which should be considered when planning future RT dose-fractionation schedules.

Conventional Versus Hypofractionated Radiation Therapy for Localized or Locally Advanced Prostate Cancer: A Systematic Review and Meta-analysis along with Therapeutic Implications

PURPOSE

A systematic review and meta-analysis were conducted to evaluate the therapeutic outcomes of conventional radiation therapy (CRT) and hypofractionated radiation therapy (HRT) for localized or locally advanced prostate cancer (LLPCa).

METHODS AND MATERIALS

A total of 599 abstracts were extracted from 5 databases and screened in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Only phase III trials randomized between CRT and HRT in LLPCa with a minimum of 5 years of follow-up data were considered. The evaluated endpoints were biochemical failure, biochemical and/or clinical failure, overall mortality, prostate cancer-specific mortality, and both acute and late gastrointestinal (GI) and genitourinary (GU) (grade ≥2) toxicity.

RESULTS

Ten trials from 9 studies, with a total of 8146 patients (CRT, 3520; HRT, 4626; 1 study compared 2 HRT schedules with a common CRT regimen), were included in the evaluation. No significant differences were found in the patient characteristics between the 2 arms. However, the RT parameters differed significantly between CRT and HRT (P<.001 for all). The use of androgen deprivation therapy varied from 0% to 100% in both groups (mean ± standard deviation 43.3% ± 43.6% for CRT vs HRT; P=NS). The odds ratio, risk ratio, and risk difference (RD) between CRT and HRT for biochemical failure, biochemical and/or clinical failure, overall mortality, prostate cancer-specific mortality, acute GU toxicity, and late GU and GI toxicities were all nonsignificant. Nevertheless, the incidence of acute GI toxicity was 9.1% less with CRT (RD 0.091; odds ratio 1.687; risk ratio 1.470; P<.001 for all). On subgroup analysis, the patient groups with ≤66.8% versus >66.8% androgen deprivation therapy (RD 0.052 vs 0.136; P=.008) and <76% versus ≥76% full seminal vesicles in the clinical target volume (RD 0.034 vs 0.108; P<.001) were found to significantly influence the incidence of acute GI toxicity with HRT.

CONCLUSIONS

HRT provides similar therapeutic outcomes to CRT in LLPCa, except for a significantly greater risk of acute GI toxicity. HRT enables a reduction in the overall treatment time and offers patient convenience. However, the variables contributing to an increased risk of acute GI toxicity require careful consideration.

Proton Irradiation with Hyperthermia in Unresectable Soft Tissue Sarcoma

PURPOSE

Unresectable soft tissue sarcomas (STSs) do not usually exhibit significant tumor downstaging with preoperative radiotherapy and/or chemotherapy due to their limited radiosensitivity/chemosensitivity. Limb amputations for tumors of the extremities inevitably lead to considerable loss of function and impairment in quality of life. Local hyperthermia at 39°C to 43°C and proton irradiation combine thermoradiobiological and physical dose distribution advantages, possibly mimicking those of a 12C ion therapy. We report the first 2 patients treated with this unique approach of proton thermoradiotherapy.

MATERIALS AND METHODS

Both patients had an unresectable STS of the left lower leg (1 grade 2 myxoid fibrosarcoma, 1 grade 3 undifferentiated pleomorphic sarcoma). Both patients had declined the above-knee amputation that had been advised due to their involvement of the neurovascular bundles. They were, therefore recruited to the Hyperthermia and Proton Therapy in Unresectable Soft Tissue Sarcoma (HYPROSAR) study protocol (ClinicalTrials.gov NCT01904565). Local hyperthermia was delivered using radiofrequency waves at 100 Mhz once a week after proton therapy. Proton irradiation was undertaken to a dose of 70 to 72 Gy (relative biological effectiveness) delivered at 2.0 Gy (relative biological effectiveness)/ fraction daily for 7 weeks.

RESULTS

Patients tolerated the treatment well with no significant acute or late morbidity. Both primary tumors showed a near complete response on serial magnetic resonance imaging. At a follow-up of 5 and 14 months, the patients were able to carry out indoor and outdoor activities with normal limb function.

CONCLUSION

This is the first report of proton beam irradiation combined with hyperthermia for cancer therapy. Our first experience in 2 consecutive patients with unresectable STSs shows that the approach is safe, feasible, and effective, achieving functional limb preservation with near total tumor control.

Hyperthermia and radiotherapy with or without chemotherapy in locally advanced cervical cancer: a systematic review with conventional and network meta-analyses

PURPOSE

A systematic review with conventional and network meta-analyses (NMA) was conducted to examine the outcomes of loco-regional hyperthermia (HT) with radiotherapy (RT) and/or chemotherapy (CT) in locally advanced cervix cancer, IIB-IVA (LACC).

METHODS AND MATERIALS

A total of 217 abstracts were screened from five databases and reported as per PRISMA guidelines. Only randomised trials with HT and RT ± CT were considered. The outcomes evaluated were complete response (CR), long-term loco-regional control (LRC), patients alive, acute and late grade III/IV toxicities.

