The hyperbaric oxygen chamber in the radiotherapy of carcinoma of the uterine cervix

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.

Hyperbaric oxygenation for tumour sensitisation to radiotherapy

BACKGROUND

Cancer is a common disease and radiotherapy is one well-established treatment for some solid tumours. Hyperbaric oxygenation therapy (HBOT) may improve the ability of radiotherapy to kill hypoxic cancer cells, so the administration of radiotherapy while breathing hyperbaric oxygen may result in a reduction in mortality and recurrence.

OBJECTIVES

To assess the benefits and harms of administering radiotherapy for the treatment of malignant tumours while breathing HBO.

SEARCH METHODS

In September 2017 we searched the Cochrane Central Register of Controlled Trials (CENTRAL), the Cochrane Library Issue 8, 2017, MEDLINE, Embase, and the Database of Randomised Trials in Hyperbaric Medicine using the same strategies used in 2011 and 2015, and examined the reference lists of included articles.

SELECTION CRITERIA

Randomised and quasi-randomised studies comparing the outcome of malignant tumours following radiation therapy while breathing HBO versus air or an alternative sensitising agent.

DATA COLLECTION AND ANALYSIS

Three review authors independently evaluated the quality of and extracted data from the included trials.

MAIN RESULTS

We included 19 trials in this review (2286 participants: 1103 allocated to HBOT and 1153 to control).For head and neck cancer, there was an overall reduction in the risk of dying at both one year and five years after therapy (risk ratio (RR) 0.83, 95% confidence interval (CI) 0.70 to 0.98, number needed to treat for an additional beneficial outcome (NNTB) = 11 and RR 0.82, 95% CI 0.69 to 0.98, high-quality evidence), and some evidence of improved local tumour control immediately following irradiation (RR with HBOT 0.58, 95% CI 0.39 to 0.85, moderate-quality evidence due to imprecision). There was a lower incidence of local recurrence of tumour when using HBOT at both one and five years (RR at one year 0.66, 95% CI 0.56 to 0.78, high-quality evidence; RR at five years 0.77, 95% CI 0.62 to 0.95, moderate-quality evidence due to inconsistency between trials). There was also some evidence with regard to the chance of metastasis at five years (RR with HBOT 0.45 95% CI 0.09 to 2.30, single trial moderate quality evidence imprecision). No trials reported a quality of life assessment. Any benefits come at the cost of an increased risk of severe local radiation reactions with HBOT (severe radiation reaction RR 2.64, 95% CI 1.65 to 4.23, high-quality evidence). However, the available evidence failed to clearly demonstrate an increased risk of seizures from acute oxygen toxicity (RR 4.3, 95% CI 0.47 to 39.6, moderate-quality evidence).For carcinoma of the uterine cervix, there was no clear benefit in terms of mortality at either one year or five years (RR with HBOT at one year 0.88, 95% CI 0.69 to 1.11, high-quality evidence; RR at five years 0.95, 95% CI 0.80 to 1.14, moderate-quality evidence due to inconsistency between trials). Similarly, there was no clear evidence of a benefit of HBOT in the reported rate of local recurrence (RR with HBOT at one year 0.82, 95% CI 0.63 to 1.06, high-quality evidence; RR at five years 0.85, 95% CI 0.65 to 1.13, moderate-quality evidence due to inconsistency between trials). We also found no clear evidence for any effect of HBOT on the rate of development of metastases at both two years and five years (two years RR with HBOT 1.05, 95% CI 0.84 to 1.31, high quality evidence; five years RR 0.79, 95% CI 0.50 to 1.26, moderate-quality evidence due to inconsistency). There were, however, increased adverse effects with HBOT. The risk of a severe radiation injury at the time of treatment with HBOT was 2.05, 95% CI 1.22 to 3.46, high-quality evidence. No trials reported any failure of local tumour control, quality of life assessments, or the risk of seizures during treatment.With regard to the treatment of urinary bladder cancer, there was no clear evidence of a benefit in terms of mortality from HBOT at one year (RR 0.97, 95% CI 0.74 to 1.27, high-quality evidence), nor any benefit in the risk of developing metastases at two years (RR 2.0, 95% CI 0.58 to 6.91, moderate-quality evidence due to imprecision). No trial reported on failure of local control, local recurrence, quality of life, or adverse effects.When all cancer types were combined, there was evidence for an increased risk of severe radiation tissue injury during the course of radiotherapy with HBOT (RR 2.35, 95% CI 1.66 to 3.33, high-quality evidence) and of oxygen toxic seizures during treatment (RR with HBOT 6.76, 96% CI 1.16 to 39.31, moderate-quality evidence due to imprecision).

