Cryoablation has been performed for hepatic, renal, breast, and prostate cancer, and it has shown acceptable results. During cryoablation, the formation of an oversized ice ball increases the complication rate and can endanger a patient’s life; an undersized ice ball can lead to the recurrence of the tumor at the edge of the frozen area[15
]. As the volumes of primary or metastatic tumors are sometimes large, adhesions to other organs or tissues and invasive growth are often present. Percutaneous cryoablation cannot guarantee complete ablation, and combination with brachytherapy might be a better choice[16-20
]. This combination of minimal invasive therapies (namely CandS treatment) can minimize the damage of radiotherapy and cryoablation, and increase the treatment response[21,22
In ≥ 80% of patients with pancreatic cancer, the tumor is unresectable at time of diagnosis. Chemotherapy, palliative surgery, and radiofrequency ablation may be the best options for patients with metastases. Along with advances in the cryosurgical system and imageology, percutaneous cryosurgery has been increasingly successful in the treatment of pancreatic cancer[9,10
]. This method avoids the risks of laparotomy, decreases the likelihood of complications[23-25
], and improves the quality of life, but the data is still lacking as to whether it can extend the IS-IV of patients. Cryoablation and chemotherapy have different effects on patients with stage IV pancreatic cancer. In 2010, Stathis et al[26
] reported that the median survival for patients treated with single-agent 5-FU or gemcitabine were 4.41 and 5.65 mo, respectively. Combined applications of other agents with gemcitabine had been frequently attempted in order to get a better IS-IV, but the statistical indication for such a benefit failed to materialize until now[4,27-30
]. In our study, the IS-IV of patients under radical treatment was significantly longer than for those under palliative treatment (P
< 0.0001), with a 4 mo extension of median IS-IV (8 mo vs
4 mo, respectively). The 1-year survival rate of patients in the radical treatment group was 32%, showing the greater superiority of radical treatment, as this was better than palliative treatment and chemotherapy. Interestingly, patients who delayed CandS treatment were associated with better IS-IV, regardless of radical or palliative treatment. For this reason we re-analyzed the data, and found that all the patients under delayed treatment had received chemotherapy before admission to our hospital, and so chemotherapy may be an important reason for the extension of IS-IV. It seems that if chemotherapy is delivered early in stage IV pancreatic cancer, it will change the systemic disease into local disease, and improve the benefit to survival time of patients. As for the frequency of CandS treatment, multiple treatments only showed a significant advantage in the radical treatment group (median survival: 11 mo vs
7 mo, P
= 0.0389). Therefore, in order to get the best therapeutic effect, early chemotherapy, radical, and multiple treatments are all very important.
With regard to the complications associated with radical treatment, pancreatic fistula, bile leakage, and intestinal fistula were seldom observed in our study, maybe due to the evasion of patients with a high surgical risk when enrolling. Other minor complications associated with radical or palliative treatment were common after cryoablation of the pancreas and liver, including an increase of serum amylase and blood glucose, a decrease in the number of platelets, abdominal distension, ascites, fever, infection, and abdominal bleeding. All complications can be decreased to normal within 2 wk after symptomatic treatment. In effectively reducing tumors and removing obstructions, the physical strength and energy of patients in the two groups improved obviously and pains were reduced significantly. These achievements are inseparable with effective tumor reduction and close postoperative monitoring.
The present study represents an early experience, with a small number of patients. Hence, extrapolation of the results to clinical practice should be performed with caution. This was not a definitive study for assessing the effects of chemotherapy on IS-IV of patients, the effectiveness of CandS in the treatment of newly diagnosed stage IV pancreatic cancer, or for determining whether CandS treatment was as effective as surgery for pancreatic tumors.
In conclusion, percutaneous CandS treatment may have a useful role in the management of stage IV pancreatic cancer evading vital organs and those < 6 cm in diameter when surgery and chemotherapy are not options. To further increase the IS-IV of patients, close postoperative monitoring and multiple treatments will be needed for recurrent tumors.