RESULTS

Eight articles were finally retained. Six randomised trials with HTRT (n = 215) vs. RT (n = 212) were subjected to meta-analysis. The risk difference for achieving CR and LRC was greater by 22% (p < .001) and 23% (p < .001), respectively, with HTRT compared to RT. A non-significant survival advantage of 8.4% with HTRT was noted with no differences in acute or late toxicities. The only HTCTRT vs. RT trial documented a CR of 83.3% vs. 46.7% (risk difference: 36.7%, p = .001). No other end points were reported. Bayesian NMA, incorporating 13 studies (n = 1000 patients) for CR and 12 studies for patients alive (n = 807 patients), comparing HTCTRT, HTRT, CTRT and RT alone, was conducted. The pairwise comparison of various groups showed that HTRTCT was the best option for both CR and patient survival. This was also evident on ranking treatment modalities based on the "surface under cumulative ranking" values.

CONCLUSIONS

In LACC, HTRT demonstrates a therapeutic advantage over RT without significant acute or late morbidities. On NMA, HTCTRT appears promising, but needs further confirmation through prospective randomised trials.

Is hyperthermia combined with radiotherapy adequate in elderly patients with muscle-invasive bladder cancers? Thermo-radiobiological implications from an audit of initial results

PURPOSE

The aim of this study was to evaluate the outcomes of loco-regional hyperthermia (HT) with radiotherapy (RT) and/or chemotherapy (CT) in elderly patients with muscle-invasive bladder cancers (MIBC).

MATERIAL AND METHODS

Twenty consecutive MIBC patients were treated with HTRT (n = 8) or HTCTRT (n = 12) following transurethral resection of their bladder tumours. Weekly HT was administered prior to RT to a mean temperature of 40.6-42.7 °C for 60 min. A mean RT dose of 54.6 Gy (SD ± 4.2) was delivered. Single-agent cisplatin (n = 2) or carboplatin (n = 10) was used in HTCTRT patients.

RESULTS

The median age was 81 years. HTRT patients received a mean RT dose of 51.0 Gy compared to 57.1 Gy with HTCTRT (p < 0.001) in a shorter overall treatment time (OTT) (30.8 ± 6.9 versus 43.9 ± 4.0 days, p < 0.001). All HTRT patients had long-term local disease control, while 41.6% of HTCTRT recurred during follow-up. None of the HTRT patients experienced grade III/IV acute and late toxicities, while these were evident in two and one HTCTRT patients respectively. Taken together, the 3-year bladder preservation, local disease-free survival, cause-specific survival and overall survival were 86.6%, 60.7%, 55% and 39.5% respectively. Even though the mean biological effective dose (BED) for both groups was similar (57.8 Gy15), the thermo-radiobiological BED estimated from HT-induced reduction of α/β was significantly higher for HTRT patients (91 ± 4.4 versus 85.8 ± 4.3 Gy3, p = 0.018).

CONCLUSIONS

Thermal radiosensitisation with consequent reduction in α/β results in a higher thermo-radiobiological BED with a relatively higher RT dose/fraction and shorter OTT. This translates into a favourable outcome in elderly MIBC patients. Any benefit of CT in these patients needs further investigation.

Brain abscess mimicking brain metastasis in breast cancer

61 year old female presented with chief complaints of headache for 30 days, fever for 10 days, altered behavior for 10 days and convulsion for 2 days. She was diagnosed and treated as a case of carcinoma of left breast 5 years ago. MRI brain showed a lobulated lesion in the left frontal lobe. She came to our hospital for whole brain radiation as a diagnosed case of carcinoma of breast with brain metastasis. Review of MRI brain scan, revealed metastasis or query infective pathology. MR spectroscopy of the lesion revealed choline: creatinine and choline: NAA (N-Acetylaspartate) ratios of ∼1.6 and 1.5 respectively with the presence of lactate within the lesion suggestive of infective pathology. She underwent left fronto temporal craniotomy and evacuation of abscess and subdural empyema. Gram stain showed gram positive cocci. After 1 month of evacuation and treatment she was fine. This case suggested a note of caution in every case of a rapidly evolving space-occupying lesion independent of the patient's previous history.

Hyperthermia and radiotherapy in the management of head and neck cancers: A systematic review and meta-analysis

PURPOSE

A systematic review and meta-analysis was conducted to evaluate the outcome of controlled clinical trials in head and neck cancers (HNCs) using hyperthermia and radiotherapy versus radiotherapy alone.

MATERIAL AND METHODS

A total of 498 abstracts were screened from four databases and hand searched as per the PRISMA guidelines. Only two-arm studies treating HNCs with either radiotherapy alone, or hyperthermia and radiotherapy without concurrent chemotherapy or surgery were considered. The evaluated end point was complete response (CR).

RESULTS

Following a detailed screening of the titles, abstracts and full text papers, six articles fulfilling the above eligibility criteria were considered. In total 451 clinical cases from six studies were included in the meta-analysis. Five of six trials were randomised. The overall CR with radiotherapy alone was 39.6% (92/232) and varied between 31.3% and 46.9% across the six trials. With thermoradiotherapy, the overall CR reported was 62.5% (137/219), (range 33.9-83.3%). The odds ratio was 2.92 (95% CI: 1.58-5.42, p = 0.001); the risk ratio was 1.61 (95% CI: 1.32-1.97, p < 0.0001) and the risk difference was 0.25 (95% CI: 0.12-0.39, p < 0.0001), all in favour of combined treatment with hyperthermia and radiotherapy over radiotherapy alone. Acute and late grade III/IV toxicities were reported to be similar in both the groups.