AUTHORS' CONCLUSIONS

We found evidence that HBOT improves local tumour control, mortality, and local tumour recurrence for cancers of the head and neck. These benefits may only occur with unusual fractionation schemes. Hyperbaric oxygenation therapy is associated with severe tissue radiation injury. Given the methodological and reporting inadequacies of the included studies, our results demand a cautious interpretation. More research is needed for head and neck cancer, but is probably not justified for uterine cervical or bladder cancer. There is little evidence available concerning malignancies at other anatomical sites.

Hyperbaric oxygenation for tumour sensitisation to radiotherapy

BACKGROUND

Cancer is a common disease and radiotherapy is one well-established treatment for some solid tumours. Hyperbaric oxygenation therapy (HBOT) may improve the ability of radiotherapy to kill hypoxic cancer cells, so the administration of radiotherapy while breathing hyperbaric oxygen may result in a reduction in mortality and recurrence.

OBJECTIVES

To assess the benefits and harms of radiotherapy while breathing HBO.

SEARCH METHODS

In March 2011 we searched The Cochrane Central Register of Controlled Trials (CENTRAL), (The Cochrane Library, Issue 3), MEDLINE, EMBASE, DORCTHIM and reference lists of articles.

SELECTION CRITERIA

Randomised and quasi-randomised studies comparing the outcome of malignant tumours following radiation therapy while breathing HBO versus air.

DATA COLLECTION AND ANALYSIS

Three review authors independently evaluated the quality of the relevant trials and extracted the data from the included trials.

MAIN RESULTS

Nineteen trials contributed to this review (2286 patients: 1103 allocated to HBOT and 1153 to control). With HBOT, there was a reduction in mortality for head and neck cancers at both one year and five years after therapy (risk ratio (RR) 0.83, P = 0.03, number needed to treat (NNT) = 11; and RR 0.82, P = 0.03, NNT = 5 respectively), as well as improved local tumour control at three months (RR with HBOT 0.58, P = 0.006, NNT = 7). The effect of HBOT varied with different fractionation schemes. Local tumour recurrence was less likely with HBOT at one year (head and neck: RR 0.66, P < 0.0001, NNT = 5), two years (uterine cervix: RR 0.60, P = 0.04, NNT = 5) and five years (head and neck: (RR 0.77, P = 0.01, NNT = 6). Any advantage is achieved at the cost of some adverse effects. There was a significant increase in the rate of both severe radiation tissue injury (RR 2.35, P < 0.0001, (number needed to harm (NNH) = 8) and the chance of seizures during therapy (RR 6.76, P = 0.03, NNH = 22) with HBOT.

AUTHORS' CONCLUSIONS

There is some evidence that HBOT improves local tumour control and mortality for cancers of the head and neck, and local tumour recurrence in cancers of the head and neck, and uterine cervix. These benefits may only occur with unusual fractionation schemes. HBOT is associated with significant adverse effects including oxygen toxic seizures and severe tissue radiation injury. The methodological and reporting inadequacies of the studies included demand a cautious interpretation. More research is needed for head and neck cancer, but is probably not justified for bladder cancer. There is little evidence available concerning malignancies at other anatomical sites on which to base a recommendation.

Hyperbaric oxygenation for tumour sensitisation to radiotherapy

BACKGROUND

Cancer is common and radiotherapy is one well-established treatment for some solid tumours. HBO may improve the ability of radiotherapy to kill hypoxic cancer cells, so the administration of radiotherapy while breathing HBO may result in a reduction in mortality and tumour recurrence.

