Ho et al. (2007) evaluated clinical response for 27 patients with hepatic metastatic lesions from neuroendocrine tumors who underwent hepatic artery chemoembolization or hepatic artery embolization (HAE) because of symptoms. This group consisted of 25 patients with hormonal symptoms and 4 with pain secondary to capsular distention. Twenty-one (78%) of the evaluated patients reported relief of symptoms after the initial cycle of treatment. When evaluated according to the tumor type, 78% of carcinoid patients and 75% of islet cell patients had relief of the presenting symptoms (22).

Eighty percent of carcinoid patients treated for hormonal symptoms had subjective relief of hormonal symptoms after one cycle of therapy. Sixty-six percent of carcinoid patients treated for symptoms related to tumor bulk reported relief of pain. Among patients with islet cell tumors, 66% of patients treated for hormonal symptoms had relief of symptoms. Reduction of the presenting symptoms was achieved in a similar manner in patients with and without extrahepatic disease. Thirteen of 16 patients with extrahepatic disease and 7 of 9 patients with no sign of extrahepatic disease experienced relief of symptoms after one cycle of hepatic artery chemoembolization or HAE (22).

In 2011, Albert et al. reported in 121 patients with metastatic CRC a median survival time of 9 months from chemoembolization. The 1-, 2-, and 5-year survival rates were 94%, 74%, and 13%, respectively (23). In 2009, Vogl et al. evaluated 463 patients with colorectal liver metastases with primarily palliative indication for chemoembolization. Results showed a median survival time of 14 months from the start of chemoembolization (24).

In 2010, Martin et al. documented in 55 patients with CRC liver metastases an OS of 19 months and progression-free survival (PFS) of 11 months using DEB chemoembolization (25).

In 2010, Schuster et al. evaluated 25 patients with liver metastases from melanoma using TACE and found no grade IV toxicity or catheter-associated complications. The median PFS was 3 months and median OS was 5 months. The 1-year survival rate was 15% (26). In 2009, Gupta et al. (27) reported in 105 patients a median OS and PFS of 6.7 and 3.8 months, respectively. Sharma et al. reported in 20 patients with stage IV melanoma mean and median OS of 334 ± 71 and 271 days, respectively. Sixty-five percent of patients had progression of the disease (28).

TPCE for the palliative treatment of unresectable lung tumors has been used with acceptable outcome. Early use of this method results in a reduction in tumor volume and alleviation of patient symptoms. After superselective
catheterization, cytotoxic agents are administered, and the pulmonary arterial supply of the tumor is occluded by injection of microspheres and ethiodized oil. Emerging data suggest that this approach is well tolerated (29).

Vogl et al. evaluated tumor response after treating unresectable lung metastases with TPCE in palliative intention. Fifty-two patients suffering from 106 unresectable lung metastases were treated with 2 to 10 TPCE sessions. Metastases originated from primaries, including colorectal carcinoma (n = 20), breast cancer (n = 6), renal cellular carcinoma (n = 5), thyroid cancer (n = 4), cholangiocellular carcinoma (n = 2), leiomyosarcoma (n = 2), and others (n = 13). All patients tolerated the treatment well without major side effects or complications. In 24%, moderate to high lipiodol uptake was found, while 75% of the tumors showed a low uptake. Partial response was achieved in 16 cases, stable disease in 11 cases, and progressive disease in 25 cases; mean and median survival was documented at 17 and 21.1 months, retrospectively (30).

Several studies have demonstrated that radioembolization is a safe and effective palliative procedure in patients with unresectable liver metastases and helps slow down the growth of the disease and alleviate symptoms (8,31,32,33,34,35). In 2011, Sangro et al. reported that radioembolization results in average disease control rates above 80% and is usually very well tolerated. Main complications do not result from the microembolic effect, even in patients with portal vein occlusion, but rather from an excessive irradiation of nontarget tissues including the liver. When compared with the standard of care for the intermediate and advanced stages (transarterial embolization and sorafenib), radioembolization consistently provides similar survival rates as hormone and chemotherapy (35). In 2009, Vente et al. showed in a meta-analysis on tumor response and survival using 30 articles on 1,217 patients who underwent ⁹⁰Y radioembolization that the proportion of “any response” (AR) for HCC and liver metastatic CRC combined varied between 29% and 100% with a median value of 82%. Treatment with glass microspheres showed a lower response than treatment with resin microspheres. They found that complications have been reported when microspheres were inadvertently deposited in excessive amounts in organs other than the liver. For HCC, response was 89% for resin microspheres and 78% for glass microspheres. For CRC liver metastases in a salvage setting, response was 79% for radioembolization combined with 5-fluorouracil/leucovorin (5-FU/LV), and 79% when combined with 5-FU/LV/oxaliplatin or 5-FU/LV/irinotecan, and in a first-line setting 91% and 91%, respectively. In patients with liver metastases from CRC, the tumor response of radioembolization is high, with AR rates of approximately 80% in a salvage setting (36).