CONCLUSIONS

Hyperthermia along with radiotherapy enhances the likelihood of CR in HNCs by around 25% compared to radiotherapy alone with no significant additional acute and late morbidities. This level I evidence should justify the integration of hyperthermia into the multimodality therapy of HNCs.

Local hyperthermia combined with radiotherapy and-/or chemotherapy: recent advances and promises for the future

Hyperthermia, one of the oldest forms of cancer treatment involves selective heating of tumor tissues to temperatures ranging between 39 and 45°C. Recent developments based on the thermoradiobiological rationale of hyperthermia indicate it to be a potent radio- and chemosensitizer. This has been further corroborated through positive clinical outcomes in various tumor sites using thermoradiotherapy or thermoradiochemotherapy approaches. Moreover, being devoid of any additional significant toxicity, hyperthermia has been safely used with low or moderate doses of reirradiation for retreatment of previously treated and recurrent tumors, resulting in significant tumor regression. Recent in vitro and in vivo studies also indicate a unique immunomodulating prospect of hyperthermia, especially when combined with radiotherapy. In addition, the technological advances over the last decade both in hardware and software have led to potent and even safer loco-regional hyperthermia treatment delivery, thermal treatment planning, thermal dose monitoring through noninvasive thermometry and online adaptive temperature modulation. The review summarizes the outcomes from various clinical studies (both randomized and nonrandomized) where hyperthermia is used as a thermal sensitizer of radiotherapy and-/or chemotherapy in various solid tumors and presents an overview of the progresses in loco-regional hyperthermia. These recent developments, supported by positive clinical outcomes should merit hyperthermia to be incorporated in the therapeutic armamentarium as a safe and an effective addendum to the existing oncological treatment modalities.

Are State-Sponsored New Radiation Therapy Facilities Economically Viable in Low- and Middle-Income Countries?

PURPOSE

The economic viability of establishing a state-funded radiation therapy (RT) infrastructure in low- and middle-income countries (LMICs) in accordance with the World Bank definition has been assessed through computation of a return on investment (ROI).

METHODS AND MATERIALS

Of the 139 LMICs, 100 were evaluated according to their RT facilities, gross national income (GNI) per capita, and employment/population ratio. The assumption was an investment of US$5 million for a basic RT center able to treat 1000 patients annually. The national breakeven points and percentage of ROI (%ROI) were calculated according to the GNI per capita and patient survival rates of 10% to 50% at 2 years. It was assumed that 50% of these patients would be of working age and that, if employed and able to work after treatment, they would contribute to the country's GNI for at least 2 years. The cumulative GNI after attaining the breakeven point until the end of the 15-year lifespan of the teletherapy unit was calculated to estimate the %ROI. The recurring and overhead costs were assumed to vary from 5.5% to 15% of the capital investment.

RESULTS

The %ROI was dependent on the GNI per capita, employment/population ratio and 2-year patient survival (all P<.001). Accordingly, none of the low-income countries would attain an ROI. If 50% of the patients survived for 2 years, the %ROI in the lower-middle and upper-middle income countries could range from 0% to 159.9% and 11.2% to 844.7%, respectively. Patient user fees to offset recurring and overhead costs could vary from "nil" to US$750, depending on state subsidies.

CONCLUSIONS

Countries with a greater GNI per capita, higher employment/population ratio, and better survival could achieve a faster breakeven point, resulting in a higher %ROI. Additional factors such as user fees have also been considered. These can be tailored to the patient's ability to pay to cover the recurring costs. Certain pragmatic steps that could be undertaken to address these issues are discussed in the present study.

Hyperthermia and reirradiation for locoregional recurrences in preirradiated breast cancers: a single institutional experience

QUESTIONS UNDER STUDY

The aim of this retrospective analysis was to evaluate the safety and efficacy of local hyperthermia (HT) and reirradiation (ReRT) in the management of preirradiated locoregional recurrent breast cancers at Kantonsspital Aarau, Switzerland.

METHODS

Twenty-four previously irradiated patients who had developed locoregional recurrences in the chest wall or breast, with or without regional lymph node involvement, were reirradiated to a mean dose of 36.8 Gy (range 20-50 Gy) delivered at a mean dose per fraction of 2.33 Gy (range 1.8-4.0 Gy). All patients received local HT at 41 to 43 °C, once or twice a week prior to radiotherapy. Online thermometry was carried out during the hyperthermia sessions.

RESULTS

An overall objective response rate of 91.7% (22/24) with a complete response in 66.7% (16/24) of patients and partial response in 25% (6/24) of patients was observed. Post-thermoradiotherapy follow-up ranged from 1 to 38 months (median 10 months). The 3-year actuarial local control rate was 59.7%. More patients who attained complete response had sustained locoregional control until their death or last follow-up when compared with those who were partial or non-responders (median local disease-free survival for complete responders not reached; for partial and non-responders 4 months; p <0.001). Post-retreatment median overall survival for all 24 patients was 10 months. Grade III/IV acute toxicity was seen in only one patient and no patient had any significant late morbidity.

CONCLUSIONS

ReRT and HT is an effective and a safe modality to treat locoregional recurrences in previously irradiated breast cancers. The approach can lead to sustainable long-term palliation with minimal morbidity.