OBJECTIVES

To assess the benefits and harms of radiotherapy while breathing HBO.

SEARCH STRATEGY

In November 2004 we searched The Cochrane Central Register of Controlled Trials (CENTRAL), (The Cochrane Library Issue 3), MEDLINE, EMBASE , CINAHL, DORCTHIM and reference lists of articles. Relevant journals were handsearched.

SELECTION CRITERIA

Randomised and quasi-randomised studies comparing the outcome of malignant tumours following radiation therapy while breathing HBO versus air (with or without sham therapy).

DATA COLLECTION AND ANALYSIS

Three reviewers independently evaluated the quality of the relevant trials using the method of Schulz (Schulz 1995) and extracted the data from the included trials.

MAIN RESULTS

Nineteen trials contributed to this review (2286 patients: 1103 allocated to HBO and 1153 control). With HBO, there was a reduction in mortality for head and neck cancers at both one year and five years after therapy (Relative risk (RR) 0.83, P = 0.03, number needed to treat (NNT) = 11 and RR 0.82, P = 0.03, NNT = 5 respectively), as well as improved local tumour control at three months (RR with HBOT 0.58, P = 0.006, NNT = 7). The effect of HBO varied with different fractionation schemes. Local tumour recurrence was less likely with HBO at one year (head and neck, RR 0.66, P < 0.0001, NNT = 5), two years (uterine cervix RR 0.60, P = 0.04, NNT = 5) and five years (head and neck (RR 0.77, P = 0.01). Any advantage is achieved at the cost of some adverse effects. There was a significant increase in the rate of both severe radiation tissue injury (RR 2.35, P < 0.0001, (number needed to harm (NNH) = 8) and the chance of seizures during therapy (RR 6.76, P = 0.03, NNH 22) with HBO.

AUTHORS' CONCLUSIONS

There is some evidence that HBO improves local tumour control and mortality for cancers of the head and neck, and local tumour recurrence in cancers of the head and neck, and uterine cervix. These benefits may only occur with unusual fractionation schemes. HBO is associated with significant adverse effects including oxygen toxic seizures and severe tissue radiation injury. The methodological and reporting inadequacies of the primary studies included in this review demand a cautious interpretation. More research is needed for head and neck cancer, but is probably not justified for bladder cancer. There is little evidence available concerning malignancies at other anatomical sites on which to base a recommendation.

Effects of hyperbaric oxygen and normobaric carbogen on the radiation response of the rat rhabdomyosarcoma R1H

PURPOSE

Hypoxic tumor cells are an important factor of radioresistance. Hyperbaric oxygen (HBO) and normobaric carbogen (95% oxygen, 5% carbon dioxide) increase the oxygen delivery to tumors. This study was performed to explore changes of tumor oxygenation during a course of fractionated irradiation and to determine the effectiveness of normobaric carbogen and HBO during the final phase of the radiation treatment.

METHODS AND MATERIALS

Experiments were performed on the rhabdomyosarcoma R1H growing on WAG/Rij rats. After 20 X-ray fractions of 2 Gy within 4 weeks, oxygen partial pressure (pO2) was measured using the Eppendorf oxygen electrode under ambient conditions, with normobaric carbogen or HBO at a pressure of 240 kPa. Following the 4-week radiation course, a top-up dose of 10-50 Gy was applied in 2-10 fractions of 5 Gy with or without hyperoxygenation.

RESULTS

HBO but not carbogen significantly increased the median pO2 in irradiated tumors. The radiation doses to control 50% of tumors were 38.0 Gy, 29.5 Gy, and 25.0 Gy for air, carbogen, and HBO, respectively. Both high oxygen content gas inspirations led to significantly improved tumor responses with oxygen enhancement ratios (OERs) of 1.3 for normobaric carbogen and 1.5 for HBO (air vs. carbogen: p = 0.044; air vs. HBO: p = 0.02; carbogen vs. HBO: p = 0.048).