For HCC, median survival from treatment was from 7.1 to 21.0 months and from diagnosis or recurrence was 9.4 to 24.0 months. For liver metastases from CRC, median survival after ⁹⁰Y-RE, irrespective of differences in determinants (microspheres type, chemotherapy protocol, and stage: salvage or first line), was 6.7 to 17.0 months and from diagnosis of liver metastases from CRC it ranged from 10.8 to 29.4 months (36).

Percutaneous imaging-guided ablative therapies using thermal energy sources such as radiofrequency (RF), microwave (MW), laser, and high-intensity focused sonography have been used as minimally invasive strategies for the treatment of focal malignant diseases (37,38). Thermal ablation therapies have been defined well by Tarcoveanu et al. These techniques are used to destroy the malignant cells by heat in a minimally invasive approach without damaging normal tissue. Electromagnetic energy has been used in the form of both RF and MW; photocoagulation uses intense pulses of light produced by a laser as the energy source; high-intensity focused sonography uses sound energy to produce heat; and injection of heated fluids, including saline, ethanol, and contrast material, has been used to induce coagulation by direct thermal contact. In nonresectable hepatic tumors, palliative treatment using focal necrosis by hyperthermia appears as a valuable alternative. These methods of treatment can be performed by percutaneous, laparoscopic, or open approach. The key element in the management of the malignant tumors of the liver is the cooperation between surgeon, intensive care physician, oncologist, and specialist in interventional radiology in order to discuss the indication of therapy (39).

In 2011, Pathak et al. reviewed ablative therapies in CRC liver metastases and showed that cryotherapy (26 studies) had a local recurrence rate of 12% to 39%, with mean 1-, 3-, and 5-year survival rates of 84%, 37%, and 17%, respectively. The major complication rate ranged from 7% to 66%. MWA (13 studies) had a local recurrence rate between 5% and 13% with mean 1-, 3-, and 5-year survival rates of 73%, 30% and 16%, respectively, and a major complication rate ranging from 3% to 16%. RFA (36 studies) had a local recurrence rate of 10% to 31%, with mean 1-, 3-, and 5-year survival rates of 85%, 36%, and 24%, respectively, with major complication rate ranging from 0% to 33% (40). In 2010, Bhardwaj et al. (41) summarized major studies in ablation technologies and presented them in a way that makes comparison between the major modalities easier.

RFA involves insertion of an electrode via skin or intraoperation into a lesion under imaging guidance. Heat created by RF energy leads to coagulative necrosis. Lung tumors that are difficult to reach may require repeated RFA treatments. The most commonly reported complications of RFA are pneumothorax and bleeding (42,43). RFA appears to be effective for rapid tumor reduction and palliation. The combination therapy of this technique can offer new treatment strategies for an improvement of the patient’s quality of life and more effective palliative medicine (44).

RFA is a tool that can potentially palliate intractable cancer pain. The scope of cancer pain ranges from minor
discomfort relieved with mild pain medication to unrelenting suffering for the patient, poorly controlled by conventional means. In 2006, Jindal et al. (45) presented a case in which RFA provided pain relief in a patient with metastatic prostate cancer with pelvic pain uncontrolled by conventional methods, and when combined with celiac ganglion block and splanchnic nerve block it has been used for visceral pain relief. Several studies reported the feasibility and effect of RFA therapy for the treatment of lung masses in patients with non-small cell lung cancer (NSCLC) or lung metastases but only few studies are related to long-term outcomes in patients with primary and secondary pulmonary tumors. Palliative RFA may be indicated for large tumors (46,47,48). In 2008, Lencioni (47) reported in 106 patients with NSCLC OS at 1 and 2 years of 70% and 48%, respectively. In 2004, Belfiore et al. evaluated palliative computed tomography (CT)-guided RFA in 33 patients with unresectable primary pulmonary malignancies. Clinical improvement in pretreatment symptoms was observed in 12 of 29 patients seen at 6-month follow-up (49). External beam irradiation is the palliative treatment of choice for osteolytic bone metastases, but additional radiation should not be offered for recurrent sessions. RFA is another alternative for palliating pain from bone metastases. Belfiore et al. evaluated the clinical efficacy of RFA with respect to pain relief in patients with refractory bone metastases or patients who are ineligible to conventional treatments. Immediate pain relief after treatment was experienced by 9 of 12 patients; however, in 2 cases pain recurred within the first week. Long-lasting palliation was obtained in 7 of 12 patients (50). In 2008, Hoffmann et al. evaluated the feasibility and effectiveness of combining RFA and osteoplasty for pain reduction in the treatment of painful osteolytic metastases. Technical success and pain relief was achieved in all patients (51). However, ablation therapy as a palliative treatment for bone tumor management and indications has been described with a management algorithm by Gangi et al. in 2007 (52) (Fig. 22.1).