Oral tuberculosis following successful treatment of oral malignancy

Coexistence of tuberculosis and neoplastic lesion in the oral cavity is a rare phenomenon. Till date, only three such cases have been reported in the English literature. A case of oral tuberculosis manifesting 3 months following the successful treatment of cancer of the oral tongue with chemoradiotherapy is presented. The diagnostic dilemma it posed, and its eventual successful control by anti-tubercular treatment, is discussed.

Chordoma with increased prolactin levels (pseudoprolactinoma) mimicking pituitary adenoma: a case report with review of the literature

The article deals with a rare case of chordoma with increased prolactin levels. It could often result in a diagnostic dilemma and problems in differentiating it from a pituitary adenoma.

Epitrochlear lymph node metastases from invasive ductal breast cancer

Metastasis to an epitrochlear lymph node from a primary invasive breast cancer has not been reported earlier. We report a case of epitrochlear lymph node metastasis that presented 10 years after the primary breast malignancy had been treated with radiotherapy, chemotherapy, and hormonal therapy. The patient was successfully treated and continues to remain asymptomatic more than 2 years after she presented with the metastasis.

Gliosarcoma: an audit from a single institution in India of 24 post-irradiated cases over 15 years

BACKGROUND

Gliosarcomas (GS) are biphasic brain tumors composed of glioblastoma multiforme (GBM) and sarcomatous component. Therapeutic approaches include maximum surgical decompression with postoperative radiotherapy. Outcomes in gliosarcoma are poor despite multimodality management.

AIMS

To analyze the outcome in patients of GS treated in our institute over a period of 15 years and compare it with GBM treated during the same period.

SETTINGS AND DESIGN

Clinical records of the post-irradiated GS patients and GBM patients seen between 1990 and 2004 were retrieved.

MATERIALS AND METHODS

Demographic and treatment variables were evaluated for their influence on overall survival (OS). The survival outcomes of GBM and GS treated during the same period were also compared.

STATISTICAL ANALYSIS

Univariate analysis was carried out using the Kaplan-Meier method and tested using log-rank test for significance.

RESULTS

During these 15 years, 24 evaluable GS patients were treated as compared to 251 evaluable patients of GBM. There was a slight male preponderance in GS (14 males vs.10 females) with a median age of 50 years. All patients underwent surgery followed by post-operative radiotherapy (median dose of 60 Gy). None of the patient or treatment related factors were found to be significantly influencing their OS. Median OS in GS was 7.3 months compared to 7.5 months in GBM patients (P = 0.790).

CONCLUSIONS

The OS appears to be similar for GS and GBM. None of the demographic variables appeared to prognosticate the survivals of GS.

Implications of contrast-enhanced CT-based and MRI-based target volume delineations in radiotherapy treatment planning for brain tumors

Delineation of various target volumes using contrast-enhanced magnetic resonance imaging (MRI) and/or computed tomography (CT) constitutes the primary step for radiation therapy planning (RTP) in brain tumors. This study presents a quantification and comparative evaluation of the various clinical target volumes (CTV) and gross target volumes (GTV) as outlined by contrast-enhanced CT and MRI, along with its implications for postoperative radiotherapy of brain tumors. Twenty-one patients of gliomas were considered for this prospective study. Peritumoral edema as CTV and residual tumor as GTV were delineated separately in postoperative contrast-enhanced CT and MRI. These volumes were estimated separately and their congruence studied for contrast-enhanced CT and MRI. Compared to MRI, CT underestimated the volumes, with significant differences seen in the mean CTV (mean +/- SD: -62.92 +/- 93.99 cc; P = 0.006) and GTV (mean +/- SD: -21.08 +/- 36.04 cc; P = 0.014). These differences were found to be significant for high-grade gliomas (CTV: P = 0.045; GTV: P = 0.044), while they were statistically insignificant for low-grade gliomas (CTV: P = 0.080; GTV: P = 0.117). The mean differences in the volumes for CTV and GTV were estimated to be -106.7% and -62.6%, respectively, taking the CT volumes as the baseline. Thus, even though, electron density information from CT is essential for RTP, target delineation during postoperative radiotherapy of brain tumors, especially for high-grade tumors, should be based on MRI so as to avoid inadvertent geographical misses, especially in the regions of peritumoral edema.

Does the evidence support the use of concurrent chemoradiotherapy as a standard in the management of locally advanced cancer of the cervix, especially in developing countries?

Locally advanced cancer of the cervix (FIGO stages III and IVA) is one of the most common malignancies in developing countries. Conventional treatment has been a judicious combination of external radiotherapy and intracavitary brachytherapy. However, prompted by the results of five randomised-controlled trials (RCTs) published in close succession, The National Cancer Institute (NCI) alert in 1999, and two meta-analyses, the management of cancer of the cervix has gradually changed. Concurrent chemoradiotherapy with cisplatin alone, or in combination, is gradually being favoured for the treatment of cancer of the cervix. This overview examines whether the published evidence is sufficiently adequate to justify the use of chemoradiotherapy using cisplatin as standard care in the management of cancer of the cervix, especially in developing countries, where most women present with locally advanced cancer of the cervix. A critical review of the various phase III randomised trials and meta-analyses indicates that, although chemoradiotherapy could be a standard form of treatment for early cancer of the cervix, its role in advanced stages needs further exploration before this could be incorporated into routine clinical care.

Does pretreatment human papillomavirus (HPV) titers predict radiation response and survival outcomes in cancer cervix?—A pilot study

OBJECTIVE

To evaluate if pretreatment HPV titers in cancer cervix could predict radiation response and survival outcomes.