CONCLUSION

Both normobaric carbogen and HBO significantly improved the radiation response of R1H tumors. HBO appeared to be more effective than normobaric carbogen, both with regard to tumor oxygenation and response to irradiation.

Significance of computed tomography-measured volume in the prognosis of cervical carcinoma

BACKGROUND

Computed tomography (CT) can visualize the volume and shapes of the deep-seated tumors and is expected to predict the treatment outcome in a more quantitative manner. This study was undertaken to learn the prognostic significance of CT-provided information in the radiation therapy of carcinoma of the cervix.

METHODS

One hundred thirty-one CT evaluations were systematically applied to 87 patients having carcinoma of the cervix uteri. The cervical mass volume was measured by CT at a certain phase or phases of treatment and was analyzed in relation to their local control at 3 years and the survival at 5 years.

RESULTS

The initial volume, measured at the beginning of radiation therapy, was not a significant prognostic guide for the local control. However, the second volume, the volume of cervical lesion measured immediately after the completion of external irradiation, proved to be a prominent prognostic factor for both the 3-year local control and 5-year survival, regardless of the clinical stage. In 52 patients whose second volume was less than 38 cm3, 47 patients (90.4%) were locally controlled for 3 years or more after radiation therapy, whereas 17 of 23 patients (73.9%) whose second volume exceeded 38 cm3 failed in the local control. Five-year actuarial survival rate was 53.1% plus or minus 6.2% in the former group and 26.1% plus or minus 9.6% in the latter group.

CONCLUSIONS

CT-aided volumetry provides for an early prediction of treatment failure in radiation therapy for cervical carcinoma.

Tumour regression as a guide to prognosis: a clinical study

The response seen at the end of a course of radiotherapy in 116 patients with advanced carcinoma of the cervix included in hyperbaric oxygen trials was assessed by reduction in bulk and by histological examination. These patients have now been carefully followed for a minimum of three and a maximum of 13 years. The degree of regression, three and a maximum of 13 years. The degree of regression, as measured by reduction in bulk at the primary site, was as measured by reduction in bulk at the primary site, was found to predict closely the subsequent local tumour failure, survival and freedom from metastasis. The histological assessment also could be associated with the subsequent course, but the correlation was much weaker. In a trial of hyperbaric oxygen, where radiotherapy was given in 27 fractions to both groups, the immediate response was significantly better in the patients treated in oxygen, so predicting the result of the trial seen in long-term follow up. In the radiotherapy of carcinoma of cervix, reduction in bulk of the primary tumour at the end of treatment is a valuable prognostic index.

Tumour regression as a guide to prognosis: a study with experimental animals

An analysis has been made of the relationship between regression during therapy and the probability of local control in a group of mice treated with single doses and fractionated doses of X rays. The tumours were first generation transplants from spontaneous mammary carcinomas in C3H mice and were irradiated with single doses 3F/4 days, 9F/10 days, 9F/18 days or 15F/18 days. The size of the smallest radiation dose approached those encountered in clinical radiotherapy. A significant correlation was observed between the shrinkage during the treatment period and the local control at 150 days, for three of the four fractionated schedules. A weaker correlation was observed for shrinkage within a week after single doses, and for shrinkage during treatment with nine fractions in 18 days. It is postulated that the rate of shrinkage is an inherent characteristic of each individual tumour and does not reflect the number of cells killed. However, the shrinkage in some tumours during the course of therapy may result in more extensive reoxygenation which makes these tumours more sensitive to subsequent doses of fractionated course. The degree of shrinkage within the period of fractionated irradiation was found to be a useful prognostic guide to ultimate local control in individual tumours.