METHODS

Twenty-one patients of cancer cervix were treated by radiotherapy (RT) alone. HPV titers were estimated using DNA Hybrid Capture II test. Loco-regional response at 1 month of RT--complete or partial response (CR and PR respectively) and survival outcomes--local disease-free (LDFS), disease-free (DFS) and overall (OS) survivals were evaluated against pre- and posttreatment HPV titers.

RESULTS

Pretreatment HPV titers ranged from 0.81 to 3966.10 RLU/cut off (mean +/- SD: 1264.39 +/- 1148.22, median: 1129.98). Of the demographic features evaluated, mean HPV titers were significantly different only for patients achieving CR or PR at completion of RT (mean +/- SD for CR vs. PR: 1616.31 +/- 1146.86 vs. 384.57 +/- 538.80, P = 0.022). HPV titers at end of RT ranged from 0.12 to 487.42 RLU/cut off (mean +/- SD: 37.31 +/- 108.60, median: 2.33). Patients with higher pretreatment HPV titers (>1000 RLU/cutoff) had a higher CR (P = 0.022) and better survival compared to those with < or =1000 RLU/cutoff (LDFS, P = 0.004; DFS, P = 0.005; OS, P = 0.012). At completion of RT, those having > or =99.5% fall in HPV had superior survival outcomes than those with <99.5% reduction (LDFS, P = 0.002; DFS, P = 0.002; OS, P = 0.004).

CONCLUSIONS

Higher pretreatment HPV titers (>1000 RLU/cutoff) could be considered as a predictor of radiotherapy response and survival in cancer cervix. A reduction in these titers to 99.5% of their baseline values at end of radiotherapy is also associated with better survival outcomes.

Role of Radiotherapy in a Recurrent Aneurysmal Bone Cyst of the Temporal Bone: Case Report

OBJECTIVE AND IMPORTANCE:

A rare case of aneurysmal bone cyst (ABC) of the temporal bone is presented which, following recurrence after surgery, was successfully treated with radiotherapy. The role of radiotherapy in such cases is reviewed.

CLINICAL PRESENTATION:

A 30-year-old man presented with a recurrent swelling and pain in right temporal region following surgery for ABC at that site.

INTERVENTION:

Local radiotherapy to a dose of 31.5 Gy in 18 fractions over 3.5 weeks was delivered to the site of recurrence. The patient had a near total regression of the ABC as evident clinically and on radiological images.

CONCLUSION:

To the best of our knowledge, radiation for the recurrent ABC at the temporal bone has not been described in the literature. However, in view of the response evident in this patient, radiotherapy seems to be effective for recurrent cases of ABC at the temporal bone and a dose of around 30 to 36 Gy could be effectively delivered with satisfactory results.

Variations in clinical estimates of tumor volume regression parameters and time factor during external radiotherapy in cancer cervix: does it mimic the linear-quadratic model of cell survival?

BACKGROUND

Tumor regression parameters and time factor during external radiotherapy (EXTRT) are of paramount importance.

AIMS

To quantify the parameters of tumor regression and time factor during EXTRT in cancer cervix.

SETTINGS AND DESIGN

Patients, treated solely with radiotherapy and enrolled for other prospective studies having weekly tumor regressions recorded were considered.

MATERIALS AND METHODS

Seventy-seven patients received 50 Gy of EXTRT followed by intracavitary brachytherapy. Loco-regional regressions were assessed clinically and regression fraction (RF) was represented as RF=c + a 1D + a 2 D2 sub - a 3T, with c, D and T as constant, cumulative EXTRT dose and treatment time respectively.

STATISTICAL ANALYSIS USED

Step wise linear regression was performed for RF. Scatter plots were fitted using linear-quadratic fit.

RESULTS

Coefficients of parameters D, D2 sub and T were computed for various dose intervals, namely 0--20 Gy, 0--30 Gy, 0--40 Gy and 0--50 Gy. At 0--20 Gy and 0--30 Gy, only the coefficient of D2 was significant (P 2 sub and T turned significant (P 2 sub and T showed significance, leading to an estimate of 26 Gy for a1/a2 and 0.96 Gy/day for a3/a1.

CONCLUSIONS

As with alpha/beta and gamma/alpha of post-irradiation cell survival curves, a1/a2 and a3/a1 represents the cumulative effect of various radiobiological factors influencing clinical regression of tumor during the course of EXTRT. The dynamic changes in the coefficients of D, D2 sub and T, indicate their relative importance during various phases of EXTRT.

An audit of postoperative radiotherapy after non-curative resection for cancer of the oesophagus

AIMS

The role of postoperative radiotherapy (PORT) after non-curative resections for cancer oesophagus is not well defined. A policy of offering PORT after non-curative resections for cancer oesophagus has been followed at our institution, and we report an audit of our experience.

MATERIAL AND METHODS

Between March 1990 and September 2002, 139 patients underwent resections for cancer oesophagus. Of these, 86 patients received PORT to a dose of 45-50.4 Gy/25-28 fractions. Eleven of these patients also received concurrent and adjuvant 5-fluorouracil (5-FU). Disease-free survival and overall survival were computed from the day of surgery using the Kaplan-Meier method.

RESULTS

Seventy-six per cent (65/86) of patients had squamous cell carcinoma and 69% (59/86) of patients had tumours in the lower-third of the oesophagus. The median interval between surgery and PORT was 41 days, and 93% of patients received doses as planned. Strictures at the anastomotic site and ulcerations in the stomach mucosa were seen in 17% and 5% of patients, respectively. The median and 5-year disease-free survival was 12 months (95% CI 9.9-14.1) and 14%; whereas the median and 5-year overall survival was 17 months (95% CI 12.4-21.6) and 17%, respectively. Local and distant failures were seen in 29% and 45% of patients, respectively.

CONCLUSIONS

PORT, after a non-curative resection of cancer oesophagus, is well tolerated with acceptable morbidity and survival.

Radiation therapy induced micronuclei in cervical cancer—does it have a predictive value for local disease control?

OBJECTIVE

To evaluate the predictive value of serial changes in micronuclei induction during external radiotherapy (EXRT) in cervical cancer with respect to local response at the end of EXRT and local disease free survival (LDFS).

METHODS

Twenty-five patients of squamous cell cancer of the cervix were treated by 50 Gy of EXRT delivered over 5 weeks followed by intracavitary brachytherapy. Serial cytological smears were taken from cervical growth at weekly intervals during the course of EXRT and stained by Giemsa and May-Grunwald's stain. Micronuclei induction were scored as (a) number of cells expressing micronuclei (MN), and (b) total number of micronuclei (TMN) in 1000 tumor cells from each of the serial smears.

RESULTS

A significant rise in micronuclei count was seen for both MN and TMN from pretreatment (week 0) to successive weeks of EXRT. For those having a near total tumor regression by end of EXRT, a significant rise in micronuclei was evident even at the end of first week of EXRT (MN: P = 0.05, TMN: P = 0.04). A superior LDFS was observed in patients showing greater than 50% increment in MN value in the first week (median survival for <50% vs. > or =50% rise: 5 months vs. not reached, P = 0.21), while it reached significance for a similar rise of TMN (median survival <50% vs. > or =50% rise: 5 months vs. not reached, P = 0.04).

CONCLUSIONS

The significant rise of micronuclei at the end of first week of EXRT in cervical cancers as observed from serial cytological smears could predict for a better local response and LDFS.

Predictors of survival end points in patients with cancer of the cervix on long-term follow-up: inferences and implications from an audit of patients treated with a specific radiotherapy protocol

AIMS

An audit of patients with cancer of the cervix treated with a specified protocol of external beam radiotherapy (EXRT) followed by intracavitary brachytherapy (ICBT) was carried out to determine the prognosticators for major survival end points.

MATERIALS AND METHODS

Patients treated between 1991 and 2003 with a uniform protocol of EXRT (50 Gy/25 fractions/5 weeks) followed by high-dose-rate ICBT (18 Gy/3 fractions/3 weeks) were selected from the database. Various clinical and treatment parameters were evaluated for extent of locoregional response at completion of EXRT, namely absence or presence of gross residual tumour (AGRT and PGRT, respectively) and survival end points. These included locoregional disease-free survival (LDFS), disease-free survival (DFS) and overall survival (OS).

RESULTS

Of the 157 evaluable patients, 145 (92%) belonged to FIGO stages II and III. Eighty-three (53%) at completion of EXRT had AGRT, which was influenced by age and gross tumour features. The estimated 10-year LDFS, DFS and OS were 38.6%, 33.1% and 38.5%, respectively. Factors significant on univariate analysis for these survival end points were EXRT duration, ICBT time, overall treatment time (OTT) and EXRT response. On multivariate analysis, AGRT to EXRT, an OTT of < or = 67 days, and patients older than 50 years were the significant favourable determinants for all the above survival end points.

CONCLUSION

The audit highlights that younger people, especially those with bulky tumours that determine response to EXRT, are poor prognosticators for survival end points. They could perhaps benefit from treatment intensification regimens using chemoradiotherapy, provided that OTT is not unduly prolonged.

A graphical user interface for automatic image registration software designed for radiotherapy treatment planning

Medical imaging forms a vital component of radiotherapy treatment planning and its evaluation. The integration of the useful data obtained from multiple imaging modalities for radiotherapy planning is achieved by image registration softwares. In radiotherapy planning systems, normally the computed tomography (CT) slices are kept as a standard upon which other modality images (magnetic resonance imaging [MRI], single photon emission computed tomography [SPECT], positron emission tomography [PET], etc.) are aligned--automatically or interactively. Following validation of successful registration, they are resampled and reformatted, as per the requirements. This paper defines the minimum requirements of automatic image registration software for 3-dimensional (3D) radiotherapy planning and describes the implementation of a suitable graphical user interface developed in Visual Basic (version 5). The automatic image registration (AIR) routines freely available from Dr. Roger P. Woods, UCLA, (USA) were used in this software. This software could be easily implemented and was easy to use for image processing suitable for radiotherapy planning systems.

Postoperative residual tumour imaged by contrast-enhanced computed tomography and 201Tl single photon emission tomography: can they predict progression-free survival in high-grade gliomas?

AIMS

To evaluate if postoperative residual tumour imaged by either computed tomography or 201Tl single photon emission tomography (SPECT) carried out postoperatively could predict progression-free survival (PFS) in high-grade malignant gliomas.

MATERIALS AND METHODS

Thirty-three patients with high-grade malignant gliomas underwent both contrast-enhanced CT scan and 201Tl-SPECT postoperatively before receiving radiotherapy. The PFS was evaluated against the individual reports of the above two imaging studies by univariate analysis.