Hyperbaric oxygen in radiation therapy

The importance of oxygen with low LET radiations has been established beyond any doubt in many different systems, both plant and animal. While some studies, especially head and neck tumors, are impressive, it has not been demonstrated unequivocally that radiation under hyperbaric conditions is superior to well fractionated, well conceived, conventional radiotherapy. Any resulting gain in survival from the addition of hyperbaric oxygen will be limited, especially with more advanced stages of disease. Well controlled studies, especially with earlier stage disease, are still necessary. It would be worthwhile to undertake such trials, especially with tumors of the head and neck constituting the most promising site of study, as others have noted, since even a 5% to 10% improvement in survival would mean many lives saved. Continued trials with hyperbaric oxygen, oxygen in other forms, neutrons and other particles, and radiation sensitizing drugs are all justified in an attempt to overcome the oxygen effect on human tumors.

Hyperbaric oxygen as a radiotherapeutic adjuvant in advanced cancer of the uterine cervix: preliminary results of a randomized trial

From September 1968 to March 1974, a randomized clinical trial was carried out, using conventional fractionation, i.e., five treatments per week, in 233 patients with advanced cancers of the uterine cervix--Stages IIB, IIA, IIIB and IVA. The age limit was 70 years and all patients had medical clearance. Lymphangiography and, in some patients, an exploratory laparotomy with selective lymphadenectomy, were done prior to treatment to determine the extent of nodal disease. The staging has not been changed either by lymphangiogram or lymphadenectomy findings. A few patients with bulky Stage I and IIA lesions were entered into the trial because of extensive nodal disease demonstrated either by lymphangiogram and/or lymphadenectomy. First, the patients were grouped according to the clinical stage. The secondary stratification was according to the lymphangiogram and/or selective lymphadenectomy findings. The patients were then randomized to air or hyperbaric oxygen within each group. The patients were pressurized in a Vickers chamber at 3 atmosphere absolute, using a 20-minute soak time prior to the irradition. The size of the external beam portal was determined by the status of the nodes. The difference in absolute NED (no evidence of disease) survival rates for both groups as a whole and by stages is not statistically significant. There is no difference in the incidence of failures in the irradiated area between the HPO and air patients. There is no increase in distant metastases in the HP group. It does not seem that the HPO has had an effect on the major complications. However, there was an increase in the incidence of complications with extended fields. The addition of lymphadenectomy had increased the incidence of fatal complications, even with routine pelvic portals. The negative results of this trial with conventional fractioantion should not lead to the conclusion that HPO could not be useful with schemes using a few high dose fractions.

The treatment of radiation necrosis with hyperbaric oxygen (OHP)

Sixty-nine patients with radiation necrosis were received by the authors from January 1, 1969 through August 1, 1975. The patients were categorized according to site of injury. Full treatment protocol is discussed including local wound care, antibiotic coverage, surgical procedures, and the administration of hyperbaric oxygen. Results indicate that the combination of hyperbaric oxygen, properly timed surgery, and antibiotic therapy has resulted in improvement in all cases of radiation necrosis and full healing in most.

Bowel gas--a cause of elevated dose in radiotherapy

The presence of gas in bowel could lead to higher than expected doses being given in the radiotherapy of abdominal and pelvic tumors. Radiation detectors were placed in the uterus and vagina of ten patients with caricnoma of cervix, and the actual dose compared with that expected when anterior fields of treatment were employed. Elvations greater than 10% were obtained in six, and severe postradiation morbidity subsequently occured in two of the three showing the highest readings.

Hypoxic cell sensitisers in radiotherapy

Solid tumours contain poorly oxygenated cells, and these are disproportionately resistant to therapeutic radiation. Several methods of overcoming this problem have been used clinically, including the administration of hyperbaric oxygen during irradiation, radiotherapy with heavy nuclear particles such as neutrons from cyclotrons, optimum size and spacing of multiple doses of conventional radiation, and, most recently, chemical radiosensitisers. These radiosensitisers mimic the sensitising effect of oxygen and are active only against hypoxic cells. They do not, therefore, increase radiation response in well-oxygenated normal tissues. They are not rapidly metabollised and so can penetrate further than oxygen from the vascular capillaries and effectively reach the hypoxic cells in the tumour. Some of these drugs are of considerable clinical promise. The results of in vitro and in vivo studies with radiosensitisers are summarised and preliminary clinical work is described.