RESULTS

CT and 201Tl-SPECT were carried out within a median interval of 17 days after surgery. Of the 33 patients, CT and 201Tl-SPECT were reported as positive for residual tumours in 23 (69.7%) and 30 (91%) patients, respectively. Sensitivity, specificity and overall accuracy were 71.4%, 40% and 66.6% for CT, and 96.4%, 40% and 87.8% for 201Tl-SPECT, respectively, and were based on their last follow-up status (P = 0.627 for CT; P = 0.053 for 201Tl-SPECT). The median PFS for patients reported to be positive or negative on CT scan was 4 and 5 months, respectively (P = 0.202). With 201Tl-SPECT, although the median PFS for patients with a positive 201Tl uptake was also 4 months, it had not even reached for those reported having a negative 201Tl uptake (cumulative survival 66.7% at last follow-up) (P = 0.198). However, Karnofsky performance status (KPS) was the only significant predictor on univariate analysis (KPS: < 80 vs. > or = 80; P < 0.001) for PFS.

CONCLUSIONS

Although both the imaging modalities have a poor specificity, postoperative 201Tl-SPECT had a significantly better accuracy to predict the status at last follow-up than contrast-enhanced CT. Nevertheless, KPS remained the most significant outcome predictor for PFS in high-grade malignant gliomas.

Early occurrence of acute myeloid leukemia following adjuvant radiotherapy and higher cumulative dose of cyclophosphamide in carcinoma breast

We report a case of cancer breast developing acute myeloid leukemia (AML) within a relatively short interval of two and a half years of her primary treatment. This could be attributed to post operative radiotherapy and a higher cumulative dose of cyclophosphamide (14.4 gm) which had to be given as a part of her combination chemotherapy regimen, initially as adjuvant and then later as salvage chemotherapy. The successful salvage therapy for secondary AML instituted in this case is also discussed.

Problems and uncertainties with multiple point A's during multiple high-dose-rate intracavitary brachytherapy in carcinoma of the cervix

AIMS

This study evaluates the consequences of point A as a dose prescription point during multiple high-dose-rate (HDR) intracavitary brachytherapy (ICBT) in cancer cervix.

MATERIALS AND METHODS

Fifty patients who had received teletherapy were randomised into two groups of 25 to receive three HDR ICBT fractions of 6 Gy each at point A with either a flexible Ralstron (Shimadzu Corporation, Japan) or rigid Rotterdam (Nucletron, Netherlands) applicator. The orthogonal radiographs of the 150 applications were evaluated for applicator geometry and point A co-ordinates.

RESULTS

Irrespective of the nature and rigidity of the applicators, its various components exhibited a highly significant variation during multiple fractionated HDR ICBT. The Cartesian co-ordinates of point A (left and right) for the applicator geometry also showed significant variation during multiple HDR ICBT procedures. This resulted in an average shift of 9.5 mm (SD= +/-4.4) and 11.1 mm (SD= +/-6.4) in right point A, 10.2 mm (SD= +/-4.5) and 10.8 mm (SD= +/-6.6) in left point A for Ralstron and Rotterdam applicator, respectively, during the three HDR ICBT. Consequently, doses to both right and left point A's showed significant variation during multiple ICBT application and were independent of the applicator type.

CONCLUSION

Applicator variation in the components and spatial position in the pelvis during multiple HDR ICBT results in multiple point A's irrespective of the nature of applicator, leading to uncertainty in the dose prescription. These uncertainties, which have a bearing on clinical end points, could be minimised by shifting from point-based dose prescription to image-based target localisation and treatment planning in ICBT.

Total reference air kerma: to what extent can it predict intracavitary volume enclosed by isodose surfaces during multiple high-dose rate brachytherapy?

BACKGROUND

The International Commission on Radiation Units and Measurements (ICRU) report 38 recommends reporting of total reference air kerma (TRAK) and reference ICRU isodose volumes during intracavitary brachytherapy (ICBT) in cancer of the cervix. The present study attempts to estimate the volumes enclosed by isodose surfaces from TRAK and evaluate its utility to represent doses to organs of interest.

MATERIAL AND METHODS

Volumes encompassed by isodose surfaces of 3 Gy, 6 Gy, 9 Gy, and 12 Gy were obtained for 90 high-dose rate (HDR) ICBT procedures. These were used to derive a relation between isodose volumes, TRAK/dose (K/D), and rectal and bladder doses.

RESULTS

Actual volumes (V) encompassed by isodose surfaces were reflected as a quadratic function of K/D (r(2)=0.998) and the expression, V=-23.09+1295.99(K/D)+5661.65(K/D)(2) gave the best estimates for various volumes. No correlation was observed between TRAK and bladder (r(2)=0.086) or rectal doses (r(2)=0.082).

CONCLUSIONS

Estimates of volumes encompassed by different dose levels from TRAK could be derived with reasonable certainty. However, TRAK fails to correlate with rectal and bladder doses.

Tumor regression dynamics with external radiotherapy in cancer cervix and its implications

BACKGROUND

To study the external radiotherapy (EXTRT) regression patterns in cancer of the cervix.

AIMS

Evaluate EXTRT tumor regression doses (TRD) for 50% (TRD50), 80% response (TRD80), normalized dose response gradient (g50) and slope (slope50) with clinical outcome.

SETTINGS AND DESIGN

Patients, treated solely with radiotherapy and enrolled for other prospective studies having weekly tumor regressions recorded were considered.

MATERIAL AND METHODS

Seventy-seven patients received 50Gy of EXTRT at 2 Gy/fraction followed by 18Gy of high-dose rate intracavitary brachytherapy at 6 Gy/fraction. Loco-regional regressions were assessed clinically at weekly intervals during EXTRT to generate EXTRT dose-response curves.

STATISTICAL ANALYSIS USED

Student's t test, logistic regression, Kaplan Meier and Cox's proportional hazard model. Scatter plots were fitted using cubic fit.

RESULTS

Age (P=0.052) and absence or presence of gross residual tumor (AGRT and PGRT respectively) following EXTRT (P<0.001) were the only determinants for complete response (CR) at 1 month following completion of radiotherapy. EXTRT tumor regression sigmoid curves obtained for various patient characteristics differed only for those with AGRT and PGRT with differences in TRD50, (P<0.001); TRD80 (P<0.001) and slope50 (P=0.001). Response status to EXTRT was a prognosticator for loco-regional disease free survival (LDFS) (AGRT vs. PGRT; P=0.046). On multivariate analysis, both TRD50 and TRD80 emerged as significant predictors for tumor status at end of EXTRT while TRD80 was the sole determinant of LDFS.

CONCLUSION

Extent of tumor regression to EXTRT is an important predictor for treatment outcome in cancer cervix as evident from TRD50 and TRD80 values of EXTRT tumor regression curves.

Problems in reporting doses and volumes during multiple high-dose-rate intracavitary brachytherapy for carcinoma cervix as per ICRU Report 38: a comparative study using flexible and rigid applicators

OBJECTIVE

The objective was to evaluate the extent of geometric and positional variations of two different applicators during multiple high-dose-rate (HDR) intracavitary brachytherapy (ICBT) in carcinoma cervix and its implication on reporting as per International Commission on Radiation Units and Measurement (ICRU) Report 38.

METHODS

Fifty patients, following teletherapy, were randomly allocated to two groups of 25 each. They received a dose of 6 Gy to point A during each of the three HDR ICBT applications by either a flexible Ralstron or a rigid geometry Rotterdam applicator. The various applicator components related to its geometry and their Cartesian coordinates were evaluated from orthogonal films. The doses to ICRU bladder, rectal, pelvic, lymphatic trapezoid points, and dimensions of 6-Gy ICRU height, width, thickness, and volume were estimated for each application.

RESULTS

Significant variation was observed with the three HDR ICBT applications for each group, for all components and for both applicators, although it was relatively more with the flexible Ralstron applicator. The average shift in each of the coordinates of os, uterine tip, and ovoids was around 10 mm for both groups. These resulted in significant variations in all the ICRU Report 38 reporting parameters for three insertions in any given patient and across 25 patients of both groups.

CONCLUSIONS

Multiple HDR ICBT applications led to significant variation in the applicator geometry and its positions in pelvis, irrespective of the applicator rigidity. This results in uncertainties in reporting as per ICRU Report 38 guidelines, and thus calls for its revision.

Summated chemotherapy dose-intensity versus loco-regional response in locally advanced breast cancer: its possible implications

BACKGROUND

Summated dose-intensity (SDI) of chemotherapy regimen could influence the outcome in malignancies.

AIMS

To evaluate the implication of SDI and identify key drugs for loco-regional response in locally advanced breast cancer (LABC).

SETTINGS AND DESIGN

This retrospective study was based on audit of records of LABC patients who had received neoadjuvant chemotherapy (NACT).

MATERIAL AND METHODS

Actual unit dose-intensity (UDI) of each drug and corresponding SDI of every doxorubicin (n=116 cycles) or non-doxorubicin (n=110 cycles) based NACT received by 42 patients of LABC were summated. Cumulative dose-intensity (CDI) for individual drugs and cumulative SDI (CSDI) for the entire course of NACT were estimated and correlated with quantum of primary tumor, axillary and supraclavicular nodal responses.

STATISTICAL ANALYSIS USED

Two-sided chi-square, t-test, step-wise regression was used.

RESULTS

Dose-response curve between CSDI and corresponding responses for both primary and lymph nodes were sigmoid in shape for both doxorubicin or non-doxorubicin based NACT. Curves were best fitted using a cubic fit for all patients (r2 = 0.82, 0.84 and 0.93 for primary tumor, axillary and supraclavicular lymph nodes respectively). CSDI emerged as an important prognosticators for both primary (P<0.001) and nodal (P<0.001) responses. Individually, CDI of 5-fluorouracil for primary (P<0.001), CDIs of doxorubicin (P<0.001) and methotrexate (P=0.006) for axillary nodes and CDI of cyclophosphamide (P=0.001) for supraclavicular nodes were significant.

CONCLUSIONS

Loco-regional responses in LABC are dependent on CSDI of NACT regimen. Drugs for high-dose intensification protocols could be identified and chosen based on the impact of CDI of individual drugs in NACT.

Spontaneous expulsion of a mediastinal lymph node in carcinoma of the esophagus

A case of spontaneous expulsion of a mediastinal lymph node, which developed during the follow up of a patient with carcinoma of the esophagus is presented. To the best of our knowledge, no such instance of natural extrusion of mediastinal lymph node has been reported in the literature.